RMCA AR8507 Low Frequency Receiver

Here are the general specification for this radio:

The model AR-8507 is an eight tube superheterodyne. It was primarily intended for marine service.

frequency range: 70 to 515 kc, divided into 2 bands: 70 to 225 kc and 200 to 515 kc, selected by panel bandswitch

Receiver circuits: tuned RF amplifier and converter with three gang tuning capacitor, two stages IF amplifier operating at 545 kc. Combined Detector-AVC-First AF amplifier. Two audio output tubes in parallel. Separate BFO.

tube complement: 6SK7 RF amp, 6SA7 converter, 6SK7 first IF amp, 6SK7 second IF amp, 6SQ7 detector-AVC-first audio amp, two 6G6G second audio in parallel, and 6SJ7 BFO.

This receiver was designed to operate from a shipboard DC line of 115 or 230 VDC, or from a 90 VDC B battery. One of the previous owners of this receiver, K7EWZ, put in an inconspicuous AC power supply for running it off the household AC line.

Don, the ham I bought this rig from, had a letter ( dated 1974 ), written from K7EWZ to a Rev. Peter Waldum in Kalispell, MT, regarding this receiver and a little bit about its history. I quote that letter briefly below, just because I think its neat:

" I believe that I told you that this receiver was given to me by A.S. Burke of Morton, PA. AL was employed for years by the Sun Oil Company. and his wife, Mae, once told me he was responsible for everything that had an electrical wire attached to it on the whole Sun Oil Tanker Fleet. AL was subject to call 24 hours a day, and had some very tough assignments in his time. "

" Mae also told me that over the years, Al obtained some 50 of these ships receivers and gave them to hams who could use them on ham frequencies by making suitable converters for them. Al and Mae are heavily engaged in public service by making their ham equipment useful for handling messages for people, especially servicemen and their families and friends in many parts of the world. They maintain the best gear that money can buy, even employing two teletype machines in addition to the usual ham apparatus, and spend many hours a day doing this fine work simply out of the goodness of their hearts."

Later on, he mentions:

" I find the ship frequencies at 500 kc ( 600 meters), and a little below that frequency quite interesting. For example just heard the ship ROBERT WATT MILLER ( call letters ELCY ) call the coast guard station, NMQ, at Long Beach, CA. A bit later KFS, at San Francisco called CQ, indicating he is ready for traffic".

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