Hi If you can see to the horizon, you can likely get reasonable timing off of sats to 10 to 20 degrees off the horizon. If you can only see to 45 degrees above the horizon, then you can likely get good timing off sats that are 55 to 65 degrees or higher. In both cases you can track further, the data just gets worse.
Just how close you can get will always depend on the type of obstruction and how much multipath it generates (if any). If you are in a deep canyon things are different than if there's one big pine tree due south. Bob -----Original Message----- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of li...@lazygranch.com Sent: Wednesday, March 16, 2011 12:36 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Thunderbolt setup My point is the Tbolt software is set up to ignore birds on the horizon. It is a parameter you can set. So I don't follow how seeing the horizon is very important. ------Original Message------ From: Bob Camp To: li...@lazygranch.com To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Thunderbolt setup Sent: Mar 16, 2011 4:51 AM Hi If you only have one sat to look at, horizon view is worse than overhead. With multiple sats you want them spaced out over the sky to get a benefit from triangulation. More TBolt opinions (there are lots of us and we all have them ...) The wonderful thing about a TBolt is that it can use foam core TV satellite coax. Since 75 ohms is lower loss than 50 ohm (all else being constant) you can get away with quite a bit of the stuff. F connectors are easy to do wrong, so get some good ones and a proper crimp tool. Most antennas are TNC or N, so you will need an adapter. Again - get a good one. Keeping the antenna away from traffic is your first goal. Up in the air is one way to do that, far from the house is another way. Last choice would be near the dinner table. Good view of the sky down to about 20 degrees off the horizon is ok. A view to 10 degrees is slightly better. Don't worry a lot about a view towards the north pole if you are in the northern hemisphere. Run the unit constantly. The OCXO will settle down that way. The holdover training will work best that way. The power required is pretty modest. Mounting the unit in some sort of enclosure is an excellent idea simply to minimize accidents. The power connector needs some protection from bumps and snags. Where ever you mount the unit, consider that they tend to multiply. You may soon have three or even more than twenty. So much fun. Bob On Mar 16, 2011, at 5:15 AM, li...@lazygranch.com wrote: > I thought for timing a view of the horizon was bad. > >_______________________________________________ > 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. _______________________________________________ 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.