Friday, April 21, 2017

Asymmetric Copy in Contests

It stands to reason that except in superb conditions that one side of the QSO copies better than the other. Indeed it would be remarkable if copy was equally good (or bad) since each station has a unique set of antennas, noise, QRM and propagation. This can make for some curious exchanges during contests.

Even when SNR (signal to noise ratio) is high there can be asymmetries in copying. On SSB this may be due to language and accent for the majority of hams who are not using their native languages, or simply by poor enunciation by those who fail to realize that a communication channel with limited band width and dynamic range makes copy more challenging than talking in person. There is also the all too common practice of poorly adjusted audio. On CW it may be poor sending, deviations from standard code element length and spacing, or sending faster than the other ham can comfortably copy.

Putting those situations aside I want to focus on QSOs between operators who are doing their utmost to get the message across: in this case call signs and contest exchanges. I'll focus on CW and SSB since I don't have sufficient experience to discuss digital modes.

Run versus S & P

Let's imagine we are tuning across the band and run across two adjacent signals, one strong and one weak. Which one do you tune in first? Even if you are disciplined enough to focus on the weak one I bet that you are still strongly drawn to the strong one. This is perfectly natural since it is less work to copy the stronger station well. Struggling with a weak signal costs time and time costs points. We are more inclined to do the hard work late in a contest when all the strong ones are already in the log.

However, it is not quite so straightforward. When you tune in a strong signal in the clear you will most likely copy the call sign the first time it is sent. You will most likely easily copy the exchange. The same is often not the case on the other side of the QSO. You may be running less power and a smaller antenna; they may be experiencing strong QRM from other callers and adjacent signals near to you that you don't hear because they are in the skip zone or off the side of the beam.

It should therefore be no surprise that for stations you copy perfectly while you S & P that less than 100% of them will copy you as well. Some of the time or much of the time, depending on many variables, they will ask for repeats or you'll have to correct their copying error. During the two years my contesting was exclusively QRP the percentage of running stations that could copy my call sign and exchange the first time was not high. On the low bands it was often no better than 25%.

Now let's return to the weak station you earlier skipped over. More S & P operators than you might imagine won't pay any attention to the ones that are hard to copy. I'll assume you're not one of those, since as a contester you should never overlook potential points (and multipliers).

So you listen and listen, perhaps taking a little time to completely copy the call sign and perhaps you'll also note the exchange being sent. For many it is only at that point you make your call.

Consider what's going on here. You spent time to copy the full call and ensure it is not a dupe. You have already had one or two opportunities to copy the exchange. Even if it's a serial number you know what number comes next and you'll be ready for it!

The running station has not had that opportunity. Their probability of correct copy on the first try is perhaps, on average, no better than yours. Yet you've already gotten past that obstacle. Now it's their turn. The weak running station is even less likely to copy your call and exchange on the first try.

The lesson here is that when you S & P you should not be surprised that the running station will need repeats of your information. For the running station many callers will not be readily copied and you'll have to spend time to correctly solicit their information.

Example: Ontario QSO Party

As an experiment I did 100% running in the recent Ontario QSO Party. That is, sitting on a frequency calling CQ and never hunting other stations. The contest has light activity and I wasn't concerned about my score, only giving out QSOs to others. This is not a bad way to make it easy for non-VE3 participants to find me, and my perhaps uncommon county multiplier. Many of the active VE3 stations spent much of their time running as well, perhaps for the same reason.

The objective of my experiment was to see just how often the callers were difficult to copy. Well, it was surprisingly often. While a sample of n=1 is not statistically significant my results do fit well with my thesis and my recollection of past years of contest experience at larger stations.

My springtime QRN levels on the low bands was quite high during the contest, with several electrically active rainstorms passing through or nearby. That could have contributed to asymmetrical listening ability. Asymmetrical power wasn't a problem since I kept to the low power limit of 150 watts, which is on par or less than the majority of callers.

On 80 meters I found I had to use the Beverage all the time even though it favours Europe and almost all callers were off the side or back of the Beverage. The SNR was almost always better than the inverted vee. This worked less well on 40 meters, partly due to the Beverage's sharper pattern on that band. The 2-element yagi's directivity is not very good, which is typical of this type of antenna.

There were many callers I could not copy at all, while with other I would only catch a letter or two of the call. It seemed surprising they were copying me. Perhaps they had lower atmospheric QRN, more directive antennas or there was power asymmetry.

One obvious problem was looking west on 40 meters soon after my sunset. At that time the other station's band noise will be lower than mine. This is typical of the low bands. As soon as propagation is enhanced by the arrival of darkness the noise level rises along with the signals from the dark hemisphere.

Stations west of the terminator hear me fine while I struggle with the atmospheric QRN accompanying that of signals from the east and south. This is the same phenomenon responsible for the difficulty of working clearly heard Europeans before sunset on this side of the Atlantic Ocean.

In many cases I could not come up with a good explanation of why copy would be difficult. QRN would be low and QRM absent. Obviously I can't know what is going on at the other side of the QSO. Maybe they were driven there by a spot (or skimmer) or maybe they had already spent some time copying me before calling. All I can know for sure is that copying asymmetry was common.

Lessons 

Let's face it, for the upwardly mobile contester it is necessary to run a lot to improve scores. That guarantees you'll be struggling with many callers that are difficult to copy. Since you must do it there are things you can do to be best prepared to deal with it to your (and their) benefit. Scores will improve and frustration levels will decline as abandonned QSOs are reduced in number.
  • Directive antennas: One sure way to improve copy on the low bands, and even on the higher bands, is with highly directive receive antennas. This can be as simple as a small loop, or can be a Beverage or phased vertical array. Transmit antennas are typically not highly directive on 80 and 160 meters so a more directive receive antenna is a good addition. The results can be surprisingly profitable. Since directive antennas are directive you'll need more than one, or at least an antenna with 2 or more selectable directions.
  • F/B: Antennas for all bands should have strong suppression off the back and sides, preferably with minor lobes that are no more than -15 db than the main lobe, and preferably much better. On the low bands phased vertical arrays are often the best at this, while on the high bands a Moxon rectangle or similar critically-coupled 2-element yagi, or optimized yagi with 3 or more elements.
  • Hunt down noise sources: Any noise source -- power line, Ethernet, USB, appliance, electric fence, etc. -- is a potential killer of QSOs, especially on an otherwise quiet band. Do everything you can to locate and silence noise. If you can you should place your antennas as far away from buildings and power lines as possible, or where productive directions for QSOs are over quiet zones.
  • Filters: Learn how to alter your filter settings quickly so that you waste little time asking for repeats. This include bandwidth, centre frequency, noise reduction, notch, and RIT. The last is important since you are less likely to hear a weak caller unless you tune above and below your frequency. You don't want to overlook them just because they failed to zero beat properly.
  • Partial call database: This one can be controversial. Many contest loggers will search for calls that are similar to the partial or full calls that you type in. This can help you to deduce that the caller is one of those, either a known contester or a call you've worked before in this or a previous contest. The technology exists and it's your choice whether to us it. Whatever you do, confirm the call with the caller. Never assume.
Effective running requires good listening habits and supporting technology.

Monday, April 17, 2017

Bracketed Tower (again)

I purchased a 29' (9 meter) light duty television tower 4 years ago soon after I returned to the hobby. After starting off using house eaves trough for an antenna I wanted something better since it seemed I wasn't going to wander away from amateur radio for another 20 years.

At first the tower was deployed as a guyed tower supporting a multi-band dipole and a 40 meter delta loop. When I replaced that with a stronger tower suitable for a rotatable yagi I bracketed the small tower to the house, installed a tall mast onto it and used that to support a fan dipole.

A small tower such as this is not part of my current more ambitious antenna farm planning. Even so the tower is up once again. Again it is bracketed to the house. Its intended use is LTE terrestrial wireless internet access. My current obsolete wireless service was a special order so that I could get connected quickly when I moved in last fall. The ISP wants to move me to the new, faster service and I am eager to oblige.

So while not a tower for amateur radio purposes I thought it might be of interest to any readers who want to press one of these inexpensive light duty towers into use to see how I did it. Bracketing a tower to a building, while convenient, must be properly done to avoid compromising the tower, personal safety and the structure of the building.

Base

This particular tower -- Golden Nugget -- is very common in Canada. Other countries have similar products on the market. This tower has three 10' sections (top section is 9' 6") made from 1" OD 18 gauge tubular steel pipes and horizontal cross members of formed sheet metal. The welds are a bronze-gold colour, hence the name. Load capacity is modest, perhaps 2 ft² when bracketed no more than 10' (3 meters) below the top.

A flat plate with flanges is designed for ground mounting the tower. The flanges bolt to the bottom section and holes in the plate are meant for driving stakes into the soil. I prefer a more engineered base so I fashioned one out of 4x4 preserved wood. I kept the one I had previously built.

I just had a garage built next to the house, which was my cue to begin the grading/drainage work between the buildings, including setting the new grade and then the base for this tower. Until now I wasn't quite sure at what level to set the base.

Choosing the location

Without considering other factors the ideal location for a bracketed tower is where the bracket can be placed at the maximum height. On a typical bungalow this would centred on one the side of the house with the bracket nestled near the roof ridge. There are more options on a two-story house since many points allow bracketing quite high.

Of course there are other factors. One is aesthetics and another is safety. My previous house allowed for several options with some being unsightly and others not allowing good placement of antennas (e.g. near the property edge). On my current dwelling there is really only one good place for the tower even though it is not the best for bracket height. All the higher options are in front of large windows or in the middle of a deck or balcony.

However my chosen location is not bad, allowing the bracket to be just under 16' (5 meters) above grade, which is more than halfway up. Since the only antenna will be a compact dish I do not have to worry about where HF wire antennas would go. This is good since the roof of the house is steel, which is less than ideal for HF purposes.

Selecting the anchor points

To be effective the brackets must tie into the frame of the house. On a typical North American wood frame house this is usually not a problem, if one is careful. Unfortunately from the outside it is not always clear where the studs, headers and trusses are located.


Being a country house with a deliberately rustic design the exterior is clad with batten board and striping. There are no indications on close inspection of where the frame members are located. However I do know that the frame is sheathed with chip board, on top of which are wood straps to which the cladding is nailed. None of those is acceptable for a tower bracket since they offer little resistance to tension.

The fascia is no better. Typical attachment of wood fascia is nailing into the ends of rafters or, in this case, short studs that bridge the distance from the outermost truss to provide an overhang. Again, those nails offer little tensile strength. Worse, the fascia and soffit block access to the top of the truss, which would be a good anchor for the bracket.

Peeking through the screened attic vent told me little. Other than a lumber frame around the vent (not a good choice for bracketing!) I could see little. The house blueprints only provided generalities not specifics of how the wall was constructed. Density meters for locating studs, pipes and wires are inadequate to locate framing from the exterior.

When my previous house was built I took lots of pictures (film, remember that?) of the house framing before the insulation and drywall were installed so I knew where everything was located. I only needed to take some measurements, compare to the pictures and I could find suitable anchor points to within an inch. But for this house I needed to see inside.


Before purchasing the house neither I nor the inspector I hired could find an access to the attic over the bedroom wing; the rest of the house is post and beam with a cathedral ceiling so there is no attic except here. I puzzled this one through, periodically looking up as a walked around the house. That's when I spotted someone odd about the overhang in front of the house. I had one of those "aha!" moments.

Minutes later with a ladder and a few tools I was in. I took pictures of what I could see of the wall I'd selected. Coincidentally we are looking directly across the roof of the shack. I did not enter the attic since quite a lot of care is needed to cross the rafters in a modern house with engineered trusses and heavy insulation that buries all the structural bits. I've done it when necessary, and I can assure you it isn't much fun. It is very easy to damage the ceiling, and yourself.

However all I needed was the picture. All that needed to do the rest is one measurement from the outside to calibrate the scale of the picture. For me that was the width of the vent frame: 24". From that I could determine the location and size of all the dimension lumber and how it all ties together.

I chose the 2x6 header over the vent frame for the bracket anchor. It provides a wide solid support for long lag bolts and it is suitable tied into the end truss. The sheathing, though weak on its own, adds to the lumber connections so that tower loads are distributed over the framing. For a larger tower with an HF yagi I would not recommend this choice. For my internet dish or for wire HF antennas or a small VHF yagi this anchor is perfect.

If you are going to go big with a bracketed tower I suggest you either hire an engineer or find a more secure anchor in the frame. On my previous house I was able to anchor into two layers of 2x6 header sandwiched between the rafter of the trusses and the exterior 2x6 support walls. That will take substantially more load than what I have selected here.

Installing the brackets

I kept all the hardware used to bracket the tower to my previous house. Some is custom and some is specifically made for bracketing a small tower. In the picture below is pretty much all that I needed, other than the hardware store perforated angle steel I use to make the bracket arms and the U-bolts to attach the arms to the tower legs.


The L-brackets are attached with lag bolts to the house (upper flange) and with grade 5 bolts to the arms (lower flange). I picked the two in the best condition. These L-brackets are sufficient high grade to resist bending under load or under bolt torque. I chose to use 5/16" lag bolts rather than anything larger since the tower load is small. The shorter bolts secure the base plate to my homemade preserved wood base.

With a little geometry I calculated the required distance between the L-brackets to that when positioned the tower faces would align with them. As it turns out I made an error during measurement and they were 1" off. Thus one of the bracket arms wasn't flat against the tower face. This is not a serious problem so I didn't bother moving the L-brackets, and avoided repairing unwanted holes in the siding.

Raising the tower

Several hours during a warm spring day was all it took to attach all the hardware and raise the tower. It helps to have a friend although I did this job on my own.

The L-brackets went into the header just as planned. In one case when drilling the bolt holes there was the expected gap between exterior board and sheathing, while in the other I got lucky and hit the wood strapping between those layers. In the latter case this permitted me to torque the lag bolts without undue concern. The other required me to not tighten the bolts too much since that would only bend and possibly break the exterior cladding board.

It is important that the holes through the intermediate layers permit the lag bolts to slip through; the threads should not bite into the siding or sheathing. Collars are available for lag bolts to allow the bolt to take full torque without bending the cladding. This requires carefully drilling a hole for the collar or it will sit too deep or too high and not do the intended job. I didn't bother with collars, even though I have them in my stock of parts.

The full length hole is smaller so that the lag bolt threads engage the frame lumber. Although you skip this hole, drilling a hole reduces the chance of splitting the wood and thus compromising the strength of the bracket. For my 5/16" lag bolts I used a 3/16" drill bit.


With the L-brackets installed I sat the bottom tower section on the wood platform and weighed it down with stones (I have plenty on my property!). From the ladder I lifted the next section and dropped it in place. Bungie cords, one per L-bracket temporarily hold the 20' of tower upright.

The small sledgehammer and scrap wood you can see were needed to press the section into place since the legs were slightly ovalized. They are easily deformed when tightening the splice bolts. Separating sections can be difficult if the installer was over-enthusiastic with the wrench.

The next step was to attach the bracket arms to the L-bracket and tower legs. If you don't have the manufacturer's bracket arms you can fashion your own, as I did, from galvanized or painted steel of suitable strength. If this makes you uncomfortable I strongly recommend you only use the purpose-designed brackets from the tower manufacturer. The previous owner of this tower fabricated his own bracket arms. Although they were very poor strength the tower survived for years. I rejected them.

With the brackets holding the tower the bungies were removed and the tower made vertical with a long level. Only then is the base plate bolted to the wood base.

To lift the top section I opted to reassemble my old light duty gin pole that I had built for raising DMX tower sections. The brackets I made fit the Golden Nugget reasonably well but require securing the gin pole to the tower since with horizontal cross member the gin pole can easily slide.

Although the tower sections are light I strongly recommend a gin pole since it is harder than you might guess to lift a 10' section above you, holding it perfectly vertical, aligning all 3 legs at the same time and pushing it down into place. I know some rare individuals with the physical gifts to do it, however I am not one of them and it is  almost certain that neither are you.

The mast is easy enough to raise and slip into place without a gin pole, if you are careful to keep it nicely vertical during the procedure. Surprisingly little deviation is enough for gravity to twist it out of your grip and cause injury to you and your house. Don't hesitate to ask for help if you need it.

All done

As the sun set the tower was complete and the tools and materials put away. Now I have only to inform my friendly neighbourhood ISP to visit at their convenience to install their equipment and upgrade my wireless internet service.

Monday, April 10, 2017

Swimming Hole

We've had a lot of rain over the last week. So much that roads are flooded and some homes are threatened throughout eastern Ontario. Couple that with spring temperatures and runoff due to incompletely thawed ground and you get something like this:


Sad, isn't it? However it is not as bad as it looks. Soon enough the water level will drop and the rest will be pumped out. Then the debris in the hole will be removed. The concrete work on two holes was completed in the fall which leaves two swimming holes (this one and one more) yet to be converted into tower foundations.

Soon enough that anchor you see will hold 2,000 kg of tension, its share of holding up a big beautiful tower. For now I thought some readers might enjoy this view of my impromptu swimming hole. The full story of planting this tower will come when I've got it done. With a little bit of luck that should happen by early May.


Friday, April 7, 2017

Listening

Many years ago I bought and absorbed The Complete DX'er by W9KNI. If there one overriding lesson from that book was the importance of listening. Of course there was no global DX spotting network -- just pockets of friends who would let each other know when a rare one appeared on the band -- making listening, and lots of it, an absolute must for the DX enthusiast.

Although I had been around long enough by then to not learn much from the book it put what I was already doing into perspective , therefore enabling me to better understand the strategy of good listening. When I returned to air a few years ago after a long hiatus from ham radio I soon learned that too much listening could actually be detrimental. While I listened someone else spotted the rare one and those receiving alerts from the spotting networks got there first.

Since I was QRP at the time showing up late was often no better than not showing up at all. I updated and honed my pile up skills to overcome this handicap, and I seemed to do pretty well at it. However the value of listening is still there, if you understand how the game is now played. Listening is a way to catch the DX before the horde arrived, especially the majority who would only stir when there was a spot. The majority have, in effect, delegated the listening to others, including the skimmers.

The why of listening

There is of course the operating awards benefit of listening, that of getting there first and not having to contend with the pile ups. Modern pile ups are like the phenomenon of flash mobs, growing from nothing to a large crowd in a minute -- spotting networks are a kind of social media. Years ago it took time for the pile up to build since there was no instant communications to one and all about where the DX was located, or that a rare one was active.

That is not the only reason to listen. Listening is in itself a pleasure. When I was very young and first discovered the magic of short wave radio I liked to listen to signals coming in from all over. But I didn't have a receiver. Instead I would "borrow" the family 5-tube AM radio from the kitchen. I had learned that by unscrewing the slug in the local oscillator coil I could lift the coverage to well above the end of the broadcast band at 1,600 kHz.

There I heard AM broadcasters, commercial operations such as ship to shore and the odd pulsations of RTTY as heard through an AM detector. I also came across the rhythmic thumping of CW and the unintelligible squawk of SSB. That was how I first discovered the existence of amateur radio and hams. A ham license was still several years in the future.

After my listening sessions I would screw the slug back down, making sure to calibrate the dial to a local broadcast station, and return it to the kitchen. My parents were very tolerant of my burgeoning hobby. That is, as long as there was no harm to what was to them an expensive appliance.

My listening habit carried over after I was licensed. Some of that was out of necessity since I did not have much of a station: an 807 to a dipole 3 meters high. I enjoyed it immensely nonetheless. In a way I found more pleasure in discovering DX on the bands than calling and, sometimes, working it. As time went on my DXing, and then contesting, became more intense so that my listening had an objective: I was hunting more than listening.

Why do it now

I am happy to say that I have rediscovered some of that early magic. At times I find myself tuning the bands for no other reason than to hear what is out there, having no inclination to transmit at all. With the new Beverage antenna I can listen in on far more distant DX on 80 and 160 meters than before. Without a decent transmit antenna I cannot work them, so listening to them is all I can do for now.

With the return of the equinox comes propagation over the pole from south and southeast Asia. I enjoy tuning the bands from 40 meters on up to catch the openings and hear what I can hear. Often the signals are very weak and not easily workable. Either I don't have enough power or they are hearing others far more strongly than from this part of the world.

Of course I do sometimes come across some moderately rare DX, and that's all to the good. Just this morning I tuned across V85TL calling CQ on 20 meter CW and getting no callers at all. No one had yet spotted him. I worked him without much difficulty. Then I listened as his subsequent CQs went unanswered. The band was busy, with stations all around, yet none seemed to be listening. After a couple of minutes I spotted him and that drew in callers.

Modern times

I think it's a shame that too many hams nowadays don't listen. This is not about getting there first or sharing the burden of hunting down the DX and spotting it for others. What I find unfortunate is that too many seem to have lost the simple pleasure of tuning the bands and listening, and perhaps finding the unexpected. Not for awards or points but for the thing itself.

Do newer hams feel the magic of radio? Perhaps not in the same way, and that's a shame. Some of my own generation seem to have lost the magical feeling that drew them to amateur radio in the beginning, yet others I know still have it. There are hams I know who in their single-minded pursuit of DXCC Honor Roll will only stir to turn on the rig when a new one appears on the bands. That leaves me cold -- to me amateur radio is much more than that.

This is not to be critical of anyone or to make myself out to be a curmudgeon. Radio still has magic to it and I regret that some may have lost that feeling or perhaps have never had it. All I can do is shrug it off, feeling that they are overlooking something of value. I will keep listening.

Tuesday, April 4, 2017

Building and Tuning the Remodelled A50-6

Sporadic E season is rapidly approaching. We can expect the regular appearance of propagation on 6 meters beginning in early May. Unlike the previous two seasons I plan to be active with a far better antenna. Hence my remodelling of my ancient Cushcraft A50-6 to conform with the optimized design by W1JR in the more recent A50-6S.

With resumption of serious tower work still several weeks in future this is a good time to prepare antennas for the season. I can't even get to the Beverage termination to continue experimentation with it since the fields and bush are a boggy mess. Eventually the ground will thaw and dry, but that takes a while in this climate and our soil conditions.

For 6 meters antenna preparation is a relatively easy task since I have everything I need. Most of my other antennas require more extensive modelling, tooling and parts acquisition before construction can commence. So it was time to work on the A50-6 and get it ready to go.

The modelling went quickly, requiring no more than minor adjustments to my earlier work. The final design largely conforms to the A50-6S dimension. I lengthened the reflector, driven element and first 3 director by ~¾", and the fourth director a little more. Half element lengths:
  • Reflector: 59-¾"
  • Driven element: 54-¾"
  • Director 1: 54-¼"
  • Director 2: 53-¼"
  • Director 3: 52-¾"
  • Director 4: 49"
The first change moved the best gain performance to the bottom of the band where all my operating takes place. The second change boosts the gain ~0.3 db (by tightening the resonance range of the array) while having little effect on F/B and not degrading SWR below 51 MHz.

Element spacing is identical to the A50-6S. All dimensions were measured to within ⅛".

The original A50-6 design used equal spacing between elements. This can work well -- as shown by W2PV -- but not in this antenna! The W1JR optimized designed does much better although it does introduce mechanical considerations due to the clustering of elements at the rear of the yagi.

Boom

Before I could assemble the boom I had to straighten one tube that had a slight bend. This goes back to when I used the boom as a wire antenna mast a few years ago. The 1-½"tube with a more pronounced bend was repairable with the pipes I had on hand. A different technique was needed for the 1-⅝" tube. Looking around my large stock of material I found a 1" solid steel rod and a large tree that suited the task.

With straight edges and careful rotation of the tube in my workshop I precisely located the peak of the bend and the section of the tube that was curved. The peak was not at the centre of that section. I marked these points on the tube and went outside to visit the tree I'd selected.

The peak point was centred within the V where the trunk branched, conveniently at shoulder height. The steel rod was measured and inserted so the end was similarly centered. A small length of pipe collared the pipe where it exited the tube in order to minimize the risk of kinking the tube.

With everything in position I proceeded to push the rod until the tube yielded. It worked quite well. I then repeated the procedure with the bend point to one side then the other of the peak to smooth out as much of the bent area as I could. Although the result wasn't perfect you can only tell by sighting along the full length of the assembled boom.

A further problem with the boom is that the centre of gravity is off-centre. The A50-6S compensates for this by using a longer length of 1-⅝" tube on the long side of the boom. The A50-6 tapers to 1-½" for the last few feet. At some point I may want to replace the boom with heavier wall tubing to increase its wind and ice survivability.

Pointing straight up

As many hams know and as I described in a previous article a convenient technique for tuning yagis is to point them straight up. The reflector can be quite close to the ground, even 0.25λ can work well. The reason is that cancellation of radiation to the rear of the antenna reduced ground interaction. Keep in mind that all we're doing is tuning for best match -- not gain -- and that F/B has to be moderately good over the desired bandwidth.

I used EZNEC to model the antenna in this position to see the effect of ground and to determine how low I could safely go. I settled on 5' (1.5 meters, or 0.25λ) for reasons of available props, modelled performance, safe handling and accessibility of the driven element. The prop is a length of schedule 40 water pipe with a 1.6" I.D. which fits reasonably snugly over the 1-½" boom (plastic end cap removed).

I didn't use the Trylon tower as the support since the tower is very wide and could interact with the antenna more than I'd like. Instead I used a log frame in my backyard. I did my best to orient the yagi so that its elements were nearly orthogonal to the 80 meter inverted vee overhead and off to one side. It seemed to work fine even though I ought to have temporarily moved the inverted vee.

Notice how the coax is routed along the boom and straight down so that it doesn't interact with the elements. A temporarily common mode choke consisting of two cylindrical ferrites reduces the effect of RF conducted onto the coax outer surface.

Tuning it up

The antenna uses a gamma match for transforming the low impedance of the antenna to 50 Ω. In EZNEC I used an L-network since it is easiest to adjust in the model. These and similar networks have almost identical matched SWR curves so they can be considered equivalent. The EZNEC model optimized SWR curve for 50 to 51 MHz is quite good. I initially setup the gamma match per the A50-6S manual. That turned out to be a good starting point despite my design changes.



The objective is to see how well I can adjust the gamma match to get the same result. This assumes the SDC (stepped diamter correction) is done properly so that the real antenna and the model have the same resonance, and therefore the same performance metrics of gain and F/B. Since I've done this before and had good results I am confident that I've got a close match to the modelled performance.

It took about 30 minutes of fiddling with the gamma match until I got what I wanted. Each adjustment required moving a step ladder into place, making the adjustment (usually in ¼" increments) then moving the ladder away.

Look at the measured SWR curve and see what you think. Perfection isn't necessary since the environment for tuning is different form that atop the tower and stacked above an HF yagi. Further tweaking can be done then, though not easily since the driven element is far from the mast.

Performance note

Tuning an antenna for a match is at best an indirect indication of good performance; at worst it is totally misleading. Optimum gain and F/B per the model can quite easily be frequency shifted in the tuned yagi.

It is the shape of the SWR curve that is of more interest since it indicates that the rate of impedance change conforms well to the model. As an example, yagis typically show a sharp decline in radiation resistance near maximum gain. The rapid impedance change will appear in the SWR curve since the matching network cannot deal with these sharp swings and the SWR will soar. Too flat a curve is similarly an indication that something is amiss.

That the measured SWR curve is so close to the model gives me some comfort that the antenna performance will be as modelled is however no guarantee. That requires field strength testing.

Packing up

Declaring success I tightened all the adjustment fasteners and took down the antenna. It has been placed out of the way and off the ground until I am ready to install it on the Trylon tower. I have high expectations for this year's sporadic E season.

Sunday, April 2, 2017

Increase Your S & P Rate

Conditions for the SP DX contest this weekend were poor from my location. Despite the solar flux climbing above 90 there was nothing to heard above 20 meters and on 20 meters signals out of eastern Europe were weak and often had an auroral flutter. The combination of a disturbed geomagnetic field and a series of flares was unfriendly to propagation at higher latitudes.

While I struggled to make myself heard in the opening minutes of the contest I did hear evidence of extraordinary rates from several contesters in the US. Only 15 minutes into the contest some had serial numbers above 40 and 50, apparently S & P since they were calling SP stations. It was amusing to see these callers asked to repeat their numbers, which were unexpected so early in the contest.

Is this for real? I don't see why not. Skilled operators can have a very high S & P rate by in select times and places. I've done it myself back when I was QRP and surely not the biggest gun on the bands! I have achieved rates as high as 4 per minute on SSB and 3 per minute on CW, sustained for 5 or more minutes. It's intense and hard work, and in my case done without assistance from skimmer and DX spotting networks.

Let's look at how it's done. It requires skills that can be learned, if you are willing.

Speed and the big gun

You don't have to be a big gun to achieve a high S & P rate, but it helps! Ideally you want to get through on the first call while sending your call once and fast. Big antennas and power help with that. Fast contacts ensure that you are soon hustling to find the next station to call.

Less time spent in a QSO is a key ingredient to achieving a high rate. But don't sacrifice accuracy.

Don't dawdle

Even if you're not a big gun you should strive to be quick. On CW don't go slow! Send at the other guy's speed even if you have difficulty copying that fast. Assume they can copy as fast as they send because it's almost always true. Presumably you already copied his call so you're already mostly there and you need not feel intimidated.

On SSB it helps to use voice memories. There is a risk of talking too fast and poor enunciation when you're in pursuit of a high rate. Send a recording that has been thoroughly vetted for intelligibility and rapidity to avoid the need to repeat your call. Use phonetics and don't use unconventional phonetics.

At the end of the QSO don't stick around. As soon as I hear the "TU" being sent I am spinning the dial or clicking on a spot. Seconds count so don't waste any. Even when I tune in the next station I will not stick around if they are struggling with a QSO since that, too, wastes my time. Self spot it and move on. You can come back later.

Skimmer

With assistance you can save time between completing one QSO and pouncing on another station. Skimmers are best for this since many stations are not manually spotted if most people consider them to be uninteresting: for example, not rare and not a desirable multiplier. Skimmers aren't subjective so they'll tell you about everyone you have yet to work.

Clean slate: call first, copy later

At the start of the contest and every new band thereafter you have a clean slate; that is, every station you hear is workable. This is an opportunity to pump up your rate since you do not need to know the other station's call sign before you call: it cannot possibly be a dupe! (Well, except for the minority of contests where you can't work a station once per band.)

As soon as you hear the tail end of a CQ or QSO just jump right in and call. You can fill in the call after they work you, when they will typically close with "TU QQ9XYZ". This is a great way to increase your S & P rate, perhaps doubling it. There is no rule that says you must copy the call sign before you call them.

Occasionally the station won't sign afterwards but that is insufficient reason to defer calling before you get the call sign. Stuff the frequency in a VFO and move on to get it a minute or two later if you must. This is low risk, high reward operating. Go ahead and live on the edge! If you still fail at getting the call (they might even QSY) you can wipe them from the log. In my opinion they are at fault for not frequently signing.

Aggressiveness

By now you must have realized that these techniques can be considered aggressive, even very aggressive. However, this is about being aggressive in pursuing QSOs for a bigger score, not belligerence against other contest participants.

Push yourself out of your comfort zone and try it sometime. Watch the clock and count the seconds between QSOs. Meeting and overcoming challenges can be rewarding. The tension you feel comes from pushing hard. That's a good sign. Soon enough you can relax and return to normal operating.

Why do it at all?

Other than very short contests it can be argued that all this S & P hard work is unnecessary since rates eventually slow for everyone and you have the leisure to work stations later on if you haven't worked them earlier. You cannot count on this. Working them sooner rather than later can make the difference between working them and not working them at all.

In a contest where you must S & P you should therefore strive to do so at speed and as early in the contest as you can. Here are a few reasons why:
  • They might not be on later. Most contesters operate far less than the maximum allowable time.
  • Propagation can quickly deteriorate. If you haven't worked them yet you might be able to work them later.
  • Getting the relatively easy ones out of the way sooner gives you time to hunt down and work more multipliers or focus on marginal bands (e.g. 10 and 160) where you need to spend more time to make each QSO.
Being fast at S & P can be far more draining of your energy than fast running. To get consistently good results you need to be good at both. Unfortunately it is difficult to maintain that speed and you might only know if the effort is worthwhile when the contest results are published. But who ever said that winning would be easy?

Give it a try

I sometimes imagine how useful it would be to have a training tool like Morse Runner for S & P rather than just for running. Fast, accurate S & P is necessary for building up your contest scores, even if you are a big gun. It can also be a lot of fun.

Monday, March 27, 2017

Struggling with CQ WPX SSB

CQ WPX contest is not a favourite of mine, especially the SSB weekend. The CW weekend, although more preferable to me, comes at the end of May when I'd rather be outdoors than indoors. Apart from the reasons I expressed in that earlier article here is one more thing I don't like about the contest.

Since prefixes count once and not once per band there is little incentive to pursue contacts on bands with marginal conditions. A quick review of top claimed scores on 3830 reveals little activity on 10 and 160 meters. There was nearly as little activity on 15 meters despite the presence of modest openings, including from here to southern Europe (EA, CT, I), and some good openings to South America. I heard many down south calling CQ on 15 with few takers.

Making it worse was a low solar flux that further concentrated activity onto 20 and 40 meters. The resulting heavy QRM limited the chances (and enjoyment) of little guns.

I put in a part time effort this past weekend if only for practice, to casually experiment with the station and operating technique and to ensure that recent repairs held up (they did). Not being serious in a contest is a good way to try things without worrying about the impact on your score.

Voice memories

I have used voice memories in SSB contest in the past. The KX3 has room for two messages in its on-board DVK (digital voice keyer). Because I was QRP the memory I programmed with a CQ was not very useful. The one I used most often was for my call sign. I sent that one a lot! The DVK was fairly easy to program by pressing lots of buttons and speaking into the mic connected to the rig. Levels and equalization were automatically the same for live voice and memories.

Editting of messages wasn't possible, making it vital to time button presses and recording to avoid silence before and after the message content. Macros programmed into the contest software (N1MM+ in my case) are used to simulate button presses on the rig to play the messages. This is a bit arcane but doable. I saved the function key file in case I decide to use the KX3 in a future SSB contest.

The FTdx5000 has an on-board DVK. Unfortunately it is, to be blunt, a joke. Too often manufacturers load up modern rigs with features that are unwanted and in any case are not designed for use in their intended applications. Again, there is no editting of messages. I can live with that. What annoyed me was playback.

The FH-2 accessory keypad could be quite handy to use the DVK. Recording isn't too cumbersome, once you get used to the sequence of buttons to be pressed. As with the KX3 and many other rig-based DVKs silence at start and end of the messages cannot be editted and so good timing during recording is mandatory.

Playback requires two button pushes and then activating the transmitter if you aren't using VOX since the rig will not automatically key the transmitter when a message is played. This is absurd and useless. What were Yaesu thinking? Indeed, were they thinking at all or just didn't care?

I therefore resolved to record messages on the computer and have N1MM play the Wave files (.wav) just as for CW memories using function keys. PTT is done with the WinKeyer interface, which offers perfect timing. This attempt was perhaps foolhardy since I haven't done software voice memories before and I undertook the task 3 hours before the start of the contest and only spent an hour at it. The experience was interesting.

In my first attempt I used N1MM's rapid programming technique of connecting the mic to the computer and pressing CTRL+Shift+Fn to record a message direct to a function key associated Wave file. It is similar in concept to direct programming of a rig DVK, with the same challenges. The played back files were noisy and the voice level was low. It seems that more work with sound card settings is necessary to make this feature perform properly.

I next chose to use Audacity, a popular free software application for recording and editting sound files. It is used by many contesters. I downloaded and installed the software and was soon happily recording and editting message files and exporting them to Wave files for playback by N1MM. Oh, if only it were that easy!

Playback requires connecting the output of the computer sound card to the rig. Unfortunately I am using a laptop where the mic and headphones jacks (sound card ports) are at the front where my hands rest. Although I have the integrated CAT/audio/data interface SCU-17 it is not yet installed on the FTdx5000.

The rig connection is as simple as a 3.5 mm Y-connector to join the mic and sound card into the mic jack. Not only did I not have a Y-connector in my junk box (I plan to order a few) I hesitated since I didn't know if the sound card output was AC or DC coupled. This matters since I wired the mic jack for my new headset with an electret microphone and it would put DC onto the sound card if there is no blocking capacitor in there.

Instead I routed the sound card output to the rear panel mic jack on the FTdx5000 which, according to the manual, is mixed with the mic jack on the front panel. Luckily I had a 3.5 mm stereo to phone mono cable in my junk box; Yaesu should have used a 3.5 mm jack on the rear panel.

That worked, sort of. The playback level was different from the mic and the audio didn't sound as if it used the same equalization setting I programmed into the FTdx5000 for the flat response mic. There wasn't time to trace the schematic and there was nothing I could do about it anyway just then. Instead I editted the sound files to add equalization and adjust the levels. Not being able to satisfactorily adjust these in time for the start of the contest I went with what I had.

When I set the mic level to best suit live voice the memories often clipped. During the contest a couple of hams helpfully informed me, thinking I had RF getting into the mic. I had to explain, briefly, what was really going on. Occasionally I gave up on the memories altogether to avoid the issue.

The experiment was instructive and pointed me towards what I need to do to get it right for the next time I enter an SSB contest.

Crowds = QRM

By concentrating most activity onto 20 and 40 meters the QRM was dreadful. SSB makes the problem far worse because of the bandwidth consumed. Unlike in CW you need at least 2 kHz separation to keep QRM managable even with the receive bandwidth dialled down to 1.5 kHz. Activity was so dense the separation was often only 500 to 1,000 Hz between stations.

There is thus little room for the little guns to run or to hear those lesser signals. The big guns were in reality not much better off since they had great difficult copying anything other than the strongest signals. The request for repeats of call signs and exchanges was routine, and rates suffered as a result.

It became comical at times. Here is a fictionalized QSO between me and a big gun. It is typical of some of my QSOs and many I listened to while waiting for my turn to call.
Him: "CQ contest QQ9XYZ"
Me: "Victor Echo 3 Victor Norway"
Him: "Victor Echo?"
Me: "Victor Echo 3 Victor Norway. Victor Echo 3 Victor November"
Him: "Victor Echo 3 what?"
Me: (repeat as above a couple more times)
Him: "VE3VN 59 1 2 3 4"
Me: "QSL. 59 3 2 4"
Him: "Your number?"
Me: "3...2...4..three hundred twenty-four"
Him: "381?"
Me: No! 3 2 4...3 2 4"
Him: "224?"
Me: No! 3 2 4...1-2-3 1-2 1-2-3-4"
Him: "Is it 3 2 4, roger?"
Me: "Roger roger roger!"
Him: "QSL. QQ9XYZ"
That final and successful method of communicating a serial number is sometimes known as horse counting. It is how purportedly intelligent horses answer math questions. For example:
Human: "What's 7 minus 3?"
Horse (stomping the ground with one hoof): clomp-clomp-clomp-clomp.
Very amusing the first time but increasingly aggravating when frequently resorted to in a contest to combat the ever present QRM.

One final note on QRM is that of F/B (or F/R and F/S). This is something I have sometimes lightly mocked since I am more often pursuing gain rather than directivity in my antenna designs. Yet this is a prime example of a contest when good directivity is useful to combat overwhelming QRM.

Often in contests there is some advantage in having only modest F/B so that stations in other directions can be worked without resorting to multiple antennas and frequently trying different directions, especially when running. It is occasionally useful in DX pile-ups as well so that the successful station can be quickly located.

In an SSB contest like this one with such intense QRM more directivity can be very helpful. My yagis -- short tri-bander and 2-element on 40 meters -- do not have great directivity. I will have better by this autumn. On 80 and 160 meters directivity can be less important in a high-efficiency transmit antenna if the antenna is supplemented with a high directivity receive antenna such a Beverage or 8-circle array. I used my Europe-facing Beverage even on the high bands in tough situations since it often helped just enough to make a difference, whether or not the station was in that direction.

Tragedy of the commons

Despite being called the dismal science, economics does contain many interesting concepts. One of these is useful for understanding CQ WPX and other contests: tragedy of the commons. In brief it explains how over-exploitation of a resource can occur by individual choices based on self interest. There is no need for a conspiracy to explain the phenomenon.

By over-exploitation in CQ WPX I primarily point to the unreasonable abundance of prefixes. As a result there is little reason to pursue prefix multipliers during the contest since you'll work new prefixes at a high rate by simply making QSOs. No one is special; when everyone is a multiplier then all QSOs are equivalent. Multiplier hunting becomes superfluous.

The implications on the contest are profound. The object becomes to work as many QSOs as possible, with only a preference for intercontinental and low bands for the higher QSO points. The bulk of the action is therefore between Europe and North America. Intra-continental QSOs are supplements to prefixes and QSO points. The rest of the world is largely excluded when yagis don't point their way. I heard many rare DX stations calling CQ without answers and even good signals from JA and VK had few takers.

Another example is power. To fight the incessant QRM inherent to an SSB contest during a solar minimum more stations are inclined to enter the high power class. That is, if you can't fight them, join them. When the majority do this the situation becomes the same as when everyone runs 100 watts: the QRM is the same and nobody really wins. It then comes down to who has the bigger antenna, a potential resource not so easily exploited by the majority.

One of the few reasons high power stations do so well relative to low power stations is that there are low power stations. Power can quite easily turn into another tragedy of the commons since amplifiers are easier to acquire and use than big towers and antennas. It can get uglier when ever more contesters choose to run illegal power.

Prospects

Get used to a high level of QRM for the next few years until the solar flux resumes its climb. Consider it one more aspect of the challenge of a contest like CQ WPX and take comfort in knowing that everyone is dealing with it as well, from little gun to big gun. Contesting is a competition so don't expect it to be easy. Use the QRM as motivation to build better antennas and improve operating tactics.

Although CQ WPX has its unique problems that drive my dislike of the contest this is one aspect of it that will apply to many contests for the next few years. With sunspots the QRM will once again relent as activity spills over onto 15 and 10 meters.

Tuesday, March 21, 2017

Perils of Expediency

As I wrote my series of articles on tower construction and antenna raising in the midst of a Canadian winter I downplayed the difficulties. Trust me, it is no fun at all standing atop a tower when the temperature is -5° C and the north wind is blowing while I am propping 20 kg of antenna on my shoulder and threading nuts on bolts to (hopefully) finally get a yagi securely attached. Of course I have to do this with gloves off.

I am thus reminded of just how driven hams can be in the pursuit of what is essentially just a hobby that we would undertake these challenges. It is little wonder that those around us sometimes think we're just a little bit crazy.

Considering the conditions it should be no surprise that I took shortcuts. I deliberately did sub par work to minimize exposure to the winter weather and the associated hazards. Although I am not proud of that I did what I felt needed to be done to get me on the air this winter. Expediency has its price, a price that I am now paying. My hope that all would survive until spring did not come true.

Here is my list of things that went wrong. Some have been briefly mentioned in preceding articles.
  • What I had at first thought was an inexplicable interaction between the XM240 40 meter yagi with the 80 meter inverted vee turned out instead to be an intermittent connection in the coax rotation loop. I had tested the coax on the ground and I taped the coax such that there were no connectors within the loop. It needs to be fixed to keep the yagi working at all times.
  • The rotator wiring has suffered two failures, both caused by reusing the only cable I had on hand that had connectors on it was long enough. The cable has several splices, the wire ends are frayed and the connectors are difficult to waterproof. One of the splices sagged onto the ground just before a heavy snowfall and subsequent thaw. This caused a few days of unreliable direction indication. I dried and cleaned the splice and made sure it was properly supported above ground. Then the rotator failed entirely due to a broken connection. Jiggling the cable and re-securing the connector at the rotator was only a temporary solution. Now I have to remove the rotator from underneath the mast to do a proper repair.
  • The mast and tower are overloaded for my wind zone. I did this to have yagis on 40 through 10 meters through the winter. For the second time the mast has slipped in the rotator clamp in high winds.
  • The galvanized muffler clamps securing the XM240 to the mast are not up to the task. These fasteners are not designed to withstand axial loads. The formed sheet metal saddles can bend under axial load. The saddles ought to be solid and have a large gripping surface. I already knew this when I chose what was locally available: inexpensive and easily acquired under a tight schedule (expediency).
  • The Trylon is almost but not quite vertical. Fighting with the gin pole and splice bolts has in a few resulted in a couple of instances of an improperly seated section. Although not a serious problem and only noticed when looked at closely -- it's about 1° out of true from about 25' above ground -- it irritates me.
  • Running cables on the ground risks damage with the amount of house renovation and construction that has continued through the winter and now into early spring. There has been one instance when a contractor spread out a bunch of tarps to dry over the cables, which means they walked over them, not noticing them due to the light snow cover. Luckily there was no damage.
  • The wire of the Beverage antenna sags in a few places low enough to reach up and touch. There is risk of wildlife damage, especially bucks being chased by coyotes (yes, this sort of thing really happens on my property). Since the antenna looks like a keeper I'll have to redo the support system to keep it high enough to prevent injury and damage.
Despite this litany of woes the station has performed very well over the past few months.

Repairs

The immediate problems that needed fixing were the coax to the XM240 and the rotator wiring. All the other problems can wait for spring.

It took a couple of trips up the tower once the weather cooperated. The first climb was to assess the problems better than I could from the ground and to haul up the things I'd need to complete the job. These items included a power cord for soldering, clamps to support the mast and antennas when the rotator was temporary removed and cords from yagi to tower to limit mast rotation during the repair period.

I slightly loosened the bolts securing the mast to the rotator and the rotator to the tower plate. This was done to ensure there would be no delays when the work was to be done. A new method of raising the mast and antennas (200 lb) was experimented with and discarded. Better to get that dealt with beforehand rather than wasting time later.

Before descending I fiddled with the rotator wiring and connector, purely out of curiosity to see if it would work again (it did). Locating the source of XM240 misbehaviour was quickly determined to be an ancient nickel-plated PL259 UHF connector on the 40 meter run of RG213.

The braid had broken off the solder to the connector body. I had mistakenly secured the coax to the tower below that connector instead of above. The connection experienced rotation stress, especially severe in cold weather when the coax is stiff. Never place a connector within a rotation loop. This is the price of sloppy work when the north wind is howling.

The next day a ham friend arrived to serve as ground crew. The forecast was promising to effect repairs, including soldering a new connector onto the main run of rotator cable. Unfortunately the weather stayed cool and turned windy making soldering too difficult; I had a small soldering torch, but that can't be used on a multi-pin connector since it'll melt the plastic body. Nevertheless I did get much of the work done.

I used a car scissors jack under the XM240 boom-to-mast clamp plate to raise the mast about 1 cm, which is enough to allow the rotator to be removed. Clamps at both bearings served as insurance in case the jack slipped. Of the many methods to lift 200 lb of mast and antennas off a rotator using a car jack is simple and fast but has the serious disadvantages of being unstable in a wind and placing undue stress on the antenna clamp. It was desirable in this instance since it was fast and easy.

With the rotator sideways on the tower plate I scraped off the old silicone sealant and then removed and discarded the wiring harness. The new one I had prepared was quickly attached and the rotator reinstalled. I then removed the jack but left the mast clamps in place in case the wiring was faulty and the job needed to be redone. Before retiring for the day I secured the XM240 coax from motion during rotation, thus protecting the broken connector.

I planned to return to the job later when the weather improved. Not only did it not improve the forecast was for moderately high winds. The next day I cut down the full length of rotator cable, brought the end indoors and soldered on the new connector there. Then back up the tower to reinstall the cable. In the end it was easier and faster this way. I then removed the mast clamps so that the full weight of the antenna systems rested on the Tailtwister once again. I left them on the mast, just in case!

Since the XM240 worked fine as is I decided to abandon repair of the coax connector for another time. The wind speed was rapidly climbing and it was time to finish up and descend. Fortunately the new wire harness and connectors worked placing the rotator back in service. If nothing else I am now prepared for CQ WPX SSB this weekend should I decide to enter: it is not a favourite contest of mine.

Spring follow-up

Since my weather associated fiasco in attempting to plant the 150' tower last fall my 2017 plans have been adjusted in accord with that event. We are now waiting for the ground to thaw and dry out enough to allow the foundation work to be completed. I predict that will happen in early to mid May. With luck the tower should be up by the end of June. I'll write up the full woe-filled story once the foundation for the tower is complete.

Until then I have the one tower for my antennas. I will need to make some compromises on operating since I need to raise the refurbished 6 meter yagi for sporadic E season starting in May. I will likely have to take down the XM240 for that and put it aside at least until the new tower is up. So I will likely have reduced capability for CQ WPX CW at the end of May. Perhaps I'll temporarily put up one of my old 40 meter inverted vees.

I can then leave the Explorer 14 where it is for a while longer, stacked on the mast with the A50-6. July will be when the major antenna work can begin.

Final

Expediency comes at a price and I paid for it this winter. I'd do it again. The success I've had in contests and DX chasing for the past 12 weeks was well worth it to me.

Should you ever do anything similar be honest with yourself. Put the risks up front, assess them and prepare accordingly. Do not fool yourself. That is a sure path to disaster. Avoid expedient choices except in a pinch. Even then don't do it unless you are comfortable with the risks.

Wednesday, March 15, 2017

I Hate Running

It is not possible to be competitive in a contest without running. You can of course have a lot of fun by cruising the bands and calling who you want, but you will never "win" that way. The greater your antenna farm and power the more of your contacts will (must) come from running. Top contesters are almost always running, using a second radio (SO2R) to concurrently S & P on other bands. Even for the QRPer or those with small stations running is an indispensible tool to run up the score.

The reason is simple enough: rate and reaching out. No matter how fast you S & P (search and pounce) the runner will consistently achieve a higher rate. At my best I can S & P up to 3 per minute on CW and 4 per minute on SSB. However that is unusual, fatiguing and unsustainable. As for reaching out, most participants, casual and semi-serious, focus so much on S & P that unless you call CQ you will never work them. So that is what you must do.

So why do so many contest participants avoid running? Some have convinced themselves that their stations or their skills are inadequate for running. That isn't true: anyone can run. I won CQ WW SSB in 2014 as QRP because I ran. True, calling CQ does not always work out. If the QSOs aren't happening switch bands or do S & P for a time. Just be sure to keep trying at intervals to get a run going. A slow run (1 to 2 QSOs per minute) can be exceedingly boring and seem unproductive yet be better than S & P. If you do not use the clusters and skimmers (assisted category) you will find it difficult to exceed an hourly rate of 30 or 40 QSOs/hour in the latter part of any major contest.

Queuing theory

I like to lean on my academic and practical mathematics experience to explain some of the challenges of running in a contest. There are aspects that are directly explainable by referring to queuing theory. In particular its stochastic nature wherein a fairly predictable hourly rate is not at all predictive of arrival rates of replies to QSO solicitations.

Let's say that your hourly rate is 180. Not only will you not typically log a QSO every 20 seconds, if you did it would be a sure sign to the log checkers that you're cheating! In reality the arrival rate of callers is stochastic: a equation with one or more random variables. In telecommunications we used the Erlang distribution to give the probabilities of intervals between events with a known or estimated long term rate.

What this means is that in that hour you can have a few minutes with no callers at all and at other times you may feel as if you were signing /P5. Even so you can predictably put around 180 QSOs in the log each of several consecutive hours (provided propagation and other factors are roughly equal, and you have not worked out the band). Each CQ or signing TU brings a surprise. You have to be prepared for anything, including typing the call in correctly when you have a caller sending at 32 wpm after two minutes of boring nothing.

Queuing theory is not so reliable these days to predict what you'll experience when you run. Rather than others coming across you as they scan the bands many of the callers are driven there by spots, whether human input or by skimmers. There is a correlation between spots and rate over the next few minutes, except late in the contest when you've worked nearly everyone. Unless of course your call is spotted incorrectly, in which case be prepared for a flurry of dupes! Yes, it really happens, so learn to deal with that as well.

Why I hate running

You don't have to enjoy running to get the benefit. This is as true of contesting as it is of the sport of the same name -- I do both, and hate both. It's about challenging yourself to reach the next level of performance. Even if you dislike the process you can appreciate and enjoy the results. So if contesting matters to you yet you avoid running you need to practice it and do it. There is no alternative if you want to improve your scores.

Everyone has their reason for avoiding running in a contest. My reason can be summed up in the following Youtube clip of a classic comedy skit by Lucille Ball:


Running during a contest is very much like that! Or if you prefer it is like sitting behind the cash register taking customer orders at a fast food restaurant or a cashier at a grocery store. Although you have some control over the situation your performance is measured by how fast and accurately you process customers, and smile while you're doing it. Running is akin to being in a front line service job.

Some love it and some hate it. I am somewhere in between. It's nice to be so well heard and wanted that stations step all over each other in a bid to get my attention. It is incumbent on the runner to process the callers fast enough that they leave satisfied and put points in your log and theirs. As the running station you have a responsibility to do it well.

Others love the attention so much they spend large sums of money to travel to exotic locales and create their own personal contest: the DXpedition. DXers such as myself appreciate that they do this and love doing it, even though I am ambivalent on whether I'd care to be on the DX end running pile ups for hours and days on end.

I feel the same way about those who build super-stations and run continuously throughout a contest. I am building a big station and I know very well that becoming good at running, and doing it lots, is what I will have to do. But I don't have to like it.

It is rare than any hobby or vocation that anyone chooses to pursue is 100% enjoyable. There are always tasks to be done that are not enjoyable. As with contesting it is the net enjoyment that counts. Therefore I can continue to enjoy contesting even though I must run. For others the task no enjoyed might be CW proficiency, SO2R, computer logging/interfacing, tower and antenna building, etc.

Because we enjoy the overall contest experience we accept the need to do the tasks that are not so enjoyable. The willingness to step up makes us better contesters.

Getting accustomed to running

If your antennas and power are good enough and the band is open you will find it easy to start a run. Just find a reasonably free frequency and call CQ. The trouble starts when stations answer. Here is the typical litany of things to watch out for:
  • Multiple callers
  • Multiple callers on the same frequency
  • Callers at the edge or outside your filter pass band
  • Weak callers
  • QRM
  • Hostile takeovers
  • Boredom
Running takes a lot of practice to do it well. Doing it well means putting QSOs in your log and theirs as quickly and as accurately as possible, and doing so without being evil. An example of the latter is not signing your call often. It is not my intent to explain or teach technique -- there are tools such as Morse Runner for that -- only to provide some guidance on what to expect before you dive in.

Multiple callers

First, about those multiple callers. Pick one and stick with it. If you only get a letter or two send that and, hopefully, only that station will respond. Of course in a contest time is valuable and many are not willing to wait. Just work them one at a time and don't worry about the others: they are not your problem. Should they become impatient and leave they'll soon be back; they want the points, too.

Picking out anything when the callers are zero beat is harder. Often you can latch onto a letter at the end of one call since they typically have different length call signs. Latch onto that when you can. Or send '?' and try again.

About pass bands

A surprisingly number of stations will be below or above your pass band. Try to keep the bandwidth as wide as possible if conditions allow. Otherwise make a point of using the RIT to check from off-frequency callers.

Reasons for the problem include: different pitch/offset preferences for CW; VFO overshoot as they tune you in; USB vs LSB CW receive; someone forgetting that their RIT is enabled; antique rigs, etc. Don't complain; deal with it.

Weak ones

Since you are now a big gun, or even just a medium gun, many of the callers will be weak. You must work them. There are some operators with big stations who refuse to work weak ones. You will never see them at the top of the contest results. I've heard a few so-called contesters telling weak callers to get lost or get an amplifier. They are the losers at that game since they lose the most points, not you. Ignore them, move on and never emulate them. Assuming, that is, you want to do well and not become a laughingstock.

The point is that you must get used to digging stations out of the noise, QRM or whatever receive challenges you might be facing. If you don't dig those marginal signals out for the noise you will lose points, and losing points loses contests. It can be hard work and it take practice. When you can't pull them through after a reasonable time thank them for calling and suggest they try again later. Then call CQ and resume your run.

Even when I ran QRP in the major contests I was surprised at how many weak stations called me during my occasional runs. Sometimes they were also QRP, driven to me by a skimmer spot or they simply had a lower noise floor than I had in my suburban neighbourhood.

QRM and keeping those elbows up

Finding a clear frequency in prime real estate (the lower end of the band) during a major contest is not easy. Nestle too close to a big gun and your CQ won't be heard and you'll have to move. Some runners don't even bother to check if the frequency is clear and will try to set up shop almost on top of you. Don't despair too quickly, but also don't stay with a no-win situation so long they you lose valuable time fighting for the frequency.

The big guns will always win when they persist at taking over 'your' frequency. That's rough play that you have to get used to. Just like in hockey the elbows always come up in the corners. Don't yell at the cat or bang your fist on the transceiver. It won't help. Move and restart your run, whether on the same band or another.

Fighting boredom

Finally, there is the matter of boredom to contend with. Late in the contest or in poor conditions the rate will slow down. Sometime it'll slow down dramatically. You must decide when to stick with the run when you only log a QSO less than once per minute. Depending on the particular situation this may still be better than changing frequency, changing band or switching to S & P.

As in baseball there is a whole lot of nothing happening most of the time. Then when something does happen you must react quickly or you'll miscopy the call or make some other time wasting mistake.

This may be a good time to learn how to do SO2R. Construct your antenna and rig switching accordingly, so you can search for QSOs during those times CQ elicits few responses. Get really good and you can interleave CQ on two bands at once.

At the very least you can feel you're doing something productive when the runs are not very productive. It's better than vaguely worrying that your run might be better done elsewhere or that you are missing an opening or a rare multiplier while you sit there waiting for something to happen.

I have never properly done SO2R. It is on my list for 2017, starting with antenna and rig switching. The setup is very similar to a multi-single operation. Then it's a matter of practice. Not only will the boredom of poor runs be eliminated it can add a lot of excitement when you try to CQ and work a needed multiplier at the same time!

Learn to love it?

As I said: I hate running. Not so much that I avoid it; it's a necessary skill for a contester, even a QRP contester. Years ago when my contest activity was more often as a member of a multi-op team I often volunteered for the graveyard shift when runs were very difficult to establish (this was during a solar minimum). That way I could spend my time S & P for new multipliers and digging weak ones out of the noise. While it might surprise some that was my idea of fun.

When dawn broke and the daytime crew arrived I would step away and watch them start the European runs on the now opening high bands. I felt little regret seeing them log more contact in 5 minutes than I did in any one hour overnight. I would of course do some running later in the day since it was unavoidable when operating as a big gun.

I suppose this is why I am more of a DXer in some respects than I am a contester. Besides, most of the time there is no contest, or one I care to enter, and I can dig away for the rare DXCC entities quite contentedly. Even so, as my new stations grows I will run more, and I will do SO2R. I have to do it and I intend to do it well.

It's results that I want and that drives me to do things I may not love. As our mothers used to tell us, "eat your vegetables, they're good for you."

Tuesday, March 7, 2017

Beverage Comparison: ARRL DX SSB

Due to circumstance I was unable to make a serious effort in this weekend's ARRL DX SSB contest. The major reason was (another) rotator wiring failure a day before the contest. It happened just as I was turning the yagis toward Europe right after working VP6EU on 40 meters Since this is not my favourite contest and the weather became bitterly cold I was unwilling to climb the tower and undertake the work. Instead I chose to tackle a slew of small chores I'd been putting off.

With the pressure off I decided to play on 80 meters Friday and Saturday nights to get a better understanding of how my new Beverage performs and to see who could hear my 150 watts to an inverted vee. I received an important education about not only my Beverage but also how well others hear. What I learned is important enough that it is worth another article, even coming so soon after the last one.

The method

It is no simple matter to compare the Beverage to alternatives. I have none. But other stations do, and it is them I must compare against. In this case it is easier to compare a receive antenna than a transmit antenna since we are both listening to the same stations.

It was quite easy to do. On 80 meters I would find a known big gun in the US northeast (reasonably close to my location) and sit on their frequency to listen for a while. If they listened split so did I with the second receiver in my FTdx5000. Conditions were poor so their rates were slow. I had to be somewhat patient, especially on Saturday evening when they had pretty well worked out the band.

When a weak European station called them I would pay close attention. The challenge was to copy the station better than the big gun. It is not unlike watching a quiz show on television where you try to outguess the contestants as they try to answer difficult questions. That can be quite a lot of fun, and so was this game I was playing.

What I found was that in most instances I could copy the really weak ones about as well as most of the big guns. Only rarely was I outgunned. In a surprising number of cases I could copy the DX better. This made me very happy since it means that my receive capability on 80 meters in that direction, but only in that direction, is comparable to the best contesters. Of course it is possible the operators were not as good as their antennas, however knowing who these folks are I highly doubt that!

On 160 meters my task was more difficult since activity was lower and rates worse. My sample of comparisons was far smaller than on 80 meters. I can only tentatively claim the same result on 160 meters.

What am I comparing against?

Perhaps the biggest unknown with my method of comparison is what antennas other stations are using for receiving on 80 and 160 meters. Even when I know they have separate receive arrays, whether those be pennants, flags, or more elaborate arrays such as Beverages and 8-circles, I don't know which they are using on any given contact. It may even be that they are sticking with transmit 4-squares on receive.

Since I can't know the answer to that question I have to assume that these operators, who are among the best around, would in each case choose the antenna best suited to getting the other guy into the log. In which case I am comparing against their best towards Europe. This is likely though not absolutely certain.

Off the main lobe

A directive antenna attenuates QRM and QRN, which is at least as important as its (relative) forward gain for copying weak signals. I had ample opportunity to test that as well during the contest. Of course I already knew perfectly well that the F/B, F/S, F/R or whatever metric you prefer had to be reasonably good or I would not have experienced such a favourable comparison. However that comparison alone is not the full story, nor should it be.

The test is to see how much signals and noise off the main lobe are attenuated. This can be precisely quantified by RDF and DMF figures used by W8JI and ON4UN, respectively. On the air a quantified measurement is not easy when the comparison signals weaken and strengthen in response to ionospheric changes, even if only Faraday location, and I don't know the precise direction of stations.

Instead I did a rough statistical assessment using as many signals as possible, thus reducing the impact of unknown factors in each comparison. DX stations were a little easier to assess since in many cases their bearings are known to within a few degrees. While I cannot easily measure the RDF or DMF of the Beverage there is the possibility of getting an approximate idea of what it might be by careful listening.

When there was QRM on frequency the benefit of the Beverage was greatly enhanced. Since in almost every instance the interfering station was in North America, and therefore far off the main lobe, the attenuation of QRM ranged from good to remarkable. The remarkable cases were most likely those that fit neatly into one of the nulls between the several minor lobes to the side and back of the antenna. For DX stations in South America, the Caribbean and Central America the results were the same, which is to be expected from my QTH.

The Beverage is a great QRM fighter. Calibrating the attenuation of signals required some quick work with the RX antenna switch and pre-amp (IPO) toggle switches on the FTdx5000. This is absolutelynecessary due to the unequal signal levels from the two antennas yet can never be perfectly accomplished. There is also the matter than my comparison antenna is an inverted vee which is horizontally polarized, while the Beverage is vertically polarized. Faraday rotation is a factor.

The worst case rejection of QRM was in the vicinity of -15 db and in the best cases was -30 db or better. Most times it fell somewhere between. I am very happy with the Beverage performance in this respect on 80 meters. On 160 meters it was more difficult to assess since the main lobe is broader and activity was less. Early indications are promising. I'll have to keep listening. I expect that a deep pile-up on a DX station will provide the best test conditions.

Higher bands

Beverages work on bands higher than 80 meters, and can work quite well. I tested mine on 40 meters and 20 meters during the contest with variable results. The main lobe becomes quite narrow on higher bands since it is long in terms of wavelength: 4λ on 40 meters and 8λ on 20 meters.

I couldn't see any benefit of the Beverage on 20 meters at all, even with the yagi fixed on north due to the faulty rotator, and therefore receiving Europe quite poorly. This may be because the 2.5 meter height of the Beverage is a substantial fraction of a wavelength. It would have to be lower to perform well since a Beverage works in part due to the lowered velocity factor caused by ground proximity.

On 40 meters it worked though with signal levels that were weaker than expected. Some European signals were received very well though not all benefitted from the Beverage. Performance was not consistent for some reason, perhaps the narrower main lobe. Once the yagis can again be turned I'll do another evaluation.

Proceeding with receive antennas

Before committing to building an array of Beverage antennas I would like to experiment with a couple of smaller receive antennas such as the K9AY or a type of flag or pennant. These are not difficult to build if there is no provision for direction switching. I would like to try them pointing southwest (US and South Pacific) and north (Asia).

I could of course build these in addition to more Beverages and have the luxury of doing extensive comparisons. That's a lot of effort that I really need to devote to other antenna farm projects this year. Perhaps the most profitable comparison will be a switchable directional antenna for 80 meters, whether a 4-square or a parasitic array. A transmit antenna with directivity is, after all, a type of receive antenna. Although these are typically not highly directive they have enough directivity to be effective, especially a properly adjusted 4-square.

Whatever path I do choose I will definitely have more receive capabilities on the low bands when fall rolls around later this year. My immediate need is better transmit antennas so that I can finally work the many stations I am now able to hear. It has been somewhat frustrating calling stations that cannot hear my puny signal on 80 meters.

SWR chart

Since my attempt to take a photograph of the analyzer display for the earlier article was so poor I decided to take one from inside the shack where I could control the light conditions. I'll close this article with that picture. You can see how nicely the SWR is from 1 through 15 MHz. A Beverage is truly a broadband antenna.

The periodicity you see is due to the termination resistor not equalling the antenna impedance; they differ around 10%. The impedance appears to be rising with frequency resulting in greater SWR swings.