[Qcwa] And now, for something entirely different.

[JIM WILHITE]

I can't help with anything but a few stories about these kind of units, m=
ost of which would take too much time to relate.

However, I do remember in 1976 when a sheriff's deputy from Mobitee, TX c=
ame into a MSS in Pampa, TX to have the new Micor installed in his auto t=
o replace the mobile version of your unit.  It had been installed in abou=
t 1961 or so and had been moved from car to car over the years by someone=
 in Mobitee.  It had never been serviced and all tubes were original.  Th=
is particular unit looked almost as new as the day it was unpacked.  The =
deputy had kept it covered with a blanket and there was not a scratch on =
the case.

Over the years he had cleaned the control head, speaker and microphone.  =
They, too, looked almost new.  The unit was had crystals for 36.180 which=
 was the channel used by all sheriff departments throughout Texas those d=
ays.  In 1973 or so all the counties in the panhandle of Texas formed wha=
t was called the Council of Governments which purchased a new multichanne=
l hiband radio system for each county giving them their own discreet freq=
uency plus a base to base frequency.  =20

There was a lot of resistance to this since all cars and base station dis=
patchers listened to everything that happened in all counties.  Anyway, t=
he service shop put the unit on the bench and ran the receive and transmi=
t tests to find out the unit was still on frequency, modulating properly =
and received as it should.  =20

Not bad for a unit of its age.

You might ask around to see if any Motorola service shops are still in ex=
istence that were in business in the mid to late 70s.  They just might ha=
ve a manual in the attic that will cover the strips.  The PL thing will b=
e a different story.  Audio from the receiver strip was routed through th=
e PL part.  You can trace it and reroute it for what you want.  Keying wa=
s provided by the PL circuit, which you will have to modify.  Wish I coul=
d be more help, but age sets in about now.  The DC remote is nothing but =
a small power supply that puts positive and negative current of 10 ma. on=
 the line to pull the relays, the multi channel units used 5 ma. to switc=
h frequencies.  Negative, I believe, would disable the PL for monitoring =
purposes.  When you pressed the PTT you put positive on the line, so pola=
rity was critical.  =20

73  Jim
de W5JPW



If a radio was first put in service in 1958 would it qualify for QCWA as
well?

This week's project was to bring back a Motorola remote base station
on a local repeater frequency. TRW Amateur Radio Club, 145.320
- 600 KHz with  PL 114.8

TTD6150 transmitter strip. A few miniature tubes, a hand full of locktals=
,
a 2E26 and that goofy glass bottle with twin plate caps in the final. Not
an 829B, that one was in the mobil units.

TU217 Vibrasender Reed for TX PL.

TRD3150 receiver strip. LOTS of miniature tubes, with a 6U8 and the
volume control sort of cobbled on top of the chassis.

TU333 Vibrasponder Reed for RX PL.

Genuine Motorola "Rock Cod Weight" power supply

Lastly, the DC remote chassis. Oh man, thems some NICE
relay assemblies.

And the whole thing sits in a 3' high indoor cabinet.

A special thanks to M H Electronics for supplying the crystals.

Now, for a few questions.

Anyone got the schematics for these chassis? Specifically the
TRD3150 and TTD6150 chassis.

Anyone know off hand how to disable the RX PL and still
have the carrier squelch work right?

Also, anyone have schematics for the CPI RD11-8 DC Remote?
That's the one that looks like a standard DM-500 desk phone.

As I'm done begging at this point, you're welcome to jump in and
offer any stories you might have regarding this vintage Motorola
stuff.

For example, this unit in particular used to live in a Bob's Big Boy
in Whittier. Although the liscense read "Delivery/dispatch" it was
channeld on the LAPD VHF dispatch frequency.

73 es GE from Jeff
wa6fwi


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