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Ham Radio

TenTec Argonaut 509

[Yesterday’s run: 3.4 miles]

One of the items I bought at the hamfest in Jackson was a box of older TenTec radio gear. It held two more-or-less complete Argonaut 509 radios and some add-on bits like a power supply and a couple of audio CW filters.

So the other day I tore into the worst looking of the two Argonauts. The cover was falling off and I figured I couldn’t do it any harm.

Besides the cover, the first thing I noticed was that the main tuning knob was frozen up. That happens with older TenTec radios. The tuning mechanism they used, called a PTO, was built with lubricating grease which eventually solidifies.

So I did some reading on that issue and tore into it. I was able to remove the PTO and disassemble it and clean all of the parts using q-tips and 90% rubbing alcohol. I tried to loosen it up without disassembly, but that didn’t get me very far. So I took it all apart. I reassembled using white lithium grease.

I then plugged it in and I was able to hear signals on 80 and 40 meter bands. The higher bands don’t have much going on these days, so I didn’t check it all out completely.

This morning I worked on the dial cord. I gather that it probably originally had one dial cord which worked against an elastic band for dial return. Someone in the past has replaced that with a more conventional setup, two dial cords with a steel spring in between to keep things taut. I think they may have had to drill a little hole and put a 2nd pin in the tuning shaft to make that work.

I think I have it working pretty good.

Next I’m going to do some more reading in the manual and try to touch up the alignment. I also need to check the transmit signal to see how it sounds, that it is not swoopy or harsh.

Modified Argonaut 509 dial cord