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OTA Transition - Xmit Power
Posted 09 October 2008 - 04:16 PM
Dish 1000.2 @ 110, 119, 129; dish 500 @ 61.5
Antennas - CM4228; RS U75-R; coathanger; Funke PSP.1922 (stillin the box); paperclip
Displays: Sony VPH D50Q with HD Fury HDMI input; Hitachi 57F59; Sony Bravia LCD;Sanyo 32" LCD; Panasonic 42" plasma
Sony 80GB PS3; Toshiba HD-DVD
Give me a Finco colinear array and I'll rule the world - HA-HA-HA-HA!
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Posted 09 October 2008 - 06:19 PM
Virtual channels are probably the stupidest thing the FCC has done in this whole mess (well, maybe their choice of encoding schemes is up there also).
It wasn't the FCC that came up with the virtual channel idea, it was the tv stations and the NAB. They wanted the stations to keep their identity. As an engineer, I agree with you. When I first heard about the proposal my immediate reaction was: why? Move on, use your new channel allocation. But I guess normal Joe and Jane viewer need to see they're still watching Channel 6 in Philly, even though it's now way up on channel 64. And my daughter in the mountains of Central PA, where she can only receive a very few OTA digital signals, is sure glad that she can receive both ABC and FOX on one RF channel. Plus a lot of people like the weather sub-channels. So we as informed technical types have to deal with it. It is confusing, I admit.
The encoding isn't a bad choice. It's the modulation the FCC chose, despite last minute efforts by Sinclair to convince them it was a mistake. Nothing new there... the FCC has a history of choosing the wrong standard (for example, NTSC).
Posted 09 October 2008 - 06:30 PM
RF channels may be susceptible to adjacent channel interference, not virtual ones.
Adjacent channels are not a problem in the digital world, as long as their signal strengths are equal (or very nearly so). There are several markets where adjacent channels are assigned, broadcasting from the same tower at the same eirp. Philadelphia has two pair of adjacent channels operating (26/27 and 66/67). The key is they must be received at the same power level (or very nearly so). Two adjacent channels, transmitting from the same tower at the same eirp will meet this requirement. Two separate adjacent channels from different markets/directions may or may not.
If you want to know what real channels are in your area, go to tvfool.com.