Mysterious RCA radio
 

I dragged this out of a landfill almost a decade ago and I've never found any information about it.

http://i11.photobucket.com/albums/a1...ndy/radio2.jpg
http://i11.photobucket.com/albums/a1...andy/radio.jpg

Details about it are very limited other than what I can find from markings on the back:

-It's a VHF-FM transmitter
-It's from the 700/700C series, type CSCL4AJA
-it's got a 25W power rating
-Using specialized modules, you can choose four different transmitting and receiving frequencies
-Two frequencies can be selected from the front. There's also unlabeled momentary and NO/NC buttons that appear to be user pinnable for custom applications.

I can find absolutely no information about it online. Zero documentation at all. It's obvious someone has made wiring changes at one point or another but I have no way to know what they've done. The relay isn't a factory job. Neither are two random loose wires. Might this ring a bell to anyone? Right now it's tuned to 14.266mhz transmit (that looks like an AR frequency) and 18.277mhz receive.

RCA was in communications for several years, but it seemed to be a separate division, like their test equipment and studio products.
Isn't RCA communications, now Harris.
You'd have to find someone who was involved with them, as their service information, was proprietery.

As you have found out this is an RCA 700 Series Repeater they made these circa 1970. It is presently been modified as a HF cross band repeater. 14.266mhz is a general use frequency in the 20 meter hambands. 18.277mHz is an odd one the only reference I can find is the frequency was assigned to Friday Harbor, city of Anacortes, Washington State. station WHV382, and is used by Sailmail ( http://www.sailmail.com/) which is a email service for Yachtsmen. For what it is worth here are the manuals http://www.repeater-builder.com/rca/rca-index.html
As for a getting it up and running, don't even bother the modifications are undocumented. I don't understand how the got a repeater that is designed to operate 6 meters, VHF, and UHF to work on HF; is this the reason why it was in that landfill?. Strip it for parts and bump it.

Ken de W7ITC

As-is it runs. I can tune in with the scanner and we can get a good transmission but right now the frequencies are somewhat useless to me. The theory was that the tuning crystals could be substituted with software controlled oscillators. I've seen it done before to eliminate the need for expensive or unobtanium crystals but the modification by itself can be quite complex and success varies from radio to radio. At least with the documents I can remove the obvious modifications one at a time.

I strongly suspect that those frequencies of 14.266Mhz and 18.277MHz were not the frequencies the radio actually received and transmitted.

More likely, these crystals were used in oscillators that were then fed to frequency multiplier circuits (amplifiers deliberately used to generate harmonics). 18.277..., for example, may have been multiplied by 9 to get 164.50 Mhz, which may have been applied to a mixer circuit to convert a signal at 153.80 MHz to 10.7 MHz to feed the IF chain of the receiver.