I suspect there are three different things being discussed here: the super-low frequency equipment used to activate teams from Prime Base; the tactical radios of the Project (symbolized by the PRC-70); and whatever transcontinental system the Project expected to set up after the Atomic War.
The Military Affiliate Radio System communicated fairly reliably from Vietnam to North American in the 1960s, with equipment that would fit in the bed of a deuce-and-a-half. I think you could justify a V150 dedicated to being a comm vehicle, with an extensible mast (similar to the ones used by television remote vans); or the same comm capability built into a MARS-One or Scientific-One vehicle. Some images and info:
http://www.fold3.com/image/244368538/
http://www.ne7x.com/web_pages/mobile1968.htm
http://www.qsl.net/ea4bb/EA4BB/Collins_KWM-2A.html
http://www.w2xc.com/KWM-2.htm
http://www.collinsradio.org/cca-coll...a-transceiver/
http://www.wb4hfn.com/COLLINS/Docume...chure-KWM2.htm
http://www.radioing.com/collins/tr01.html
The 4000 kilometer range quoted for the PRC-70 is for sending and receiving CW (morse) or FSK (modem, more or less) with a doublet antenna (i.e., not just the usual whip on Project vehicles). While the doublet antenna is normally stretched out parallel to the ground, I'm sure a well-designed vertical pole could do something similar. Between two PRC-70s, with the right conditions, time of day and operators, ranges are more like this:
- doublet antenna, Morse code or modem: up to 4000 km
- doublet antenna, voice: up to 800 km
- whip antenna, FM voice or SSB voice: up to 40 km
- whip antenna, AM or FM voice: up to 24 km
(this information is converted from "Operator's Manual, Radio Set AN/PRC-70", page 1-10).
I imagine the super-low-frequency system can't be picked up by the tactical radios, so the details may not be too important to game play.
--
Michael B.