rjr@mgweed.UUCP (Bob Roehrig) (10/17/85)
I have been receiving newspaper articles and other dope on ELF from friends in Michigan for some time. For those that may not be aware of it, The Navy has this BIG transmitter/antenna thing covering many acres of ground to send data to subs. The last I heard, the site was commissioned and is on the air. Its center frequency is 76Hz and uses low speed frequency shift modulation swinging between 72 and 80 Hz. Obviously, the transmissions are encrypted, but is anyone curious enough about it to attempt to receive it? I was thinking that a "TRF" type receiver would not be at all difficult to build but that the biggest difficulty would be rejecting 60Hz. I have always been attracted to the idea of playing around on frequencies below 10kHz (where the FCC doesn't care) for short range local communications. I have been on 1750 meters and managed to be heard a mile or so away (with a legal transmitted signal level) using a very innefficient vertical antenna). I have also thought about trying carrier current transmission on the power line for controlling my 2 meter repeater, a mile away. Has anyone else messed around with low frequency stuff? Bob, K9EUI