[Motorola] Research Line for amateur use

[Geoff Fors]

Jack's note brings up another topic...the Motrans used an inverter power
supply to run the final transistors at something like 24-36 volts.  That was
a popular design at the time, other radios such as the GE Porta Mobil I pack
set portable did the same thing.

I have several of those Motrac accessory tone burst heads in my junkbox; too
bad they weren't something more useful like multi-PL encoders !

So far I haven't mentioned the Mark 12 UHF radio, also seen as the MK type
UHF Bell System car phone, with duplexer + supervisory board and 12 channel
capacity.  I have one of those in the car phone "museum" which was owned
originally by AT&T Labs.  A surprisingly good performer for a radio with a
varactor tripler to get to UHF.  The filter system in the RF section was
said to be a complex affair best left untouched except by the factory.  AT&T
appears to have been experimenting with this one to make a vehicular speaker
phone.

Maybe we should start a thread about the weirdest Motorola SP- products
made... I submit as the first example a 1965 vintage California Highway
Patrol "5&9 Motrac" which was a 5 channel receive, 9 channel transmit
"administrator" car low band radio, created out of two long-case "X"
prefixed Motracs patched together by a "siamese" cable coming out the side
heat sink panel of each.   I have the manual for one but alas, no radio
(yet...).

Or how about another weird thread, about "what ever happened to" the used
two-way dealers which once were with us, such as long-gone Mann
Communications of Tarzana CA (later Agoura, CA), Gregory Electronics in
Saddle Brook NJ, or Spectronics in Oak Park, IL.  Then there are the rare
ones such as DuPage FM of Lombard, IL or Sherman Wolf (he of the FM
Schematic Digest fame ) plus about two others I have forgotten the names of.

Geoff WB6NVH