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Old December 11th 05, 01:33 AM posted to rec.radio.amateur.antenna
Charlie
 
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Default Coax recomendations

Roy the kind of test results you cited would be extremely evident whether
someone has a network analyzer or just an swr meter.
That defense is sorely transparent in my opinion. To suggest that most
amateurs would not even have any interest if their bent or coiled 9914
suddenly jumped off the scale for loss and mismatch is ludicrous to say the
least.

Let me be clear ...I am not disputing what you claim you got as test
results. My conclusion is either the 100ft length you had was bad or
something skewed your calibrated setup. My career was in microwave r&d and
I know that it takes repeatable test results to form a valid, verifiable and
publishable data.
This is not personal Roy....but it is somewhat stimulating.


--

Charlie


"Roy Lewallen" wrote in message
...
Charlie wrote:
I have emailed Davis RF and asked them to send me their test results.
Yes it will be interesting.

Roy..doesn't seem a bit odd that NO ONE ELSE in over 10 years of BuryFlex
production has cited these same alarming "test results".


No. My experience is that the vast majority of amateurs don't have the
ability and/or confidence and/or interest and/or equipment to make good
measurements. And lacking the ability to measure it, very few would be
able to discern the difference in loss. If my measurements are typical,
commercial and government users (if there indeed are any for this
particular cable type) would quietly reject the stuff on incoming
inspection and order something else.

I do have a high degree of confidence that my measurements are accurate. I
took a lot of care in characterizing the cable before using it for making
remote antenna impedance measurements in the course of a consulting job.
But it's entirely possible that the particular piece of cable I have is
defective. That would just point to a quality control problem rather than
overzealous specsmanship.

In your query of Davis, I hope you asked them if they routinely test
production batches for loss, and if so how often and when the last test
was run. It's possible that something in their process changed relatively
recently.

If no other reader of this newsgroup has some of this cable and the
ability to test it, I'll see if I can arrange for someone else to make
measurements and post results.

Roy Lewallen, W7EL