Thread: annealed coax
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Old March 7th 09, 03:34 PM posted to rec.radio.amateur.antenna
JIMMIE JIMMIE is offline
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First recorded activity by RadioBanter: Jul 2006
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Default annealed coax

On Mar 6, 6:05*pm, Jim Lux wrote:
JIMMIE wrote:
I have heard there is a process where coax cable is baked in an oven
to lessen the effects of temperature change of the cable on phase
shift. I havent been able to find any information on this process.
Direction to any information on the subject would be greatly
appreciated.


Jimmie


mostly it's done by empirical methods..

The idea is to relieve internal stresses by several temperature cycles,
reducing at least one source of phase change.

In reality, what you want is "consistent and repeatable phase change vs
temperature without hysteresis"... hysteresis or randomness is usually
due to mechanical effects (stick/slip, etc.), so temperature cycling
fixes it.


Yes, I think this is the problem. There are multiple cables that must
remain phase matched fairly closely and they are exposed to the
weather. If there was a sudden change in phase of the signal on one
cable that would definatly be a problem. Any cable that does not have
hysterisis would probably work. I also realize now that the type of
cable being used is probably the worst possible choice. Just swiching
to a foam dielectic cable may solve the problem.


Jimmie