Quote:
Originally Posted by Piggie
Anyway the FCC approved not only insanely low VHF power levels but closer spacing because of the lower power levels. They didn't figure the man made and electrical noise on VHF was so much higher than UHF, that the distance the radio waves alone traveled was not the range of the station, like it is on UHF. For example at 20KW a station's radio waves actually get to the edge of the contour but it can't be locked to the edge of it's contour. More power is needed. But I am a little ahead of myself. |
Holy cow piggie, thanks for taking the time to explain.
What I quoted above seems like a huge oversight, especially now that some stations are going back to the
FCC and applying for boosting power output (as Trip noted
here about 6ABC in Philadelphia).
Don't know if you've seen k2pg's post yet in the Philadelphia thread, but he has an interesting
synopsis of DTV signals as well,
Quote:
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Although the American DTV system has improved somewhat, areas with a lot of multipath will still get lousy DTV reception. Channel 6 is particularly bad for DTV use, as it is adjacent to the FM broadcast band and strong FM signals may interfere with the DTV tuners and converter boxes. The same interference that would put "worms" (diagonal lines that wiggle with the modulation on the FM station) on the picture of an analog channel 6 station will cause a complete failure of DTV reception on that channel. In Philadelphia, WPVI-TV transmitted at 100 kW visual ERP, which is sufficient to override FM interference within the city grade contour of the TV station. The low ERP of the digital signal will not override this interference. Electrical noise, such as ignition noise from passing cars, will also cause dropouts in DTV reception and low VHF channels are especially susceptible to this.
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