[time-nuts] GPS Filter

[Bob Camp]

Hi

Ok, now it's pretty obvious the RF world near your GPS will be changing a *lot* in the near future. Lightsquared and a bunch of similar outfits will be camping out right next door with very high power gear. They will be running 1.5KW from somewhere in town. GPS is running 30 watts from off planet. 

Has anybody tossed the various HP / Symmetricom GPS splitters on a network analyzer? If so, what do the filters in them look like? 

I probably should corner the market on these things before asking a question like that. 

The new neighbors will be at 1525 to 1559 MHz.  GPS L1 is at 1575.42 MHz.  That's what we are using for timing. L2 is down at 1227.5, right now it's mainly military use. Obviously these guys are a bigger deal for civilians than the military. 

So the question is - do the built in splitter filters have any real rejection 15 to 50 MHz off of center?

Probably worth checking. It would be a pleasant surprise if they turned out to be useful. 

Bob