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Author Topic: Comco Model 779 Aeronautical VHF AM Ground Station  (Read 283 times)

Offline skeezix

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Comco Model 779 Aeronautical VHF AM Ground Station
« on: June 15, 2019, 0443 UTC »
I was at a local small airport today and spied a large radio sitting behind the counter. It turns out to be a topic of great interest. The radio has been handed down for decades there and the manual has long since disappeared.

This thing is a Comco model 779 AM transceiver that is on the local airport frequency. Comco is short for Communications Company and they were in Coral Gables, FL, before being bought out by E.F. Johnson.

The poor radio has seen better days, but considering its age, its in pretty decent condition. A couple of the protective coverings over the lamps are broken and all three lamps do not light. The mic is intermittent when keyed (and the mic connector is loose, which is more than a clue). We did hear an aircraft in the area, so the receiver works, but tx usefulness is unknown.

I opened the top and looked in, assuming it was a tube radio. Didn't see any tubes when looking in, or much of anything. It seemed to be mounted under a shield and I didn't dig too deeply into it.

Appears to have a receiver module and a transmitter module. The receiver module has printing on the plate for four channels, but no knob. Therefore single receive (which is perfectly fine in this case).

The transmitter module is more interesting. It has a switch with the following labels: AOC, R-1M, T-1M, T-2M, PA, A-12, A-24.

I can only guess at them-
- PA: Public Address or Power Amplifier. 
- R-1M: Might be remote control.
- T-1M and T-2M: Two transmit channels perhaps?
- A-12/A-24 and AOC: No idea. A-12 and A-24 seem to hint at perhaps a voltage level, but at the transmitter switch? That makes no sense.


Has anyone heard of Comco before or might have information (or ideally the manual) for the 779?

I have found a few other unrelated Comco things on the Internet, but they're of no use (mobile unit or VHF/UHF FM).

« Last Edit: June 15, 2019, 0500 UTC by skeezix »
Minneapolis, MN

Offline Josh

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Re: Comco Model 779 Aeronautical VHF AM Ground Station
« Reply #1 on: June 15, 2019, 2125 UTC »
If it came from a larger airport mebbe it's Ramp, Taxi, Approach, etc?
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Offline skeezix

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Re: Comco Model 779 Aeronautical VHF AM Ground Station
« Reply #2 on: June 16, 2019, 0326 UTC »
Its a smaller reliever airport in the Twin cities and used for UNICOM there for the FBO to communicate with the aircraft as needed.

No mention if it came from ATC, pretty much that its been there forever. But I don't think it came from ATC.

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Offline R4002

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Re: Comco Model 779 Aeronautical VHF AM Ground Station
« Reply #3 on: June 17, 2019, 1443 UTC »
UNICOM would be one frequency, the FBO might have their own frequency - plus ground control frequency (ramp) and then the associated approach/departure area frequencies (if monitoring them was required). 
U.S. East Coast, various HF/VHF/UHF radios/scanners/receivers

Offline skeezix

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Re: Comco Model 779 Aeronautical VHF AM Ground Station
« Reply #4 on: June 18, 2019, 0125 UTC »
Its a single channel receiver as there is no knob for changing the receiver's frequency. It appears Comco also made a four channel model using the same plate. This one just has no hole & no knob.

The FBO uses the UNICOM+CTAF frequency; there isn't a secondary frequency for them. Its an uncontrolled airport, so no local ATC and the FBO doesn't need to monitor them (if something weird did come up where they need to talk to them, they do have airband HT's that could be pressed into service, but ATC would probably just call on the phone instead).

There is approach/departure and clearance delivery available at the airport using other frequencies for ATC.
Minneapolis, MN