Mike - Thanks for that snippet. Thats the reference I was referring to when I determined it was non frequency dependent. With the absence of further responses from the group, I will consider my answer confirmed. Thank you all for your time!
*This unit came out of service from a UHF repeater. There are no channel elements but I guess it can be used for VHF stations as well with a simple board change, right?* John Hymes La Rue Communications 10 S. Aurora Street Stockton, CA 95202 http://tinyurl.com/2dtngmn ----- Original Message ----- From: Mike Morris To: [email protected] Sent: Tuesday, June 01, 2010 2:45 PM Subject: Re: [Repeater-Builder] Chassis Question 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 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).
