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A question !

L

latindj

Guest
I may come off ignorant but i have a real question, and was wondering if anyone would take the time and explane. I had a freind a few years ago who was the PD at KILE 1560AM here in houston and i remember hearing that he was using a sub carrier i'm not sure if this is the correct term or name but he was selling this special radio (not like a normal Am ,Fm sterio ) these radios would pick up his programing on what i belive was 90.9 here in houston and i belive only that frequency it's kinda wierd but i never understood how that worked but always wondered how 90.9 could do that i also remember seeing on a magazine radio caracol 90.9 here in Houston but it worked the same way .

Do sub carriers carry the same power and is this legal does the fcc get involved?<P ID="edit"><FONT class="small">Edited by latindj on 07/19/05 04:34 PM.</FONT></P>
 
> Do sub carriers carry the same power and is this legal does
> the fcc get involved?

You are refering to FM SCA, which are services carried on subbcarriers of the main signal, much the same way the SAP channel on television works. The two subcarrier frequencies most often used for audio services are 67 and 92 kHz, while other frequencies can be used for datastreams. FM SCA actually predates FM stereo by several years.

SCA used to be popular for Muzak type services, but cable and satellite delivery made that use obsolete. Today you mainly find ethnic niche programming, distributed via special receivers that can be rented or purchased from the program supplier.

The last time I did an SCA scan here in Houston (maybe a year ago) we still had the Reading for the Blind service on 88.7, Spanish language religious on 90.1, plus a couple of Asian language programmers (one was on 92.1, and the other was on 102.1, IIRC.) 99.1 had a simulcast of KBME (this was where Muzak used to be.) These were all 67 kHz subcarriers (I don't have a 92 kHz demodulator.)

Some of these services have come and gone...some years ago 97.9 had the "Physicians Radio Network", a talk and information network aimed at the medical community. And 102.9 had a rival music service to Muzak (can't remember the name.) 101.1 also had an Asian language service at one time, and KHCB used their subcarrier as an STL for their separately programmed AM station in Galveston.

From what I understand the FCC really doesn't regulate SCA, other than making sure everything is within proper technical specs.

Guess I shall have to fire up the 67 kHz demodulator in the next few days and give a report of what I hear.

BTW, listening to FM SCA is probably a grey area legally. Some of these services require a modest subscription, but demodulators are openly sold, and I've never heard of anyone getting in trouble for simply checking it out on a hobby basis. One thing you don't want to do is use the services in any commercial application, which would definitely get you in hot water.
 
> Where could i buy one of these decoders?? (special radios)and at what price lets say i use the subcarrier from a 100,000 watt fm would i reach the same place they do ?? is the sound quality fm am



> Do sub carriers carry the same power and is this legal
> does
> > the fcc get involved?
>
> You are refering to FM SCA, which are services carried on
> subbcarriers of the main signal, much the same way the SAP
> channel on television works. The two subcarrier frequencies
> most often used for audio services are 67 and 92 kHz, while
> other frequencies can be used for datastreams. FM SCA
> actually predates FM stereo by several years.
>
> SCA used to be popular for Muzak type services, but cable
> and satellite delivery made that use obsolete. Today you
> mainly find ethnic niche programming, distributed via
> special receivers that can be rented or purchased from the
> program supplier.
>
> The last time I did an SCA scan here in Houston (maybe a
> year ago) we still had the Reading for the Blind service on
> 88.7, Spanish language religious on 90.1, plus a couple of
> Asian language programmers (one was on 92.1, and the other
> was on 102.1, IIRC.) 99.1 had a simulcast of KBME (this was
> where Muzak used to be.) These were all 67 kHz subcarriers
> (I don't have a 92 kHz demodulator.)
>
> Some of these services have come and gone...some years ago
> 97.9 had the "Physicians Radio Network", a talk and
> information network aimed at the medical community. And
> 102.9 had a rival music service to Muzak (can't remember the
> name.) 101.1 also had an Asian language service at one
> time, and KHCB used their subcarrier as an STL for their
> separately programmed AM station in Galveston.
>
> From what I understand the FCC really doesn't regulate SCA,
> other than making sure everything is within proper technical
> specs.
>
> Guess I shall have to fire up the 67 kHz demodulator in the
> next few days and give a report of what I hear.
>
> BTW, listening to FM SCA is probably a grey area legally.
> Some of these services require a modest subscription, but
> demodulators are openly sold, and I've never heard of anyone
> getting in trouble for simply checking it out on a hobby
> basis. One thing you don't want to do is use the services
> in any commercial application, which would definitely get
> you in hot water.
>
 
>99.1 had a simulcast of KBME (this was
> where Muzak used to be.)

I remember while listening to "When Radio Was" on KBME 790 (when they were still Adult Standards) on Sunday nights, sometimes the WRW recording would end many minutes before the top of the hour (automation glitch?), and then the silent 790 carrier would suddenly be replaced by a muffled "AM-sounding" KODA Sunny 99.1 audio. Then at the top of the hour KBME's ID would come up and the automation would kick back in.

weird!<P ID="signature">______________
I listen to what I like.
Ratings be Damned.</P>
 
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