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Author Topic: Allen & Bradford SW rx?  (Read 5724 times)
KJ6ZOL
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Posts: 346




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« on: June 17, 2014, 09:20:22 PM »

Weird find on a nearby city's Craigslist:

http://chico.craigslist.org/ele/4522347253.html

The beige radio was made by "Allen and Bradford". I've been around radio for a while, I never heard of this company. Looks to be a tube SW rx from probably the 50s or 60s. Any ideas?
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AC5UP
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« Reply #1 on: June 18, 2014, 01:26:29 AM »

The Allen & Bradford rig is a marine receiver used for direction finding and navigation.  It's a specialty piece you wouldn't be aware of unless you were in the maritime trades.  You can barely see it in the photo but on the top of the radio is an AM BCB ferrite rod antenna that rotates and is marked in degrees.  Tune an AM station from a known location, rotate the antenna for a null in the signal and you have a relative position.  Tune another station further up or down the coast, read the new antenna position, and where the two lines cross would be a more exact location.  Top scale on the dial is the old HF marine band, middle scale is AM BCB, lower scale appears to be LF beacons.  The Conelrad markers on AM BCB tell me it's 60's vintage.

Even more interesting is the Bendix Skipper immediately under the DF receiver.  That's a 25 watt plate modulated AM transceiver rockbound in the 2 MC range that was used before the marine band moved to VHF.
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