Sunday, March 20, 2016

VFO Baggage

After returning to amateur radio after a 2012 hiatus I had to familiarize myself with very different technology used within the shack. When I went QRT in 1992 the typical transceiver had few memories and settings of various features was universal, not associated with a VFO. Indeed there usually was only one VFO.

Several generations of transceiver technology later we see the opposite. A large number of features are associated with each VFO, of which there can be many and even many registers per band. These include frequency, filter, bandwidth, mode, attenuator, pre-amp, noise blanker and noise reduction, VFO tuning rate, CW offset, antenna port, ATU and more.

Our rigs are more software than hardware these days so it is easy to keep this data around. It is intended as an operator convenience. It can be very helpful that when you change modes, bands, memory or VFO that you return to exactly where you were when you last used that selection, with same selection of feature settings.

Can it go too far? Let's look at a few examples from my recent experience.

Other operators

At a multi-op contest operation I brought along my FT-950 for the group to play with during the day (this was a 160 meter contest). Of course everyone has their own ideas about filtering and other feature settings to use. On switching bands or VFOs they'd naturally make adjustments to suite themselves. The next person would do the same.

By the end of the weekend the rig was pretty much unusable. Before putting it back on the air at my home station I had to undo all the changes. With 9 HF bands, 2 VFOs and 3 registers per band that amounts to a lot of changes! It wasn't quite as bad as that since not all combinations were touched.


In the recent ARRL DX SSB contest I changed the AGC setting to fast. Slow is more typical for SSB to make listening more pleasant by covering up band noise and lower-amplitude QRM and QRN. This is detrimental in a contest since many of the stations you need to copy are boxed in by louder stations that dominate the AGC.

In similar fashion I would narrow the SSB filter to as narrow as 1,800 Hz to contend with the crowded bands. Copy is enhanced despite the unnatural sound of the result.

Every band change, VFO change and band register selection required setting the AGC and filter width. After the contest these changes had to be reversed.


When noise appears I make adjustments. I may select a noise blanker or noise reduction, or I may narrow filters, turn off the pre-amp and make other tweaks. Some noise is frequency dependent while other noise affects multiple bands. In other cases it is antenna dependent.

Since these settings are all settable by band, VFO and register I am repeating the same sequence of feature settings every time I select a band, VFO or register. When the noise goes away I gradually undo those changes. That's annoying.

Counter-trend move

I purchased the Elecraft KX3 in late December 2012. It was the rig I chose when returning to amateur radio after 20 years of inactivity. At the time a small, QRP, moderately priced modern rig appealed to me. The research I had to undertake to reach that purchase decision leads me to sympathize with new hams. There is so much out there, and so much that was unfamiliar to me, that getting to a decision was difficult.

One thing that puzzled me about the KX3 was their design choice of having the filter settings associated with mode and VFO, not with the band. I thought that an odd and potentially annoying choice, though nothing more than a minor irritant. My opinion gradually changed.

Someone at Elecraft had clearly given the matter some deep thought. It is a design choice that I grew to appreciate. Filter settings do make sense when associated with the mode and not have change on me when I change bands. On rigs that do make the association it seemed I was often surprised at what filter settings came up. They were whatever seemed best to use the last time I was on that band. But who remembers that or even cares?

What about all the other settings that are remembered with every band, mode, memory and VFO register? Have we overloaded these registers for good reason, or only because it is easy to do with modern technology? That's what I have come to wonder.

Solutions are possible

There is great value in having many feature settings uniquely settable for different bands, modes, VFOs and memories. I believe that "feature creep" has overridden good operating practice. The question is where to draw the line. It isn't even clear that a line can be drawn that most would agree with. What Elecraft has done is one example of walking back the feature creep that makes sense to me.

One kind of solution is to assign personalities to a rig. If you use N1MM Logger or a WinKeyer in contests you will understand the concept. In a multi-op contest with Logger when you sit down you log in with your call and many of the feature settings and memories (include voice messages) switch to your own preference. The next operator does the same. It works well.

For CW contests with the WinKeyer the memories and feature settings are pushed aside while Logger is in use. This allows the full set of contest-friendly feature settings to be programmed in Logger and easily invoked. When you exit Logger the WinKeyer features return to their previous settings.

I can imagine the same being done for our transceivers. This could be directly programmed in rig software or via external software such as Logger. You could set personalities for yourself for when you're DXing, contesting or casual operating. All the settings follow the selected personality. When a visitor operates your station you assign them a personality. When they leave you get your station back to where it was with one simple command.

Most transceiver manufacturers are unlikely to take the initiative. It is more likely to come from the developers of software applications for rig control, including those for SDR. Most of the CAT (computer aided transceiver) controls needed are already present in the majority of late model rigs. It needs only to be done.

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