[time-nuts] Newby with questions
lists at rtty.us
Mon Feb 28 18:01:51 UTC 2011
One long term issue with the skylight:
Stuff (snow, rain, birds, space aliens) can pile up on the skylight. That
messes with the GPS signal. You really want to get the antennas outdoors if
at all possible.
When you do get them outdoors, don't forget that the electric code (and
common sense) requires that you put a proper ground and lightning arrestor
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of David VanHorn
Sent: Monday, February 28, 2011 12:45 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Newby with questions
The 24 GPS satellites are in orbits that never pass over the poles.
I think they are about 60 degree inclinations. By your description
you must be in the northern hemisphere. If you can, set up your
antenna so it can see to the south and don't worry if the view of the
north is blocked because as you found there is nothing to see there.
I see! So I could move the antennas closer to the north side of the
skylight, letting the skylight wall on the north side get up around 60
degrees, so that my view to the south is more optimized.
I also see the notes on the temp sensor, just ordered some rev C parts that
I can change out here as needed.
I'm going up on the forklift today to connect the second feed (didn't have
enough adaptors Friday for N-F) and I'll nudge the positioning a bit, then I
can do the survey on the other antenna.
I understand that the Tbolt should be giving me WAY better than 1PPM, but
that's exactly what I wanted. Until I started pushing this issue, we didn't
calibrate anything, and our test gear was in constant disagreement. If you
can't measure it, you can't improve it, and I'm tired of measuring with
unmarked string.. <VBG>
My next problem to solve, is distributing the signal through the production
floor. I won't need phase accuracy between the drops, but I don't want to
induce any significant error. My initial thought was simply to amplify and
split like CATV drops, but I'm seeing that this may not be the best
approach. I have a 75 ohm video distribution amp on order that will serve
my immediate needs, maybe something better later on.
Question: Is there a way to have the Tbolt shut off the 10 MHz output if it
is not reliable? I'd rather have no signal than an unreliable signal.
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