Tuner swap, Tempo VFO repair …

Sunday, March 7, 2021

Just got out of the shack following my CW traffic net. Propagation was rather whack-a-doodle, up once moment then in the crapper the second. But we got through the net with everyone checked in.

I finally got around to doing something I’ve put off — I took out the Heathkit SA-2060 antenna tuner and replaced with the the MFJ Differential T antenna tuner.

The MFJ tuner is deeper but more narrow than the Heathkit tuner. I had previously placed a parts bin on top of the Heathkit tuner, but its not going to work on top of the Differential T tuner. The Heathkit tuner was pretty much buried in various and sundry, so my goal is to NOT bury the MFJ tuner the same way.

Due to its design, the Differential tuner was quite simple to dial in for a match. Basically, all you need to do is set the capacitor in mid-range and then tune the roller inductor and listen for an increase in band noise. That’ll get you in the ballpark; a little fine tuning and your are done.

So now, I’m awash in antenna tuners. I have 2 SA-2060 Heathkit tuners; 2 SA-2040 Heathkit tuners; and now, not one but THREE MFJ Differential T tuners!

The third MFJ tuner was a damn mistake; just for kicks, I submitted a low-ball offer on a tuner on eBay, and the buyer took it!

So for now, it looks like I’m going to sell the third Differential T tuner; I’ll also sell the SA-2060 tuner I took offline today. I have one or two SA-2040 tuners in the basement, and I will probably sell both of those.

THE SA-2060. The SA-2060 I took offline tonight looks original, but the metering circuitry and the antenna switch section have been removed. It was that way when I got it, but it does not affect its performance. It only meant that I had to run the tuner with an external SWR meter, which was no problem. Besides, I like the cross-needle meters much better than a separate “forward” and “reverse” meters that are standard on the SA-2060.

In the main shack right now I have a fully stock and functioning Heathkit SA-2060 that I plan to hold on to forever. My fear is something happening to the MFJ tuners, so I’ll keep the SA-2060 as a “spare” … I might keep both of them and shed the rest.

TEMPO 2020 VFO PROBLEM. While excavating recently in the attic, I ran across the external VFO that I bought with the Tempo 2020 now in Studio C. I bought my current VFO off eBay because I wanted to complete the station; I found the original VFO, so I dug it out to put in place.

While the VFO was sitting in the Studio C, I backed into it and it took a spill, face down, on the floor. Tonight I swapped the VFOs, expecting the original to work. When I tried the external VFO, I could hear the rig changing frequencies; however, the numbers on the VFO — which are on a drum — did not move. After my CW net I took the cover off the VFO and found that due to the VFO’s fall, a thin plastic toothed belt had popped off the VFO; the belt turned the numerical drum as the VFO shaft was turned. I replaced the belt and all was good.

I was thinking about selling the second external VFO, but after seeing how thin and fragile that little belt is on the VFO, I’m tempted to keep the damn thing in case I need a spare. We’ll see.

I still have that third Tempo 2020 that actually works but I bought as a parts rig. I scavenged the top panel from that rig for the 2020 I’m running now, but I know that the original top panel still exists, and its most likely still in the attic. If and when I can find that top panel (or find a spare on eBay), I plan to sell the third Tempo 2020.

That’s all for now … 73 es CUL … de KY4Z … SK …. SK …. (dit dit) ….