the TPU as an antenna and possible sources

[BEP]

Are you guys sure it was used only for reception?
I thought it was a two way comm system with submarines.  Hmm , I better do some more research.   I drove by that thing so many times, but never noticed any radio distortion or anything, might have been decomissioned by then (2003 time frame) 
BEP, do you think the freq are still classified?   (or were they ever?)
If this thing is just a reveiving station then it's unrelated, but what if the TPU's caused interference to their reception?  By the size of it, we know it has to be a low frequency antenna.   By the way Earl,  the picture I included is not in that list of the FRD-10 and FRD-9 arrays, this one is in San Diego.  But it looks simular doesn't it.

EM

The Navy and some Canadian stations were sometimes used for two-way communication. The primary purpose was direction finding using the Doppler Effect. For those that had transmit capability they were really good for it as they could also direct a signal in virtually any direction. The operating frequencies were primarily high frequency (HF). It did quite well as low as a couple hundred Kc but was designed to operate a bit higher and up to 30 Mc.

Last I heard there are two Canadian stations still operating but via remote control. There is more than one current system but the ground based ones can be a single point and be just as accurate and be remote controlled. They have an option of using an antenna that would fit in a breifcase.
While I've been out of 'the business' for quite a while I hear that packet burst transmission in the sub 100 Hz range is the big thing now. I would like to know how it is done. I've seen signals in this range. The only way I can imagine data on these is via phase shift.