Aw, are you gonna' leave us hanging Shango ? I really wanted to join you on your field trip to the station. RIP Joe Hart, a visionary that will be missed. Thanks for the memories, Joe.
Let me start by saying I'm not into any type of electronics or repairing them, I just stumbled across your channel a few months back and subscribed. I've been a mechanic for over 30 years I found your channel when you were doing an automotive ECU repair and have watched a number of your videos since. You have excellent diagnostic strategy and problem solving skills, this video compelled me to comment, plus I love the occasional satire and sarcasm.
PART 1 ruclips.net/video/I1HIF0toZO8/видео.html PART 2 ruclips.net/video/IDYEUqC9YO0/видео.html Part 4 and 5 next 2 weeks. Part 5 is an amazing tour of the WION studios and transmitter and is one not to be missed
The preemphasis curve has a lot to do with that. Earlier radios rolled off at 8khz or so. Most would reproduce 10khz. Then later, it went to 5, and some world radio packages roll off at 3.5! Pretty much shortwave. 10Khz, with the AM style preemphasis, is good! Many people, especially older listeners, can't tell, or can, but prefer that full sound. FM has a different preemphasis and it is more open, less full, but wider overall. For voices, the AM scheme is great. Talk, news, and a lot of music just hits our sweet spot and that tends to overshadow the lack of bandwidth. AMS, at 10Khz, even 8khz, rocks in a car. Road noise competes with the program. In addition, the FM fuzz is very tiring to many and it subtracts from the program. AM noise is added! Less tiring overall on a good receiver. These days a lot of stations do brick wall 5khz and it makes voices nasal sounding and the muddy sound is tiring. They did that to make HD AM work. Some stations appear to be rolling that back to 8khz, which is much better for voice. For a time, I had an AM Stereo kit I would listen through on good radios as a demo. People generally liked it. All of this is true on a mone signal too! The older GE Super Radios have a wide mode that sounds like about 8khz roll off. As an office radio or casual table radio listening, working outside, etc, that full sound appeals and is not generally tiring. Music on AM on a station that does not brick wall filter listened to on one of those, or the many respectable radios out there, will sound way better than most people realize because so damn many crappy car radios have been produced.
@@DougDingus I know GM offered AM stereo radios through the 90s. I just wish there was some AM music stations where I live, even better in Am stereo. The only music I can ever hear on AM is WSM which is eight hundred miles from my house and tends not to come in real strong.
I can hear stereo through my laptop speakers. Sounds surprisingly pretty good. Now, put on some Led Zeppelin ,ELP. Yes, or, Pink Floyd. Geez, even Zappa And The Mothers Of Invention for that matter.
Your hacked AMS modulation worked pretty well!! Sure would be nice to see this come back. It's a great experience in the car. And frankly, TALK or podcast type material is excellent. The warm AMS sound works with voices extremely well.
One of the best hacked C-QUAM schemes that I have ever heard was WOWO from Fort Wayne, IN. The station was using a Magnavox exciter but adding the 25 Hz pilot tone to trigger C-QUAM receivers. Their "faking" was so good that I did not realize that I was hearing Magnavox. It was not until some years after WOWO discontinued stereo operation that I learned that their reason for doing this was not due to programming changes but because the FCC finally declared C-QUAM the official stereo standard.
That sounds pretty damn great. Especially considering you're doing AM/PMX modulation. I did a similar experiment with my Uniden 2510 on 11 meters to myself to myself
I didn't have a 25Hz pilot but my SRF A100 didn't need one anyway. Used a Sony shortwave receiver as a conversion device and ran 450Khz before the final IF filters for wideband audio using the AM stereo radio to do All the IF work. Nice. And that's awesome that you found pin 9 being shorted to ground. When you said pin 9 shorted to pin 10. I'm liy. YUP! I've known about pin 9 to ground for forced mono since AM stereo was marketplace. That chip could actually decode 3 of the systems already with pilot tone frequency modified at the chip. VCPM CQUAM and AM / PMX all used the Motorola chip. Native Harris exciters modified for 25Hz pilot still sounded cleaner than a native CQUAM unit.
Amazing! I must say, AM is very much alive over here in Holland. Low powered, up to a maximum of a 100 Watts the stations are all around the country. We even can use frequencies originally not allocated to The Netherlands. Amd, as Germany and many other countries left AM completely, we can hear stations from far away locations. AM radio is something magic, no boundaries! Freedom to listen to what you want to listen to. Greetings, Willem, Holland.
Hopefully the late owner of the station in Arizona put together a solid succession plan. While it may not have been "true" stereo, there were certainly some interesting phase differences between left and right. They came through loud and clear even on Chromebook speakers.
Nice touch using period correct HP equipment. I'm still in awe of whoever built that circuit board. Listening through a 7.2 system, the stereo is very noticeable. Funny that this radio's IF was microphonic, I worked on 165 mHz marine radios at the big M at this time and we had serious issues with this. Must be the same coil vendor!
Former broadcast engineer here. It sounds like the L-R (fm) portion is missing highs that the L+R (am) side has. This is NOT a fault of the Motorola chip or the receiver. It is simply that the generator used does not have "pre-emphaisis" (usually 75ms) in the L-R feed. (There clearly is "de-emphasis" of the same value built into the receiver). We boost the treble (pre-emphasis) to improve the S/N of the fm component which is generally noisy, but more so here because it is very low level modulation (deviation) of the carrier. It's very much akin to how Dolby works. You boost highs on record, and cut by the same amount on playback to reduce tape hiss. Same for over the air. You can clearly hear the bass greatly increase when the L-R input is connected. You can use a simple RC network to boost the highs starting at about 6KHz and peaking out at 15Khz. You will need to carefully adjust the modulation on the L-R input to compensate with the RC filter. I'm very glad that you got this one working! The audio bandwidth is superb and is PROOF that AM does not have to sound like an old telephone. We used to take great pride in our AM signals back in the day (before FM became a strong competitor). Many stations had audio that went out to 15KHz or higher. Then the FCC oversold the AM radio dial and boxed everyone into a 10KHz lane. Today we have so many buzzes and noises from switching power supplies, it's nearly the end of the AM broadcaster. So thank you again for letting everyone actually hear what I heard over the air, many moons ago. 73
Are you able by chance to give me a reference or link to an explanation of why preemphasis is expressed in terms of a unit of time? I've always wondered about that. Thanks.
Mot was an engineering powerhouse that helped shape modern technology. We’re paying for the 2000s disregard for the importance of semiconductors and industrial infrastructure in general… Freescale was debacle and a huge loss of capability.
AM Stereo is one of the most frustrating technologies. It is so much better, and we had a fairly high adoption rate among broadcasters in the 1980s, but was so poorly managed that it buried itself. My Carver TX-11a is capable of CD quality (20hz-20khz) full stereo analog audio on the AM band (better than FM). Such an opportunity squandered by others pushing there own separate standards (Kahn) for far too long during rollout.
There is good news I been working on a new form of AM stereo (C-QuAMv2) for last 4 years and made a few improvements. Such as new type of QAM modulator, noise reduction system and also has a Position Navigation and Timing (PNT) signal encoded. The prototype transmitters are in the process of been tested before on air testing starts. As stated AM stereo has a few advantages of FM stereo, I will be making more information available soon on this technology.
@@granttaylor3697 YES! Someone should demo a stereo talk or news program in a well equipped car. Beats FM and is an experience people will crave. Of course we all know music will do well too. I am just floating this idea out there to give even talker stations a reason. Probably already way too late, but who knows?
@@shango066 do you repair short wave radios for the public? I have a older Sony, looks to be in good shape, but doesn't work. If you don't do this as a business, could you recommend someone? I'm in SC.
Sounds pretty good! Never believed there was a true AM stereo sound.and I worked as a DJ in an AM oldies station. I noticed the chanel separation was pretty amazing.
Done right, separation can be better than FM. For a while we had an alt. rock station, KBBT that was pretty well engineered. Great listening in the car experiences.
Yeah, the .MP3 should at least not be encoded with _joint stereo_ enabled, but it would be much better if he had just sent you raw PCM in a .WAV file or whatever... *VERY COOL!* Nice work!
Nice ! I remember repairing a motorola Built Car stereo which also had AM stereo I still have that radio infact it was in our old 1985 Ford F series truck .
Well done! Yes, the stereo demod compared to mono is VERY noticeable, using PC and amplified speakers! We had a 1991 (?) Jeep Cherokee with a factory radio that could do AM stereo. I tried it a few times, but it was only available locally on a sports talk station of all things (KFH), so it wasn't any help.
Shango, first of all, I'm not a big analog guy but love this damn channel. Your delivery is compelling and your snark is on point. That said, onto my purpose for commenting.. you can generate your own C-Quam with an SDR. I use a HackRF, I have flowgraphs for everything from C-Quam to ATSC to NTSC to that bastardized standard known as HDRadio, SSB, COFDM. It's really cool, but also very useful. There's certainly a learning curve, but for diagnostic purposes, it could be invaluable to you. Definitely worth looking into, very convenient to be able to generate whatever modulation you want on whatever frequency you want.
R.I.P. Joe. Good spot with the IC pins and resistor.. The stereo effect sounded awesome through my stereo system. (The speakers are either corner of the room.)
Nice! I heard the stereo though my monitor speakers. In the 80's I heard WGN's very first stereo broadcast. Roy Leonard at the start of his show 10am Central Time stated that WGN is now broadcasting AM Stereo. He then played Bohemian Rhapsody.
S, Years ago in the early 80's I worked for Mr Kahn. As you know his system was an ISB, and the others were AM/PM systems. We had a very special edition of the Boonton 103 that supported ISB and AM/PM AM Stereo. Have no idea where that ended up. Nice to see you can make your own pilot signal. Mr Kahn noticed an interesting problem with the early Cquam units. At night when distant carriers would zero beat with the AM stereo station, the stereo image or platform he called it would shift around at the rate of the zero beat. So if there was a 2hz difference the image would bounce around in the listeners ears. Weird issue. Like I said, long ago and far away for that. Be well, and keep it safe. Mike
Just finished watching! Great work so far.. we have a light! be interesting to see how it receives OTA! btw it's not unusual for companies to require prototypes to be intentionally disabled before they are sold / disposed etc, I remember buying some old proto computer hardware years ago labelled as "junk / for parts".. most had things like a jumper wire from one of the chips reset lines to keep it in reeset and a couple of resistors missing permanently disable it.
IT SOUNDED BETTER THEN FM STEREO! Sad AM stereo came at time when AM was dying. This does bring life back to stereo sound. Too bad I did not get an AM stereo receiver back when AM stereo was at it's peak. Can't wait for your next video on AM Stereo!
I owned a Motorola Two-Way Comms dealership from 1977, (an investment my family purchased), through 2017; 40 years. The previous owner started out as a Motorola Consumer Electronics Dealer and service center sometime between 1937, and 1940 when "Lend-Lease" was just beginning to 'really' crank up. Morrill hung around the service end of our shop, which was on our property, and in another town; he had to be 'pushing' 80, or maybe even more by that time. He 'phased-out' the consumer end of the business, when the 'guts in a drawer' (modular design due to Solid State's inception, and/or the appear of "Quasar" into the picture. Ours was one of the markets where Peirce-Phelps acted as our area's wholesale distributor, under contract to Moto's Consumer division, with the Two-Way Comms and Industrial divisions having access to warranty replacement components, and the Motorola "HEP" Semiconductor wholesaler/retailer/distributor scheme. Because of this strange set of circumstances, he received regular technical briefings, and also "warranty and non-warranty" upgrade and replacement kits, which came with the stipulation that he maintain the inventory of the kit's components for at least five years. Whilst I'm certain that I don't have any MC13020P IC's hanging around, it's likely that 'technical notifications' regarding CQUAM are located somewhere in filing cabinets which have an inch of dust as their decoration. I'd betcha that California has several 'vintage' Two-Way Comms service centers hanging around, at least somewhere?? Maybe there's an HEP stash containg those same IC's, with an HEP suffix??
I have decent PC speakers and during your experiment, I could easily make out stereo separation. Wasn't too bad. When I saw that solder blob connecting pins 9 & 10, I thought that could be why stereo wasn't working. Being that this set doesn't have a switch to force mono, the only way to do it was to solder it permanently to mono. Neat video.
I'd say that was a pretty decent demo, you can definitely hear the channel separation. I'm also was impressed how much better it sounded. Too bad it didn't become a main stay on the AM band. AM long term is probably doomed unless the right people in charge realize sometimes the simpler things tend to be the best when there really needed. Again GREAT Demo !
It works... I had at one time a 98 ford explorer... It had am radio! Then the display died and the replacements that followed didn't have that feature... But I remember when the am radio kicked in, I was surprised to hear the separation, then noticed the little am stereo indicator on the fluorescent display. I'm south of you in Orange County...
Interesting experimentation. Once I used a tool on PC called StereoTools to encode FM stereo modulation directly into a cheap mono FM transmitter and it worked.
@@shango066 Well, so much for 40 years in the broadcast business building, operating, and maintaining all kinds of facilities including stereo AM. Shame on You Tube.
I run a pair of small-yet surprisingly punchy and dynamic A-L barrels (first gen with wallwart) and a 500 watt JBL sub from my laptop ~this sounded awesome! Such a cool thing to mix AM with FM and achieve that warm, full-frequency range tonal juggling act of waves and surf the sets like .. Buttons or somebody really awesome. awesum.
Some years ago, (about 1990) I purchased a car radio from Tandy (also 'Realistic'), and it had AM stereo, and in Australia the broadcast was in 9kHz multiples. I did listen to many stations with music, but the medium didn't 'take off' the way FM stereo did (about 10 years earlier). It also had the Motorola C QUAM chip. Since then, many stations ceased broadcasting AM stereo, and at this point, in the last few years, moved to DAB+ as a duplicate to the AM broadcast with a 48kHz bit rate...
Def can hear it ! our shop at work had a Plymouth voyager w/ factory radio that played AM stereo . Benson High School here in PDX b/casts AM stereo KBPS 1450.
Absolutely convincing! 14:51, 15:03 amazing! You can't just unplug left or right signal cables because your multiplex pilot signal is in one channel. I don't understand how the FM modulation worked. Possibly it was the 25 Hz pilot? Anyway, this was excellent. I just got a TM152 recently. Plus I'm an auto mechanic that works at a..... So used car radios are everywhere. I know many of the GM Delco units were stereo. I think you showed your Ford was also. VWestlife showed a Toyota stereo which was a high line option. I just need a list to know which ones have the AM Stereo. I could nag my favorite local AM station. I even know the main news guy through a friend. I doubt they'd go through the effort to upgrade to stereo. I think they're 5,000 watt daytime. There is a littler town station which is part of a larger conglomerate. They bomb in all over my single conversion SW while I'm listening to AJ at work because their tower is several hundred feet away.... I'm in this stuff since I was a kid and will be until I'm done here on earth. Thanks again, Dan! I really enjoyed this episode. Stay well.
First time I've heared A.M. Stereo. I think it sounds quite good. Watching the moment the pilot triggered the stereo light was great. Looking forward to the official result from the radio station H.Q. "WION cactus central"
This might have been a control unit for another working CQUAM radio, explaining why it was disabled. By comparing the two, they can find differences in reception, performance, etc
That was pretty clever using the signal generator to produce the pilot signal for AM stereo...and then actually transmit AM stereo with the MP3 files. Nice. Now if only we could get the "this is a test lady"...to bounce back and forth on the speakers as she says "this is a test"...now that would be really cool...lol
OK at 14:40 My pilot light was turned on and i didn't need some blue pilot pills all I needed was some CQUAM. Awesome idea with the mp3 that really is some genius engineering, hope that engineer keeps a job after his boss died.
although only a few can listen to CQUAM stereo anymore with the MC13020 ic- the chip has provision for I and Q outputs that can be engaged to listen to LSB and USB through a 90 PSN and matrix. Those interested can check out "Build a synchronous detector for AM radio" by David Hershberger in Popular Electronics April 1982 for the PSN build.
That makeshift AM Stereo using the AM/FM signal generator worked surprisingly well. BTW, what kind of video camera do you have that has the direct aux input for the audio like that? With my Handycam I have to feed audio into the external mic input using an attenuation cable, which isn't as good as a direct line-level input.
I also thought that maybe the builder removed the resistor and bridged those pins - maybe to say its no longer a prototype and it can leave the building? Intellectual property protection?
my thoughts.. i've bought proto hardware before that was sold off as "parts only" and they all had some intentional tampering to disable functionality.
With a modern function generator, you can generate most of the signals you need to test the decoding. Using AM modulation to test the AM detector circuit, and Phase modulation to test the quadrature circuit. Peak deviation of +/- 45 degrees phase should equal 100% L-R, so 3 degrees or so of 25 Hz should fire the pilot detector circuit.
Wow! Definitely in pure stereo even through the monitor speakers. Very cool to have it working again. It begs the question if this was an engineering prototype for Motorola why disable it? It is very strange. On a side note, I'm curious about the choice of the base radio to marry the daughter board to. Sure the Radio Shack12-656, successor to the similar12-655, was a decent performing DX radio for the price. They dropped the 656 in 1983. Why would Motorola choose that one? All very interesting questions we will probably never get answered. Thank you for sharing the adventure.
iPhones can play stereo audio without anything plugged in. I could hear the stereo separation well. I’m now convinced to research to what it would require to convert my 1670 AM signal to stereo.
I used a Dolby prologic decoder to listen to the mono only through the center channel, the difference signal coming out of the rear surrounds, and the right and left mains channels off. This made the phase changes real obvious that is going on.
The sound quality seems every bit as good as its more successful frequency-modulated VHF-band counterpart. It never occurred to me that *any* amplitude-modulated signal could have audio fidelity like this. It is suspected that better sound quality would require more AM frequency signal bandwidth, which is what one doesn't see in AM broadcasts today, but it seemed to me to be more commonplace 40+ years ago, as I recall.
![CHILE vs. BRASIL [1-2] | RESUMEN | ELIMINATORIAS SUDAMERICANAS | FECHA 9](http://i.ytimg.com/vi/5ObJt_71AYc/mqdefault.jpg)
Aw, are you gonna' leave us hanging Shango ? I really wanted to join you on your field trip to the station. RIP Joe Hart, a visionary that will be missed. Thanks for the memories, Joe.
Let me start by saying I'm not into any type of electronics or repairing them, I just stumbled across your channel a few months back and subscribed. I've been a mechanic for over 30 years I found your channel when you were doing an automotive ECU repair and have watched a number of your videos since. You have excellent diagnostic strategy and problem solving skills, this video compelled me to comment, plus I love the occasional satire and sarcasm.
The satire and sarcasm is why I keep coming back. You're hooked now! 🤣
That satire and sarcasm is why we’re all here, Shango is the man!
^^ I'm with them 😄 Keep those zingers coming Shango!
Not everyone. I've never met a better troubleshooter. I'm here for the best consumer electronics technology education in the universe.
@@directcurrent5751 Shango is excellent at many things. You are correct.
PART 1 ruclips.net/video/I1HIF0toZO8/видео.html PART 2 ruclips.net/video/IDYEUqC9YO0/видео.html Part 4 and 5 next 2 weeks. Part 5 is an amazing tour of the WION studios and transmitter and is one not to be missed
Hey, so I've been watching u for awhile. My father was a dj at WION and we don't live far. Can we meet up he has some great stories???
It's incredible how much better the sound quality is under the AM radio scheme. It sounds much fuller.
The preemphasis curve has a lot to do with that. Earlier radios rolled off at 8khz or so. Most would reproduce 10khz. Then later, it went to 5, and some world radio packages roll off at 3.5! Pretty much shortwave.
10Khz, with the AM style preemphasis, is good! Many people, especially older listeners, can't tell, or can, but prefer that full sound. FM has a different preemphasis and it is more open, less full, but wider overall.
For voices, the AM scheme is great. Talk, news, and a lot of music just hits our sweet spot and that tends to overshadow the lack of bandwidth.
AMS, at 10Khz, even 8khz, rocks in a car. Road noise competes with the program. In addition, the FM fuzz is very tiring to many and it subtracts from the program. AM noise is added! Less tiring overall on a good receiver.
These days a lot of stations do brick wall 5khz and it makes voices nasal sounding and the muddy sound is tiring. They did that to make HD AM work. Some stations appear to be rolling that back to 8khz, which is much better for voice.
For a time, I had an AM Stereo kit I would listen through on good radios as a demo. People generally liked it.
All of this is true on a mone signal too! The older GE Super Radios have a wide mode that sounds like about 8khz roll off. As an office radio or casual table radio listening, working outside, etc, that full sound appeals and is not generally tiring.
Music on AM on a station that does not brick wall filter listened to on one of those, or the many respectable radios out there, will sound way better than most people realize because so damn many crappy car radios have been produced.
@@DougDingus I know GM offered AM stereo radios through the 90s. I just wish there was some AM music stations where I live, even better in Am stereo. The only music I can ever hear on AM is WSM which is eight hundred miles from my house and tends not to come in real strong.
@@tarstarkusz I may actually be driving one. Next time I'm in range I plan on trying the local station here.
I can hear stereo through my laptop speakers. Sounds surprisingly pretty good. Now, put on some Led Zeppelin ,ELP. Yes, or, Pink Floyd. Geez, even Zappa And The Mothers Of Invention for that matter.
Congratulations on reaching the 70,000 subscriber plateau.
In sure you'll be getting a lot more
Your hacked AMS modulation worked pretty well!! Sure would be nice to see this come back. It's a great experience in the car. And frankly, TALK or podcast type material is excellent. The warm AMS sound works with voices extremely well.
One of the best hacked C-QUAM schemes that I have ever heard was WOWO from Fort Wayne, IN. The station was using a Magnavox exciter but adding the 25 Hz pilot tone to trigger C-QUAM receivers. Their "faking" was so good that I did not realize that I was hearing Magnavox. It was not until some years after WOWO discontinued stereo operation that I learned that their reason for doing this was not due to programming changes but because the FCC finally declared C-QUAM the official stereo standard.
That sounds pretty damn great. Especially considering you're doing AM/PMX modulation. I did a similar experiment with my Uniden 2510 on 11 meters to myself to myself
I didn't have a 25Hz pilot but my SRF A100 didn't need one anyway. Used a Sony shortwave receiver as a conversion device and ran 450Khz before the final IF filters for wideband audio using the AM stereo radio to do All the IF work. Nice. And that's awesome that you found pin 9 being shorted to ground. When you said pin 9 shorted to pin 10. I'm liy. YUP! I've known about pin 9 to ground for forced mono since AM stereo was marketplace. That chip could actually decode 3 of the systems already with pilot tone frequency modified at the chip. VCPM CQUAM and AM / PMX all used the Motorola chip. Native Harris exciters modified for 25Hz pilot still sounded cleaner than a native CQUAM unit.
Amazing! I must say, AM is very much alive over here in Holland. Low powered, up to a maximum of a 100 Watts the stations are all around the country. We even can use frequencies originally not allocated to The Netherlands. Amd, as Germany and many other countries left AM completely, we can hear stations from far away locations. AM radio is something magic, no boundaries! Freedom to listen to what you want to listen to. Greetings, Willem, Holland.
Hopefully the late owner of the station in Arizona put together a solid succession plan.
While it may not have been "true" stereo, there were certainly some interesting phase differences between left and right. They came through loud and clear even on Chromebook speakers.
I love the bonus Sunday morning videos! Miss having them!! 🙂
It's amazing! AM stereo remained mostly unknown to me. So I made a discovery!
In the UK they used HiFi AM (not stereo)for the audio signal for TV Broadcast. Not FM like most countries.
Nice touch using period correct HP equipment.
I'm still in awe of whoever built that circuit board. Listening through a 7.2 system, the stereo is very noticeable.
Funny that this radio's IF was microphonic, I worked on 165 mHz marine radios at the big M at this time and we had serious issues with this. Must be the same coil vendor!
Former broadcast engineer here. It sounds like the L-R (fm) portion is missing highs that the L+R (am) side has. This is NOT a fault of the Motorola chip or the receiver. It is simply that the generator used does not have "pre-emphaisis" (usually 75ms) in the L-R feed. (There clearly is "de-emphasis" of the same value built into the receiver). We boost the treble (pre-emphasis) to improve the S/N of the fm component which is generally noisy, but more so here because it is very low level modulation (deviation) of the carrier. It's very much akin to how Dolby works. You boost highs on record, and cut by the same amount on playback to reduce tape hiss. Same for over the air. You can clearly hear the bass greatly increase when the L-R input is connected. You can use a simple RC network to boost the highs starting at about 6KHz and peaking out at 15Khz. You will need to carefully adjust the modulation on the L-R input to compensate with the RC filter.
I'm very glad that you got this one working! The audio bandwidth is superb and is PROOF that AM does not have to sound like an old telephone. We used to take great pride in our AM signals back in the day (before FM became a strong competitor). Many stations had audio that went out to 15KHz or higher. Then the FCC oversold the AM radio dial and boxed everyone into a 10KHz lane. Today we have so many buzzes and noises from switching power supplies, it's nearly the end of the AM broadcaster. So thank you again for letting everyone actually hear what I heard over the air, many moons ago. 73
Are you able by chance to give me a reference or link to an explanation of why preemphasis is expressed in terms of a unit of time? I've always wondered about that. Thanks.
That was so cool, We never had AM stereo in the UK, Our AM radio sounds very poor, but that sounded amazing.
I understand some AM Stereo experiments were carried out at Radio Orwell 1170Khz MW in the 80s by the IBA but came to nothing sadly.
A list of AM stereo stations on Wikipedia shows one in Ireland, maybe not close enough? 'Zenith Classic Rock' 1584 in Waterford.
Mot was an engineering powerhouse that helped shape modern technology. We’re paying for the 2000s disregard for the importance of semiconductors and industrial infrastructure in general… Freescale was debacle and a huge loss of capability.
AM Stereo is one of the most frustrating technologies. It is so much better, and we had a fairly high adoption rate among broadcasters in the 1980s, but was so poorly managed that it buried itself. My Carver TX-11a is capable of CD quality (20hz-20khz) full stereo analog audio on the AM band (better than FM). Such an opportunity squandered by others pushing there own separate standards (Kahn) for far too long during rollout.
Next sunday video...
There is good news I been working on a new form of AM stereo (C-QuAMv2) for last 4 years and made a few improvements. Such as new type of QAM modulator, noise reduction system and also has a Position Navigation and Timing (PNT) signal encoded. The prototype transmitters are in the process of been tested before on air testing starts. As stated AM stereo has a few advantages of FM stereo, I will be making more information available soon on this technology.
there zero AM Stearo that ever been around me now there only 3 AM Stations
@@granttaylor3697 YES! Someone should demo a stereo talk or news program in a well equipped car. Beats FM and is an experience people will crave.
Of course we all know music will do well too. I am just floating this idea out there to give even talker stations a reason. Probably already way too late, but who knows?
@@shango066 do you repair short wave radios for the public? I have a older Sony, looks to be in good shape, but doesn't work. If you don't do this as a business, could you recommend someone? I'm in SC.
The AM Stereo audio sounds surprisingly good! Looking forward to Part 4!
Puzzle solved. Voila! Stereo. Great fidelity, too. Kudos, Shango.
Beautiful imagining. I can still hear the 25 hz in the background
This is just totally impressive. One can only wish that AM stereo took off. Keep it up Shango! Very much into this series!
I really enjoyed this video series Shango - IIRC, here in the UK, AM stereo wasn't used. Superb work.
Sounds pretty good!
Never believed there was a true AM stereo sound.and I worked as a DJ in an AM oldies station. I noticed the chanel separation was pretty amazing.
Done right, separation can be better than FM. For a while we had an alt. rock station, KBBT that was pretty well engineered. Great listening in the car experiences.
Yeah, the .MP3 should at least not be encoded with _joint stereo_ enabled, but it would be much better if he had just sent you raw PCM in a .WAV file or whatever... *VERY COOL!* Nice work!
Shango066 Channel is turning into a "Must Watch" Channel. keep up the excellent work. 🙂
Nice ! I remember repairing a motorola Built Car stereo which also had AM stereo I still have that radio infact it was in our old 1985 Ford F series truck .
Thank you for another fascinating video, and thank you for the respect you give to the old generation of technicians.
-Boaz- , ISRAEL
Well done! Yes, the stereo demod compared to mono is VERY noticeable, using PC and amplified speakers! We had a 1991 (?) Jeep Cherokee with a factory radio that could do AM stereo. I tried it a few times, but it was only available locally on a sports talk station of all things (KFH), so it wasn't any help.
Too bad they did not try a stereo sports broadcast. It can add a lot to a play by play, or even interviews.
Shango, first of all, I'm not a big analog guy but love this damn channel. Your delivery is compelling and your snark is on point.
That said, onto my purpose for commenting.. you can generate your own C-Quam with an SDR. I use a HackRF, I have flowgraphs for everything from C-Quam to ATSC to NTSC to that bastardized standard known as HDRadio, SSB, COFDM. It's really cool, but also very useful.
There's certainly a learning curve, but for diagnostic purposes, it could be invaluable to you. Definitely worth looking into, very convenient to be able to generate whatever modulation you want on whatever frequency you want.
Damn, that stereo sounded good! When you have it dialed in just right it gives FM a good run for its money.
Pretty nice save Always cool to see old school equipment working again
R.I.P. Joe.
Good spot with the IC pins and resistor..
The stereo effect sounded awesome through my stereo system. (The speakers are either corner of the room.)
Nice work. I’ve been known to run down a rabbit hole, for no other reason than just to “see if” .. you hit the cool zone.
Separation came through loud and clear on PC speakers, JBL's grabbed at Goodwill for about $5. Sound quality and "presence" was amazing.
Wow, what a find on that radio! It's probably been decades since that stereo indicator came on!
Nice! I heard the stereo though my monitor speakers. In the 80's I heard WGN's very first stereo broadcast. Roy Leonard at the start of his show 10am Central Time stated that WGN is now broadcasting AM Stereo. He then played Bohemian Rhapsody.
S,
Years ago in the early 80's I worked for Mr Kahn. As you know his system was an ISB, and the others were AM/PM systems. We had a very special edition of the Boonton 103 that supported ISB and AM/PM AM Stereo. Have no idea where that ended up. Nice to see you can make your own pilot signal. Mr Kahn noticed an interesting problem with the early Cquam units. At night when distant carriers would zero beat with the AM stereo station, the stereo image or platform he called it would shift around at the rate of the zero beat. So if there was a 2hz difference the image would bounce around in the listeners ears. Weird issue. Like I said, long ago and far away for that. Be well, and keep it safe. Mike
Loved using the 8640 on LOS VHF/UHF AM radio comm equipment. Many of techs mistaked the display lock for a freq lock function.
Just finished watching! Great work so far.. we have a light! be interesting to see how it receives OTA! btw it's not unusual for companies to require prototypes to be intentionally disabled before they are sold / disposed etc, I remember buying some old proto computer hardware years ago labelled as "junk / for parts".. most had things like a jumper wire from one of the chips reset lines to keep it in reeset and a couple of resistors missing permanently disable it.
IT SOUNDED BETTER THEN FM STEREO! Sad AM stereo came at time when AM was dying. This does bring life back to stereo sound. Too bad I did not get an AM stereo receiver back when AM stereo was at it's peak. Can't wait for your next video on AM Stereo!
Great video Shango! I could definitely hear the stereo separation! I really enjoy your videos, thank you for the content!
Great piece of detective work finding the modifications to the original design. Look forward to part 4 and 5.
I owned a Motorola Two-Way Comms dealership from 1977, (an investment my family purchased), through 2017; 40 years. The previous owner started out as a Motorola Consumer Electronics Dealer and service center sometime between 1937, and 1940 when "Lend-Lease" was just beginning to 'really' crank up. Morrill hung around the service end of our shop, which was on our property, and in another town; he had to be 'pushing' 80, or maybe even more by that time. He 'phased-out' the consumer end of the business, when the 'guts in a drawer' (modular design due to Solid State's inception, and/or the appear of "Quasar" into the picture.
Ours was one of the markets where Peirce-Phelps acted as our area's wholesale distributor, under contract to Moto's Consumer division, with the Two-Way Comms and Industrial divisions having access to warranty replacement components, and the Motorola "HEP" Semiconductor wholesaler/retailer/distributor scheme.
Because of this strange set of circumstances, he received regular technical briefings, and also "warranty and non-warranty" upgrade and replacement kits, which came with the stipulation that he maintain the inventory of the kit's components for at least five years. Whilst I'm certain that I don't have any MC13020P IC's hanging around, it's likely that 'technical notifications' regarding CQUAM are located somewhere in filing cabinets which have an inch of dust as their decoration.
I'd betcha that California has several 'vintage' Two-Way Comms service centers hanging around, at least somewhere?? Maybe there's an HEP stash containg those same IC's, with an HEP suffix??
That sounded closer to 15kc of audio bandwidth! Amazing!
Sounds as good as the AM Stereo I used to hear over the air.
I have decent PC speakers and during your experiment, I could easily make out stereo separation. Wasn't too bad. When I saw that solder blob connecting pins 9 & 10, I thought that could be why stereo wasn't working. Being that this set doesn't have a switch to force mono, the only way to do it was to solder it permanently to mono. Neat video.
fascinating it sounded great through headphones looking forward to the next part.
I'd say that was a pretty decent demo, you can definitely hear the channel separation. I'm also was impressed how much better it sounded. Too bad it didn't become a main stay on the AM band. AM long term is probably doomed unless the right people in charge realize sometimes the simpler things tend to be the best when there really needed. Again GREAT Demo !
This is coolest vid Can hardly wait for part 4. Hope KYAT keeps it going with the owner gone.
Dear shangooo6, Sorry to hear about your friend, I will watch parts 1 and 2, Have a good day...
COOL!!!!!! I was listening on my PC and it REALLY came through!
I was able to hear the stereo separation easily on my stereo TV, with RUclips, sounds good!
Wow! On my PC speakers I had no problem hearing the stereo difference. Wow, sounds GREAT!
A couple years ago, I toured WION, Ionia, MI, met Jim Carlisle, very nice guy.
It works... I had at one time a 98 ford explorer... It had am radio! Then the display died and the replacements that followed didn't have that feature... But I remember when the am radio kicked in, I was surprised to hear the separation, then noticed the little am stereo indicator on the fluorescent display. I'm south of you in Orange County...
This is some really unique stuff! And it sounds pretty good.
Absolutely insane, AM stereo is alive!!
Sounds great, I am super impressed.
Interesting experimentation.
Once I used a tool on PC called StereoTools to encode FM stereo modulation directly into a cheap mono FM transmitter and it worked.
My last two comments on the subject of AM stereo were removed and not by me. So much for the exchange of useful info. I'm gone.
Yep RUclips does that and I can't even see them.
@@shango066 Well, so much for 40 years in the broadcast business building, operating, and maintaining all kinds of facilities including stereo AM. Shame on You Tube.
I run a pair of small-yet surprisingly punchy and dynamic A-L barrels (first gen with wallwart) and a 500 watt JBL sub from my laptop ~this sounded awesome! Such a cool thing to mix AM with FM and achieve that warm, full-frequency range tonal juggling act of waves and surf the sets like .. Buttons or somebody really awesome. awesum.
very cool. it's obvious on headphones when the stereo signal kicks in.
With headphones on I was quite impressed as I had never heard AM stereo before, it is quite noticeable from monoaural.
Some years ago, (about 1990) I purchased a car radio from Tandy (also 'Realistic'), and it had AM stereo, and in Australia the broadcast was in 9kHz multiples. I did listen to many stations with music, but the medium didn't 'take off' the way FM stereo did (about 10 years earlier). It also had the Motorola C QUAM chip. Since then, many stations ceased broadcasting AM stereo, and at this point, in the last few years, moved to DAB+ as a duplicate to the AM broadcast with a 48kHz bit rate...
Def can hear it ! our shop at work had a Plymouth voyager w/ factory radio that played AM stereo . Benson High School here in PDX b/casts AM stereo KBPS 1450.
Don't think I've heard AM stereo until now. I remember the buzz about it, and it faded away.
Sound is magnificent with stereo headphones plugged in to my lap top !
Absolutely convincing! 14:51, 15:03 amazing! You can't just unplug left or right signal cables because your multiplex pilot signal is in one channel. I don't understand how the FM modulation worked. Possibly it was the 25 Hz pilot?
Anyway, this was excellent. I just got a TM152 recently. Plus I'm an auto mechanic that works at a..... So used car radios are everywhere. I know many of the GM Delco units were stereo. I think you showed your Ford was also. VWestlife showed a Toyota stereo which was a high line option. I just need a list to know which ones have the AM Stereo.
I could nag my favorite local AM station. I even know the main news guy through a friend. I doubt they'd go through the effort to upgrade to stereo. I think they're 5,000 watt daytime. There is a littler town station which is part of a larger conglomerate. They bomb in all over my single conversion SW while I'm listening to AJ at work because their tower is several hundred feet away.... I'm in this stuff since I was a kid and will be until I'm done here on earth.
Thanks again, Dan! I really enjoyed this episode. Stay well.
First time I've heared A.M. Stereo. I think it sounds quite good. Watching the moment the pilot triggered the stereo light was great. Looking forward to the official result from the radio station H.Q. "WION cactus central"
That's cool I heard the difference clearly on my old tablet it has left and right speakers
Very cool to hear it working! I'm looking forward to the next two parts.
Looking forward to part 4!
This might have been a control unit for another working CQUAM radio, explaining why it was disabled. By comparing the two, they can find differences in reception, performance, etc
That was pretty clever using the signal generator to produce the pilot signal for AM stereo...and then actually transmit AM stereo with the MP3 files. Nice. Now if only we could get the "this is a test lady"...to bounce back and forth on the speakers as she says "this is a test"...now that would be really cool...lol
OK at 14:40 My pilot light was turned on and i didn't need some blue pilot pills all I needed was some CQUAM. Awesome idea with the mp3 that really is some genius engineering, hope that engineer keeps a job after his boss died.
Amazing! It's amazing how the big brained come up with these solutions working with limited bandwidth.
That was a cool video when you went to the station and RIP to him as well.
although only a few can listen to CQUAM stereo anymore with the MC13020 ic- the chip has provision for I and Q outputs that can be engaged to listen to LSB and USB through a 90 PSN and matrix. Those interested can check out "Build a synchronous detector for AM radio" by David Hershberger in Popular Electronics April 1982 for the PSN build.
Wild how you can figure all that stuff out.... LOL Great video! Cheers! 🍻 -Al Cox
California dreamin is an excellent song for playing with stereo...plus...its a good song.
That makeshift AM Stereo using the AM/FM signal generator worked surprisingly well. BTW, what kind of video camera do you have that has the direct aux input for the audio like that? With my Handycam I have to feed audio into the external mic input using an attenuation cable, which isn't as good as a direct line-level input.
JVC
@@shango066 Thanks... but which model?
I also thought that maybe the builder removed the resistor and bridged those pins - maybe to say its no longer a prototype and it can leave the building? Intellectual property protection?
my thoughts.. i've bought proto hardware before that was sold off as "parts only" and they all had some intentional tampering to disable functionality.
With a modern function generator, you can generate most of the signals you need to test the decoding. Using AM modulation to test the AM detector circuit, and Phase modulation to test the quadrature circuit. Peak deviation of +/- 45 degrees phase should equal 100% L-R, so 3 degrees or so of 25 Hz should fire the pilot detector circuit.
Your best video yet…
I'm amazed you got anything out of that radio
This sounded incredible on my pc speakers!
I'm listening to this with a Dolby Atmos surround sound setup. Sounded interesting when you played the mp3s.
On a headphone, the sound is very good, wide stereo and good frequency response when your settings are on the spot.
The ceramic resonators, Good name for a Band
my favorite station,….this is only a test today is a great day testing testing
Wow! Definitely in pure stereo even through the monitor speakers. Very cool to have it working again. It begs the question if this was an engineering prototype for Motorola why disable it? It is very strange. On a side note, I'm curious about the choice of the base radio to marry the daughter board to. Sure the Radio Shack12-656, successor to the similar12-655, was a decent performing DX radio for the price. They dropped the 656 in 1983. Why would Motorola choose that one? All very interesting questions we will probably never get answered. Thank you for sharing the adventure.
Very Cool! Sounded great on my iMac.
I could TOTALLY hear the stereo separation on my mac book pro speakers!
iPhones can play stereo audio without anything plugged in. I could hear the stereo separation well. I’m now convinced to research to what it would require to convert my 1670 AM signal to stereo.
I used a Dolby prologic decoder to listen to the mono only through the center channel, the difference signal coming out of the rear surrounds, and the right and left mains channels off. This made the phase changes real obvious that is going on.
The sound quality seems every bit as good as its more successful frequency-modulated VHF-band counterpart. It never occurred to me that *any* amplitude-modulated signal could have audio fidelity like this. It is suspected that better sound quality would require more AM frequency signal bandwidth, which is what one doesn't see in AM broadcasts today, but it seemed to me to be more commonplace 40+ years ago, as I recall.
That works really well!
It works fine, Its stereo for real! ! the quality is not bad eather!! (To my amazing!)
That is pretty cool works better than I would expect.
So all it took was separating the pins and adding the proper resistor and stereo AM was unlocked. 😮
That is my kind of video, knowledge building. Inspiring ; I think I will go to my shop and do something...73 Leo K