Wednesday, Oct. 10, 2018 — I apologize to my readers for this entry in advance because I (again!) have written about antenna tuners.
I have written frequently about tuners lately, but I can’t avoid the topic today as I have finally purchased the “Tuner of My Dreams” — a Heathkit SA-2060.
I have owned one of these tuners for well over a decade; however the one in the shack lacks the antenna switching and metering circuitry. For whatever reason, that circuitry had been removed and discarded. And it was never a big deal; I have an MFJ standalone SWR/wattmeter that’s served me well in conjunction with the tuner.
The SA-2060 sells on eBay a premium, but I ran across one with not only a comparably low Buy It Now, but also “Make Offer.” Long story short, we negotiated a bargain price. The tuner looked great inside and out.
Of course, the UPS gorillas hadn’t yet had their turn working over the packaged tuner; what damage may be inflicted in transit may change the value of my bargain. I was very happy to see UPS deliver the tuner in a heavy duty box that originally contained a Yaesu FTDX-3000. The tuner was unmolested … or was it?
The knobs turned freely, however the turns counter on the roller inductor wasn’t registering turns. ACK!
My son was amazed that how simple the internals of the tuner really are — two large variable caps, a roller inductor, balun and the assorted coax switch and SWR circuitry. The problem is that finding a tuner built today of equal quality that’s also affordable is tall order. But what’s wrong with the turns counter on my new arrival?
If you have ever owned the SA-2040 or 2060, you probably know that the turns counter is driving by a gear on the roller inductor shaft. Its pretty damn simple; the gears mesh, one turns the gear on the shaft of the turns counter. As you might expect, the gears weren’t meshing.
The problem was horizontal movement of the roller inductor; there was probably 3/8 of an inch of horizontal play in the roller. When the roller was at the rear of its horizontal movement, the gears didn’t mesh; you could manually pull the roller forward by gripping the knob and pulling it and the gears meshed.
The issue was surprisingly simple to fix.
On the rear part of the roller shaft there’s a bushing and a collar secured with an allen head set screw. All that was necessary was to loosen the set screw and push the collar to the rear to eliminate the horizontal play in the roller shaft. In the end, it took longer for me to find the right size hex key than it did to make the adjustment.
According to the assembly manual, when the roller is at minimum inductance, the indicator should read “000.” This matches how my other SA-2060 and 2040s were assembled. But every tuner has its own quirks and settings, even if they are the same model. I broke out my MFJ-259 analyzer and used it to determine the tuner settings for the HF bands. It was amazing how close the settings were between my “old” SA-2060 and my new one.
Of course, now I have several tuners to deal with. The old one and the SA-2040 will go in storage on a shelf in the basement; I’m waiting on the o-ring “belt” for the MFJ-989B, and it will be ready to roll. I don’t know how many “spare” tuners a man needs, but if my bug collection is any indicator, I probably need to invest in more shelving to store my growing “collection” of antenna tuners, LOL.
73 es CUL … de KY4Z SK SK …. dit dit