On 10/17/2011 02:28 AM, Mark Sims wrote:
Yes, at one time there was some very precision surveying antennas that were temperature
controlled. I'm not sure if they were just controlling just the preamp or the whole
antenna, but I got the impression that they were controlling the temperature
Anyone know what the propagation delay temperature coefficient is for RG6U coax
and how much it varies between different brands of cable?
In my efforts to improve the Tbolt's performance to make it into a better Cs
substitute,
test suggest that the temperature coefficient of the antenna lead-in
Using the cable delay message is probably not a good idea... it resets the
internal filters and state every time you change it.
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Thanks John
Any chance using 75 ohm cable (as suggested in the Tbolt manual) like RG6U,
when used in a 50 Ohm system could be orders of magnitude worse than
LMR-400?
Sounds like may be time to do some controlled cable experiments comparing
different cables.
I do know that Cheapie GPS timing
I wouldn't think the cable type will make an order-of-magnitude difference.
Referenced in the Haystack note is another paper that goes through the
theoretical derivation that produced the expected results column. I think
it's the same URL but 067.pdf as the file name.
John
On Oct 16, 2011,
Its merely a calculation of the change in inductance due to the
temperature induced change in skin depth due to the resistivity tempco
of the inner conductor wich varies the inductance per unit length.
Since RG6 uses a copper plated steel inner conductor there may be
significant differences in
Sounds like its time to do some testing and see what the effect is on the
actual hardware.
1) Heat and cool the Tbolt box and see if that effects THIS Phase delay,
maybe by way of its internal GPS amp/BPF.
In the past I have not seen a need to use LH's temperature controller on a
Tbolt that
Yes, at one time there was some very precision surveying antennas that were
temperature controlled. I'm not sure if they were just controlling just the
preamp or the whole antenna, but I got the impression that they were
controlling the temperature everything inside the radome package.
At
: Mark Sims hol...@hotmail.com
To: time-nuts@febo.com
Sent: Sunday, October 16, 2011 5:28 PM
Subject: [time-nuts] Cable delay correction for Tbolt Cs substitude
Yes, at one time there was some very precision surveying antennas that were temperature controlled. I'm not sure if
they were just
On 16 Oct, 2011, at 11:21 , WarrenS wrote:
Does anyone ever add a temperature controller on the antenna? Maybe that
should be my next test.
I've seen commercial temperature-controlled antennas. Here's one:
http://adriang.com/AACE-Industries/products.htm
Dennis Ferguson
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