[time-nuts] GPS Antenna Feed Line Decision

Mike Naruta AA8K aa8k at comcast.net
Sat Sep 2 23:07:40 UTC 2017


On 09/02/2017 02:57 PM, Clay Autery wrote:
> Having decision-making problems for the materials for my GPS main
> feedline.  Going to use a TM LMR stock, just can't decide how big to go
> with it...
> 
> 26 dB 5vdc antenna on top of a 38 foot mast.  Feed will come down the
> inside/center of mast and exit near the bottom, thence routed through a
> window and to the GPS distro amp. Antenna will feed GPSDO, NTP Server,
> Blitzortung System Blue station, and one other device TBD.
> 
...
> 
> I'd appreciate your recommendation and reasoning. Thanks in advance!
> 
> 73,
> 

Clay, you may wish to consider using a quality RG-6 with F 
connectors.  Grounding blocks are readily available for the base 
of your mast and the entrance to your house.  Also, 
off-the-shelf over-voltage protectors (Zap-Tech) are available. 
I even found an F-to-N adapter for the antenna on Amazon.  Watch 
out for the ones with metric N threads though.

For my 25 meter run I was going to use an existing one inch 
Heliax, but pulled a run of Belden RG-6 instead after learning 
that Trimble used RG-6.

It worked well directly connected to a Trimble Thunderbolt; now 
it is connected to a Symmetricon 58535A GPS L1 distribution 
amplifier.


My Blitzortung System Red station has been running fine in my 
attic (Michigan) on a Motorola 97 Oncore patch antenna fastened 
against the roof underside.  It is looking through wood, 
shingles, and nails (and a tree and antennas and utility lines).


How are you planning to do strain-relief on the vertical run of 
coax inside of your mast?


Mike - AA8K




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