[AMRadio] FS AM Transmitters in Pittsburgh

Don Merz n3rht at yahoo.com
Mon Jan 21 19:44:27 EST 2008

GWE III AM Transmitter. This is in a 5 foot tall heavy wooden 19 inch rack--very pretty with many matching meters. It uses plug-in coils and puts about 120 watts. This seemed to be working perfectly when I bought it but then discovered a strong parasitic in the exciter. This was fixed and the TX tests out good on 40 meters. No other bands were tested. It is not OSHA-certified and could use the AC power rewired using 3-conductor grounded line. It could also use new HV connectors for additional OSHA-class safety. It was all built by N3GWE, Ed Mantick. It was purchased by me in September, 2002 after Ed needed to sell it due to the onset of health problems. Final: 812, Exciter: 6AG7’s driving 807s, Modulator: 45s driving 809s, Power Supplies: Solid State. Ed’s original documentation goes with it. This uses Ed’s modified Eico 722 VFO. This rig uses plug-in coils and a full set is included. $389 with coils and modified Eico 722 (N3GWE Modified Eico 722:
 Modifications include 6AH6 in place of 6AU6 and power supply changed to full wave rectifier using a better transformer. Repainted nicely with black case. Looks good. Working perfectly and quite stable after 20 minutes.) Pick-up Only In Pittsburgh, PA.
Gross CB-80 transmitter. This is the only one of these transmitters that has survived--there are no others anywhere on Earth. This is a 1936-vintage 5-foot high rack transmitter for AM and CW covering 10 through 80 meters with plug-in coils. It has a 42 crystal osc into a 6L6 buffer driving an Eimac 35T in the final. The modulator is a pair of 6L6's. I think it is all original looking, though it may have some very old mods that I can't tell from original. The one unoriginal appearing thing about it is the RF ammeter in the antenna matching section, which is definitely not original--though it looks very close. Also, the antenna matching section has been basically gutted and will have to be rebuilt if you want to use it. The matching section originally had two caps and some coils in it. But only the caps remain. This rig has the optional meter panel with 4 surface-mount Gross-logo'ed meters that plug into various spots on the rig with 1/4 inch phone plugs.
 The one coil installed in this thing probably isn't right--it's a EFJ edgewound type. So you should plan on building a set of coils for it. I have most of the original documentation including schematics. The documentation is very fragile but I also have photocopies. The rack is made for this rig and each chassis can be slid out on metal flanges. It has the original paint, Gross name tag and looks pretty sharp for its age. Naturally, this is pickup only in Pittsburgh, PA. If you want something absolutely unique and one-of-a-kind in your shack that connects you to the first golden age of ham radio in the 1930's, then this will be quite a conversation piece for you. This rig appeared in CQ Classics calendar one year. $499.

Buy both rigs and I'll pay up to $88 for your gas to get here and back.
Contact Don, N3RHT at n3rht at yahoo.com. Ask for pictures if you are seriously interested.
Please pass this along to anyone you think might like a good classic rig.
Date: January 21, 2008

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