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FM Stereo

Y-100/Miami had a quad hour on Sunday nights, around 1974-1975.... of course no one ever heard the Quad effect on a radio! And, back around '74, Y would switch to mono on big beach days, so the portable radio audio would be better. Or, that was the plan...
 
In the 1970s/1980s, the FM Stereo indicator light on home on radios was long considered audiophile reassurance that this was a real broadcast from a real competent radio station who can afford FM Stereo. So much so that some mono stations even added a 19 kHz pilot, even if they were still mono (LPFMs often still do.)

I still see it that way. It means my radio isn't spazzing out. Even if I am.
 
Y-100/Miami had a quad hour on Sunday nights, around 1974-1975.... of course no one ever heard the Quad effect on a radio!

Those with either a dedicated Quad receiver or a Quad decoder did. There's a big difference between "not enough" people bought them and "no one" did.

Here's the real-time progression of Billboard's coverage:

1974: https://www.worldradiohistory.com/h...rd-Page-0037.pdf#search="quad receiver sales"

1975: https://www.worldradiohistory.com/h...rd-Page-0026.pdf#search="quad receiver sales"

1976: https://www.worldradiohistory.com/h...rd-Page-0006.pdf#search="quad receiver sales"

Competing formats, higher receiver prices and a shortage of recorded material to carry all-quad stations all contributed to the failure. But it was slo-mo. There was a good five years from stations in the U.S. starting Quad broadcasts (1972) to it being pretty much over (1977).
 
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I recall the old KZEW in DFW would occasionally broadcast a test tone for adjusting quad receivers. It was IIRC sort of a steady pulsing sound. Anyone remember that or how it worked?
The Zoo may have very well had a "tone" at one point, but I only remember the test as a type of "hash" sound, kind of a static if you will, that would be fed into each speaker separately. This would have been in the early 1980's. My folks had an old Zenith stereo console that had 4-channel capabilities.

I can't begin to tell you how many times I got the belt for "fiddling with my <blankety blank> radio." He always knew, regardless of how careful I thought I was being.
 
I recall the old KZEW in DFW would occasionally broadcast a test tone for adjusting quad receivers.
Are you sure you're not confusing that with Dolby FM? Stations that used it periodically transmitted a tone for listeners to calibrate their Dolby NR decoders.
 
Quite a few small town FM's were still mono until the early 80's.
When I drove west from Chicago to move to the San Francisco Bay Area in January 1999, I took a more southern route through New Mexico and Arizona. That also meant going through the Texas Panhandle. On one segment of the trip, I stopped off in Dalhart, Texas for lunch. The local station, KXIT, was on AM and FM, simulcasting. The AM had started out as a daytimer on 1410 kHz but moved to 1240 kHz sometime around 1983, gaining fulltime status. So a 100% AM/FM simulcast really wasn't necessary. Not only that, though; the FM was still in mono. In 1999.
 
When I drove west from Chicago to move to the San Francisco Bay Area in January 1999, I took a more southern route through New Mexico and Arizona. That also meant going through the Texas Panhandle. On one segment of the trip, I stopped off in Dalhart, Texas for lunch. The local station, KXIT, was on AM and FM, simulcasting. The AM had started out as a daytimer on 1410 kHz but moved to 1240 kHz sometime around 1983, gaining fulltime status. So a 100% AM/FM simulcast really wasn't necessary. Not only that, though; the FM was still in mono. In 1999.
Mono sounds bigger in Texas…. šŸ˜†
 
When I drove west from Chicago to move to the San Francisco Bay Area in January 1999, I took a more southern route through New Mexico and Arizona. That also meant going through the Texas Panhandle. On one segment of the trip, I stopped off in Dalhart, Texas for lunch. The local station, KXIT, was on AM and FM, simulcasting. The AM had started out as a daytimer on 1410 kHz but moved to 1240 kHz sometime around 1983, gaining fulltime status. So a 100% AM/FM simulcast really wasn't necessary. Not only that, though; the FM was still in mono. In 1999.
Looks like KXIT-FM came on the air in 1966, so it was useful as a nighttime extender back then. But why they didn't do something else with it after 1983.....?
 
Matrixed quad systems like SQ, QS, and EV-4 work over any two-channel stereo format, so any stereo radio station that plays one of those recordings instantly become a "quadraphonic radio station", even today. But the front-to-rear separation isn't nearly as good as discrete quad systems, in which the four channels of audio are kept separate.

Various methods of using a subcarrier to transmit discrete rear channel audio were experimented with in the 1970s, but none became a standard. Lou Dorren, who worked with JVC and RCA to develop the CD-4 Quadradisc system, claims the FCC chose his method of discrete quad FM in 1983, but actually all the Reagan-era FCC did was deregulate FM subcarriers and allow stations to use them for anything as long as it doesn't cause any interference.
There has always been unintended Quad matrix in nearly all commercial stereo recordings. In every format from vinyl to digital.

Some sounds, are mixed somewhat to completely out of phase to achieve an effect in conventional stereo. And those out of phase sounds, instruments and voices will sometimes end up coming out of the rear speakers of Quad receiver/amps. Often randomly. Including on recordings made long after Quad's heyday. Even today. It's a simple by product of stereo.

It can still even be heard from FM radio. The F/R separation still isn't huge, but certain sounds often come through noticeably from behind. If it's a commercially made stereo recording, production music, vocal effects in imaging, rear sounds will randomly appear sometimes.

A good test song for hidden Quad is "Bennie And The Jets" Elton John.

Even though it was a fake live stereo recording and never promoted as Quad, his engineer, David Hentschel was brilliant. On a Columbia Masterworks SQ system, you could distinctly hear the reverb and ambient noise predominantly in the rear while the music mostly remained up front. And the crowd noise completely surrounded you to a near 3-D effect. That was from the stock MCA first pressing of Goodbye Yellow Brick Road.

I'm sure Elton knew about it. Such subtle surprises are on brand for him.

Even on digital music formats, the F/R separation on "Bennie And The Jets" is still noticeable on that old Columbia Masterworks SQ receiver/amp. It should be on some DSPs too.
 
I recall FM stereo in the early 60's. My older brother had a friend at the time that was really into HI-FI . . . had a nice turntable, speakers, AM/FM RX, AMP and a STEREO ADAPTER he got later . . . if I recall correctly he even had the ability to tune on his tuner an AM station and an FM station at the same time that was broadcasting the LEFT CHANNEL on AM and the RIGHT CHANNEL on FM.
It had two dials.
In the NYC area where we were located, I think WQXR AM / FM did this, before FM stereo.
Then he got a STEREO ADAPTER when they came out, that worked very good on the NEW NYC FM STEREO stations. It worked on his tuner that an input for such an adapter.

The guy that messed around much with QUADRAPHONIC in SF was Jame Gabbert when he owned KIOI-FM 101.3. . . I believed he had a special show on at night that was all QUAD, in the early 70's

I got to know Gabbert when I was doing transmitter maintenance for KQED-TV at Sutro Tower, he had moved his Channel 20 TV from San Bruno Mountain to Sutro . . . he was a nice guy and a real character.
 
KING-FM in Seattle did some experimental quad broadcasts on Sunday eveings for a few months. The story (related much later, BTW) was that it negatively affected fringe reception without netting much in the way of improved sound quality. Multipath is an issue in Seattle, and KING at that time was broadcasting from a fairly low antenna. Supposedly quad reduced useful coverage to about an 8 mile radius? Not sure I buy that, but this was supposedly reported at the time.

Of much more humorous interest was KQIV 106.7 Lake Oswego/Portland OR. They advertised their AOR format as "Rockin In Quad" and stated they were running full time in Quad. They, ummm, were not capable of transmitting quad...but they always wanted to. LOL their studio was an upstairs office of the local Elks lodge.

Rockin' In QUAD, baby!
 
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Quite a few small town FM's were still mono until the early 80's.
Today, there are still mono stations operating, at least in my city. 5 years ago, 100% of the stations were stereo, today there are 25% operating in mono.
 
If you run a spoken word format (news, sports, preaching etc) mono works fine. You also gain a slight very slight coverage and building penetration. Simpler STL too.
 
Today, there are still mono stations operating, at least in my city. 5 years ago, 100% of the stations were stereo, today there are 25% operating in mono.

If you run a spoken word format (news, sports, preaching etc) mono works fine. You also gain a slight very slight coverage and building penetration. Simpler STL too.
It's somewhat common for talk and sports stations to be in mono. In Denver, the following stations are in mono:

89.7 - KXGR - religious, Calvary Chapel, mostly preaching
90.1 - KCFR - news, Colorado Public Radio
91.5 - KUNC - news, Community Radio for Northern Colorado (transmits from northwest of Fort Collins but gets into Denver well)
92.5 - KKSE-FM - sports
93.7 - translator for KDFD(AM)
94.1 - translator for KOA(AM)

In addition, 88.5 KGNU from Boulder (99.1 translator in Denver) turns on stereo broadcasting only for music programming. AM drive and PM drive informational programming ("Democracy Now" and the like) are in mono.

Mono gives greater noise-free coverage compared to stereo, though actual signal strength isn't altered. It's important to keep these two concepts separate. That's why better radios and other receivers have a "mono" button if the added noise of the stereo subcarriers gets to be too much.
 
Many AM stations have mono FM translators now, even if they play music. All three of 1510 WRNJ's FM translators were mono until a few months ago, when they upgraded to stereo.
 
IIRC The failed 106.7 all news in Atlanta, WYAY when they first signed on, rigged up the server that played commercials to be in stereo while everything else was in mono. Cool engineering but could not make up for poor execution of on air programming. (That's just my opinion but compared to WBBM and NYCs 1010 very down tempo and really bad sounders)
 


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