[time-nuts] LORAN-C questions...
cfharris at erols.com
Sun Mar 6 17:43:10 EST 2005
I have had little success with the Austron 2100F's
frequency error display. It appears to be poorly
done at best. Use the Phase Offset error numbers,
and do the calculation yourself over some favored
interval of time (eg. 24 hours).
Loran C is specifically designed to be completely
immune to sky wave problems. The receivers all track
the ground wave signal only. If you are within the
design range of the station you are tracking, that is.
You don't really want to use any kind of E-field antenna
for Loran. The E field is where all of the atmospheric
noise lives. What you want is a 3 to 4 foot diameter
shielded loop antenna. This can easily be made using
some plumbing fittings, copper tubing, and a small pot
core transformer. For the internal loop, two full turns
of 5 conductor flat ribbon cable, with all the leads in
parallel works nicely. Make sure that your loop has a
PVC fitting to break the continuity of the tubing or you
will just have a faraday shield.
=======PVC====== <-- PVC is a 1/2 inch PVC pipe coupling
|| || <--1/2" soft copper tubing
Also, have your C-beams ever been checked for proper
operation? Just because they say they are locked is
not an indication that they are operating properly.
wa1zms at att.net wrote:
> I have an Austron 2100F running and have been
> noting the reported frequency error against one
> of my cesium standards.
> What I note is the error value (as reported by
> the 2100F) always "bottoms out" to a few parts in
> 10^12th around 3pm and 2am local time. All other
> times the error is parts in 10^11th.
> I assume this is due to a mix of skywave and ground
> wave propagation. I'm currently building an active
> E-field antenna to substitute for the 75m dipole I'm
> using right now. I'm tracking my closest LORAN
> station which is Carolina Beach, NC. About 400km away.
> Are my observations typical of LORAN multi-path?
> Thanks in advance.
> -Brian, WA1ZMS
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> time-nuts at febo.com
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