Didier
As jammers those devices are extremely inefficient.
They may well rely on the inefficient generation and radiation of a very
high order harmonic of the clock of an unshielded legal device.
A commercial GPS receiver may require a signal as small as 60dB (depends
on the operating mode, and receiver design) above the GPS signal at the
receiver input.
An ERP of a few microwatts should suffice to achieve the claimed range.
Bruce
Didier Juges wrote:
The commercial jammers referred to in an earlier post advertise 10 to 45m or
so range, with significant power levels and battery life measured in a few
hours. Considering that these devices are illegal to begin with, I have to
assume that these figures are probably optimistic (optimistic advertisement
is probably the least of their concern.)
If I were a pilot, I would probably be more worried about the kid playing
with his Nintendo in 15A (or his father trying to retrieve his email with
his GSM smart phone) during approach than a jammer on the ground.
Didier
-----Original Message-----
From: time-nuts-boun...@febo.com
[mailto:time-nuts-boun...@febo.com] On Behalf Of J. Forster
Sent: Sunday, November 15, 2009 6:38 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] The Demise of LORAN (was Re:
Reference oscillator accuracy)
Even 10 KM is pretty useful. If the thing were solar powered
with a supercap "battery" it could easly transmit for say 2
minutes per hour w/ significant power. It'd be hard to find
if the on times were generated by a multiple fedback CMOS
shift register.
-John
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