[time-nuts] GPS / GNSS front-end board

Peter Monta pmonta at gmail.com
Wed Jun 6 17:24:12 UTC 2012


Hi Attila,

> Could you also add just the option of a power splitter at the input?

I'm not really sure what the most appropriate RF interface is.  I was
planning to make another much simpler board with just a bias tee, a
3:1 splitter, and some hairpin microstrip filters.  Then it would be
three short SMA cables over to the main board.  (Right now I just have
a 2:1 splitter and I'm relying on the L1/L2 antenna for filtering.)

Maybe it would make sense to integrate the splitter, filters, and bias
tee at some point, since an auxiliary board is always more hassle, and
the connectors and cables are expensive.

One thing I didn't want to do is commit to any particular filter
technology up front.  Ceramic filters, and, worse, SAWs, have delays
that vary with temperature (to say nothing of the large NRE costs
involved).  Microstrip filters would have a lower temperature
coefficient I think, though they are not as sharp and have more loss.

Cheers,
Peter



More information about the time-nuts mailing list