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Multi-GPS feed



At the 11th hour, I needed to feed 3 GPS's from a single external antenna.
Not having time to build DC blocks/splitters, here is what worked well:

I took an old BNC Barrel and jammed three 1/4W 100 ohm resistors in one
end (with very short leads).  THen fanned out 3 coax cables to each of the
GPS's and soldered them to the resistors all with very short leads.  Then
soldered the braids all to the outside of the barrel.

The result is a 3 way (10dB) splitter that:
* is reasonably matched to a 50 ohm antenna while still passing DC
* Has about 10 dB loss per leg (more than made up by the antenna LNA)
* Has reasonably good protection of each GPS's 5v antenna supply (any or
all will power the external antenna, with or without the others being
attached...)  And even shorted, current is limited to prevent damage.

No, it aint the right or best way, but at 1 AM before the family left on
vacation, it provided a working solution to letting the kids each have a
GPS in the backseat to see FOR THEMSELVES where we were and so that I dont
have to answer the questions over and over "where are we" and "when do we
get there?"

Each GPS showed FULL BARS on all satellites... even with about 10 feet of
coax in each leg..

de WB4APR@amsat.org, Bob

ISS-APRS FAQ:       http://web.usna.navy.mil/~bruninga/iss-faq.html
PCsat Design        http://web.usna.navy.mil/~bruninga/pcsat.html
CUBESAT Designs     http://web.usna.navy.mil/~bruninga/cubesat.html
APRS SATELLITES     http://web.usna.navy.mil/~bruninga/astars.html

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