[time-nuts] Best location for a GPS antenna...?

[Bob Camp]

Hi

The simple / stupid approach to the feed lines:

Put up the tower away from all structures
Put the antennas up on the tower.
Ground the tower well.
Run the feed lines down the tower
Ground the feeds both at the antenna and at the base of the tower
Put in a *good* arrestor at the base of the tower
Run the feed lines underground to where ever you are going to need them
Put in a separate ground at the outside wall of the destination 
Bond all the lines to that ground
Protect the lines again with *good* arrestors
Run them off to where ever you need to use them
Plan on checking / replacing the removable cartridges in the arrestors a few
times a year.

Yes that's a lot. Fires are no fun.

Bob



-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Michael Baker
Sent: Wednesday, April 11, 2012 8:50 AM
To: time-nuts at febo.com
Subject: [time-nuts] Best location for a GPS antenna...?

Time-Nutters--

My workshop is surrounded by tall trees (70 to 80 ft).  There
is no easy way to place my T-Bolt antenna above the tree-top
foliage.   Since choke-ring antennas do not provide much benefit
for dealing with multi-path that originates from directly above
the antenna I have considered putting the antenna on a 10-ft
pole and mounting the pole in the top of the nearby trees so
as to have the antenna just above the tree-top foliage.

However, here in north-central Florida lightning is a serious
problem.   In the 12 years we have lived here, 3 trees have
been hit within 75 meters of my workshop building behind
my house.

Here is a DropBox link to a map of lightning-strike-days
in USA locations:
http://dl.dropbox.com/u/60102282/Lightning%20Isokeraunic%20map.JPG

I have a number of VHF and UHF antennas mounted on my
workshop building but when not in use, they are kept
disconnected where they enter the building.

I have thought about finding some way to bring the GPS
RF signal into my workshop via an optical fiber interface
and sacrifice the RF to optical fiber interface if lightning
strikes it in a treetop but have not found a way to implement
this idea.

Two years ago lightning struck a neighbor's TV antenna
mounted on a pole attached to the side of his house and
started a fire in one of their 2nd floor bedrooms which
did a lot of damage before it was put out.  The tower
was well grounded and the coax leading into the room
was fed through a grounded lightning protector but none
of these precautions prevented the fire from the lightning
strike.

Any list folks have ideas on this?

Mike Baker  WA4HFR
Gainesville/Micanopy, Fla





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