03 Mar 08 07:13, TOM WALKER wrote to ROY WITT:


 RW>> TW> That is correct. And a basic principle of Radio Physics is that
 RW>> the
 RW>> TW> NARROWER the Signal the Better chance it has at getting Through
 RW>> TW> Interference.

 RW>> Nice thing about a digital signal...it doesn't need to get through
 RW>> 100%, as the signal can be put back together at the receiving
 RW>> station from perhaps 60% of the info transmitted and received.

 TW> Tell that to the San Diego Sheriffs Department that let Motorola
 TW> convince them to put digital Radios in their Helicopters only to find
 TW> that when they transited faster then about 100 MPH the radios ceased
 TW> Functioning.

Which wasn't due to the digital signals being lost at 100mph. Those
satellites sent to different planets use digital radio and their signal
isn't lost as they travel at speeds hundreds, if not thousands of times
faster than 100mph.

 TW> Becasue of the Doppler Effect.
 TW> They removed them al and went back to the Analog radios.

I can't believe they were that dumb.

 TW> BUT there is a finite limit to "Line Averaging" and at
some point you
 TW> loose the signal altogether.

That's true...San Antonio tv and some radio transmitters are located on a
knob hill (highest point in SA area) in Elmandorf, southeast of SA
central. Then there is the PBS affiliate, whose transmitter is downtown
SA. Elmandorf is 198 degrees from here, while downtown SA is 226 degrees.
A UHF antenna pointed at 198 degrees can't see the transmitter at 226
degrees and vice versa. I've stacked two UHF antennas together and point
them in different directions to receive both. Waiting on the mail order
(internet order) antenna for the Austin (24 degrees from here) digital
stations. I've got a brand new, in the box, Alliance rotor that I bought
back in the sixties, but I don't want to waste it on TV antennas, as I've
got plans for a pair of stacked UHF yagi's for the 440 ham band.

                R\%/itt



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