On Sat, 09 May 2009 22:24:11 -0700, Michael Tope wrote:
>Yes, the keyless entry on my wife's camaro gets blocked up on Mt. Wilson
>above
>Los Angeles where the big antenna farm is located (all manner of
>repeaters, paging
>transmitter, TV transmitters, FM radio transmitters, etc). If you don't
>have a physical
>key, you are SOL to get back into the car. The keyless entry just didn't
>work at all.
No surprise there -- the RF up there is in the same spectrum as the control
systems. OTOH, I don't recall anything comparable in downtown Chicago, where
all the broadcasters are on two buildings only 1,500 ft above the street. Two
important differences -- broadcasters out west have at least 10dB more power
than those in Chicago, and virtually all Chicago UHF broadcasters are using
lots of vertical antenna gain that shoots out at a nearly horizontal
elevation. I also suspect that since the antennas on Mt. Wilson are on shorter
towers.
73,
Jim K9YC
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