sky9,
Just checked a few live navigational databases, TFS should be on your charts as N28.0024337768554, W16.6879320144653 what does your chart say it is ?
Ham Phisted,
I was not trying to go into too much detail....
The GPS signal for civil use are sent on the L1 carrier at 1575.42 Mz using spread spectrum techniques.
It transmits pseudorandom noise on modulated L band waves with bi-phase shift keying of the carrier.
The signal level is well below earths natural radio noise level, the receiver detects it, and then it uses the predicted P and C/A code to normalise the signal back to the original carrier frequency above the natural noise level.
The receiver only needs to have between 160-163 dbW signal power level to work.
The FAA is presently investigating worm holes in the GPS system, these are thought to be as a result of blocking and/or jamming of GPS signals.
Possible thought on how the worm holes are being created ...
[list=1][*]direct inband interference around 1.57-158 Ghz[*]harmonic interference (UHF TV)[*]intermodulation of two or more signals[*]suppressing or blocking using strong RF to desensitize the receiver[*]sidelobe interference[*]intentional jamming (read military)[/list=a]