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HD vs SCA

Scott Fybush said:
The trouble, I think, with petitioning the FCC to make FMeXtra a public broadcast service is that you can't really easily have it both ways. Make it public and you're now obligated to maintain program logs and EAS and do legal IDs...and then what happens when ASCAP and BMI and SESAC come around for their money, too? Kind of defeats a lot of what they were originally marketing FMeXtra to do, doesn't it?
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Paying royalties wasn't the issue. Using an AM station to feed the translators requires paying ASCAP, BMI and SESAC too, so that is really a wash. I was simply looking for a way to program the translators separately in order to super-serve the communities they were located in. Technically ,FMeXtra would have worked, but it wouldn't have been legal to do so.

I actually tried FMeXtra on a 74 watt LPFM. It worked amazingly well. It is too bad this technology has gone the way of the 8-Track tape player.
 
FMeXtra would have been a good backup to the HD2 and HD3 channels if they drop out.

Could there theoretically be an unlimited number of subcarriers? Since a subcarrier is modulation of the audio frequency that itself is modulated on the FM carrier, why not modulate the audio up to 1 megahertz?
 
All this talk of SCA is making me wish I could get my hands on an SCA capable radio, just to see what's kicking around on my local stations, if anything. The earlier mention of FM Atlas was the last time I remember anyone keeping track of SCA in print form. It would kinda nice to put that info on my website, just for the nerd factor.
 
Zach said:
All this talk of SCA is making me wish I could get my hands on an SCA capable radio, just to see what's kicking around on my local stations, if anything. The earlier mention of FM Atlas was the last time I remember anyone keeping track of SCA in print form. It would kinda nice to put that info on my website, just for the nerd factor.
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It is fairly easy to make / buy an SCA adapter that will go into an existing radio. I never cared about SCA musical content, so I never tried - but the circuits look easy. The biggest problem is finding the right place to tap into your existing radio.
 
Chuck said:
Paying royalties wasn't the issue. Using an AM station to feed the translators requires paying ASCAP, BMI and SESAC too, so that is really a wash. I was simply looking for a way to program the translators separately in order to super-serve the communities they were located in. Technically ,FMeXtra would have worked, but it wouldn't have been legal to do so.
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The royalties might not be an issue for you, but I think Scott's point was that making any form of SCA a non-private service comes with quite a lot of regulatory baggage. In other words, this cannot work unless the digital system is strictly intended and sold as a public service from the outset. That includes all of the ID, EAS and content regulations that come with being a non-private service. Obviously, this would not be very likely to occur on an existing service like FMeXtra since there are already private service users of the technology that would object to becoming non-private.

So, it's very likely that tuneable radios are legally possible for FMeXtra, provided that the FMeXtra contract explicitly allows this and provided that every user had to sign such an agreement. The prospect of getting FMeXtra setup as a non-private service that could be broadcast via translator are less certain. Every existing user would have to agree to the change along with all of the regulations that come with it before any PRM could be filed.
 
rbrucecarter5 said:
It is fairly easy to make / buy an SCA adapter that will go into an existing radio. I never cared about SCA musical content, so I never tried - but the circuits look easy. The biggest problem is finding the right place to tap into your existing radio.
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An analog SCA can be decoded using a phase locked loop, like a 567, attached to the discriminator output. This method works but tends to be drifty and is subject to cross talk. It's cheap and easy to build, though. If the radio has a stereo decoder IC, attach the PLL at the stereo decoder's input pin.
 
Kmagrill said:
So, it's very likely that tuneable radios are legally possible for FMeXtra, provided that the FMeXtra contract explicitly allows this and provided that every user had to sign such an agreement. The prospect of getting FMeXtra setup as a non-private service that could be broadcast via translator are less certain. Every existing user would have to agree to the change along with all of the regulations that come with it before any PRM could be filed.
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The bottom line for me was it was cheaper and easier to purchase an under-performing AM station and put it on the translators. No PRM needed....
 
FMXtra was an awesome technology. If memory serves me correct a mono-FM could squeeze 192kbps of FmXtra bandwidth allowing for 6 32kbps audio channels encoded in AAC+ which sounded dang good. A stereo FM could have 96kbps of bandwidth while not walking on adjacent stations. The better digital technology did not prevail!
 
@Zach--

http://metrosonix.com/

The MS-1026 is a pretty decent rig with digital-readout tuning. Don't have one, myself, but I have used one.

Last time I was there, Seattle had quite a lot of SCA activity (10 stations operating), mostly ethnic programming. I understand New York City is another fairly big SCA market.
 
Darth_vader said:
http://metrosonix.com/

The MS-1026 is a pretty decent rig with digital-readout tuning. Don't have one, myself, but I have used one.
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These can also be found on ebay as direct imports from China. Cost is about the same, though. Look for sca radio or sca receiver or just subcarrier. Searching ebay has gotten much harder since they killed off the wildcard searches, but you can still find some items if you think about lots of search terms.
 
http://radiosca.com/ also has (or had) a very good SCA rig (I have two of them myself) but I don't know if the company is still around or not. Check E-Bay; their file is either called "radiosca" or "subcarrierusa", if I recall correctly. (It's admittedly been almost 10 years since I've last done business with them.) This is probably the "direct import from China" Kmagrill mentioned above.

"Is there any published list of SCA feeds for each market, by chance?"
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I'm not immediately aware of one, aside from the FM Atlas. That may be the only one there is.

Just for the record, here's what's currently available here:
88.367 Radio Svoboda (Russian)
90.792 Vietnamese programming (ĐÀi ViỆt Nam HẢi NgoẠi)
There was also Korean programming on 90.767, but they took it off about a year and a half.
 
Ramsey also sells a companion FM tuner kit which easily interconnects with their SCA decoder, so you don't have to concern yourself with tapping into the discriminator circuit on an existing receiver (results can definitely be mixed.) The Ramsey tuner also has a wider tuning range than typical FM radios.
 
I built both Ramsey kits, but they stopped Muzak SCA broadcasts from our FM here, and the other stations ceased broadcasting once they installed their HD gear; so a nice SCA radio that does nothing now. (unless there's a way to hack it read RDS)?
 
Why did they do that? Are they repeating the SCA audio on their Ibiquity channels now?

KBOO (90.7xx) had both its SCA channels running alongside their Ibiquity installation for several years, and it worked well.

We used to have Muzak on SCAs here, but it was dropped in either the late 1980s or early 1990s. I don't recall which station it was carried on. Satellite distribution was mainly what started killing that whole affair as far back as the late '70s (higher fidelity and increased capacity for future expansion, not to mention that it was more efficient and widely available.)
 
It is my understanding that bandwidth set aside for any auxiliary use (RDS, SCA, even the stereo pilot) is bandwidth that IBOC could otherwise use in hybrid mode, so perhaps stations ditched SCA for better HD fidelity thinking it would actually matter in the long run.
 
They are all FM with subcarriers at 67 & 92 KHz deviating +/- 5KHz and they both sound like crap: poor frequency response, hissy, and main channel incursion. Some of those signals, as well as L-R stereo information, begin as AM, but eventually get injected into and mixed with the audio that frequency modulates the transmitter. The power output of the transmitter shows no modulation.

What is this DRE ???
 
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