Need an AM stereo generator

[rickradio]

I'm looking for a low-cost (?), no-frills AM stereo generator for my part 15 AM. Can anyone point me in the right direction? I'm already on the air with a transmitter that I'm happy with and am just looking for a companion to generate a tone. I already know about the Greek company that makes Part 15 AM stereo transmitters and sells 'em on eBay, but like I said, I already have a transmitter/antenna setup in place and am not looking to replace either.

Thanks to all.

 

[kevtronics]

I have not heard of any low-power AM Stereo exciters. In the 100 mW power range, it is much better to design an integrated AM Stereo transmitter, because trying to interface one person's AM Stereo exciter with another person's mono AM transmitter would be very difficult due to the lack of industry standards for such devices.

For my own low-power AM Stereo broadcasts, I use a Panasonic VP-8253P AM Stereo generator. It is identical to this VP-8254P that is currently on eBay, except that it is a multi-system generator (C-Quam, Kahn, Harris, and Magnavox), while the VP-8254P is C-Quam-only:

http://cgi1.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270185133588

The seller's comment about poor stereo separation could either be a problem with the generator or with the radio he tested. I have measured up to 38.5 dB of stereo separation at 400 Hz on a C-Quam receiver with my VP-8253P, but some radios have noticeably poor stereo separation on AM, especially car radios.

 

[rickradio]

Thanks a bunch, Kevin. I guess it's that Greek company if I want to go AM stereo. The problem is, like I said, I already have a transmitter I'm happy with, and if my hunch is correct, this Greek stereo transmitter has no on-board processing, which means, like the Rangemaster I already have, I'm gonna have sink gobs of money I don't have into an audio chain to go stereo.

Oh well, another day, I guess...

 

[RadioMan203]

I don't see the external processing as the problem. The thing I'm a little put off with is that the Greek unit isn't Part 15 certified yet. I had corresponded with the manufacturer and they are trying to find an American vendor to assist them with it. I would buy a couple of these in a heartbeat if it was Part 15 certified - I don't want the feds knocking on my door (or the high school where I'd like to set them up).

 

[CW]

I'm looking for a low-cost (?), no-frills AM stereo generator for my part 15 AM. Can anyone point me in the right direction? I'm already on the air with a transmitter that I'm happy with and am just looking for a companion to generate a tone. I already know about the Greek company that makes Part 15 AM stereo transmitters and sells 'em on eBay, but like I said, I already have a transmitter/antenna setup in place and am not looking to replace either.

Thanks to all.

I have a Motorola CQUAM exciter which goes into the xtal spot of any AM exciter....you feed the L+R into the AM transmitter as normal but L-R goes into the CQUAM exciter which then replaces the xtal in the transmitter. The CQUAM exciter requires a xtal 4x operating channel. Have exciter AND Monitor for $250 + shipping..Also have Chris Cuff AM Stereo QUAM exciter that is on 1000KHz but a BAD buzz on that freq makes it useless at my house....

 

[dtube1]

I have a Delta ASE-2 AM stereo exciter sitting here, collecting dust. It was working when pulled from service 5-yrs ago. Audio goes in - AM stereo goes out (and no one is there to hear it) E-mail if you're interested.
-Darren

 

[rickradio]

I don't see the external processing as the problem. The thing I'm a little put off with is that the Greek unit isn't Part 15 certified yet. I had corresponded with the manufacturer and they are trying to find an American vendor to assist them with it. I would buy a couple of these in a heartbeat if it was Part 15 certified - I don't want the feds knocking on my door (or the high school where I'd like to set them up).

Looks like you're in a different situation than I am, Bill. I certainly don't blame you for wanting Part 15 certification...if I were doing what you are (involved with a school and all that), I'd want certification, too. But in my situation, I'm pretty much indifferent about that. The transmitter I have isn't certified, and it hasn't presented a problem. But then, I'm not a loose cannon with my setup, causing all kinds of problems with everyone around me, and I keep a close ear on my signal. My priority is having excellent audio, which I currently do, and am not willing to give that up. If it comes down to a choice between excellent audio and certification, I go with good audio. Now, if our Fed friends come calling, they'll tell me what their problem is with my facility, at which time I'll tip my hat and either fix it or go dark, but until then, I'm not going to try to fix what isn't broken.

 

[Tube Shortwave]

I spoke to an engineer today that has a COMPLETE Khan AM stereo setup! It all is rack mount and there is one BIG box and a couple smaller boxes. He even has the matching Khan AM modulation monitor. He says he would be willing to sell at the right price.. Hmmm.... Gonna go check my couch cushions for change.

 

[RadioMan203]

I don't see the external processing as the problem. The thing I'm a little put off with is that the Greek unit isn't Part 15 certified yet. I had corresponded with the manufacturer and they are trying to find an American vendor to assist them with it. I would buy a couple of these in a heartbeat if it was Part 15 certified - I don't want the feds knocking on my door (or the high school where I'd like to set them up).

Looks like you're in a different situation than I am, Bill. I certainly don't blame you for wanting Part 15 certification...if I were doing what you are (involved with a school and all that), I'd want certification, too. But in my situation, I'm pretty much indifferent about that. The transmitter I have isn't certified, and it hasn't presented a problem. But then, I'm not a loose cannon with my setup, causing all kinds of problems with everyone around me, and I keep a close ear on my signal. My priority is having excellent audio, which I currently do, and am not willing to give that up. If it comes down to a choice between excellent audio and certification, I go with good audio. Now, if our Fed friends come calling, they'll tell me what their problem is with my facility, at which time I'll tip my hat and either fix it or go dark, but until then, I'm not going to try to fix what isn't broken.

Believe me, audio quality is a concern for me as well. I have several things to be mindful of in my case. I actually engineered an AM in the general area of the school district I work for and I know some of the local engineers for the stations in my area. While I'm sure they would be alert me to any problems which may be caused by the transmitter if they caught wind of it I don't want to make any ill will with the locals. I also know a couple of the engineers at the local (more like regional) FCC field office and I really don't want to have to answer a question of "why do you have a non-certified unit" - especially considering it's not my money purchasing it. Personally, I want both audio quality and certification.

I had actually thought if I was lucky enough to get a regular broadcast stereo generator I would just go with carrier current since it would probably be near impossible to interface the generator with, let's say a Hamilton Rangemaster.

I do remember the Kahn stereo generator, too. The one I had at my AM was the first version generator, Kahn model STR-77 if I recall. It interfaced rather well with the Harris MW-1 that served as the main transmitter. A very large box with the card cage, then a chassis with the metering and another one with the power supply. I actually ran it in a psudo-PowerSide mode by adjusting the audio processing differently for each channel. I did an overnight test for the Nation Radio Club and a couple of people actually picked up on the fact I was emulating PowerSide.