[time-nuts] 75Z vs 50Z for GPS receivers
Brooke Clarke
brooke at pacific.net
Mon Jan 29 00:15:02 UTC 2007
Hi Didier:
The Tek 1502 is great for doing this, especially if you have the
optional strip chart recorder. It's what it was made to do.
http://www.pacificsites.com/~brooke/Tek1502.shtml
Have Fun,
Brooke Clarke
w/Java http://www.PRC68.com
w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
http://www.precisionclock.com
. . . .
>
>I have 3 coax runs going from my ham shack to the top of my tower to
>feed the HF (14 to 30 MHz) and two VHF antennas (6m and 2m, or 50 MHz
>and 144 MHz). One cable (HF) is regular RG-213, another (6m) is RG-214
>(essentially like RG-213 with double shield), the last one (2m) is
>Ultra-flex air dielectric (more like 9913). All 3 runs are close in
>length, about 135 feet. I have fed them with the 1 PPS signal and looked
>at reflections with the storage scope (that's how I know the length). It
>is interesting to see the big reflection when the signal gets to the
>antennas. Of course, the antennas are a poor match for the 1 PPS signal
>(fortunately), so they are essentially a short circuit.
>
>I need to take pictures, now that it is relatively cold here (everything
>being relative) and take the same pictures in the summer and look for
>differences between the 3 coax lines. Out of the 135 feet, 60 feet are
>in the air going up the tower, 50 feet are in the ground (in a 4" PVC
>pipe), the rest is in the garage and the attic, so temperature is not
>well controlled or constant, but it should all vary in the same direction.
>
>Didier
>
>
>
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