AM Stereo (C-QUAM) Conversion

[Titan1a]

I'm ordering a Meduci AM STEREO C-QUAM DECODER CONVERTER ADD-ON BOARD for a tube-type table model radio. This would involve taking the IF signal before the detector. Is this feasible or should I purchase a transistorized table radio? This is to complement a Radio Shack AM-STEREO tuner.

[Dave A]

Rick, this looks like a board to create an AM Stereo receiver on various modern/xstr stereo sets. The tube version is a non-starter. Tube radios of the day are not capable of AM Stereo as they have one discrete channel unless you want stereo mixed to mono on one AM frequency. A few Japanese plastic sets from the 70's did FM Stereo but not C-QUAM.

The Meduci site shows various receiver/boom box conversions that look awkward. You already have the RS receiver as do I. That is all you need for a receiver...just send it to an amp and the speakers. You need a xmtr.

And here are a few OTA stations still doing AM Stereo if you live in the area;

http://meduci.com/st_stations.html

What are you using for an AM Stereo C-QUAM xmtr? I have a kit I bought years ago at Kutztown. Here it is at the bottom of the page but I am not sure if he is still selling it;

http://www.amstereo.org/ccuff.htm

And I just bought a 1995 Cadillac with an AM Stereo radio installed. I may have to try mine to listen in the driveway. Good luck.

[Titan1a]

I copy you. I'll pursue a different tack by purchasing a recommended tuner from the list. I appreciate your reply.

[NJRoadfan]

Even if you don't have too many AM Stereo stations nearby, many of the C-QUAM compatible tuners have excellent FM Stereo sections in them as well. The Sansui TU-D99AMX is one of the best FM sections I've heard, while the "unobtainium" Denon TU-680NAB is a close second. I really can't judge the Marantz SR-940 at the moment as its FM tuner needs to be realigned (you have to tune 50khz above a station's broadcast frequency to get stereo), but it is a nice amplifier.

[colorfixer]

Irrespective of whether there are any stations still encoding C-QUAM (and if so, how many of 'em are not pure talkers), the synchronous AM detection, plus the proper AMAX/NAB spec for the tuner justifies their existence.

[wa2ise]

I've modified a Sony SRF42 AM stereo portable set to have its synchronous AM detector operate on receiving the main channel, good for mono station reception
http://pw2.netcom.com/~wa2ise/radios...d.html#syncdet

[loopstick]

Originally Posted by colorfixer

Irrespective of whether there are any stations still encoding C-QUAM (and if so, how many of 'em are not pure talkers), the synchronous AM detection, plus the proper AMAX/NAB spec for the tuner justifies their existence.

Hit the brakes! SCREEEEEEEECHHHHHHHH .......

Do all AM Stereo receivers have synchronous detection? Does my MCS 3050? The only local AM stereo is ESPN but I'd still like the Sych Detect if it has it. It would I assume reduce selective fading with CHZM AM-740 Toronto. Might even clean up normal daytime groundwave DX. Dunno. Asking.

[jr_tech]

At least in one case the inverse is true... The Sony ICF-2010 portable Shortwave receiver, which is noted for its high quality sync detection, uses nothing more sophisticated than a Motorola C-QUAM chip for sync detection. For several years my 2010 had a couple of shielded cables sticking out through the side of the battery cover for AM stereo reception (I did *not* drill holes in the fairly collectable piece ! )... Worked great!

http://users.hfx.eastlink.ca/~amstereo/sony2010.htm

jr

[loopstick]

I was actually at a "crossroads" in the mid-80's and was deciding between the Sony 2010 and the Sangean ATS-803A. I decided against the Sony because it looked too small to be a good DX machine.

I remember cleaning out an apartment after I moved all the furniture out and the only "furniture" I had was the Sangean. Then breaking news on SW: Chernobyl. Reports from around the world on where the cloud was heading. That was a weird time in Russia anyway because Glasnost was happening and you heard some wild stuff on Radio Moscow that you'd never hear in the days of Vladimir Posner. I digress.

Here's the Motorola chip in the MCS:





edit: Here's what an AK'er who used to work at Harris IIRC thinks about it:

KAHN AM Stereo/FM Stereo "Stereo, Stereo" tuner – Post 12 - W9TR

________________

[Steve D.]

Just for yuks, thought I'd post my 1983 Sony SRF-A100 AM stereo radio. Not sure any L.A. stations are broadcasting in AM stereo anymore.

-Steve D.

[Titan1a]

I purchased the decoder/converter. Let's see what's next...

BTW One of Chicago's flamethrowers is still broadcasting C-QUAM.

[old_tv_nut]

Originally Posted by Titan1a

BTW One of Chicago's flamethrowers is still broadcasting C-QUAM.

Really - which one?

[Titan1a]

Wls 890.

[old_tv_nut]

Thanks - too bad it's a talk station.

[colorfixer]

Yes, the SRF-A100 does by virtue of the fact that it has C-QUAM...