[No run today, yesterday we did 7.75 miles]
This picture shows two (three) of my recent ham radio related projects.
The radio on it’s side is an old National NCX-5. It’s a 5-band transceiver, mostly vacuum tubes. It puts out 150 watts (my most powerful transmitter!). I received this thing from another ham, Mark, KK5EK when he and I lived in Colorado. He had it floating around and it didn’t work. He gave it to me, very generous of him! I was able to get it working again and I used it for awhile. I have some notes on the schematic about things I fixed in 2002, so I know I’ve had it at least 10 years now.
For the last few years it has been sitting on a shelf in the garage while I’ve used my TS-820 or the TenTec Century 21. [You know, all of those radios were given to me in unworking state. I sense a pattern here.]
I read a website about an improvement to the CW operation. The thing was almost unbearable on CW. Every dit or dah would cause a nasty sound in the speaker. Anyway, W7CPA, on his website, details a modification that will mute the audio more quickly in the transmit/receive switchover. I finally got around to doing that and it works much better now. But I notice that it doesn’t have a sidetone. I don’t remember if it is supposed to have a sidetone… maybe not. Makes it a bit harder to use on CW. But that little lacking can be surmounted by using a keyer with a sidetone or by turning on the Century 21 and tuning in to my own signal (with no antenna attached).
Success #1.
You may also note in the picture that the O-scope is on and showing a 10 Mhz signal, somewhat square-ish, and the counter says 9,999,999.936 Mhz (trust me, that’s what it says). The counter is off by 0.064 hertz(!). Not too bad. Those results are from my much worked-over GPSDO (frequency standard). I think I finally have it working correctly. I touched up the soldering of a couple of spots on the circuit boards inside the HP crystal unit. That seems to have done the trick. The control voltage is now doing it’s thing and the controller card can “steer” the oscillator to keep it in line with what is coming in via the GPS card. I’ll run it for a few days (weeks.. months..) and see. The laptop to the left is recording the log from the GPSDO so I can tell when it adjusts up or down and how far off it gets.
Success #2 (tentative).
Project #3 is the radio in the upper right corner of the picture which also has it’s cover off and is lying on one side. That is a Kenwood TR-751A 2 meter all-mode radio which I bought from an estate. It works fine for awhile then the audio quits. The rest of the radio appears to keep working fine. So I’m letting it run for awhile to see if I can make it happen. Then I’ll poke around with a pointy stick to find if there are any loose connections.
