This link will take you to John Vendely's (K9WT) analysis and restoration information for the Pierson KP-81, a must-read if you need to restore one of these beauties.
K9WT's KP-81 Restoration Guide
I'm listing these two transmitters under one heading because they are so similar. Both appear to have been designed and built just after WWII, both companies were located in New York, both used rather odd tube lineups, including an ultra-compact graphite-anode tetrode PA (3D23, A.K.A., Taylor TB-35), had apparently identical VFOs, and used iron built by Electronic Transformer Company of NYC. The appearance, size, shape, and chassis layout of the two transmitters is also very similar.
I now have a pair of AF-100's in my shack. One of them has been seriously hacked--both the mod transformer and HV power transformer have been replaced (badly!), and in place of the tiny 3D23 final, a big ole' 813 has been crammed in there. The second rig, found under a tent (in the rain, of course) at Dayton, is pristine inside, all original, but has a pretty crufty case. At the time of this writing, one of the cabinets is off getting powder-coated, so I have fairly immediate plans to put the best of these parts together and get one of these things on the air! I'll attempt to be more disciplined than usual and take some photos of the restoration as it progresses and post them here.
Many of these rigs have been modified to replace the 3E23 PA tube. (Replacement with a 4-65 seems to be a popular, and I have to say, very practical mod.) Fortunately, I seem to have the world's entire supply of these rare tubes, thanks to a lucky find at the Shelby hamfest a couple of years ago, so I'm hoping to keep at least one of my Supremes in original condition.
Here's what little I know about the 3D23:
|Filament||6.3V @ 3.0A|
|Full Rating Freq||250 Mc|
|Vp (CW)||1500 V @ 110 mA|
|Vg2 (CW)||375 V @ 22 mA|
|Vg1 (CW)||-300 V @ 15mA|
|Pin/Pout (CW)||4.5 W / 130 W|
|Vp (AM)||1000 V @ 85 mA|
|Vg2 (AM)||300 V @ 14 mA|
|Vg1 (AM)||-200 V @ 10mA|
|Pin/Pout (AM)||2.0 W / 60 W|
Another ham kindly sent me a copy of the Temco GA-75 manual, and it was on reading this manual that I discovered the remarkable similarity between the two transmitters. They are so similar, in fact, that it appears likely the same engineers designed both.
If you have any information about either the Temco or Supreme transmitters, any leads on where I could locate/purchase examples of either of these, or information about sources for replacement iron for my Supreme, OR, if you simply want to swap info about these interesting transmitters, send me email at
Scans of the Cosmophone 35 manual are thanks to John Brewer (K5MO). I have purchased, but not yet picked up, one of these rare beauties! Will post pix of the rig as soon as possible.
This is a scan of the original TM for the CV-116 rtty converter. The scan is not very high quality, as it was done in haste at 200 dpi for the most part. The manual has a couple of huge fold-out schematics. I scanned them at 300 DPI 11x17 format, with 6 overlapping scans. They could be printed out on 11x17 paper, then reassembled into one schematic, with some effort.
This is a scan of the manual for the Scientici Radio System Inc SR-206 and SR-210 HF SSB Transceiver family, dated May 1973. Note the file size.. this will take a while to download!
What's this doing here??! Hey, I've got a ViewSonic, and I had to put the manual somewhere.. :)