[Milsurplus] Early police radio

[William Hooper]

"...A lot of the early mobile communications was done at frequencies we now
consider "too low". The original police communication nets were just  above
the AM broadcast band.  The system was a one way (base to mobile)  setup..."

I believe that in L.A. they used the dispatch frequency just above the BC band (1700+ KHz)
and the police vehicles were equipped with a Motorola T-69 transmitter that operated
somewhere near 40 MHz so their 7 to 8 foot whips would load and they could get back to the
"central" or dispatch on 40 MHz - their receivers were RCA 2-channel radios with no tuning
controls - but they had two xtals with a switch - perhaps one for the main dispatch and
the other for "tak" (tactical) use - where the heavy traffic from some large incident
would clog up the main dispatch frequency - but this was also very near the top of the BC
band.  Both the receiver and the transmitter had vibrator power supplies, the receiver's
was internal and the T-69 had two identical cases - one for the transmitter and one for
the vibrator power supply.  This was my first ham rig - (the police dumped them in about
1946- 48 when both transmit and receive went up into the 150 MHz region) - I used the RCA
T-69 lowered to 10 Meters (easy job)  - it had an 807 modulated by a pair of 6L6s - only
ran about 15 watts AM output (with significant vibrator hum) - and I used a Gonset 10-11
converter ahead of the RCA xtal-controlled receiver mentioned above.

So I was rock-bound on 28.8 MHz and ran 15 watts AM mobile, not much - but in '49 and '50
you could work the world with that kind of set-up.  I lived in Phoenix AZ at that time and
we had 20 or 30 locals on 28.8 AM - more fun!  Had hidden transmitter hunts etc etc.

I have re-collected all the above except the RCA receiver - still looking.

Fun !

            Bill and Arlene Hooper

            billnroo at earthlink.net

            http://home.earthlink.net/~billnroo/

             <}}}><

            ******  John 3:16 *****

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