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Old July 21st 04, 01:45 PM
jc
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Chad Irby wrote:

snip
You're forgetting something.

Power.


So what is the power of the satellites at what distance. Square dist law.

Not to mention, of course, that you're transmitting that 1 watt
omnidirectionally,


Last (only) time I have tried for an isotropic ( within ~ 3 dB, which is
what you need for GPS jamming from balloons, not omnidirectional) antenna
with 125 mW input we got ~ 120 dBm at 30 clicks which in flat terrain,
enough to get a reliable signal with an 11 dB omnidirctional recieve
antenna. Now what is the level from the satellites?

Suddenly, the "$5 balloon-borne jammer" is a "$500 balloon-borne jammer
that only lasts a few hours."


How long does an RPG blast go for and how much does it cost


--

regards

jc

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