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jimbofish 06-13-2009 12:58 PM

Quote:

Originally Posted by wa2ise (Post 2808536)
Many stations have a direct video feed to the area's cable companies, so they may not have worried too much about the over-the-air viewers that much... And they may have wrote off the day's lost commercials.

I have a feeling they've written off all the OTA viewers too.:tears:

BTW, the other two channels came back today shortly before noon. So it looks like the entire switchover process must take approx. 11 hrs. Too bad their signal is so variable that we won't be able to watch their programming, even though we are within the published circle.

ChrisW6ATV 06-13-2009 03:10 PM

Quote:

Originally Posted by ChrisW6ATV (Post 2807840)
Interesting-they are running one of those out-of-band "pseudo-FM-radio" stations like the one in New York City. Since it is low-power, it may stay on the air indefinitely and be a remaining source for OTA analog tuner testing.

Quote:

Originally Posted by wa2ise (Post 2807903)
Only if the TV set isn't the "intercarrier" IF strip type. That is, a 6MHz wide passband that feeds a video detector, which also produces a 4.5MHz FM sound carrier. Older sets had a completely separate sound IF.

Why would the type of sound IF matter with that low-power TV station? Isn't the sound going to be on 87.75 MHz with 25 kHz deviation, 10dB below the video carrier on 83.25 MHz in any case?

wa2ise 06-13-2009 05:05 PM

Quote:

Originally Posted by ChrisW6ATV (Post 2808865)
Why would the type of sound IF matter with that low-power TV station? Isn't the sound going to be on 87.75 MHz with 25 kHz deviation, 10dB below the video carrier on 83.25 MHz in any case?

If there's no picture carrier 4.5MHz below that FM station, most analog TV sets won't demodulate it, as there won't be a signal at 4.5MHz at the video detector diode. (I assume that the FM station at 87.7 or 87.9 has no "video" signal associated with it. Though someone could put up an MTV LPTV station on channel 6 so as to become a fake FM radio station).

If you set a TV to channel 6, or cable channel 96 (cable channel using the spectrum between 88 and 108), inject a local oscillator into the TV set antenna port, along with an antenna picking up FM radio stations, and tune that oscillator to a frequency 4.5MHz below a desired FM station, you should hear it out of the TV set's speaker. It will probably sound overdeviated though.
If your town happens to have two FM stations approx 4.5MHz apart, you may hear a really yucky mix of both their audio.

zenithfan1 06-13-2009 09:17 PM

Quote:

Originally Posted by wa2ise (Post 2809051)
If there's no picture carrier 4.5MHz below that FM station, most analog TV sets won't demodulate it, as there won't be a signal at 4.5MHz at the video detector diode. (I assume that the FM station at 87.7 or 87.9 has no "video" signal associated with it. Though someone could put up an MTV LPTV station on channel 6 so as to become a fake FM radio station).

If you set a TV to channel 6, or cable channel 96 (cable channel using the spectrum between 88 and 108), inject a local oscillator into the TV set antenna port, along with an antenna picking up FM radio stations, and tune that oscillator to a frequency 4.5MHz below a desired FM station, you should hear it out of the TV set's speaker. It will probably sound overdeviated though.
If your town happens to have two FM stations approx 4.5MHz apart, you may hear a really yucky mix of both their audio.

It does have picture, scenes of Chicago. I think it is a rule that if there is sound being broadcast, there must be a picture too.

mid-fi-ry 06-13-2009 09:27 PM

In Chicago I heard that the WGN nightly news, I think they said twice a day, will still be broadcasted on another station (not 9 in chicago) for a few weeks.

bandersen 06-13-2009 10:04 PM

Quote:

Originally Posted by mid-fi-ry (Post 2809509)
In Chicago I heard that the WGN nightly news, I think they said twice a day, will still be broadcasted on another station (not 9 in chicago) for a few weeks.

Yep.

"For those who have not yet made the switch, WGN's 9pm news will be simulcast on WWME Channel 23 for a few weeks, every night. The simulcast only applies to the News at Nine and not other WGN programs."

ChrisW6ATV 06-15-2009 02:45 AM

Quote:

Originally Posted by wa2ise (Post 2809051)
If there's no picture carrier 4.5MHz below that FM station, most analog TV sets won't demodulate it, as there won't be a signal at 4.5MHz at the video detector diode. (I assume that the FM station at 87.7 or 87.9 has no "video" signal associated with it. Though someone could put up an MTV LPTV station on channel 6 so as to become a fake FM radio station).

As Zenithfan1 said, it does have video programming, though that seems to be just to meet the 'letter of the law" for a TV station license, but not its "spirit". The obtaining of a low-power TV station license on channel 6 with the specific intent to act as a radio station is what I meant by "pseudo-radio-station". New York City has one of these as well, and I saw comments by someone who was disappointed that a particular FM radio tuner could not tune down to 87.75 "properly", when it is of course not in the radio broadcast band at all.


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