My experiences with ATSC HDTV

[wa2ise]

Originally Posted by peverett

I have seen the same issue in high winds. However, I am not sure the power increase will fix this. What is happening is that the digital locking circuit(probably some sort of PLL) is losing lock temporarily(and dropping data) due to the incoming wave varying. The variance is due to the distance from the transmitter to the receiver changing as the transmission tower moves in the wind. This is a basic problem with all broadcast digital transmissions.

A very directional antenna aimed at the transmitter tower solves this. The directivity allows your receiver to ignore the ghosts, as the antenna doesn't let those ghosts get into the receiver. The ghosts that add and subtract signal strength and varyingly messing up the digital symbol "eye pattern". An "eye pattern" is a diagram (or scope trace) that shows the ability for a receiver to tell 1's from 0's in the received signal. Ghosts also cause earlier bits to mess up the bits now being received from the direct signal from the trannsmission tower. As the ghost signal path is longer, and the speed of light is not infinite, but is about a foot per nanosecond.

If there are no ghosts, the transmitter tower moving back and forth in the wind won't hurt reception. It doesn't impose enough doppler shift to be anything close to become a problem for the receiver.