Reacting to Honest Feedback

In my first years as ham, oh so long ago, I had no money and could not afford decent equipment. Those days I used a Hammarlund HQ129X receiver and a bizarre mix of hacked equipment for a transmitter that I picked up at a flea market for a few dollars.

The foundation of the transmitter was originally a crystal controlled multi-band mobile AM transmitter with an three 807 tubes: one for the final and two for the modulator. In combination with a home brew AC power supply it had been converted to an HF CW only transmitter that put out perhaps 30 watts. The modulator tubes were still lit due to the peculiar way in which the filaments were wired to a 12 VAC transformer, and I was too green to attempt changing that. A VFO was bolted on somehow.

As you might expect this was not the cleanest transmitter. The chirp wasn't too bad although it did drift quite a bit for the first hour after being turned on. Harmonics were almost certainly there even though I couldn't test for that and instead relied on the dipole resonance to filter those out. I received two OO (official observer) notices with this setup.

It is a rare transmitter indeed nowadays that has drift or chirp. We have more sophisticated flaws to deal with than the simple ones of an earlier day. Now we have phase noise, harmonic distortion, key clicks and more. Some are inherent in the commercial gear we buy while others, with a measure of knowledge and bravery, can be fixed. Too many hams are blithely unaware of what their transmitters are doing.

Yaesu, for one, is notorious for key clicks which exist to a greater or lesser degree over several generations of transceiver. They were particularly bad in the FTdx1000, which I dealt with soon after purchasing one. Happily they are old enough that fewer and fewer of these are heard on the bands since not many make the effort to fix the problem.

The FTdx5000 I now use is not innocent. For some odd reason they (and other manufacturers) include an option to vary the amount of key clicks the transmitter generates rather than fix the problem when it was designed. The menu option is 064 "A1A SHAPE" with a selectable rise/fall time of 1 to 6 milliseconds. The default value is 4 ms.

I was aware that the default value was problematic. I somehow failed to remember to raise it to 6 ms. That is, until I learned about it in the worst way possible.

The report

During a contest earlier this winter the stations were tightly packed on one of the low bands. With the benefit of modern receiver technology we could successfully operate when spaced just 300 to 400 Hz apart. Like most I was looping CQs to attract any new stations that might appear. There were stations doing the same both below and above me. All seemed well.

In the midst of this one of those operators, a well known contester with a competitive station, dropped down to complain that I was causing him grief due to my rigs's key clicks. He asked me to QSY a small amount. I don't know what others would do, but I hurriedly agreed and sidled a little closer to the station below me. I really did not want to hurt anyone else's prospects in the contest, especially one whose signal was so clean despite running a kilowatt.

I kept operating that evening as I normally would, other than being more self-conscious than usual about how close I got to others. That there were many others splattering the spectrum with key clicks did not make me feel any better.

Resolution

The next morning during off time I plunged into the FTdx5000 manual and those K9YC technical reports I linked to above. There were two things to considers: firmware version and keying rise/fall time. As already mentioned I was surprised to find that the keying parameter was set to the default 4 ms.

I connect the FTdx5000 to a dummy load and tuned my second rig, with no antenna connected, to the same frequency. Cycling through the parameter settings I monitored how widely the FTdx5000 key clicks could be heard. The difference between settings was large. Only at the maximum 6 ms setting was the signal narrow enough to satisfy me. I locked in that value.

There was a firmware update released by Yaesu in 2014 that improved CW keying bandwidth; there is at least one later firmware update but it addressed other issues. This was only measured and reported on by K9YC (link above). The previous owner of the rig told me that he kept the firmware at the latest version. It was only now that I confirmed that he had indeed applied the 2014 firmware update. That was reassuring.

With further testing I concluded that the key clicks were at an acceptably low level though not as good as the best rigs on the market. I might be possible to do better by modifying it, however I am reluctant to attempt that without guidance from someone with relevant expertise. It is too easy to do it wrong and make the problem worse. More than keying rise/fall time is involved, including ensuring linearity all along the amplifier chain. That's a tall order.

Path forward

In my previous article I spoke briefly about changes I plan within the shack this year. One of those is to sell a couple of transceivers -- KX3 and FT950 -- and use the funds to purchase a second high end rig. Most likely it will be is an Elecraft K3 or K3S, but not a Yaesu or any other manufacturer with a poor track record of transmitter cleanliness.

I have tended to favour Yaesu rigs out of both habit and comfort with the control panel and feature access from the back panel. My first Yaesu rig was a FT101B purchased new in 1974 (one of only two HF rigs bought this way), and along the way I had an FT101E, FT102 (a favourite of mine at the time), FT726R, FTdx1000 and more recently a FT950. It is now possible that this is the end of the line for Yaesu rigs in my shack.