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Old 26-Aug-2015, 4:25 PM   #42
rabbit73
Retired A/V Tech
 
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,544
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So, I need a house in that subdivision! lol
Nah, you wouldn't be happy there. The taxes would eat you up and the neighbors wouldn't tolerate antenna experiments. Your location has a higher elevation:



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Now, if they'd only crank up the power on Wjrt just another 10k watts...
The FCC set the power levels for DTV based on the assumption that everyone would have an outdoor antenna at 30 feet. They soon found out that their assumption wasn't realistic and have had to grant power increases to many transmitters.

DTV Coverage and Service Prediction, Measurement and Performance Indices

Oded Bendov, John F.X. Browne, Charles W. Rhodes, Yiyan Wu, and Pierre Bouchard

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Abstract-- It is now clear that methods used to predict the replication of NTSC service in the US were idealized and, for the most part, not validated. The need to review the methods and procedures now in
use is highlighted by the various field tests conducted in the US and elsewhere.

This paper outlines potential improvements in the modeling, methods and procedures now in use for prediction and measurement of DTV service.

INTRODUCTION

Early on, even before the 8-VSB standard was adopted, it was suggested that low-power HDTV transmission, as low as –12 dB average power relative to NTSC peak visual power, would provide for service replication to at least the Grade-B contour of NTSC stations.

It was generally thought that with incident field strength of 40.8dBu at 615 MHz, DTV receivers would be able to decode the signal and that higher field strength would not improve the reliability of reception. Those predictions were based on an idealized receiver, a multipath-free propagation channel and coverage prediction software that uses only terrain elevation data, but not terrain clutter data. Clutter data specify the land cover, such as forest, water etc. on top of the terrain elevation data. For these and other reasons, such as time availability statistics, it is now believed that the current predictions of DTV coverage and service will not be realized.

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Dr. Bendov was certainly correct, as you have found out.

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At least with analog tv, you could watch a show even if it was snowy and faded-out.
Right, there is no "Digital Cliff" with analog. With digital it's all or nothing.

Attached Images
File Type: jpg AnalogVSDigital2 (2).jpg (108.6 KB, 1108 views)
File Type: jpg MikeBearTVFelemap.JPG (136.3 KB, 1109 views)
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Last edited by rabbit73; 27-Aug-2015 at 2:17 PM.
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