MCX100 radios - The Canadian
MCX100 radios were engineered and manufactured by
Motorola Canada Ltd. in the 1980's using circuitry very
similar to the Syntor.
Performance is as good as current commercial radios
and, with their small size plus scan and pl options, make
great radios. (picture)
Control heads have LED channel indicator, volume
and channel knob, non adjustable squelch on/off
button, one or two digit channel LED, and
additional buttons depending on options.
The frequency algorithm is virtually identical to
the Syntor. Frequency is held in an inexpensive
82S129 bipolar prom.
The radios are about half the size of a Micor or
Syntor trunk radio. Integral control head radio
uses the same Microphone as a Syntor or Micor.
Speaker, although appearing the same as the
Syntor is a 2 ohm speaker as no output
transformer is used.
These radios trade hands for as little as $10 as
access to programming hampers most users. They
use an inexpensive bipolar prom for frequency,
and similar proms for pl and scan options.
Squelch action better than a Micor - absolutley
Sensitivity 0.25 or better - no preamp available
Two channel switches: 16 and 32 position binary
encoded. The 32 channel switch is no longer
available from Motorola.
Remote head: about 2 by 2 by 8 inches and 20+
foot cable. Microphone hard wired to backside.
Front ends: Standard helical was 4.5 MHz
bandwidth, the wide one was 6 MHz and a dual wide
was used to cover non contiguous frequencies. For
example, one could have the weather channels
(receive) and ham frequencies in the same radio
without compromising out of band rejection.
Output: 10W or 30W - I have never seen the 10W
VHF band splits: Range I 114.6-162 MHz Range II
124.6-174 MHz Bits in the prom set subrange. Use
high side injection on Range II radios to receive
UHF band splits: Rand I 403-430 Range III
418.6-470 (there is no range II)
PL: optional board uses 82S129 bipolar prom.
Enabled with front panel button and hangup box.
Scan: optional board uses 82S129 bipolar prom.
Enabled with front panel switches. Many
variations of scan available.
Stops were used to mechanically limit to fewer
channels. Remove knob and nut and discard the
stops. A toggle switch can be added to the front
panel to extend the 16 channel radios to two
banks of 16.
Tune the helicals and local oscillator filter.
Most radios are under deviated at 3.5 kHz from
the factory. Crank up the VCO MOD.
Too many times when the radios are removed from
service, the power cable is discarded and the
frail cable connector lock is lost. Power
connectors are $6+ from Motorola but if you paid
$5 for your radio that doesn't seem like much of
a bargain. Remove the main radio board and
hardwire leads to the inside of the power
connector using two fused leads, 1 or 2A for the
controls and 10 A for the PA.
Consider building the
bipolar prom programmer
and contact me about software to produce the MCX-100 bit pattern to drive it.
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