Monday, August 14, 2017

Monitoring 6 Meters

Monitoring 6 meters for openings was very time consuming when I was very active during the 1980s. Aside from spinning dial there were the following options:
  • Monitor 28.885 MHz where 6 meter aficionados gathered. This was a good choice during sporadic E season since 10 meters would open before 6 meters. That is, when 10 meters had sporadic E propagation there was a reasonable chance that it would rise to 6 meters.
  • Monitor commercial VHF broadcasters and other services at known frequencies and locations either just below or above 6 meters. Of course your directional yagi would have to be rotated to each in turn. Some had non-directional vertical and horizontal antennas dedicated to monitoring.
  • Monitor 10 and 6 meter beacon frequencies. See previous point.
  • Use the scan feature on the rig to continuously cycle through the beacon and high-activity band segments, typically from 50.000 to 50.150 MHz. 
For VHF DXers there was the other problem of activity since back then most countries in the world did not have a 6 meter band. Among those that did there were many whose band did not overlap that in North America. This required monitoring other frequency ranges, mostly up above 52 MHz. Cross-band QSOs were often attempted with 10 or 4 meters, or at least a shout out on 28.885 MHz of "yes, I can copy you!"

Now that the 2017 summer sporadic E season is rapidly winding down, and being my first time being serious about 6 meters in many many years, I though it would prove interesting to review how I went about monitoring for activity. It is very different! In believe the change is for the better.

Still irritating after all these years

This lowest of VHF bands remains both intensely intriguing and challenging. Having a 6-element yagi up 24 meters doesn't change that. In a way it makes it worse since there are more marginal openings than with a less capable antenna.

Despite the numerous new techniques to monitor for activity it is still terribly irritating in many ways. Some of the old irritations are gone but have been replaced by new ones.

Beacons

There are more beacons on the band than ever before. This is good although it often contributes little to the logbook. Many of the best beacons are in great locations that may not indicate that anyone in the beacon's vicinity are workable. That's okay since it is still useful as an early warning of possible QSOs.

Worse are the beacons in rare or out of the way locations where there is no one active. How frustrating to hear beacons and have the opening go to waste since there's no one to work.

More beacons means more beacons nearby. I quickly learned to recognize that many of the beacons I can hear weakly while scanning the band are coming in by tropospheric propagation from within a 500 km radius. My antenna is big enough and high enough to make them audible. Interesting but not useful to me since I am primarily interested in ionospheric paths, especially DX.

Clusters

How nice to be able to sit back, pick up the smart phone and connect to a cluster to see what's happening on the VHF bands. From a perusal of the spots I can decide whether it's worth my time to head over to the shack.

While in the shack the stream of incoming spots keep me aware of what's going on at other stations in this part of North America and elsewhere. This is particularly true when the spots are from better equipped stations which again serve as an early warning of an opening that is workable. I can now better decide whether to leave the shack or stick around.

I also like to see spots for paths far away from me, especially among European stations. Intense sporadic E propagation over there can be an indicator that conditions for clouds to form here as the clock rolls around to the same local time. Similarly it tells me to watch for clouds over the Atlantic that can support propagation to Europe. The same is true for activity far to the south since all it takes is a E-layer cloud to form and link VE3 into paths to South and Central America.

FM broadcast band

Back in May I got annoyed one morning when a radio station I sometimes listen to developed distortion and would abruptly be interrupted by completed different program material. At first I assumed they were having technical difficulties. Then it dawned on me that is was sporadic E propagation from a US station that was interfering. The MUF had risen above 90 MHz.

This style of monitoring is nothing new. However it is new to me since I now live in what is a fringe reception area for FM broadcast. Back in Ottawa this would never happen no matter how good the propagation since the local transmitters always win the battle of FM capture effect. Living in a fringe reception area gives me a new monitoring tool.

Band monitor scope

It is no longer strictly necessary to have the receiver scan the band for openings. A pan adapter or simple wide band scope provides a snapshot of a large portion of the band at a single glance.

Although the monitor will miss the very weakest signals it is still a very useful tool when an opening appears imminent from other indicators or to keep an eye on the band when the opening is patchy, coming in at random intervals.

Digital

This was an interesting year for digital modes. When I got on the air in June most activity was SSB and CW along with a steady but not extreme amount of JT65 activity near 50.276 MHz. Then the FT8 beta arrived and within a couple of weeks not only did it supplant a large proportion of the JT65 activity it also displaced quite a lot of SSB and CW activity. The relative rapidity of QSOs compare to JT65 and the ability to exploit marginal opening that do not support traditional modes have made it wildly popular.

I did not operate digital modes this season. This was due to a combination of not great interest on my part and difficulty interfacing my FTdx5000 to my ancient Vista laptop. The laptop has become quite unreliable when interconnecting via the USB ports for reasons only a Microsoft engineer could understand. The laptop will be replaced but it is what I use for now.

What I did with digital this year is use it as a beacon. I would watch spots for 50.313 MHz to check for possible openings for CW and SSB, and keep the rig's second VFO tuned to that frequency to check for signals. I had only limited success with this monitoring technique. The problems were twofold. First, marginal openings often stayed marginal and therefore only usable with digital modes that can operate at negative SNR (signal to noise ratio). Second, FT8 became so popular that even with good propagation many hams stuck by 50.313 MHz rather than move to CW or SSB.

There were numerous times when beacons were loud and there was heavy FT8 activity that I would repeatedly call CQ on CW or SSB and get no response. Next year I'll have to decide whether to make the switch to digital. The technology fascinates me -- I have experience writing signal processing software -- but it leaves me a bit cold when it comes to operating. Having my computer talk to your computer doesn't excite me.

How I did this year

So with all that monitoring my results this sporadic E season ought to show it. Yes and no. Knowing the band is open or close to opening is no guarantee that the log will rapidly fill up. I missed some excellent openings in May and early June before the antenna went up. The day after the antenna went up I worked 10 new countries in the Caribbean and South America. So far so good.

Then my progress slowed drastically. This was not a great sporadic E season from around here where DX is concerned. Those operating JT65 and FT8 did far better. Good monitoring options help little when the openings are few in number or not bringing in signals strong enough for CW and SSB. As I write this I have 33 countries on 6 meters, up from 19. As with all my counts this does not include my activity earlier than 2013 when I chose to reset all counters after returning to the air after 20 years away. Counting those I would now have DXCC on 6.

I paid little attention to most single hop openings except during the CQ WW VHF contest in July. Those are common and no longer of great interest to me outside of contests. It also means less time spent running to the shack to work the same old stuff. I am not obliged to work every opening just because I'm a 6 meter aficionado. Whenever there was a hint of DX or cross-continent propagation I was there. That's what interests me.

Particularly disappointing was only working one mainland Europe station this year. I heard the CS5BALG beacon quite often but few stations. Perhaps the biggest surprise DX was TF3ML/P calling CQ on 50.110 MHz. I was looking east on CW when I saw a signal up band on the rig's monitor scope. He sounded as surprised to hear me as I was to hear him. At the time of our QSO there no spot for him; I changed that.

I discovered that to many stations my grid square -- FN24 -- is wanted for VUCC. There are other stations in this grid, both in VE3 and W2 so this surprised me. In the contest a few stations asked me to go to 2 meters, which I had to unfortunately decline. I may have 2 meters capability next year.

All in all a mediocre summer on 6 meters for me. I enjoyed it nonetheless. Modern monitoring options make operating more relaxing since I no longer have to sit in the shack or have a rig on in the background scanning the band. I am looking forward to next year, and even the winter sporadic E season.

Thursday, August 10, 2017

Battling the Calendar: Time to Set Priorities

It's August and warm. This is great weather for building towers and antennas. Unfortunately it won't last. My plans for 2017 are ambitious and I am increasing worried about running out of calendar room before contest season gets seriously underway this fall. Worse, winter comes in fast and hard around here. This calls for setting of priorities so that if I do run out of time I will have the best station possible before winter puts an end to antenna farm construction.

Before getting into the topic of this article -- setting priorities -- there is one important observation I would like to make: the interchangability of money and time. It is always possible to accelerate the plan with money. For example, I can hire a company to put up towers. I have quotes and experienced hands ready to go to work. Another example is antennas. I can buy commercial products rather than design and build my own.

For me the building of a competitive station is not only about achieving a result. The journey is itself an objective. Designing and building what I can is a tremendous learning experience and can be a lot of fun. I am willing to forgo or delay some projects so that I can do it myself (or with friends). At the other extreme I need only sit at my desk with a telephone, credit card and cheque book and soon enough I will have a complete and highly competitive station. That approach does not interest me.

Therefore I resort to picking and choosing where to apply my effort. Spending where necessary and applying my own time to projects I want to do myself. With that preamble I will now jump into the main topic: how I set priorities for the time remaining to me this year.

Height

The tower is in fact perfectly vertical. It's the
photographer (me) that has developed a lean.
For DX and contests height cures many antenna ills. Even an inverted up high will usually outperform a low yagi or vertical. Therefore the 150' tower is my highest priority. If it's all I get done this year I can put up a few inverted vees and side mounted a couple of tri-banders, and in combination with the TH7 up 21 meters I can do very well in the fall and winter contests.

This is why there have been few antenna articles lately. The tower is consuming most of my available time. It is not that I haven't been modelling and planning antennas and gathering construction material, but that these are very much works in progress and dependent on the tower being built.

As you can see in the picture I am not quite there yet! However this is one of the most difficult 20' of tower I've ever done. Getting to this point took a lot of time, worry, effort and money.

As I write these words I am ready to put up the remaining 13 sections. I have the parts and the tools and all the problems I've encountered have been solved. I will write more about all of this in one or two future articles.

Minimum viable antennas

In the high tech industry we are always talking about minimum viable products. The same thinking can be applied to contest stations. My time and resources are limited so I have to think about the least amount of antennas that will make me effective and competitive this fall.

Assuming the big tower will be ready I have tentatively selected my minimum viable antennas:
  • Rotating at the top of the 150' tower will be the Cushcraft XM240 and, preferably, a long boom yagi for 20 meters. The XM240 will go at the top of the mast and the 20 meter yagi at the bottom. They'll be turned with a prop pitch motor. With just the one tall tower I had to decide between a large yagi for 20 or 40 meters. I decided to go with the easier project for this year. Design and construction plans are underway.
  • TH6 at 110' (35 meters) side mounted and fixed on Europe.
  • Explorer 14 at a to be determined height side mounted and fixed south.
  • Inverted vees or wire yagis for 40 and possible 80 meters on one long boom at ~80' to 85' (25+ meters). If built the wire yagis will be electrically reversible between Europe and the US/Pacific. Design work will be required to allow effective interlacing of elements.
  • Vertical for 80 and 160 meters, using one radial field as the core of a future 80 meter 3-element vertical yagi. I've already warned my neighbour that this will take 1 acre out of hay production due to the radials.
  • One or two small flag or pennant receive antennas to the west and south to complement the Beverage to Europe.
  • The Trylon will continue to support the TH7 at 21 meters. The 6 meter yagi will be left where it is atop the mast and will occupy that mast space in preference to any HF yagi. I may install a multi-band inverted vee on the Trylon to complement the low 80 meter inverted vee and cover short paths on the low bands.
High bands

My strategy for the high bands is to have good all around coverage on 20 meters with a decreased emphasis on 15 and 10 meters. For this part of the sunspot cycle I will take my chances with less height, less gain and fewer direction choices for the upper two bands. I may miss some multipliers but I will have decent coverage for the most productive paths: Europe, South America and US.

The long boom 20 meter yagi up high will catch marginal openings to Europe in the early morning and overnight and allow pursuit of long paths to Asia, South America and the Pacific.

On 10 meters I will only have the TH7 at 21 meters and perhaps the Explorer 14 up higher and pointed south. Even with a low solar flux the South American path will open and I want to to be ready. I expect nothing on 10 meters with the TH6 fixed on Europe.

I am most compromised on 15 meters with this minimal plan. The TH7 will adequately cover the US and Caribbean and other short paths. With the only other 15 meter antenna -- the TH6 -- fixed on Europe I will have to do all other 15 meters operation on the TH7. Hopefully I won't miss too many multipliers in South America, the Pacific and Africa. I don't expect much from Asia on 15 meters this winter.

My best performance will be on 20 meters, which along with 40 meters are the most productive contest bands at this point in the sunspot cycle. With a large yagi up high, the TH7 low and two tri-banders fixed on Europe and to the south I expect to do quite well.

Low bands

The XM240 rotatable at ~46 meters height should perform well on all DX paths. If I can get a wire yagi completed I can search out marginal openings with the XM240 while the wire yagi is dedicated to Europe and the US. While not ideal antennas I expect this combination to be effective. If the wire yagi doesn't get built in time an inverted vee at 35 meters would still be an asset.

On 80 meters an inverted vee at 35 meters can address most of my needs, although it is not going to be very competitive. That changes if I can expand it to a 2-element wire yagi, switchable between Europe and the US. The vertical, which I fully expect to get built, will complement the horizontally-polarized yagi or inverted vee.

The 80 meter yagi array, for which the vertical is the driven element, can be worked on over the winter by adding switching systems at each element. However the radial system will need to be put down before the snow arrive or the array will be deferred to 2018.

For 160 meters I would like to make the 80 meter vertical switchable between those two bands. This is per my design plans from some time ago. As a backup plan I will run a vertical wire up the big tower and lay down temporary vertical for the winter. This is not ideal since it can compromise SO2R operation with the other antennas on the big tower.

Receive antennas

The one Beverage pointing northeast is a good start but wholly inadequate. The lack is especially acute if my minimum viable antennas do not include directional antennas for 80 and 160 meters. Without directivity copy on weak signals (whether QRP or marginal paths) will suffer, and that means lower scores. As it is said: you can't work them if you can't hear them.

For reasons I may elucidate in a future article I am strongly leaning to a set of 4 bi-directional Beverages (8 directions) as my preferred receive antennas. Those take some time to design and build. Not only must almost 2,000 meters of overhead wires be run there are the transformers, terminations, grounds, switching system and feed lines.

That's a lot of work to fit in this fall. Unfortunately receive antennas must be placed lower on my priority list. Simple but efficient transmit antennas come first. Low band directional antennas, if any can be built by the fall, are higher priority than receive antenna since they give some receive advantage and also a transmit advantage.

Work on Beverages can proceed during the winter when work on towers and other antennas slows or stops completely.

Cabling

Burying cable on my property is a problem. Although hay farming doesn't interfere with shallow burial there is a greater concern: trees. The previous owner did a wonderful job planting trees and plants everywhere, with flowers blooming in sequence throughout the spring and summer. There are apple trees and other kinds of fruit I haven't yet determined. Trees provide shade where shade is useful and visually complement the house, stone walls and field boundaries.

All very pretty but ever try to bury cables where there are tree roots? I don't recommend it. When we were excavating for tower anchors near the edge of the field I purposely sited them to be far enough away to avoid roots. I was wrong -- those roots extended horizontally farther than I'd thought possible.

Because of that and as a matter of expediency I will run the cables overhead, with grounding for lightning at select locations. How this will be done is not finalized. Many cables will, I expect, lie on the ground for the winter. Once haying is completed in early autumn there will be little traffic in the fields.

In the yard itself I will likely stay overground up to a central switching location. From there I may go underground for the final 10 or 20 meters to the house (and another ground). Again, this may all end up lying on the ground for the winter.

Station automation

Effective contesting requires integration of the rigs, logging software and antenna switching. The requirements are even greater when operating SO2R or multi-op. However I expect that what I'll have time to design and build this year will be mostly manual rather than automated.

As a minimum I will simply run multiple transmission lines from the switching box location into the shack and use manual coax switches to select antennas. While hardly modern and an operating inconvenience the automation can be done over the winter or next year. The QSOs I'll miss due to long duration antenna switching and verbal negotiation between operators are relatively few.

Alternatively I may purchase one or two remote coax switches that would be located outside at the switching location. I can always sell them later when a fully automated system is in place.

What I must do this year is buy a new computer for the shack that can handle the multitude of connections and have the CPU power and RAM to support all the features of N1MM Logger. My ancient laptop can only handle 3 windows open concurrently and even then will occasionally fail to keep up with operating demands.

Power

QRO is in my plans. Whether I get to it this year I don't yet know. Buying an amplifier is easy enough, and wiring it for 240 VAC is not a problem, but there are other issues that power will only exacerbate. For example, the filtering requirements are more onerous with a kilowatt compared to 100 watts. Building receive and transmit filters takes time I likely won't have.

To operate SO2R or multi-op requires two amplifiers. That's another burden that may not fit into this year's schedule. My alternative would be to use low power on the multiplier or S & P band.

Back to work

Writing for this blog takes time that could be put to building the station. The same could be said of every other activity in which I partake, including seeing family and friends. I am not so fervently dedicated to station building that I will exclude everything else from my life. Sometimes I even like to relax and read or do nothing at all.

With the garage and workshop built I now find that evenings can be put to use. With the doors closed and windows open the hordes of biting insects can't get in. It's almost cozy in there. Of course it'll get cold in the winter but for now it extends available work time into the evenings and darkness. For example, this evening I spent an hour in the garage fitting thimbles to turnbuckles. It's a job easily done indoors and therefore perfect for doing in the evening.

Of course I already have a tower and there is maintenance to be done by the fall. All the cabling on the Trylon will need to be redone and the antennas adjusted.

Lots of work remains to be done on the station this year. All I can do is prioritize, keep at it and hope for the best. Luckily I have a few friends who will help on the big job. Doing the work with others can make it more enjoyable and sooner strike the high priority items from my list.

Sunday, August 6, 2017

Wrestling With Steel Guys

In an earlier post I mentioned that I am guying my big tower with steel. Although non-conductive guys eliminate interactions that can compromise antenna patterns they are more expensive. In my modelling of potential interactions I found that for my intended selection and placement of antennas there is a pattern of non-resonant lengths that is perfectly acceptable. Interactions among the antennas will likely be the greater concern.

Having selected steel I was faced with the perils and other difficulties in working with steel guys.


On the left you see a large reel of LDF4-50A Heliax. On the right is a much smaller reel of 5/16" 1x7 Grade 180 EHS guy strand. Their weights are similar (heavy!) and contain approximately the same length of cable. Both appear entirely innocent. Appearances are deceiving.

The Heliax is light and somewhat fragile. It is easy to handle provided you properly unreel it to avoid kinking.. The reel of guy strand is not light and it is not fragile. Indeed it is a serious hazard to your health, fortitude and sanity when not handled with extreme caution. That's no exaggeration.

The first thing to realize is that the guy strand is not comfortably coiled on that reel. Those coils hide an extraordinary amount of stored elastic energy. When released from the restraining staples the cable releases that stored energy as it rebounds to its resting state: straight.

My procedure for freeing the cable for use is to lightly hammer a pointed tool, such as an awl, between each staple and the cable to create space for the cable to move. It will stay coiled if you are careful not to go so far that the staple is ripped out of the wood reel by the cable.

With the staples loosened the cable is pulled back out of the first two staples. This isn't easy since the cable is pushing hard against the outside surface of the staples. It violently snaps to attention when exiting each staple. Take that as a warning!

Move off to one side of the reel when pushing the cable through the final staple. A long steel rod tapped with a hammer against the end of the cable is a good way of doing this. However you do it you should not have any part of your body between the sides of the reel. Alternatively use very strong vice grips on the cable and position the reel so that it can recoil. It can work but I don't like the risk since the reel recoil takes too long due to its weight, then if the pliers aren't quite tight enough the cable will whip back and around the reel at high speed.

When the cable emerges from the final staple the cable will kick backward as it unwinds and straightens. If you're in the way you will be hurt, perhaps badly. Stay out of the way.

Unreeling the guy cable for use can be done in several ways, provided you provide a barrier or other restraint so that the reel or cable doesn't get away from you and make a big mess. The risk of the cable whipping out and striking you remains right up until the reel is emptied.

Cutting and joining non-resonant lengths

EHS is not difficult to cut with the correct tool. For 5/16" guy strand I use ⅜" bolt cutters. The jaws are large and hard enough and the arms have enough mechanical advantage to enable anyone with average strength to cut 5/16" EHS.

If you don't have sufficient strength brace one arm of the tool against the ground and carefully push down on the other with two hands using your body weight. Open the jaws wide so you can push the EHS in deep for the greatest mechanical advantage.

Do this carefully! When the cable severs the two ends will spring away from the cutter if not restrained in some way. Make sure you're wearing skin and eye protection and do not place your body where the ends are likely to jump. Alternatively use clamps or heavy weights to restrain the cable. Standing on both sides of the cut with heavy duty work boots can work well if you can operate the cutters with your arms alone.

Watch out for the cut ends: they are hard and sharp. If the strand partially unravels during the cut -- a common occurrence -- wind them up again so they sit flat. Wear gloves since it's easy to pinch your skin doing this.

To minimize waste it is best to cut the longest non-resonant lengths first (43' in my case). This way when you reach the end of the reel you can cut the remnant into the needed short lengths. You'll also want to keep long lengths on hand for the variable length from the anchors to the linked set of non-resonant lengths.


The non-resonant lengths are joined with insulators and pre-forms. At each joint you need one insulator and two pre-forms. Since the portion of the pre-form from the insulator to the EHS is part of the segment length you should cut the EHS segments at least 6" less than the required length. A few inches either way is not critical so don't fuss over the measurement.

I won't give a lesson on attaching pre-forms since I am not an expert. What I will tell you is that it takes some muscle, hand protection and a clean surface. Don't do it on grass or dirt! The only grit you want between the grip and cable is that with which the grip is coated. Foreign material will reduce the strength of the joint. I did most of the work in the garage then moved to the gravel driveway when the length required more space.

The larger the insulator the farther out the wrap begins. The pre-forms have helpful paint markings. The inner one should only be used for thimble terminations. The outer one is for insulators, but you can sometimes start the wrap sooner depending on the insulator. I did that for 502 size insulators while the 504 lined up pretty well with the outer paint mark. Don't force the wrap since you could add unwanted stress to the pre-form and insulator.


Eventually the guys will start coming together. It takes time and should not be rushed. Take a break if you get tired. Fatigue causes mistakes and injury. The most common risk in my experience is pinching fingers while wrapping the pre-form around the EHS. Most dangerous are the start and end of the wrap. Holding the thimble or insulator down with a work boot or gripped in a work bench helps to hold everything in place when you begin the wrap.

Coil the guys and put them out of reach

The relaxed coil diameter for the 5/16" EHS I am using is about 5' to 6'. Don't force it into smaller diameter coils for storage and carrying since you'll need restraints to prevent accidents. You'll also discover that the completed guys are heavy. A 500' reel of 5/16" EHS weighs approximately 120 lb so you can see that even a short 6' length is not an inconsiderable weight. Insulators and pre-forms add even more weight. When fully assembled a guy for my tower can weigh up to 100 lb.

If you need to temporarily store the completed guys put them where people and pets won't tangle with them. Curious children can quite easily hurt themselves. Not only are the ends sharp they will easily tangle feet when you try to step over and around them when they're lying on the ground.

Attaching guys to the tower and anchors

Thimbles are used to terminate guys at the tower and the anchor. They allow the pre-forms to maintain their shape and therefore their strength. Since pre-forms are wider than the guy strand for which they're made the proper thimbles are typically one size larger. For example, for my 5/16" guy strand the thimbles should be at least ⅜".


Don't go larger unless you must since larger sizes are more difficult to use (more force required to spread and close) and may be a tight fit in turnbuckle eyes and some brands of guy station. Thimbles made for pre-forms are thicker, deeper and larger radius than those for more flexible aircraft cable. They should also be hot-dip galvanized to last a long time outdoors.

Since as I write this I don't have thimbles in hand the above picture is of a used ¼" guy termination that I have in junk pile. I have lots of used guys broken into non-resonant lengths, but I am guying with entirely new hardware and guy strand. This is not because the old guys are unsafe but rather to ensure maximum longevity. Galvanizing isn't forever.

Work, work, work

Constructing non-resonant steel guys is hard work and there is potential for injury. The guys are also heavy and therefore difficult to carry, lift and attach at height. For these reasons many hams are happy to pay more for fibreglass or kevlar guys.

Even then the bottom segments of non-conductive guys are typically made from EHS to minimize risk of damage, whether accidental or deliberate. Break a guy and the tower will fail.

As of now the first set of guys is ready to go. The other 3 sets are partially complete. I am delaying the rest of the cuts until the first set is installed so that I can minimize waste once the long lengths from the non-resonant upper sections to the anchors are cut to the actual required length. Making guys is tedious work so I make it more palatable by doing a little at a time.

One thing I've realized is that I will almost certainly need another 500' reel. Since the 2,000' in the 4 reels I have is too close to the total length I'll need any amount of waste will cause a shortfall. That's okay since I can use for the rest of the 5th reel in the future. Reel remnants can be used to make short non-resonance lengths for a future tower. Yes, I do have another tall tower in my plan.

Next steps

The tower is currently two sections high. Additional work was necessary once the gin pole and lifting method were tested and found wanting. Other issues have also cropped up. I'll talk about these in later articles since all of it is relevant to anyone contemplating putting up a guyed tower.

And I still have 8 sections to paint. I am hopeful of getting the tower completed this month.

Saturday, July 29, 2017

Hay Baron

Owning 50 acres of land has a few downsides. It has to be looked after. My antenna farm when fully built will consume far less than the available space, requiring no more than 5 to 8 acres. The forest, bush and swamp take care of themselves so it is only 20+ tillable acres that are of concern.

It is therefore an asset that my neighbour farms the land. At present it is all hay. Years ago when he had a dairy operation he had several acres of feed corn where the big tower is now planted . Hay is pretty compatible with antenna since there is no plowing, just cut and bale however many crops the weather allows per year. We are having a record setting wet year which makes it difficult to find 2 or 3 consecutive days to do the harvesting.

Harvesting has finally begun.


It's all very neatly done. He works around the big tower anchors and base, not disturbing anything. You can see that the base section is now standing. It is temporarily guyed until I reach the 40' mark and can install the first set of permanent guys. Since the temporary guys are so low to the ground some hay could not be cut.

Freeing me from having to cut the field on my own is not the only advantage. I make money from the crop. Although I certainly won't get rich off the hay the income will buy small items for the station. Hay prices are up this year since the wet weather has impacted the crop across eastern Ontario.

To keep the haying operation going I need to minimize impediments for the farm equipment operating in the fields. For example I need to decide whether to bury cables running from the tower to the field boundary or suspend it overhead. Haying is compatible with both, although burial will disturb the crop along a path at least 1 meter wide.

When I build an 80 meter vertical array it will take one acre completely out of production. Haying is not compatible with radials. I will not start construction until after the fall crop is harvested.

The low band receive antennas will occupy a bush area of several acres where my experimental northeast Beverage is currently located. No farm equipment ventures out there. That field is behind the trees running between where you see the tower and the centre of the photo. The view is toward the northeast.

Keeping the tillable acreage to the maximum possible benefits me and my neighbour. Being a hay baron has benefits and responsibilities.

Were I to turn the big tower into a vertical on 160 meters I would put the radials down in the fall and roll them up in the spring. If I decide to build a wire yagi for 40 or 80 meters I would need to either make it a winter only antenna or arrange the element anchors to make it easy for the harvester to navigate. To do work on the tower I will mow paths and work areas just as I did for the foundation work.

So far I am happy with the dual use of the land. My neighbour has been very careful while working around the tower installation and has even moved stray cables aside to avoid driving over them.

Mid-summer update

The pace of blog posts has slowed. This is due to a combination of hard work on the tower and other station tasks, plus my disinterest in spending time in front of a computer during the fine summer weather.

Nevertheless there are several articles in the pipeline, all of which will eventually get done. The tower itself is progressing well, though not as fast as I'd like. I could raise sections right now if I wished since all is in place to do it. But I need to slow down since I received guying components that were the wrong type. The correct ones will arrive later this week. I don't want to have 40 to 50 feet of tower supported by temporary guys attached to the base section for longer than a day or two.

I am also shopping for the large amount of aluminum and steel I need for antennas and their supports. For a resource rich country that manufactures everything a ham could ever need it unfortunately does not follow that the distribution and retail side of the industry keeps pace. Most goes to export since Canada is a small market for the goods that are produced. It's annoying to often have to resort to buying from the US. Yet I persist in trying to source domestically when I can.

Tuesday, July 18, 2017

Tower Prep -- Almost (but not quite) Vertical

The big tower is still not up even though there has been a lot of activity. Consider this list of tasks I have been up to recently and you'll see why:
  • Repairing tower sections
  • Cleaning, scraping and repainting tower sections
  • Making the first set of lower guys
  • Gin pole design, construction and testing
  • Acquisition or refurbishment of a multitude of hardware: splice bolts; thimbles; turnbuckles; shackles; tower guy yokes; etc.
  • Transportation of tower sections to the site
There are also the environmental challenges such as a continuing very wet year, delay in my neighbour harvesting the hay crop and ticks. Of course tower work has to fit around the other items that fill my days. It is all taking longer than I'd like. Big stations involve big work.

Consider this a progress report. You'll get an idea of what's involved in working with big towers if you've never done this before. Most hams never do, and for good reason! None of this is a surprise to me and went into my plans from the start.

Bending jig

Used tower will usually have flaws. Commercial tower when taken down is often not treated with tender loving care since its resale value is rarely more than as scrap metal. Ham towers may be mistreated or carelessly handled. Expect to do some repairs.

In my case several sections had bent metal at the splices and a number of dented diagonals and girts. All were reparable without too much trouble. A few questionable damage areas were discussed with an engineer who knows this tower very well.

For example, several of the sections had old welds at the splices where they were tack welded for continuity assurance in an AM broadcast antenna. I removed those with a hand grinder so that the sections would smoothly slide together.

Simple bends were repaired with a block of wood and a small sledgehammer or with a pair of large adjustable wrenches. For the few cases where these were not effective I constructed a bending jig to hold the tower section while I applied some extreme force with improvised tools and snipes.

The jig is quite simple as can be seen above. Two short 1' screw anchors hold the ends of a heavy chain that is adjusted to fit snugly over a tower section adjacent to where the damage is located. This allows a force far greater than the section weight (120 lb) to be applied to the area to be bent with a long pipe acting as a snipe. When some of the force is axial to the tower I pressed lengths of rebar into the ground to prevent the section from sliding.

The jig also serves to hold the section in place while another is slid into the splice area. I did this to confirm proper alignment of the sections and holes for the splice bolts. Doing this on the grass helped since I was working alone and the heavy sections could be dragged into position.

Cleaning and painting

When I had 7 good sections (base section included) to reach the second guy station at 70' I set up an assembly line to clean and paint them.

This is a tedious process although not difficult. I stood them on the ground where the sun would be blocked from mid-afternoon onward -- never paint in direct sunlight. With a hose I washed off the dirt and debris that collected from years of outdoor storage. Stubborn stains were scrubbed off.

I then removed loose paint and rust spots with a set of steel wire brushes. There was little rush despite the tower's age. The sections are hot-dip galvanized and then had the standard aircraft red and white paint baked on at the factory. But they're old and needed to be refreshed. Frankly I could have skipped all of this since the tower will certainly outlive me. I expect the tower will be demolished if it's still standing when I move on.

Unfortunately galvanizing requires a special primer before the metal rust protective paint can be applied. I used the primer to cover the bare spots and then painted over the damaged and primed areas with the finish coat. To avoid an overly odd appearance I painted the exterior of all sections. Now all the sections are white except for two sections that were never painted (bare galvanized steel). I was free to use any colour since at 150' the tower is too short to require aircraft hazard colour banding.

Transportation

From the house yard the travel distance to the tower site is ~150 meters (500'). I cannot carry these sections on my own at all and it is very arduous for two strong men. Since I had no intention of conning a friend (or friends) into doing this I had to devise something to allow me to transport the tower sections on my own without undue effort.

Indeed I prepared for this two years ago. After I transported the sections to my home in Ottawa and paid several teenagers to load and unload them and stack them in the back of my yard I knew that I'd need a wheeled device if I was to be able to move them on my own. So I designed and built a very simple device with a couple of scrap lawnmower wheels, a short length of 2x4 lumber a threaded rod and a few fasteners. Simple it is but it works and has been heavily employed recently.


The device can be seen in this photo taken after the 7 repaired and painted sections were moved to the tower site. It is still attached to the second section from the left. Two bolts secure the lumber platform to the splice bolt holes in the section. The 120 lb sections are moved rickshaw style but with the driver facing backward to avoid being poked by the unforgiving tower legs. Attaching and detaching the device takes no more than a minute and usually can be bolted and unbolted with fingers alone.

Although the wheels are small it has had no trouble dealing with the countless rocks, holes and vegetation along the route and more than a few tight turns. The design isn't perfect and I've had to occasionally adjust the wheel nuts and threaded rods when one of the wheels locked up. If I'd built two of them transport would have been easier though at the expense of doubling attachment and detachment time and more cumbersome towing and steering. Feet are nimbler than wheels.

Where it fell short was with the base section. The device can only attach to the top of the section so the other end, the heavy end, had to be carried. That was fine while working with it in the yard but not for the long route out to the site. Although it looks smaller the base section is heavier than the others. So I improvised.


I admit it looks ridiculous yet it worked. The heavy base plate fit nicely inside the front end of the wheelbarrow frame without interfering with the wheel. Since the plate is rectangular and not suitably oriented with any of the section legs it has a habit of trying to twist the section and whatever (or whoever) is holding it. This includes the wheelbarrow, as you can see.

A little bit of muscle is needed to keep the wheelbarrow level during the tow out to the site. What I couldn't do was make turns of small radius. In several places I had to turn the section by hand and then remount it on the wheelbarrow. Despite these inconveniences the trip was done in less than 10 minutes. You can see that I used the system to carry scrap lumber and other material out to the tower site.

But wait, there's more!

The 7 completed sections are less than half the total of 15 sections I am raising. There are 8 more of them to be cleaned and painted.

When I took the adjacent picture the metal was repaired and I had done a first pass with a wire brush. There is more scraping and painting ahead of me even while I go about the task of getting the first set of sections up in the air.

Coming up

All going well tower raising will begin shortly. I will follow up with articles on my gin pole design, guy design, temporary support for the lower sections (until the first guy station is reached) and other topics that may be of interest.

In the meantime I have other station work to perform on the Trylon tower. My T2X rotator is acting up again, coax will be upgraded and I need to adjust the yagi positions to better accommodate rotation loops. I have even been doing a little bit of operating and contesting though nothing serious during the warm summer months.

I'll leave you for now with the following pretty picture. This is looking east from the house toward the field where the tower is going up in the aftermath of a storm that moved through as I was wrapping up this article. Imagine if you will a 150' tower rising from behind the trees in the centre of the picture and piercing the rainbow. It will easily rise that high.


Thursday, July 6, 2017

Computer Contest Logging in 1977

As this year's IARU Radiosport contest approaches my thoughts turn back to the very first one. It was in 1977, 40 years ago. As I recall how it came to be the ARRL had such great success with the one time running of the Bicentennial contest in July 1976 that they saw an appetite for a summertime international contest. They must have been right since it's still going strong.

Back in 1977 I was in university working on my B.Sc. in Computer Science and on the cusp of exiting my teen years. I was an enthusiastic contester with a small home station and I was a member of club station VE4UM at the University of Manitoba. Since 1977 was the university's centennial we got a most unusual special call sign: VC9UM. At the time there was no 9th call district in Canada; it is now assigned to New Brunswick.

Dupe sheet from my 1970s files: contest unknown; the other side has US 6 to 0 and VE; one sheet per band
Every contester who predates K1EA's CT has painful memories of paper logging and dupe sheets. It was easily the worst aspect of contesting. There were a talented few who could simultaneously operate a keyer and write the log and use a dupe sheet. The rest of us cursed as the rate picked up and we scrambled to manually check the dupe sheet, fill it in (or chase away the caller) and log the QSO. Big gun multi-ops often had one person on the radio while another managed the log and dupe sheets. Unlike today dupes typically involved a penalty, and you didn't want that.

Imsai 8080: Not good enough, unfortunately (photo credit)
Personal computers at the time were wholly unsuited to the task of contest logging and dupe checking. Hams were experimenting with the simple home computers then available, such as the IMSAI 8080, using teletype machines as terminals and paper tape for storage. Soon enough the PC (including an updated IMSAI) would have the capability but in 1977 it was still a few short years in the future. The major impediments included:
  • No operating system: All I/O and other core tasks had to be manually coded.
  • No high level programming languages: It was all machine code or symbolic (assembly) machine language, or cross-compilers that ran on mainframes and minicomputers and downloaded to microcomputers.
  • No direct access to mass storage: Even floppy disks were not yet available, let alone anything larger. Programs were typically stored on and loaded from paper tape, either on the teletype terminal or the recently available electronic paper tape readers.
  • Insufficient RAM: Directly accessible semiconductor was typically no more than 4 KB. Try to fit a contest log and the logging software into that!
  • It cost money and we didn't have any. We were poor students barely scraping by.
Nevertheless computer logging was being done by a few. The early baby boomer contesters were by that time in their late 20s and working in industry. Many were engineers or an early generation of computer programmers and worked in large companies or other organizations with mainframes and minicomputers. An enterprising few were able to negotiate personal use of those machines over contest weekends.

This was no small accomplishment since those computers filled machine rooms and were expensive to power and required salaried operators to keep them running smoothly. It was typical for these computers to only be run during regular business hours except when dedicated to supporting clients with longer hours.

An idea is born

A friend and I talked it over. He -- Derrick VE4VV (SK) -- was also a fervent contester and a fellow student one year behind. We were too young and lacked influence to convince anyone with any power to grant us use of the university IBM S/370 mainframe or one of the several departmental PDP-11 minicomputers scattered across campus. I did try. The furthest I got was polite interest. The needs of graduate students and faculty would not be adjusted to suit my requirements.

From my personal library -- I enjoy hanging on to a few mementos
Since it was summer break I was working for a government agency as a systems and application programmer. I regularly used the a government owned S/370 and we had our own PDP-11/45 minicomputer. My attention focussed on that minicomputer. Like any machine that size it was turned off at the end of every workday. Could I get it left on for the weekend? That was my challenge. Software development was the least of my worries.

I shared my desire with my supervisor. Although he had no power to grant my request he became a strong ally. He was not a ham but had an interest in it. He also liked the idea of getting management to do something unconventional, to kick them out of their comfort zone so to speak. He talked it over with his boss. It took some persuasion to at least turn him neutral on the project. But it was his boss who would have to make the decision and he was a stereotypical senior government bureaucrat. He was not a mean person but one with a very narrow and well-defined comfort zone.

Of course he refused. Not only would it involve an expense for no sensible reason he could fathom it was a valuable government resource he was in effect turning over to a couple of teenagers. He saw it as risking unwelcome public exposure for him and his political masters should something go wrong. It was pointed out to him that I was in position every hour of every day to do anything at all with that computer, including access to confidential data and an ability to severely disrupt operations.

It took a few days when to my surprise and delight I received grudging approval. I never found out what was said to finally clinch the deal and at the time I didn't much care. What I did care about was that in fact we had no plan, no software and no idea how it was all supposed to happen in the few days we had until the contest started.

Putting a plan together

We had access to a minicomputer, but that was it. Every other problem was entirely up to us to deal with by dint of hard work. We needed remote access to the PDP-11/45 since downtown Winnipeg and the university are 10 km apart. The only possibility was 300 bps dial-up telephone modems of which we had two on the minicomputer for staff use.

Acoustic modems I've used (Columbia University)
If you've never heard of these contraptions they involved dialing the computer modem on a telephone then inserting the handset into the "ears" of the modem when you heard the carrier tone. If all went well the modem would detect the carrier and establish the data link. They were terribly unreliable and often dropped calls or failed to connect on the first attempt. At least we were only calling across town. Long distance calls and especially overseas calls often experienced phase shifting (it was almost all analogue transmission at the time) which was not tolerated well by the modems.

The terminal itself was a challenge. After exploring a couple of alternatives we borrowed a VT52 from my office and transported it to the club station. This wasn't easy since these "dumb" terminals were large, heavy and fragile. I didn't want to think what would happen to me if I dropped it or bumped into a wall as my friend raced ahead opening doors for me and guiding me around obstacles on the downtown streets towards his car.

VT52 from Wikipedia
It was remarkable that we got the terminal and communications link working at all. For the duration of the contest Derrick only experienced two line drops.

Software constraints and features

As already mentioned, when I got approval I had not yet written a single line of code. There was only a little over a week to develop a contest logging application from scratch. I didn't even have a clear idea of how to do it, what the user interface would look like and how I would deal with bugs and other disasters. All of this needed to be fleshed out, and quickly.

People are often surprised that many poets do not feel constrained by the need to fit their thoughts and emotions into a strict meter and rhyme template. Although a challenge it limits the range of possibilities to a solution space that is more tractable. My dilemma was much the same. I was limited by an interface that could paint no more than 30 characters per second on the screen, a couple of bulky hard disk drives and 32 KB of address space (the computer had 80 KB of magnetic core RAM, but each process was more limited by the system architecture). It simplified the problem by limiting me to what would fit these constraints.

The first thing to recall is that there was no such thing as computer control of rigs. Back then all transceivers were dumb. Neither were there integrated keyers. Well, that's not entirely true but very uncommon for contest software at the time since PCs were still terribly inadequate. There was no way a simple 300 bps ASCII connection to a dumb terminal in the shack was going to do anything like that. So the rig, keyer and microphone were manually operated.

All we were going to do was log and dupe. That's it. But that's a lot. If you're too young to remember those days it may not register just how difficult that was to do manually while operating, especially for a single op.

The software we decided would do the following, and nothing more:
  • Manually set the band and mode; Radiosport is a multi-mode contest.
  • Check for a dupe when a call is entered, and report log details for the earlier contact.
  • Enter an exchange and log the contact. The computer fills the time.
  • Check the band and mode, just in case.
  • Simple real time reports of contacts and zones logged.
  • Ability to back fill QSOs in case of temporary computer or communications outage.
  • Print log and dupe sheets and calculate score.
That's it. But as already said that's a lot.

The programming language was FORTRAN. Only that and assembly code were available. The DEC compiler for the RSX-11D operating system on the PDP-11/45 had libraries to support use of the data management services on the various storage devices. For our purpose these were two disk drives of 20 MB storage that were the size and weight of large washing machines. I forget the model number but they were roughly equivalent to the IBM 3330. Access time was not fast; that was a critical consideration if we were to achieve acceptable performance.

The VT52 has a graphics mode whereby the 24x80 character matrix could be directly manipulated. I eschewed that option since it added complexity and didn't seem to add much value for our limited feature set. I stuck with a scrolling text screen to keep it simple. It worked surprisingly well for the operator.

Development phase 1

With the clock running down I soon realized not all the planned features could be developed in time. Yet I was able to get the core functionality working within a few days, designing and coding in my spare time and, to be honest, during work hours. My supervisor knew what I was up to but chose to say nothing since my work assignments were progressing on schedule. More days were consumed in tweaking the software and data management to boost performance.

My design choices were greatly limited by the technology available to me. That a program could only be 32 KB, including code and dynamic data storage forced my hand. Think about the length of a call sign. Let's assume 16 bytes per log entry for a call sign, exchange data and time stamp. A log with 1,000 QSOs requires 16 KB, or half the address space. I had to support more than twice that number of QSOs and still have room for the program and the library routines that the compiler would include.

I investigate a variety of data compression algorithms. Unfortunately all involved substantial complexity. Then I discovered the program was consuming more space than I'd hoped for. I thus opted to put the log on the hard disk and optimize access with extensive hash tables and other techniques.

Happily it worked quite well during testing. Derrick came in one evening and I had him log random QSOs for a couple of hours to test the data base process. Afterward I analyzed the tables and adjusted the hash algorithm. Performance depended heavily on the QSOs being reasonably evenly distributed by a randomized hash key derived from the call sign.

For disasters in which the log data base was lost due to system or program failure I stored a plain text journal file on the second disk drive, writing to it after a QSO was logged. Although we never needed it there was comfort in knowing it was available. The journal file could only be used for post-contest log recovery since I had not yet developed code to recreate the log from the journal file.

User interface

The user interface was extremely simple, and surprisingly effective despite the simplicity. After connecting to the minicomputer the user signs in and executes the logging program. There was no setup to be done since only the one contest was supported. In case of a crash you run it again and carry on logging.

Whether running or S & P the UI was the same: enter a call sign and hit return. If it isn't a dupe nothing happens except for another prompt. You then enter the exchange, signal report optional. A dupe was flagged with log details and the sound of the terminal buzzer. It might look something like this (I forget the details so this is not precisely as it was). Plain text (not bold) is user input:
>=b20
>=c
>k3lr
>k3fr

>8
0334
>g3aa
>57927
0336
>f6abc
DUPE: *** F6ABC *** 1/2315 20 CW
>=s
>ve1xx
>9
0341
The first two commands (user input with the "=" prefix) set the band to 20 meters and mode to CW. Then a call sign is entered. The operator either made a mistake or didn't work the station and enters a new call sign. This action automatically erases the earlier entry.

The subsequent entry of an exchange (zone number) causes the call to be logged. Since no report was entered it defaults to 599 in the log. The time of the QSO is the only feedback given. Recall that we're working at 300 bps and brevity is important.

For the next call entered -- G3AA -- a signal report other than 599 is received. It is entered before the zone, just as it is sent by the the other station. The software parses the line to extract both items. The software assumes that 59 (or 599) is always sent so there is no way to log a different sent report.

The next call entered is a dupe. The log details are presented. The "1/" in front of the time indicates the day of the contest -- could be 1 or 2 since the first Radiosport was a 48 hour contest. The other data is parroted since the operator could have quite easily forgotten to change band or mode or typed the call incorrectly. Either way the operator proceeds to the next QSO. If it was a typo the correct call is entered followed by an exchange in the usual sequence.

Next, the operator changed mode to SSB and successfully logs an SSB contact.

The software did not fully validate call signs since the variety was too great and I didn't want to cause problems for the operator should the program improperly flag a valid call sign. Only simple errors such as a call beginning with a "0", no numeral present, trailing numeral and a few others were flagged. It was up to the operator to retype the call or ignore the warning and proceed to enter an exchange and log it. Although simple it worked well enough that we only found one badly formed call signed in the log after the contest.

There were a few other commands available. There was "=q" to report the number of QSOs in the log and "=z" to report the list of zones worked on the current band. Before entering an exchange a QSO time could be entered with something like "/20404" to override the computer clock and log the time as 0404Z on day 2 of the contest. This was needed in case of system outage so that manually written log entries could be put into the computer log during a break or after the contest.

I had a couple of debugging commands in there as well. These were of no use to the operator so I didn't even both to tell Derrick about them. If needed I could have walked him through their use over the phone.

The contest weekend

Late Friday afternoon Derrick drove over to my office to pick up me and the VT52. We had already acquired a modem from a helpful professor at the university -- it was summer and there was unused equipment available. I was given a key to the building front door and computer room by my boss. As the office closed for the weekend the operator shut down the computer per his procedures.

I restarted the minicomputer and ensured that it and the telephone ports were operational. I created a user account for Derrick to use. Then I shut the lights, locked the door and crossed my fingers. Off we went to the university to get him set up for the contest. I took a bus across town to my own home and station. Derrick was doing a single op, as was I from my own station. But I was on call in case disaster struck and I had to get downtown in a hurry to fix things. My attention was split between the contest and worrying that the phone would ring.

The phone never rang. That is, not until a few minutes after the contest ended. Derrick gave a enthusiastic report of the logging software. He couldn't stop laughing because it was the easiest and most relaxing contest he'd ever done. Apart from typing all he had to do was talk into the mic or press buttons on the memory keyer. Duping was a suddenly a relic of the past.

Since we were both tired from the contest we wrapped up and met the next day. In 1977 computer contest logging was a rarity. No one I personally knew had done it so I had no direct knowledge of how big a difference it would make. The difference was big, very big. We both realized right then that contesting would never be the same after the introduction of computers in the shack.

We got down to a serious post mortem discussion. Since he'd already practiced with it there was no learning curve to deal with during the contest. The limited feature set was itself a feature. He made a crib sheet with the commands written on it and found he didn't need it. We began talking of new features we could add.

A few problems did occur during the weekend though nothing too inconvenient. One was the expected line drops. Bell 103 modems with those bunny ears were not exceptionally reliable. We were lucky the problem only occurred twice. Each time he was able to redial and get back to business in a couple of minutes. He never had to resort to paper logging.

A bigger problem was that dupe checking became noticably slower with more than 1,000 QSOs in the log. Although the delay never got to be much more than 1 second in the heat of the contest it can seem an eternity. A few minutes of forensic analysis after the contest uncovered the problem. It had an easy solution. I counted myself lucky that nothing worse happened. The problem wouldn't have appeared if used at my small low power station since I made only 625 contacts in that first Radiosport (I actually found a copy of my old log).

The most delightful experience Derrick reported was the amazement from other hams, particularly when operating SSB, when he could not only tell stations they were dupes but the exact time of the QSO. Time and again they'd be suspicious and then astounded that the QSO was in their logs right where he said it was. Some even called back minutes later just to tell him he was right.

What they imagined was going on they likely never figured out and Derrick never told anyone on the air. Recall that this was 1977 and even technically savvy hams typically had zero experience and knowledge of computers. This was great fun!

Development phase 2

At the end of the contest we had a log and nothing more. I made backup tapes of the data base and software to protect our investment. Our next task was to print and score the log so that the VC9UM entry could be submitted. Those were features that I had deferred since they were not needed during the contest.

The log sheets were easy enough to format to look similar to the official ARRL/IARU log sheets. The one significant task was to parse the call signs in the log to determine the country and combine that with the zone (continent?) to calculate points for each QSO. At least that's the way I remember it. My memory of the scoring in that first Radiosport contest is hazy.

Dupe sheets were a problem. Of course there were no dupes since the software had already taken care of that. I went ahead and developed the features to score and print the log while Derrick made a few calls to the folks in Newington CT. There was an unanticipated difficulty.

Bureaucracy and the computer

The ARRL contest desk of 1977 refused to accept computer generated logs. They also demanded handwritten dupe sheets. This is despite the fact that the printed log sheets were nearly identical to the official sheets and there were no dupes. Both demands were nonsensical. Nevertheless they were unmoved by his protestations.

When it was pointed out to them that neither added any value, they would only point to the rules that declared entries must use the official log sheets (or copies of same) and that logs of over 200(?) QSOs must include dupe sheets. Flexibility was not in their vocabulary. That rigid compliance with the rules involved a substantial amount of work to manually transcribe the log and generate dupe sheets moved them not at all.

Derrick gave up the fight and spent a summer weekend doing what they demanded. It would be many years yet until the ARRL looked upon computer logs as helpful and even desirable. We were ahead of our time.

Aftermath

With a great success in our pockets we wanted to do it again. CQ WW was coming up in the fall and we set that as our goal. We had many ideas for improvements and new features that I was eager to build. This time it would be a multi-op effort so that I would not be left out of the fun.

It was not to be. Once I was back in school and no longer employed by the government the same senior bureaucrat was adamant that access to the PDP-11/45 was absolutely and categorically out of the question. My friends on the inside tried their best to no avail.

I made another play for the university department's PDP-11. It was even more impossible than before because the fall semester was in full swing. While there was still interest in what I was doing, and nothing sells better than proven success, they told me that, unfortunately, academic priorities would not and could not be set aside for even that one weekend.

That was the end of my foray into computer contest logging. I never did it again although I thought of it often.

Not long after that initial experiment I was working towards a post-graduate degree, and after that I moved across the country to start my professional career. PCs were by then very capable of contest logging and that's what many were doing. In my files I located notes from early 1980s of a far more sophisticated computer logging system. Those plans predated CT by a year. But I had no time for it and not even a station of my own to use it with.

When CT came out I was intrigued and thought of what might have been had I stayed with it. But by then my contesting activities were entering a lull as I put what little radio time I had into DXing and fooling around with antennas and modelling software. I did use CT a couple of times but that was for me and contest software for many years to come.

I missed a few generations of contest software and the computerization of radio equipment while I was absent from hobby between 1992 and 2013. When I made a serious return to contesting in 2014 I adopted N1MM Logger as my contest software from among the many excellent alternatives available. Three years on it remains my software of choice.

There is no reason at all for me to think about developing my own contesting software. I am more than happy to use the superb software that others have developed. I am content to be a user and put my energies into station building and operating.

Tuesday, July 4, 2017

The Price of Safety

I've been thinking lately about personal safety when it comes to hams and towers. It's come up on this blog from time to time. Too many hams are injured or killed pursuing the hobby we love. Many more come close to harm without really appreciating the precipice they were teetering on. They were just lucky someone else saw the danger and either warned them or did something about it.

When I say I've been thinking about safety I mean thinking about it more than I usually think about it. One reason is that I am about to put up a very tall tower. I've worked on big towers though never one of my own. This means I'll be at a great height more often than ever before. The other is that I recently did several tower jobs for others, involving both hams and non-hams who are not experienced with towers or tower safety.

How much is safety worth? Is it worth a friendship? This is not idle speculation. When you're up the tower and you see a friend step into the jaws of danger you have a choice to make: say something or don't say something. If the situation is urgent you may end up shouting words that are far from polite. Words that we never want to pass between friends.

When I was young I paid little attention to danger. Teenagers are immortal of course. Many times I climbed towers without any safety equipment to perform a routine maintenance task. Teenagers live in the moment where a one or two day delay to borrow even as little as a leather lineman's belt from a friend is too much. As I grew older I became more sensible as I hope most of us do.

When you've been on towers as much as I have over the decades you get to see far too many things that speak of mortal danger. I've been lucky not to have ever been seriously injured or had it happen to others I've worked with. Mostly that's due to good planning and a sensible crew. Other times it's just good luck. Face it, hams take stupid risks far too often.

When I was younger and most of the other hams were older I was reluctant to speak out when stupidity sprouted up around me. I am now far less likely to hold back. It is not a spontaneous eruption but rather a calculated urgent and forceful tone, a technique I learned from many years in corporate management. I want to incite an immediate response to mitigate a present danger.

What are these dangers? There are too many to list! Let me give a few examples:
  • Children allowed to play in the work area, including the tower base directly below me.
  • Refusal to wear a hard hat, or taking it off to be more comfortable.
  • Undoing a safety harness because it's "in the way".
  • Insisting on standing in exactly the wrong place when pulling on a rope and thus putting everyone at serious risk due to imminent mechanical breakage.
  • Acting with zero regard for the safety of the rest of the crew and risk to property.
  • Putting their hands or other body part where a sudden change in rope tension could result in severe injury.
  • Unsafe use of power equipment.
  • Chatting when they should be paying close attention.
  • Disappearing for a personal break without telling anyone.
  • Making mistakes out of no fault of their own other than a lack of experience. This is a management fault, often with me being the guilty party.
  • Not asking for a break when they need one or they aren't strong enough to accomplish a task. We all have our limits.
  • When a mistake is made the person loudly casts blame elsewhere. Ill will is bad enough but more worrisome is that failure to own up is a signal that more and worse mistakes will follow.
It's the innocent errors that most concern me. The others can be managed by not inviting or uninviting those who are unwilling or incapable of learning and correcting behaviour. Sometimes it can be accomplished diplomatically by finding a suitable task that puts them out of danger to themselves and others. The person may take offense so be prepared.

It can't always be done diplomatically and the need to act may be urgent. That's when I raise my voice. That's the moment when a friendship can be put in jeopardy. Afterwards or sooner if possible I make a point of apologizing to those I shouted at. I go on to explain that I was compelled to do so because I was concerned for their immediate safety or that of others. Usually they understand and all ends well. But not always.

July is the midpoint of antenna season in these northern latitudes and therefore marks a good time to revisit safety. Pardon the preaching but this is a message that cannot be repeated often enough. Sacrifice a friendship if you must. It is better to have a living ex-friend than a dead friend.

I am not immune. There are times when I am the target of a warning or unexpectedly stern advice. I've learned not to take it personally. I listen and usually discover that the warning or advice is warranted. To err is human and I am human. Welcome the intervention of your friends. They care about you.  I swallow my pride and gracefully adapt to the situation. And I learn.

When it's done right everyone gets to go home with a smile on their face, happy with a tower job done well, and still be friends.

Sunday, June 25, 2017

Planting the LR20 150' Guyed Tower

As I write this the foundation work for the LR20 150' tower is complete. Really complete. It has been a long road, one that began in November. At the time I planned and expected to have the tower ready to be raised before Christmas. As I mentioned at the end of the article about planting the Trylon Titan tower we got socked with an early winter storm that forced many woes. Suffice to say the tower did not go up this past winter.

Yet we went ahead. It didn't work out well. In this article I'll let you in to the full story, warts and all. Aside from the many problems encountered, and overcome, much went right. Regardless it is a story worth telling. I haven't seen many articles on the internet that described the full procedure of planting a large guyed tower in amateur stations. Just small snapshots.

Yet it's a major project that can provide many lessons to those who want to do the same. I hope you enjoy it, and perhaps learn a few things. That includes the things you should not do.

Hiring out

A local tower construction and service company, Ontower. They are happy to offer their services and expertise to local hams who have turned to them for assistance. This has become common as the ham population ages and fewer are able to help out their friends as they have in the past. In any case it is only a minority of hams with big tower experience. I have put up high guyed towers but I do not consider myself an expert.

I got to know them over several months. They were free with their advice and sensitive to the needs of non-commercial projects. It also helped that they have the equipment and parts on hand to put up towers far bigger than my own. So we came to an understanding.

Act 1 - Clearing a path

The day before the big day the weather unexpectedly turned. The ground was covered in snow. They were unable to drive their truck and backhoe float across the hay fields to reach the tower site. The backhoe operator used its small blade to plow a 250 meter path to the tower base, and then to each of the anchors. Wherever there was a turn a clearing was made to allow for the large turning radius of the truck and trailer, and also for the arrival concrete truck.

Tower work in Canada, eh?

By the time all was done the fields were crisscrossed with paths made by the backhoe and by people walking from point to point. So far so good. It wasn't to remain that way. The day warmed and the snow began to melt.

Excavation

I surveyed and staked the field in advance. The crew of two brought a small backhoe. I could have hired a large backhoe but there is an advantage when the equipment operator and crew don't just have experience digging holes but digging holes for towers. Their backhoe had just enough reach to excavate the 6' depth of the anchor holes.

Other than exchanging a few ideas at key points they knew exactly what to look out for and what to do. There were no mysteries to be explained. Our only serious concern was whether we'd hit bedrock since their machine could not cope with that. My luck held and other than some large rocks the excavation for the base and three anchors proceeding without drama.

We did have contingencies in mind in the case we did hit bedrock. For the base it is possible to anchor the pier to the bedrock, at some trouble and expense. Or if the level was sufficiently below the frost line to modify the base to suit. For the anchors they and another expert I consulted suggested sitting the anchor on the bedrock and adding overburden on top and ahead of the anchor (building a mound) to compensate. An anchor's tension limit is not set by its depth but by the mass and solidity of the soil it is pushing up against when the guys are under load.

The excavations were greater than the specification for this size of LR20 tower since the anchors they supplied and the squares and hoops for the rebar cages were for a 350' tower. This requires more concrete, which is an acceptable trade off.

Rebar cages and concrete forms

While one person operated the backhoe the other built the rebar cages. I did the cutting and bending, leaning on my experience and tools from building the Trylon base.

They supplied the square wooden case for the base and round tube for the pillar. For the anchors we dispensed with cases; what they call "mud holes". The downside of the latter is that the holes are inevitably larger than required and require more concrete to fill. It's a trade off: more concrete or more time and expense to build and work with casing. It doesn't have to look pretty.

Left: anchor and rebar in mud hole; Centre: anchor cage almost ready to go; Right: forms and rebar for base

Notice that the anchor has two large buttressed vertical plates. When under tension the load is distributed over the reinforced concrete, preserving its rigidity. The reinforced base platform distributes the load over a wide area of undisturbed soil. Numerous J-rods bound with circular ties run the height of the pillar to preserve pier integrity under vertical load.

But are these reinforced concrete foundations up to spec? There is no clear answer to this question. Tower manufacturers have become increasingly coy on this point. No one prescription or set of options is sufficient for all soil conditions. And that's what counts. Commercial towers require soil tests and the services of an engineer to specify the foundations for the prevailing soil and environmental conditions, including seismic activity and ground water.

What I have done instead is to oversize and overbuild the base and anchor foundations. I also know that the soil in this area is very stable and the water table is deep. There is an extended period of saturation in heavy rains and spring thaw. The top soil is less than 2' (60 cm) deep, below which is a dense mix of clays and rock. It is so hard that shovels barely dent it, even when soaked in water.

Aligning the anchors

Overnight most of the snow melted, turning the fields into a muddy mess. Half a day was spent finishing the forms, setting the anchors, levelling everything and aligning the anchors to the base. The alignment was done by sight to ensure the anchor rods pointed directly at the base. An inclinometer was used to set the vertical angle of the rods according to the tower spec.

They recommended against using the anchor plate as an equalizer plate since it adds a potential point of failure. Instead the plates were welded square to the rods. With the vertical angle correctly set the pre-load tension on the guys will net to zero vertical force on the anchor rod.

Of course with maximum antenna wind load at the top of the tower there will be an upward force when the wind blows. However that is true whether or not the plate pivots. As they explained, with a round bar for the anchor this is well within the load spec for the material. Alternatives that some use, such as angle iron for the rods, overbuilding is required to maintain anchor integrity.

Concrete - Uh oh!

Early afternoon of the second day we were ready for concrete delivery. Or so we thought. The plan was to have the concrete trucks -- we needed two in sequence -- drive across the hay field and pour directly into each hole in turn. Two time-separated pours were planned for the base, a point which I'll return to later in the article.

Unfortunately by the time the first truck arrived the surface was softened by melting snow and stayed wet due to the heavy overcast. The driver was dubious but trusted the crew since the companies regularly worked together on tower sites. But the final decision was mine. Hoping for the best I gave the go ahead signal. That was a mistake. As I've said before, hope is a 4-letter word that it is best to avoid.


The truck didn't get far. No matter how many tires the load is spread over or how many axles are driven (they have this option) 60,000 lb needs a strong surface for support. I found myself in a difficult spot since I was responsible for getting the truck out of there.

Happily I was dealing with professionals. Ontower got a local construction firm to send out a front end loader. It had two tasks: quickly unload the concrete and pull the unloaded truck out of the mire. While we waited for it the concrete truck driver told me dark stories about the cost of freeing a stuck concrete truck or a ruined truck due to the concrete setting. I reciprocated with how stories of how technology would enable driverless trucks and put him out of a job.

A little laughter goes a long way when you are in a tight spot waiting for rescue to arrive. Every so often he'd interrupt the conversation to add water to the concrete to keep it from setting.

Eventually the front end loader arrived. I have to say I was very impressed at how well it all went from that point. That scoop you see holds a lot of concrete and had no problem going over 200 meters of muck to dump the concrete into the excavations. It took fewer than 20 trips to transfer over 7 cubic yards of concrete. An hour later the concrete truck was empty and towed back to the road. Two anchors were complete. But it was late in the day and we had already cancelled the second truck. The remainder of the concrete work would have to be rescheduled.

There was the unanticipated effect on the anchors of pouring tons of concrete from a height. Front end loaders are not gentle machines. The anchors shifted slightly and were no longer directly pointed at the base. The error was approximately 2°. None of us caught the mistake until it was too late. We discussed it the next day and decided that it would not be a serious problem. The anchor was oversize and round and the deflection would be modest when the guys were tensioned. I still worried about it, but nothing could be done. At least not yet.

Intermission - Winter doldrums & spring floods

We tried to reschedule the concrete work several times, included the depths of winter. The weather did not cooperate. Not only was this job delayed so was the concrete work for my garage. The early end to the season inconvenienced many in the construction trade.

Concrete work can be done in frigid weather if you are willing to pay up. After several weeks we decided it would be best to put the work off until the spring. Although a sensible decision there were a couple of factors not taken into account. First, the excavations and forms were stable when the ground was frozen and ice filled the holes. Spring thaw changed that. Several cubic yards of topsoil slumped into the holes, covering the forms and rebar and allowing the water level to rise higher. Second, we had a record breaking wet spring.


So the delay continued. It continued so long that the work had to be fit into their summer high season. I did what I could by periodically pumping the water and removing some of the slumped material. Saturated topsoil is a gummy soup that is pretty much impossible to shovel. There was also the danger of additional slumping while working below ground. I had to give it up and wait. Besides which I was getting tired of removing ticks that leapt onto me with glee from the head high hay. Protective clothing was little help.

Act 2 - Getting it done

Finally the great day arrived. A new crew arrived and so did a large backhoe with front end loader the same size as the one we used in the fall. Although this machine was a significant expense it meant we could clean the holes, deliver the concrete and back fill all four holes in one day. This time everything went according to plan. It was also an opportunity to renew my respect for heavy machine operators. He demonstrated a care for the work and fields and an artistry in how he went about the job.


The first job was to clean the holes. This involved carefully scraping off the overburden to expose enough of the forms and rebar that they could be lifted without breakage. Mission accomplished. But it was tense and dirty work. The bucket you see is ~3' (1 meter) wide and required gentle manoeuvering. Those machines pack a big punch.

I took on the job of cleaning the rebar so that the crew could do more important work. I ended the day covered in muck, as was the crew. Something died inside the base hole rebar cage which added to the unpleasantness. As if that wasn't enough didn't I already mention the ticks? What I go through to boost my contest scores!

While marking the lines to the two misaligned anchors the senior crew member noticed that if the base was moved 2' (60 cm) he could get all three anchors pointed at the base. That's why the base excavation seen above was extended. Many problems can be solved when you have the right tool at hand.

The backhoe bucket is so large that the anchor hole had to be widened even more than before. A form was prepared in advance with scrap lumber they had on hand. This saved some money on concrete, but require a lot of shovelling to back fill around the form. Without it the form would burst or float on top of the concrete.


The base is done differently. First the forms were rebuilt. Concrete blocks are used as rebar chairs. They must be concrete to ensure a good seal that will repel water infiltration. We used 20" tube for the pillar which is the minimum to sufficient concrete around the rebar. Previously we used 24". It is higher than required so the vertical rebar isn't visible. It'll be dealt with later.

The second frame shows concrete delivery using the "small" scoop. Once the concrete for the platform is poured it is enclosed with plywood. The hole is then back filled halfway and the concrete for the pillar is poured with a shovel. Only a few feet of unsupported tube is exposed so that the concrete does not burst the form.

Afterwards the hole was fully back filled, then compressed and levelled. Extra soil for all excavations (displaced by the concrete) was dumped off the edge of the hay field. Under the crew's direction the areas near the anchor plates were untouched. This will be filled by shovel to avoid damage by the backhoe.


Finale

The vertical rebar in the pillar is not centred while the concrete is poured. That's difficult to do. Instead the rebar is manually centred when the pillar is almost full. The concrete holds the rebar in position as it sets. The same procedure was use for my garage pad. That crew lifted the mesh as the concrete was poured to, again, avoid the problems of using chairs.


The final act was to push in the tower 1" round pier pin into the centre of the pillar and level it. It is a myth that concrete is self levelling. That only works when the concrete has a lot of added water, which slows curing. One of crew dribbled some water over it and used a trowel and a small level.

Three days later I drove out on the tractor, mowing tick-bearing hay along the way. I cut the form from the pillar and inspected the result. It looks good! You can see the top 4' of the 10' ground rod that the backhoe operator helpfully pushed in with the bucket until it hit an obstacle. Later I'll try to pound it in further with a sledgehammer.

Looking back, or, to err is human

Many things went right and many things went wrong. My first mistake was being overly ambitious about getting this tower in before winter. It cost me some money and a bit of grief but did not in the end cost me any time. If I'd moved more cautiously it would not have been done sooner.

Another thing I'd do is start with the big backhoe rather than try it with the less expensive small one. I was tentative in the beginning since I wanted to reduce the expense if a smaller machine could do the job and also limit the loss if we hit bedrock and had to resort to an excavator with a rock breaker. Should there ever be a second big tower on this property I now know what to do.

Relying entirely on the judgment of professionals is not always recommended. An important lesson I've learned is that although they are good at their jobs and give good advice they are perhaps too sensitive to the customer's costs and wishes. That is, they have learned in their careers that they must work quickly and get approval for anything that entails extra money or time. Risk doesn't always get the attention it deserves.

I had a few "Gimli Glider" moments with the concrete. Although Canada is a metric country there is a lot of building material that is measured the old way. Thus I am used to ordering concrete in cubic yards. But the concrete company works in cubic meters. They will do the conversion but you must be careful that they in fact do so. For the final stage I needed 4 yards, and I added a half yard margin. The order was relayed through the crew to the operations manager to the concrete company. They assumed and delivered 4.5 meters. The unused concrete was delivered elsewhere. We're working on getting a refund.

The ground in this region becomes saturated quickly in late fall and doesn't percolate downward until late spring. For all the pumping I did to get the work going again the holes completely dried on their own by the time the work recommenced. Fighting with water is a losing game. There are more powerful pumps around than the sump pump I used, but they're expensive even if only rented for a day. I spent an hour or more yesterday disassembling and cleaning the sump pump so that it will again be ready for emergency backup use in the house.

Looking forward - plans to raise the tower

I have not yet finalized how I will raise the tower. I could call in the professionals, which would be quick if more costly (and less fun) than calling in friends. Going the professional route would also require having everything prepared in advance, including all the guys, hardware, tower section repairs, prop pitch motor assembly and more.

Alternatively I can call in a small crane to lift the first 40' so that the bottom guys can be attached. I would then continue upward by gin pole. The method that involves the least equipment is to drop the base section on the pin and temporarily guy it until the tower is high enough that the first permanent set of guys can be installed.

I have decisions to make. Since the concrete will cure faster than I make my choices I can proceed whenever I'm ready. It would be nice to wait until the ticks are gone or the hay is harvested.