Sylvania Subcarrier Receiver Radio
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Comments • 106
Radio Korea on fm subcarrier...
Possibly being used as an uplink between that station and the tower? Normally they use a microwave signal
CANCEL
COMMENT
Matt
cool did not even know about this FM subcarrier stuff
3 years ago
11
Jasey Like noodles
I found this channel and I love it and me being only 15 I've now set off to tinkering with things #InsporationalShango
3 years ago
23
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SHOW MORE REPLIES
fred fabris
Seems to me that possibly the performance sucks because it was tweeked originally for the one specific limited station??
3 years ago
4
ScotTex83
Who else was singing along to Margaritaeville?
3 years ago
4
1
SHOW MORE REPLIES
Igor Peruchi
Big thanks for another great video, Shango!
3 years ago
4
PC No
9:00 I wonder if all those parts they added to the bottom of the board with heat shrink tubing were part of the modification; seems a little hack for a stock radio. Anyway, I'd think that that alone could pick up enough noise and cross talk to compromise the performance.
3 years ago
1
Papi Uuhmelmehahay
This answers a question I've had for 42 years: what the heck was that station I heard when I was a kid that I could never find on the stereo in the living room.
3 years ago
1
Robert Hardwick
The first one Ive ever seen was on Radio ,Phono Nut.Thanks for Explaning how it works!
3 years ago
1
Rob Calhoun
Your description of sub carrier broadcasting is pretty accurate.
3 years ago
2
dynamic881964
Very interesting stuff Shango066 ! Please keep 'em coming ! D in Michigan
3 years ago
5
Walt's Channel
Really great video. Yes, enjoyable!! Thank you for the research on subcarrier tech. That was very interesting.
3 years ago
1
Craig Nehring
Good to get a Monday Shang066 fix... Thank you for the video
3 years ago
3
Mr. Shyster
Interesting, learned something new. Thanks for sharing!
3 years ago
North-Hankspin
such a cute range of variations
3 years ago
2
GROUP GALAXY Entertainment
That is the first time I heard that Talking Heads song on the radio
2 years ago
2
Clive
RDS is transmitted on WFM subcarriers these days me old mate.
3 years ago
2
wifi404
Thanks for another intriguing video!!!!
3 years ago
Tony Fleetwood
thanks to you i found out about unforgettable la ( i live in connecticut but they let you listen online ) its just a shame that the good stations in your area are still outnumbered 20 to 1
3 years ago
2
tsevetgestoorde
Yesss a video thanks!!!
3 years ago
circuit blog
nice work my freind good job
3 years ago
1
Dan van voorst
cool stuff enjoyed the video!
3 years ago
Manchild Addventures
good stuff
3 years ago
Pecan pie
Its a sweet radio but has a lot of hash. Are you going to recap it in a follow-up vid
3 years ago
2
Rick Johnson
Good to see your still out there shango
3 years ago (edited)
Danish Native
Remember all that lo-fi Muzak and elevator music? The cluster I worked for turned off all sub-carriers 20 years ago. No more $ in it. For a while it was also used for distributing stock market data locally.
3 years ago
5
1
Jim E
Our subcarriers read Wall street Journal, Barons and Readers Digest too
3 years ago
fred fabris
I look forward to your videos
3 years ago
Average Joe
AFC wonky? dunno, well beyond my knowledge.
3 years ago
cat 11
I thought SCA was used to broadcast background music for restaurants and stores.
1 year ago
1
1
Walter Reyes Productions
It used to
7 months ago
Jim E
hardest part is finding a Yaesu at a reasonable price
3 years ago
Marc C
I connected my HF receiver to the discriminator/4CH adapter output of an older stereo receiver, that works quite well.
3 years ago
Jim E
Or maybe IRRL?
3 years ago
DriveInFreak
Wouldn't a wider ( or lack of) ceramic filter open it up enough to pass the high frequency?
3 years ago
audubon5425
Can I buy your fingerprints?
3 years ago
ke4mcl
Got that same educating radio, sounds just as lousy.
1 year ago
gravis346
I wonder if the radio dial is hidden behind that logo?
2 years ago
Jim E
or mebbe its the speaker wires from the FM into the s/w..... been a hundred years ago. go check back issues of the swl ers mag from the eighties
3 years ago
City Spiders
I think this is interesting. I dunno if any stations openly advertise the sub carrier thing or not; unless it is merely transmitted so it can be put onto a web audio podcast perhaps?
3 years ago
DriveInFreak
Very strange FM dial on that one. I don't think I've ever seen another one with the 9s and 10s marked bigger (i.e. NINETY two MC).
That's right up there with those dime store radios that split the AM dial into two (fake) bands split at 1100 KHz...below 1100 "AM", and above "Sports"...for some reason.
..or that Zenith AM/FM portable from the '60s that has an FM dial that goes up to 109.
3 years ago
Corinna T Roberts76
Did a search on eBay for this using the model number & nothing!
3 years ago
jake michael
This channel is the best!!! well I have played with the decoding of subcarriers , but I modified a standerd FM receiver. what I did was took the demodulated FM audio before it was filtered ,and feed it to a communications receiver that could tune down to 30 KC!! so in a nutshell you tune the FM band on the Fm receiver, then the demodulated audio before the audio is filtered,is tuned in on the communications receiver. so their is probably a small long wave receiver inside the subcarrier receiver radio. all so the audio is FM in the subcarrier band but their could be different modulation types!! the cool thing using this method is you can really explore the FM band subcarriers and, listen to the mane channel audio at the same time!! so I would take a guess that the subcarrier radio you have has poor filtering. well keep up with the cool electronics and cool left coast stuff as this stuff is getting rare by the second!!
3 years ago
Ross Man
Shango, loved this video, would you please look into the past of Heath Kit electronic kits. America has given away to the Chinese and only slaves of their population build electronics. I grew up with so many kits that an American Company could offer to teens my age at the time to discover and find hope in lifetime job in a America. I did, worked for Polaroid Corp. for 24 years until Dr. Land became so frustrated with how is investors were treating his company....I met Dr land, really great man.
3 years ago
mjg263
Very interesting video. I saw radio-tv-phono nut's video on that subcarrier receiver a while ago and I wondered what it's original purpose was, also wondered what radio the whole thing was built around. I'm sure it's all done on HD radio now but fascinating what they were able to do with the available technology at the time (even though it wasn't all that long ago to me). Great follow up, thank you!
3 years ago
Peter Atkinson
The null part of the FM signal may be it being heard in the AM mode. That would be a cheap way to get the 5KHz bandwidth. The extremely narrow bandwidth may also account for the crappy FM audio. They may have bypassed the radio's standard FM circuitry.
3 years ago
Jim E
don't over complicate it Shango
3 years ago
Ron Thompson
I take it sub carriers aren't a thin t any more right?
2 years ago
HECKTOR andersson
yaay
3 years ago
Scott Diburro
I thought sub stations are hd radio
3 years ago
Godfrey Poon
This system is clearly for transmitting the secret instructions to finally capture Pearl Harbor.
3 years ago
10
Chris's Tech TV
I think they tap the discriminator output before any filtering for the subcarrier demodulator. there were kits you could buy to receiver the subcarrier channels at one time.
3 years ago
1
1
klafong1
That is exactly what they do. The 1984 Radio Shack Semiconductor Reference Guide shows a schematic and description of a decoder using the LM565 PLL. There is also a 1987 issue of Radio Electronics with schematics for a complete SCA receiver, as well as theory of operation.
3 years ago
1
Kane Seven
Pay to listen to stations with non stop music no adverts
1 week ago
RODALCO2007
Your commentary is fabulous ! man you are the King in radio & TV repair and diagnosis.
3 years ago
3
Jim E
Usually a sub carrier on an FM broadcast. NPR is a good place to start, but any FM channel could have a subcarrier
3 years ago
HPad
I'm guessing a subcarrier could be picked up with an SDR?
3 years ago (edited)
3
ElfNet Designs
YES but you need to run SDR# and HDSDR to do it, its a convoluted process but it can be done.
3 years ago
1
HPad
ElfNet Gaming yeah I use SDR#
3 years ago
ElfNet Designs
Yeah there are tutorials on how to do it, I have done it once and found a few subcarriers in my area.
3 years ago
drussell
"In both monaural and stereo FM transmission, some stations also include "storecasting" or SCA (subsidiary carrier assignment) information. The SCA modulation extends from 60 kHz to 74 kHz, with a center subcarrier frequency of 67 kHz, the SCA signal must be removed, or "trapped" in a stereo FM receiver since it would interfere with the operation of the stereo detector circuit. A "swishing" sound will be heard in the receiver if the SCA signal is not removed. The SCA is removed from the decoder by a band-elimination filter or by a low-pass filter. Only frequencies below 53 kHz are permitted to pass through the decoder circuit."
It then goes on to show a diagram of the "Total signal spectrum that can be transmitted by an FM stereo station" showing 0-15 being "L+R", 19 being the 1 kHz pilot tone, 23-38-53 being the upper and lower sidebands around the 38 kHz suppressed subcarrier carrying the "L-R" in each sideband then the 60-74 kHz range for the SCA.
This is from an old RCA's "Solid State Servicing" that I happened to have handy.
Also, as mentioned by another commenter above, Is there not some relatively easy way of pulling a signal like this off of a modern digital tuned amateur radio somehow or do you really need an SDR?
3 years ago
1
uxwbill
Seemingly there is at least one amateur radio receiver that can be "tricked" into tuning SCA programs, the Icom R-71A with its optional FM board. I'd not be surprised if there were others.
Decoding SCA on an SDR is fiddly, but it can be done if you're willing.
3 years ago
1
Chet Pomeroy
I believe this is referred to as an "SCA" receiver. These had been in use for decades, and were often used as a source of music on the overheads/intercoms of retailers, as well as being piped to the inside of elevators. The audio on NTSC television broadcasts had something quite similar to that, called SAP, which was intended for translation into a language different from the one spoken on the main audio carrier, and it was also intended for the blind/sight-impaired. (That AM/FM radio looks like it's from the post-CONELRAD era, probably 1967-68.)
3 years ago (edited)
maximborn23
radiotvphononut's subcarrier had revisions for a dial and dialstring, and even a tuning knob i believe, just like the model you showed. Very cool!
3 years ago (edited)
1
MisterTalkingMachine
From what I get, they take an existing FM station and then they modulate the amplitude of it. Normal FM receivers won't tell the difference. It appears it may be as simple as having a wide band AM radio tuned to the FM bands.
3 years ago
50sTransistorRadios
It's nice to finally see the Sylvania AM/FM radio the Educasting radio was made from. I have a few of these Educasting radios as well, but I don't remember them being poor performers, so I will have to dig one up to check.
3 years ago
2
2
shango066
I fixed it, one of the detector diodes was open. Its really good now
5 months ago
1
50sTransistorRadios
@shango066 It's good you got it working right again. If I can find an example of that Sylvania consumer model, I plan to Frankenstein it together with the Educasting radio, to get a full-featured AM/FM/subcarrier radio.
5 months ago
SPACE TRUCKER
PRN..........physicians radio network.
2 years ago
1
ModMokkaMatti
PRN = pompous republicrat narcissist..
1 year ago
Jim E
If you poke the fm antennae from an fm radio into the antennae jack on a s/w reciever that recieves under 100 khz then tune around on both bands. Takes some farting around, but you might find somebody reading Readers Digest
3 years ago
Robert Johnson
To answer your question on station id at the top of the hour the answer is no. Id is made on FM and the Broadcast Liscence for the station would show the authorization to broadcast the SCA but no call letters. In the case of our network using KROC, that audio was propagated thru 8 - 10 stations. Remember however this was in the 70's rules and regulations may have changed. A better test for any stations still using SCA is to get the McMartin tre5 unit, on the board is a connection to put detector out from a FM receiver and feed the signal into the tre5. Then you can tune thru the band while the tre5 is detecting the sca. I had it connected to my truck radio so as I was going to stations to work on the equipment i could verify it sounded fine, or check which station would give the best reception at a grain elevator I had to hook up. Love your videos, brings back old memories.
READ MORE
3 years ago
1
klafong1
The FCC specifies the maximum SCA subcarrier injection level, but they do not specifically call out the modulation format. In practice, FM with about +/-5 kHz peak deviation is used.
Years ago, I experimented on and off with SCA reception. I tried
1) LM565 PLL IC; these suffered from heterodynes (as this receiver does, if one listens closely). The main channel crosstalk was annoying.
2) Narrowband FM IC from a discarded cordless phone. The on-chip mixer was used to up-convert the SCA subcarrier to 455 kHz. This decoder did not have the heterodyne issues associated with PLL decoders, however, I was not happy with the main channel crosstalk.
Then, somebody on a USENET newsgroup explained to me how persnickety SCA can be. For professional quality results, one needs a wide IF bandwidth (340 kHz, if one wants to receive the 92 kHz subcarrier), a very linear composite FM detector (dual-tuned, not the more common single-tuned configuration), and multipath-free reception. When Muzak was on SCA, the restaurants and businesses that used the service had a four or five element Yagi on the roof, even in very strong signal areas.
I have also heard AM stations simulcast on SCA. It is possible that the SCA channel is being used as a cue channel, and during a remote broadcast, the talent would be able to use it to hear the board operator at the main studio.
3 years ago
1
Jim E
Or a Drake for that matter
3 years ago
NJRoadfan
A company called Metrosonix based out of Bayonne, NJ exclusively sells SCA FM radios. VWestlife did a video on one of their retail radios (with a channel sweep of the NYC market stations) and a custom built single frequency receiver.
3 years ago
1
thehappylittlefox aka benji
are these anything like the Russian cable radio ?
3 years ago
2
Catswhiskerdetector
That's also really interesting. the first channel is just audio but the other channels are AM. I remember walking around Kyiv and being able to hear the 60/120khz 2nd and 3rd channels on a longwave radio being radiated by the overhead cables
3 years ago
1
maxhifi 123
Not aside from the appearance of the receiver.
3 years ago
Bob Weiss
Subcarriers are still in use in the NYC area. WBAI (a public radio station owned by the same network that owns KPFK) carries religious content on their subcarrier channels.
Renting out the SCA channels is an extra source of reliable income for perennially cash-strapped public radio stations.
3 years ago (edited)
Quantum Leap
Hi Shango066 I built a subcarrier demodulator back in 1967. There were three FM stations using 67 kHz subcarriers back then. All of them were Muzak type of broadcasts. Not exactly top-40 fare. but nice to listen to when you just wanted background music (noise?). Thanks for the video.
3 years ago
Scott Diburro
You can pick up hd radio on it you are saying
3 years ago
4
maximborn23
Scott Diburro it's too old to pick up HD stations on it, besides, its mono.
3 years ago
davek12
I'm sure that any station which is broadcasting a subcarrier signal would also run that same program on one of their HD channels, too. You're probably right, in a way.
3 years ago
Travis Parker
Yes but it can't decode it. Subcarrier 3 on that one station sure sounded like a data stream.
3 years ago
Stephen Hinkle
Travis Parker Yes I suspect that was likely an HDRadio stream but you need a decoder capable of deciding the digital signal to receive it.
3 years ago
Jim E
Even my crappy Grundig cost $400
3 years ago
4
Monica Opper
SO TAKE IT BACK TO THE STORE
3 years ago
Jim E
Y you yell? Just sayin' that a China Yeasu is better than a China Grundig. Yeasu costs northwards of $1000
3 years ago
Jim E
And the Yeasu tunes below 100 khz.... Grundig, not so much. Plus, why would the Germans with their impeccable craftsmanship farm out work to China?
3 years ago
Jim E
It's like saying "Telefunken, Now with cheapass Chinese build quality" I would not get a better Grundig unless I bought a sixties model. And I don't care enough about subcarriers to go there. Question remains. Y yell?
3 years ago
1
Apex Gemini
Christ, the sub carrier bands are now used by coyotes to tell illegals which border stations are easiest and what fence holes are unguarded at any given time. They probably get CA government funding.
2 years ago
4
RF Burns
Actually, the subcarrier is FM. The modulation index is low (not much more than 1.1), making the noise immunity not much better than AM. That and the fact that the subcarrier is so far away from the main carrier (67 - 92 Kc), is why the signal is usually noisy without an outside antenna.
The baseband signal from the ratio detector when tuned a stereo station with one subcarrier will contain L+R (50cy - 15Kc) @ 70%, the 19Kc pilot tone @ 10%, the 38kc double sideband suppressed subcarrier (which is AM - w/o the carrier - it occupies 23 - 53kc) @ 10%, and lastly the FM subcarrier at 67, 72, 88, or 92 Kc @ 10% - for a total of 100% modulation.
3 years ago (edited)
sirmugman
russain radio's? gasp! maybe that's how they talked to trumppy pumppy in the eletrcions you have to buy one of these radio's a say "my mother makes the best radioactive cakes in russia" and you get a extra channel that lets you wire up to russia's presedent, or is it just me in the tinfoil helmit?
3 years ago
6
4
Walt's Channel
sirmugman Hahaha, "radioactive cakes" indeed!!!
3 years ago
4
Jim E
I heard that wrapping your house with chicken wire is better than a tinfoil hat. Don't go outside though ;)
3 years ago
1
John Howard
trump lives rent free . . .
1 year ago
ModMokkaMatti
@John Howard we're all paying for the orange-a-tang to live, and it's too high of a bill.
1 year ago
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