From: andy@cbrown.claremont.edu
Subject: Errata: CATV channel frequencies USA
Organization: Harvey Mudd College
Date: 29 Jul 92 18:36:26 PDT

Alert reader eric@napa.Telebit.COM (Eric Smith) inquires:

> Are the HRC and IRC frequencies you listed for 95 through 99
> reversed?  For all others, the IRC frequency is 1.25 MHz higher than
> the HRC frequency.
>
> Cheers,
> Eric
>
>>        Common  EIA    STD      IRC      HRC   Band
>> --------------------------------------------------------------------------------
> ...
>> CATV    A-7 5  05             79.25    78.00   LO
>> CATV    A-6 6  06             85.25    84.00   LO
>> CATV    A-5    95    91.25    90.00    91.25   MID
>> CATV    A-4    96    97.25    96.00    97.25   MID
>> CATV    A-3    97   103.25   102.00   103.25   MID
>> CATV    A-2    98   109.25   108.00   109.25   MID
>> CATV    A-1    99   115.25   114.00   115.25   MID
>> CATV    7      07   175.25   175.25   174.00   HI
>> CATV    8      08   181.25   181.25   180.00   HI

Eric,

    Yup, you are right. Swap the IRC and HRC freqs for 95 through 99.


Alert reader schmidt@auvax1.adelphi.edu (John H. Schmidt, P.E.) observes:

> The FM Channels start at 200, in the FCC's numbering scheme.  The bottom
> Non-Commercial channel is channel 200, 87.9, allocated only for 10 watt
> "secondary" stations who can find no other NCE frequency, and only on a
> noninterference basis with channel 6 and other NCE stations, and finally, not
> within 250 miles of the Canadian or Mexican borders.  88.1 is channel 201, not
> 1, 88.3 202, etc.  87.9 (200) to 91.9 (219) are reserved for Non Commercial
> Educational stations.  Alaska also has some special rules due to grandfathered
> "point-to-point" relay stations operating in part of the FM band
> 
> This chart is generally very good, and should be made part of the FAQ for
> either this group or rec.radio.shortwave.
>> 
>> FM    1              88.10   FM
>> FM    2              88.30   FM
>> FM    3              88.50   FM
>> FM    4              88.70   FM
>> FM    5              88.90   FM
>> FM    6              89.10   FM
>> FM    7              89.30   FM
[tedium omitted]

Yup, right again. I also ran across this fact while looking up stuff for the
previous erratum. Please note that the correction itself probably needs a small
correction in that 91.9 is actually channel 220 not 219. John's message also
adds data that was missing from mine, to wit: apparently there are 101 FM
channels not just 100. Neither of the charts from which I cribbed this made
mention of channel 200.

John's comments bring up another point which is that "your milage may vary",
and there are probably a lot of obscure facts about FCC regulations and
matters of practice in the industry that are not represented here (of which
John's illumination is but one good example). The apparently haphazard
assignment of chunks of bandspace to TV channels is testament both to the
evolution in fits and starts of spectrum usage and to many other arcane facts
of engineering that might, for example, have caused a small bit of bandspace
to be eschewed to avoid risk of interference with some other essential service.

I will mail the corrected list to those who post corrections, and then in a few
days either repost or post an anonymous FTP location.

Andy Davenport
Harvey Mudd College
Newsgroups: sci.electronics