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AM HD Stereo or Mono

There is always the jingles, bumper music, and camersials for AM stereo talk. I remember when WPHT was in AM Stereo, and man did it sound good, especially on an AM Stereo receiver such as the Sony SRF-42 and A100 radio's.
 
AM Stereo 630 from Chatham Ontario has stereo music and it sounds fantastic - even 80 miles away! Another great sounding stereo AM station if you're in the North Country of NY State is "Hometown Radio AM Stereo 1340" WIRY in Plattsburgh, NY.

The stereo coverage at night was unreal - the Grand Ole Opry from WSM came booming in, as did WHAS, WJR, all the Chicago AM's - even the stereo spots were sweet. CQuam is a good technology, and the FCC should have mandated that all FM HD radios have CQuam AM Stereo included with DSP noiseblanking - that would have been a good call, in my opinion.
 
Not being an engineer, could someone please advise what the cost would be on installing a CQuam system on a typical AM station? What would these cost be compared to an HD setup? What are the maintenance costs with each?
 
KyDXIn said:
If I can receive a good quality AM stereo signal from Iowa to Kentucky on 1630AM, and also from WLS Chicago, then I'm sure more can be received if stations would give up the ghost on HD radio. WSM sounded great when it was in stereo. We should do all we can to promote this. I wonder how many stations still have AM stereo equipment that was turned off in favor of the HD system?
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The mass turnoff of AM stereo predates HD, so there's probably well over a hundred AMs with dormant, functional stereo equipment (not necessarily C-QUAM) out there. I do know of a few that held out until converting to HD, mostly Crawford stations…

As for cost, I'm no engineer but I've read several times on here that stereo is in-built to many modern transmitters so other than upgrading the sound path to stereo if it isn't already, the costs to go C-QUAM should be minimal compared to the tens of thousands for HD upgrades (new TX, new tuning system, etc) and the ongoing license fees.
 
KyDXIn said:
Not being an engineer, could someone please advise what the cost would be on installing a CQuam system on a typical AM station? What would these cost be compared to an HD setup? What are the maintenance costs with each?
Click to expand...

I'll take a crack at this and say about $4,000 difference for AM stereo. That was the difference between a straight AM transmitter and one with a stereo exciter quite a few years back, although I haven't bought any new AM equipment in a while. BUT... (there's always a but) the antenna system has to have decent phase response across the entire channel. It doesn't have to be nearly as broadband as it does for HD, but it needs to be better than required for straight AM - especially the narrow-band signals that pass for AM these days.

HD cost will depend drastically on the power level of the station. But it's WAAAY more than AM stereo. Probably a delta somewhere between $20,000 and $100,000 but that's just a wild guess. I haven't had a need to even investigate the cost of AM HD.

Again, the antenna system is the serious wildcard. Antenna upgrades might cost nothing, might cost way more.

Dave B.
 
KyDXIn said:
Not being an engineer, could someone please advise what the cost would be on installing a CQuam system on a typical AM station? What would these cost be compared to an HD setup? What are the maintenance costs with each?
Click to expand...

I should mention - a fair number of HD receivers out there can also decode C-Quam, so it might be a sneaky way for a station to go stereo and improve sound quality without the hefty license fees to iBiquity!
 
My understanding is that almost NO directional AM operating-as-designed will function as-is with HD. Tinkering is always required; the common point impedance curve is never suitably flat or linear. And many, if not most, directional systems can't be flattened and wide-banded sufficiently without a complete rebuild, which explains why very few AM stations operate with HD at night (note that a large proportion of AMs, particularly those dating to the 1945-65 period, run NDA daytimes and go directional at sunset.) So rather than spend potentially hundreds of thousands on antenna rebuilds which would require FCC licensing, even the few HD-AM fans out there are simply opting to turn off the Hissmaster at sundown.

My information is that adapting WMVP (former WCFL) 1000 Chicago for HD cost millions. And eventually it was turned off anyway.

There are of course exceptions, but many of them are high-powered AMs owned by companies whose people have invested heavily in HD, either financially or career-wise, frequently both. And many are 1A clears which are nondirectional anyway (although there are problem cases even with NDA 50kw'ers like KDKA.)
 
Even single tower omni clear channel 1A's shut off their HD buzzoids at night, such as WJR and WLS. And WLS runs their CQuam stereo too. Wish WJR would, but now their engineer is gone, so I don't know if that will ever happen.
 
I think a lot of C-QUAM was shut down in preparation for HD since it was well know the two couldn't co-exist.

WBZ shutdown C-QUAM I think in 2002. I wrote a complaint and the response was that a new transmitter for HD use had been installed. For quite a while after that, they still had a backup transmitter that was C-QUAM equipped and when it was online my AM-Stereo receivers would light up. I have tape from early 2004 with them in C-QUAM.

A lot of vehicles in the late '90's early 2000's had C-QUAM recievers and I'll bet if HD hadn't come along that would have continued.
 
Maybe the FCC could give some tax incentives to stations to broadcast in AM Stereo, in an effort to clean up the horrible noise-laden band.
 
kc1ih said:
The FCC has nothing to do with taxes.
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However, for a number of years the FCC was the overseer of a tax credit program where sellers would benefit if they sold to minorities. This was supposed to allow sellers to give better prices and encourage sale to minorities.
 
Stereo AM stations also got preference when they did the initial allotment of Exbanded AM band stations, but KCJJ is one of the few that have kept it up and honored their promise and didn't hog BOTH an original frequency and XBand frequency. The idea was that after you got your Xband station going that you went dark on your original frequency to help clean up the AM band, but most of the sows sold their original station so that band was/is just as cluttered!
 
Since KCJJ has come up, I have a bit of useless trivia. They're the only AM stereo station I know of that's ever aired a show of all quad-channel songs. The Robb Spewak show did four hours of quad, re-encoded for Dolby Pro Logic II analog surround.

Talk about catering to a TINY audience! But I heard it (via mp3) and it was very entertaining. I've also heard an AM stereo aircheck of one of Spewak's music shows recorded off KCJJ. Their AM stereo still sounds good.
 
Ah a maduci fan too. Jeff has made it so that AM can sound good. even mono AM. hard to tel with stereo music in spanish, 1310 WEMG. hey the stereo works, but i dont know spanish music.... but WVLG is wow. now what would really be interesting is a station on AM with a tuner like that with less processing in the air chain.
More dynamic range would be nice to hear.
 
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