Hi With an 8 port splitter, each of the 7 GPS's sees 50 x 7 = 350 ohms. That's pretty close to the "typical" 330 ohm load that gives you around 15 ma of sense current. The antennas pull a wide range of currents, so there is not a "one size fits all" sort of load.
If your antenna has 36 db of gain, an 8 port should use up about 9 db of that. There's still a lot of gain left to have >=10 db past the loss. If your receiver is a modern one it should have a 1 to 2 db noise figure. If the antenna is at 0.3 db (pretty good antenna) then 10 db is plenty. Bob On Jun 29, 2013, at 8:14 PM, Magnus Danielson <[email protected]> wrote: > Hi Bob, > > On 06/30/2013 01:50 AM, Bob Camp wrote: >> Hi >> >> From what I've seen, a 50 ohm load on the 8th port of an 8 port splitter >> does a pretty god job of doing the DC correction. No need for an inductor, >> everything matches up just fine. >> >> Since you have an amp in the antenna, you don't *always* need an amp in >> front of the splitter. A lot depends on how much cable loss you happen to >> have (and the gain of the amp in the antenna). With a modest amount of cable >> (< 50') eight port splitters seem to work pretty well. > > From my experience, what is needed depends on the GPS receiver and it > expectance of the antenna current. Some may need that extra load. > > The DC load may not match 50 Ohm. > > For an antenna-splitter to be gain-neutral it needs an amplifier. If you have > good conditions, you do not need it. But I have been fighting gain problems > and seen how it limits my ability to lock-up. > > Cheers, > Magnus > _______________________________________________ > 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. _______________________________________________ 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.
