Looks good, but I would have gone for a different GPS antenna. The timing antennas are weather proof. I have a Marine grade GPS antenna, also weather proof, but the timing antennas are probably a little better since they have less response to GPS birds on the horizon. -----Original Message----- From: "George Race" <geo...@mrrace.com> Sender: time-nuts-boun...@febo.com Date: Fri, 28 Sep 2012 10:53:25 To: <time-nuts@febo.com> Reply-To: geo...@mrrace.com, Discussion of precise time and frequency measurement <time-nuts@febo.com> Subject: [time-nuts] Up And Running
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 _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.