Il 2012-09-28 16:53 George Race ha scritto:
Hello to all the Time-Nuts:
I Have been acquiring parts for a few weeks and finally have a
Thunderbolt-Trimble system up and running.
Though I would share a few pictures of what I did and how it looks
now that
it is all together and working.
First, here is an overall look at what I have put together.
http://www.mrrace.com/TrimbleGPS/TrimbleParts.jpg
I had to use the attenuator to reduce the amplitude of the 10MHz
signal from
the Trimble. It was overdriving the Extron causing distortion in the
output
waveform. The 6db attenuator is just what was needed.
I was running on a temporary old GPS antenna mounted on the edge of
my
garage roof for a while. I ordered a Trimble antenna from China,
took about
10 days to get here. What a difference that made in the overall
signal
strength and stability of the unit.
Here is a Lady Heather shot after running on the antenna over night.
http://www.mrrace.com/TrimbleGPS/MyLadyH.jpg
I am still having trouble knowing what all the indicators on the
screen
mean, but it appears that everything is working.
Sure wish there was an index somewhere that told what each and every
thing
on that screen means!
As I mentioned, the antenna arrived yesterday and I built a mount and
installed it yesterday afternoon.
Though you might like to see what I ended up doing. We have a lot of
rain,
snow, and ice here in Michigan, so I wanted to do something to
protect the
antenna and connectors the best that I could from the elements.
First, here
is a picture of the antenna from China, along with the adaptor cable
to get
it to an “F” connector to hook to my 50 foot RG6U cable with “F”
connectors
on each end.
http://www.mrrace.com/TrimbleGPS/TrimbleAnt.jpg
Here is the mount that I built. I am going to put it on my TV
antenna mast
that is mounted on the house. The 10 degree elevation pattern should
see
open sky in all directions.
The mount is a piece of aluminum angle with a mast clamp on one end,
the a
sealable tea container on the other. The container is one of those
push
button kitchen containers that has a very tight air seal when the
button on
the lid is pressed in. It really holds well, and you cannot remove
the lid
when it is locked into place. Also this configuration makes it
really easy
to get to the antenna and connectors if necessary. Just release the
button
on the bottom and lift off the unit. The “F” barrel connector
through the
side of the container makes it easy to just unscrew the cable if
necessary.
The seal on the container is about ¾ of an inch wide, and really
holds on to
the inside of the container.
http://www.mrrace.com/TrimbleGPS/BuildingTheMount.jpg
To hold the GPS antenna in place at the top of the container, I cut a
small
aluminum plate, carefully drilled 3 holes for 2-56 hardware through
the top
of the container, using the aluminum plate as a template. The
antenna is
“clamped” into place by bolting the plate up against the bottom of
the
antenna, inside of the container. You can see from the next picture
how the
cable connectors and antenna wire is coiled up in the bottom of the
container, and terminates on the “F” barrel connector inside. Looks
like it
is all ready to put up on the roof and connect to the cable.
http://www.mrrace.com/TrimbleGPS/ReadyToPutUp.jpg
Here it is, mounted about 25 feet above the ground, below the TV
antenna.
http://www.mrrace.com/TrimbleGPS/MountedHigh.jpg
And here is a close up of the finished installation.
http://www.mrrace.com/TrimbleGPS/UpAndWorking.jpg
A lesson to be learned, about “F” connector barrels!
When I hooked up the basement end of the cable, total disappointment!
On
the screen it said in yellow letters, “Antenna Open.”
As I had tested the system end to end, BEFORE I put it all in the
container,
the only place that could be a problem was that “F” connector barrel.
I brought the container back down to the bench and carefully looked
at the
connections. It was so simple, and I had caused the problem during
early
bench testing of the cables. The jumper cable from the antenna to
the inner
part of the “F” connector has a extremely small diameter center
conductor.
On the other hand, the RG6U cable has a greatly oversize, compared to
RG59U
cable, center conductor. In testing I had pushed the RG6U center
conductor
into both ends of the “F” barrel. This pushed the center part of the
connector to its limits, and it did not close back down when the
cable was
removed. I installed a nice brand new “F” barrel into the side of
the
container. Starting the “F” connector on the inside barrel
connection, I
could feel the center conductor pushing into the connector. Taking
it all
back to the roof, tightening the “F” connectors in place, solved the
problem!
Somebody is probably going to ask, what I am using this system for?
I have
an HP synthesized signal generator and a Racal-Dana digital frequency
counter that both have provisions for a 10MHz external standard input
signal. I wanted to have them driven by the GPS system to give me
the best
possible accuracy I could get on both instruments.
Picture of the messy work bench below!
http://www.mrrace.com/TrimbleGPS/TestEquipment.jpg
Comments and suggestion are always welcomed,
George
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George and now?
hi!
Luciano
timeok
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