[time-nuts] FASTRAX GPS

Chris Albertson albertson.chris at gmail.com
Wed Jul 2 12:22:26 EDT 2014

I tried using a long serial cable.  Just because I had some 100 feet
of cat-5 wire already installed.  It did not work reliably I was using
a MAX232 chip as a driver.  I could have made it work by using
differential drivers/receivers at each end but I had some good antenna
lead, pulled that into a closet space and used a shorter serial cable.

The advice to use the cable TV wire for antenna lead is good.  Yes it
is 75 not 50 ohm but even the Trimble user manual says it works best.
Those compression type F connectors are 100% water proof, the cable is
double shielded and inexpensive.

On Tue, Jul 1, 2014 at 10:17 PM, jim s <jwsmail at jwsss.com> wrote:
> Bob,
> I was being a bit lazy.  The 15' distance gets from a couple of spots in the
> room with my systems and lab, and also is already terminated, and there is
> no issue with the power since it would be totally contained in the unit.
> But your suggestion and some work making the cables would work best.
> To you and Hal who suggested it, is this unit suitable for outputing a 1pps
> timing signal?  Wouldn't the long serial option Hal suggestion mess that up,
> vs. using this method to put the Fastax as close as possible to a system
> which which would have the systems gpio and serial ports attached?
> Thanks to you both for answering.
> jim
> On 7/1/2014 9:30 PM, Bob Stewart wrote:
>> Jim,
>> Are you trying to find out how to hook up a receiver in your office/radio
>> room to an antenna that is some ways away?  Or are you specifically trying
>> to remotely hook up a receiver near your antenna?  If the former, just use
>> RG-6, like for cable TV, with adapters on each end.  RG-6 has such low loss
>> that the impedance change is not an issue.  I've got a 30+ ft run up to the
>> attic to a cheap GPS puck antenna for my setup.  Others have much longer
>> runs and it works OK.
>> Bob
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Chris Albertson
Redondo Beach, California

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