Most of the "cans" I used in the 50's had a flat metal disk diaphragm that vibrated in the field of a pair of magnets behind it. They had a pronounced "peak" in their audio response in the 1 to 1.5 kHz (kc/s to be period-correct) range.
I, too, often just laid them on the table while working around the operating room at K6USA (Ft. Ord Army MARS station). The R.O. on the SS Californian used to wind up his magnetic detector and listen to traffic from his cans laying on the operating table while he fell asleep in his bed after his shift ended for the night. They estimate it was just a few minutes at most after his detector wound down and the signals went quiet before the CQD/SOS started blasting out from nearby MGY (SS Titanic). That's why she never responded. 73 Ron AC7AC -----Original Message----- From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Fred Jensen Sent: Wednesday, September 21, 2016 12:20 PM To: firstname.lastname@example.org Subject: Re: [Elecraft] Running stations with k3 OK, this is probably a good place to ask: When trying to copy a weak-ish signal in noise and "other stuff" in the 50's, one of my crewmates at the coastal marine station told me to lay the cans on the desk, face up. It works. I don't know why, maybe someone here knows. Surprisingly, I generally didn't need to turn the gain up much if at all. The receiver I used most on our HF frequencies was a brand new Collins 51J4. The military version was the R-388A. It had 6 and 3 KHz mech filters, and a separate, adjustable crystal filter. Did not cover 500 Kcs which was particularly noise and full of signals at night, however the trick worked on those receivers too, so it wasn't just the mech filter. 73, Fred K6DGW - Sparks NV DM09dn - Northern California Contest Club - CU in the Cal QSO Party 1-2 Oct 2016 - www.cqp.org ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com