[time-nuts] GPSDO module connections

Chris Albertson albertson.chris at gmail.com
Mon Mar 3 16:49:05 EST 2014

As a rule I'd say to minimize the number of connectors.  The ideal is
to use one long cable but you can't do that.  Soldering to connectors
is fine  but it is really hard to do correctly with that double
shielded cable.  The compression fitting are very good and even water
proof.  I would use those.  Custom cables that have the correct ends
on them minimize the number of adapters.  Note that there are TWO
TYPES of BNC connectors,  50 and 75 ohm.  Use whatever matches the
cable you are using.

Also think again if you really plan to connect and disconnect the
antenna more then once every few years.   A rubber grommet might be
better than a BNC.  It would save two connectors.

All that said It may not matter at all, the antenna has an amplifier
in it and you may have dBs to spare.  Trimble even says in their
manual that impedance mis matches between 50 and 75 oms don't  matter.

For the PPS it hardly matters if we are talking about a 12 to 18 inch
cable.  But if you are going 50 or 100 feet you want the coax AND you
want to properly terminate it.

On Mon, Mar 3, 2014 at 10:01 AM, d0ct0r <time at patoka.org> wrote:
> Hello,
> I am looking for the advise: what will be the better method to connect GPSDO
> module by short extension cable to put its antenna input on front or back
> panel ?
> Lets say, GPSDO module has female "F" connector. And I would like to have
> BNC connector on back panel of my project. Manufacturer of GPSDO recommend
> to use RG-59 cable for antenna connection.
> Is it OK if I'll take some RG-59 from CCTV, cut 6" or 12" of it, connect one
> end to GPSDO (let say this cable has compression type connector) and solder
> other end to BNC on the panel ? Or its better to use adapters and no
> soldering ? Like "F connector-to-BNC" adapter , then short BNC-to-BNC cable
> connected to BNC panel connector ?
> And other question: is it worth to use RF cable to connect 1PPS output from
> GPSDO to distribution amplifier ? Or regular AWG-22 could do that job ?
> Thanks !
> --
> WBW,
> V.P.
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Chris Albertson
Redondo Beach, California

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