Four Corners

[DYNAMIC STALL]

Woomera

Just taking up the issue of GPS interference from GSM Mobiles.

The GSM system is digital, TDMA, which means it switches on and off very quickly.

This causes a peculiar RF Interference which has little to do with harmonics (although it causes extra ones) or blocking (but the harmonics could do this if strong enough), rather the 'switching frequency' is demodulated in the power circuitry of a lot of equipment.

So, depending on how good the power circuit is, you could hear the 'ta -da -da -da -da dah' rectified interference in the speaker of your radio OR the GPS receiver could be interfered with by it.

So, can a GSM phone interfere with a GPS, the answer is yes depending on the shielding of the GPS and the proximity of the phone.

But, is there a GSM base station in Lockhart River?????

(I would have assumed it was CDMA).

Addendum.

There is no GSM base at either LHR or Bamaga, so it is unlikely anyone on board would have a GSM turned on (or even had one) and even if they did it would not have 'polled' the base and thus the likelihood of interference is almost zero.

CDMA does not do the same 'noise' stuff.

B