[time-nuts] Advice on sighting a roof mounted gps area please

[Chris Albertson]

First off, why only 50mm and why plastic?   The PVC will degrade in the
sunlight over the years.   Use galvanized iron pipe.   Make the mast as
tall as you can.  It can extend sever feet below the roof and attach to
house structure using u-bolts. (Hight limited only by appearance from the
street.)  Using iron pipe strength will not be an issue.  Run the cable
inside the iron pipe to the attic space.

I would use two masts, one for each antenna.  It will look better and be
easier to build and it will handle high winds better.

If you are worried about how this all looks use some spray paint to make it
either sky blue or light grey.

Do you need two antenna?  You can feed multiple GPS receivers using a
splitter and amplifier from one antenna.

Be sure to follow the local rules for grounding antenna.   In most places
you will need a heavy coper wire leading directly to a grounding rod.  You
want to give lightening an easy path to ground that is not routed through
the interior of the house.

On Sun, Oct 12, 2014 at 4:34 AM, swingbyte <swingbyte at exemail.com.au> wrote:

> Hi All,
> I am building a house extension and part of the works involves adding a
> new hip roof made of corrugated iron.  I was thinking I would pass a 50mm
> pvc pipe through the roof with a tee and then mount two conical gps timing
> antennas on top of it.  I am in a low point and don't have visibility of
> the horizons ( I'm not in the out-back).
> My question is should I mount on the peak of the roof?  How close can I
> mount two antennas from each other? Can they interfere with each other?  I
> am also in the midst of some tall trees - although my new roof will be
> pretty high it will still be below the tallest trees.
> Of course the main reason for this is I want to do some accurate timing
>
> ASCII art of proposed set-up
>
>   A                  A
>   |                  |
>   --------------------
>            |
>            |
>            ^
>           /  \
>          /    \
>         / roof \
>
> Thanks for your advice
>
> Tim
>
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-- 

Chris Albertson
Redondo Beach, California