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Re: WWV 25MHz very useful.

March 05, 2015 12:31PM
Hey Boomer? Well, you're kindda' right. What I was referring to was an analog TV stations video carrier's RF FREQ. I tuned a scanner up that way once. WNED-TV CH17 wasn't strong enough to even be detectable on a TV set. The station had its TX on Grand Island, NY (Right between Buffalo / Niagara Falls.) and even though it was about 90 air miles from me, the RX sensitivity of a scanner radio could RX both the AUD and VID carriers. (With lots of fading from that distance, but the signal was still there.) Knowing that the VID RF carrier for TV analog CH17 was 489.2500MHz I had a dead-nuts UHF signal source to tune scanner radios to. Couldn't use the AUD carrier at 493.7500MHz since the +/-25KHz DEV was too much for a NBFM scanner. What you are referring to is the VID HORZ sync pulse FREQ of 15.75KHz and that's what you TV syncs up to when displaying video from a TV station. At a TV station there is a master sync oscillator called a GEN LOCK that makes that happen. However, today you are right about one thing, TV stations today use GPS as their GEN LOCK for that HORZ sync, and I suspect more with digital 8VSB. getting back to analog TV stations, if you with close enough to a TV TX site where the signal strength was mV, you could have a FREQ counter lock on to that TV station's VID RF carrier FREQ and tweak your counter to that. Assuming, of course, that the TV station was well within its RF FREQ tolerances. WETM-TV CH18 in Elmira, NY was one station that came to mind there as being off FREQ.
Subject Author Views Posted

WWV 25MHz very useful.

ThaDood 542 March 01, 2015 04:35PM

Re: WWV 25MHz very useful.

Radio Animal 409 March 05, 2015 03:43AM

Re: WWV 25MHz very useful.

ThaDood 336 March 05, 2015 12:31PM



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