[time-nuts] GPS / GNSS front-end board
attila at kinali.ch
Wed Jun 6 22:12:24 UTC 2012
On Wed, 6 Jun 2012 10:24:12 -0700
Peter Monta <pmonta at gmail.com> wrote:
> 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.)
I would at least give the option to use one antenna for multiple inputs.
> 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.
Yes, i dont have a good solution either. Maybe someone of the guys
here with more knowledge on RF design could have a look at that?
Why does it take years to find the answers to
the questions one should have asked long ago?
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