At 11:01 AM 06/01/10, you wrote:
Gentlemen - (And Ladies)
I have a Micor Unified Chassis here model TCN1187A. Am I right in
confirming that this Chassis is not frequency dependent? There are
no channel elements in this unit so I cannot confirm what frequency
is would work for. Can anyone shed some detailed light on this unit
for me please?
Thanks!
John Hymes
La Rue Communications
10 S. Aurora Street
Stockton, CA 95202
<http://tinyurl.com/2dtngmn>http://tinyurl.com/2dtngmn
Most any frequency dependent part in a Micor
(actually most any Moto radio) is marked with
a part number in the format of three letters
and 4-digits, possibly followed with a revision
code... Like TLD8272B1...
The secret is the third letter. The text below is cut
and pasted from
<http://www.repeater-builder.com/motorola/aaannnn-numbering-scheme.html>
Mike WA6ILQ
A Under 25 MHz
B 25-54 MHz (yes, the table in the buyer's guide included 10 meters
and 6 meters)
C 72-76 MHz (see note 1)
D 144-174 MHz (see note 2)
E 406-470 MHz (see note 3)
F 890-960 MHz
N Not frequency dependent (like an audio-squelch board, or a power
supply) (see note 4)
NOTES:
[1]: C was limited to the 72-76 MHz USA assignment (one split) until
Motorola started making land mobile equipment for the European 66-88
MHz band (which usually required two splits). Some books say that the
so-called "mid band" is 60-99 MHz. There is no 30-50 MHz low band in
Europe, when they refer to low band they are referring to 66-88 MHz.
In the USA, 60-66 MHz is television channel 3, 66-72 MHz is TV
channel 4, the 72-76 MHz frequencies are used as "Operational Fixed /
Repeater" frequencies (essentially commercial point-to-point links),
76-82 MHz is TV channel 5, 82-88 MHz is TV channel 6, and 88-108 MHz
is commercial FM broadcast. One rumor is that as part of the HDTV
conversion in the USA the FCC and the military want to eliminate TV
channels 4, 5 and 6 then reassign the 66-88 MHz range as a military
band that aligns with the rest of the world (i.e. for joint
operations and exercises).
[2]: D was redefined downwards to 136 MHz at some point. There are
high band equipment models specified as 136-174 MHz, and others that
are 150-174 MHz.
[3]: E was redefined downwards to 390 MHz in the early 70s and then
to 360 MHz in the early 80s for certain military, government and
spook equipment. It was expanded upwards to 490 MHz and later to 512
MHz as the 470-494 MHz then 494-512 MHz frequencies were allocated. A
1990s salesmans order book has the UHF band listed as going from 400
MHz to 520 MHz. There has also been some "interesting" equipment
found on frequencies as high as 550 MHz.
[4]: N is still used as a "Not frequency dependent" identifier even
when there is some difference between wideband and narrowband
equipment (like in the audio recovery circuitry in an IF /
discriminator board). Most of the time a variation like that is
handled in the final letter suffix (i.e. a TLN9999A1 might be
wideband and a TLN9999A2 might be narrowband), but there are exceptions.
The four numbers after the three letters are simply a design sequence
number. One or two letters after the numbers are a version, variation
or revision identifier (the term used depends on which book you
read). Almost all assemblies have one letter after the sequence
number (i.e. the first shippable design is dubbed version A), some
have two characters, a few have three (i.e. TLN9999A1A).
