[time-nuts] Low-cost GPS distribution using DVB-T parts?

Arthur Dent golgarfrincham at yahoo.com
Mon Nov 7 17:51:34 UTC 2011


Azelio Boriani-
"Yes, as some GPSes need a DC path to recognize a valid antenna I
modify the cheap satellite/TV splitters with a 270ohm (also 220, 180,
150 will do)  resistor between output F connector center and the GND."

I 've done the same. I use a Mini-Circuits ZAPD GPS two output amp
and feed each outputs to a 4-way 2.4Ghz TV splitter with "F" connectors 
(just like item number 250865005544 on the popular auction site, $14 for 
2 including shipping costs) with one power pass output and 3 blocking 
outputs. This allows me to run a number of GPS units I'm testing with the 
amp gain-splitter loss not swamping the receiver. Another advantage is that  
the Thunderbolts use a type "F" connector and I can use ready made low  
loss TV cables to connect everything. 

I've used up to a 330 ohm resistor to fool the GPS into thinking there is 
a direct connection to the antenna on the 3 blocking outputs, or just live 
with the open antenna message.  I just have to make sure I have at least 
one of the GPS receivers connected to one of the power pass outputs so 
the amp is powered.

-Arthur 



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