Patrick,
a very interesting article. The 121.5 MHz beacon system is old and primitive.
All it takes is a carrier to get noticed. And when you do get noticed it
requires up to 90 minutes to get a fix on your location as it takes two passes
of the satellite. This system will be phased out by 2009. The beacons run 100
mW. It would take a milliwatt or so to alert the satellite- this TV problem
must have been more than just a bit of leakage. Perhaps the front-end
amplifier oscillating? Got to make sure the amps are unconditionally stable.
Radio Shack and Weingard, I believe, have had problems with TV antenna
amplifiers oscillating.
While designing some in-house test equipment, that operates around 120 MHz, we
were careful to keep it away from 121.5 MHz and added spread spectrum for good
measure.
Dave Cuthbert
Micron Technology
From: [email protected]
mailto:[email protected]] On Behalf Of Conway, Patrick R (HOU)
Sent: Tuesday, October 19, 2004 8:21 AM
To: [email protected]
Subject: ... And they wonder why we test...?
I thought this was worth sharing.
<http://www.cnn.com/2004/SHOWBIZ/TV/10/18/odd.television.reut/index.html>
http://www.cnn.com/2004/SHOWBIZ/TV/10/18/odd.television.reut/index.html
How many people and how much money do you think were spent tracking
this one down?
…this reminds me of all the times I've had to justify to someone why
we test, and why we fix something "that no one cares about" (not my quote -
just one that I've heard many times at previous job sites).
Thank goodness my present employer doesn’t think that way! But, I
think I'll archive this article just in case I ever run into this question
again.
Best Regards,
Patrick Conway, NCE
Senior EMC Engineer
Hewlett-Packard Company
281.514.2259
281.514.5473 (fax)
<mailto:[email protected]> [email protected]
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