UHF TV Audio

[bonnevillemariner]

I realize this thread may be better suited in some ways to the TV section of this forum, but it's mainly a radio question. Feel free to move it if it's more appropriate there.

We lost power in my neck of Tooele Valley yesterday afternoon, so I grabbed my scanner to see if any of the local hams were talking about it (they weren't; nobody ever does). Just scanning around, I chanced upon an audio broadcast on UHF 450.212 that sounded like TV. This didn't surprise me because I know many stations broadcast an audio feed in this band. A quick Google search told me this was a KUTV frequency.

What did surprise me was when the frequency suddenly went silent. I listened for several minutes, then moved on. When I checked back a few minutes later, still silent.

Can anybody tell me why I would pick up KUTV audio one minute and it's gone the next? Does the station only selectively broadcast audio on those frequencies, or could my scanner be faulty? (I wondered later if the silence was commercial breaks.) Scanning the other frequencies dedicated to TV channels yielded only silence. 450.287, which the Internet says is dedicated to KSL TV audio, was silent all day, despite my house in Stansbury Park being line-of-sight unobstructed to Farnsworth Peak. Can anybody help me out here?

[christopherjohn]

I wonder if they were doing a live broadcast and that had something to do with it....

[CAwasinNJ]

Exactly my thought too. I would guess it was the audio from master control being sent out on an ENG channel so someone in the field could hear when the anchor throws to them for a live report. Once that was over, no need to send that audio anymore. Was there a news broadcast going on at the time?

[kenglish]

Those are IFB ("Interrupt-able Fold-Back" or "Isolated Fold-back") channels. They usually come from different mixes out of the news audio board, since they are tailored to exclude the field reporter's own mike, to eliminate the delay caused by encoding and decoding the digital microwave feeds or satellite delay.

The 450.2875 MHz, with the hum and everything, is the old KSL IFB. KSL and KUTV are both now using a new system which keeps the audio up continuously during the newscast production (minus the commercials), and the field folks have a radio that also monitors an "interrupt" channel that the producer and director can talk "in-their-ears" on. That one is tone-controlled, so only one reporter gets talked to at a time, with the program audio squelched. They don't get the cues intended for anyone else. Those are on some new frequencies, both in and out of the Broadcast Auxiliary Service bands (which, at UHF, are 450-451 and 455-456).

Happy listening...just remember that privacy rules apply, under the ECPA-1985 .

[bonnevillemariner]

Thanks for the info, guys. Yes, I believe it was a newscast. I heard what seemed to me to be an extremely lengthy weather report by a female voice followed directly by a sports report by a male. I kept waiting for somebody to say a call-sign, but no luck. I remember the good old days, pre-digital (when I could actually pick up channels on my TV without buying $100 worth of extra equipment), when TV channels broadcast their full audio 24/7 on frequencies your radio's 'TV band' could receive.

[David]

FYI, there are several other frequencies in the 450-451 and 455-456 MHz bands that are infrequently used for remote broadcasts, helicopter traffic reports, etc. which at times are very interesting to listen to. If you have a full frequency coverage base scanner (e.g. Realistic PRO-2006) with a good outdoor antenna mounted at least 20 feet above ground, you can even hear some of the studio to transmitter (STL) links in the 25-27 MHz band when the E and F layer DX favors the West; that is, if the bootleg CB operators aren't dominating the frequency with a 1,000 watt linear amp!

[kenglish]

www.ecfr.gov/cgi-bin/text-idx?SID=bae22e7684fb3e084140ae4a2dfaf3d3&node=47:4.0.1.1.3.3.1.2&rgn=div8