Hello time nuts,
I finally have my long awaited Trimble Thunderbolt up and running. I am
not thrilled with the coverage using a Symmetricom 58532A antenna on the
roof about 20 feet above ground level. Here is what I get after ~24 hours:
http://n1bug.com/gpssig.png
Sometimes I have 8 satellites with usable signal, sometimes as few as 5.
The problem to the west is trees. I believe the chaotic signal strength
in the east is due to reflections from a metal roof.
I have three options:
1. Leave the antenna where it is.
2. Side mount it at 80 to 90 feet on a radio tower that has yagis for
50/432/222/144 MHz at 105/110/115/120 feet. These antennas are used for
high power transmitting. Potential interference to GPS reception? I
don't know if the filter in the 58532A is before or after the amplifier.
Blockage from the tower and/or yagis? I assume mounting a few feet off
the south tower face would be best.
3. Mount at the top of a mast on another radio tower, at 110 feet. This
would have a completely unobstructed sky view but would have antennas
for 7/10 MHz about 3 feet below and 14/18/21/24/28 MHz about 13 feet
below. Those antennas are used for high power transmitting. There will
at some point be a 10 GHz dish about 8 feet below the top of that mast.
Any comments on these options? Is it good enough where it is? I am only
using it as a 10 MHz reference now, but I may care about the 1 PPS later.
Paul N1BUG
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