[time-nuts] Thunderbolt setup

lists at lazygranch.com lists at lazygranch.com
Wed Mar 16 12:35:30 EDT 2011

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: lists at lazygranch.com
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Thunderbolt setup
Sent: Mar 16, 2011 4:51 AM


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.


On Mar 16, 2011, at 5:15 AM, lists at lazygranch.com wrote:

> I thought for timing a view of the horizon was bad. 
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