Hi. The "Monterey Bay" jammer, was indeed a UHF TV active antenna. But, it was hooting at about 1500MHz, that's what corrupted the GPS signals in that area. It's not unusual, there are many such documented cases from all round the globe of similar instances, and it's not just GPS systems getting hit either. A recent case in the UK, a digital TV set top box, was taking out the VHF comm's to a nearby local airport! Lucky there was an alternative channel to use, but it was found and "removed from service".
As to "resistance to signals at the input" That's probably for one clean and stable carrier, like a local harmonic from a broadcast FM receiver's own local oscillator. I kid you not! It happens, and is again well documented in several cases, mostly in the US with one particular make of SUV, suffering more than most, the symptoms being that the built in sat-nav gave up, if you had the FM radio tuned to one particular station! It is all to trivial to successfully jam a spread spectrum signal.. You just blot it out with another wide band signal, such as rapid sweeping, or broadband noise. Some systems are also all to vulnerable to pulse type interference too (Terrestrial DTV for one! OK, so not "true" spread spectrum, but......) The UK military often notify "other users" of "GPS Jamming Exercises" in various places at odd times, all around the UK. I don't know the purpose of such "exercises" other than to perhaps prevent squaddies out on a navigation training jaunt, not to cheat with personal GPS devices? But I do know that the result varies from total loss of signals as the receiver sees things, to a fix of sorts, but way off from where it should be. No doubt also screwing with any pps timing if that was in use. (to keep tenuously on topic?) Unintentional emissions from electronic systems are one of the worst things to find and fix. Regards. Dave B. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
