The correct antenna for the PRC-25 in vehicular use is the AS-1729/VRC.
This antenna consists of one each MX-6707 base, one each AS-1730 mast
section, and one each AT-1095 mast section. The overall length (height)
of the antenna is about 116 inches, plus the height of the base above
its mounting bracket which is about 9.5 inches.
The base contains the coils and capacitors necessary to match the
antenna to the radio set. On the bottom of the base is a bandswitch to
manually select the operating frequency range, a connector to connect a
cable to an optional remote bandswitch, and a BNC connector for the R.F.
The outside diameter of the base unit, which would be placed through the
opening in the vehicle mounting bracket is about 3.4 inches. This means
the base will NOT fit an MP-50 bracket in which the hole for mounting an
AB-15 antenna base is about two inches in diameter. Unless a suitable
bracket can be located, one would have to be fabricated. The bracket
would be similar to an MP-50 but somewhat larger. Not a really tough
job for a competent welder.
Fair Radio Sales has the AS-1729 antenna assembly in used condition for
$59.50 plus shipping. Fair has a home page at:
http://alpha.wcoil.com/~fairadio (note only one "r"!) and E-mail at
fairadio@alpha.wcoil.com
Contact them by E-mail to request a catalog, etc.
The AN/PRC-25 was designed to be a man-pack set. The "P" in the type
designation means portable. If it were purpose-designed to be a
vehicular set the "P" would be replaced by a "V" - vehicular. While the
set can be used as a vehicular one with suitable accessories as Murdock
mentioned, one should not expect outstanding performance as the power
output of its transmitter is only one to two watts, depending on
frequency. Reasonably reliable communication PRC-25 to PRC-25 would be
on the order of a couple of miles. Greater range would be expected if
both sets were on hilltops with little or no intervening obstructions.
Good luck finding the other accessories needed for a proper vehicular
installation!
Ed Greeley