GPS Good and Lost

Theoretically, GPS is at a much higher frequency than FM radio, but there could be harmonic distortion out of the transmitter reaching the GPS frequency.

 

Wow, that's some dirty FM modulator!
GPS civilian frequencies are at 1575.42 MHz which is 18 x the 87.5 meg that she was transmitting on. 18th harmonic?

Of course, the ipod transmitter was probably putting out 50 mw, the signal level from the GPS is probably over 100dBm lower and very easy to swamp.

 

Sure, but at the 18th harmonic? Geesh.

Of course, RF signals are 'captured' by beating them with another but lower frequency (Intermediate Frequency or IF) and capturing/filtering/amplifying the difference frequency. Similar to how a musician tunes his instrument by adjusting his frequency against a known good frequency and adjusting until he gets a null beat. It could be the IF that is being interfered with.

 

shulmda - I have been having exactly the same problem! I've recalibrated it several times while sitting on the street in front of my home. Everytime I turn the car back on it shows me in some (and generally new) bizarre location.

There is a nav update, I rec'd a letter about it recently. I have an '04.

Because I've been having a lot of other work done (see wierd false alarm issue in troubleshooting) the FTS believes that the antenna was not correctly reconnected the last time it was in the shop.

I do have an iPod but no transpod and the iPod is rarely in the car. Until this problem showed up 2 weeks ago the nav system was working just fine, perfectly in fact, and never showed me driving aimlessly through fields. While entertaining to be on a major highway and have the nav system think I'm driving through a field or the Pacific, it's not very helpfu.

When I go in I'll bring this thread to see if they have anymore luck.