[time-nuts] RF isolation requirements for multiple GPS receivers

[Dana Whitlow]

I want to run about 4 separate GPS units of disparate
manufacture from a single antenna.  My plan is to
provide power for the antenna via a bias tee (power
inserter) at the bottom end of the antenna's cable, then
use an isolating splitter on the receiver side of the bias
tee to split to the various receivers.

My question is: how much isolation between receivers
is likely to be necessary?  Real life splitters are only
so-so in isolation performance (15-25 dB), and may
e significantly worse if the antenna's LNA's output is
a poor match.  So I'm wondering if I'm going to need
more amplifiers in the splitter's outputs just for the sake
of adequate isolation between the GPS receivers.

Thanks,

Dana    K8YUM