[amsat-bb] Re: Government control has exceeded constitutionallimitations.
bruninga at usna.edu
Tue Apr 24 14:25:27 PDT 2007
> - The antenna is 2.2 degree beamwidth (3dB)
> Hard to believe ham repeaters are bothering something
> that well-engineered.... Sounds like they need some
> smarter RF engineers, if they can't figure out how
> to filter out ... constant-carrier FM...ham repeaters.
The laws of physics are pretty hard to beat. The radar equation
is 1/R^4th and normal radio is 1/R^2. Hams know that that it
takes 4 times the power to double the range. For a Radar it
takes 16 times the power to double the range.
Or, said another way. For a 100 mile repeater (line of site)
lets say it takes 1 watt for communications. For the Radar that
might be trying to track some debris headed for the Space
Station at 1000 miles, then it takes an effective power of
10,000 watts. Reverse that and it is easy to see that, a 1 watt
Ham signal at 100 miles can mask the signal coming back from the
Carry that one step further, and this means a 10 milliwatt
signal from a ham repeater at 10 miles is the same as the radar
return signal from the 10,000 watt radar. Unfortunately,
"filtering" is not the answer, just like when a ham radio is
interferred with by a birdie on your favorite frequency, then
"filtering" doesn't help there either...
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