Charlie wrote:
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.

Would you really notice if your cable loss was about 3 dB higher than
specified at 400 MHz and if it varied by a dB or two when the cable is
flexed and bent? What measurement equipment do you use which would cause
this amount of extra loss to "jump off the scale"? And what causes you
to think that increased loss would cause mismatch to "jump off the
scale"? Increased loss will improve, not degrade, the impedance match.

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.

What you have as evidence is Davis' spec on the one hand, and my
measurement report on the other. You've chosen to believe that Davis'
cable all meets its published specifications. I have exactly the same
evidence, but know my capabilities and that of my equipment, so I
believe my measurements -- but always keeping in mind that it's a single
sample. Additional measurements made by someone else on another piece of
the cable would increase the knowledge base, although I'm sure there are
people who would choose to ignore the evidence no matter how much is
presented.

My career was in microwave r&d and
I know that it takes repeatable test results to form a valid, verifiable and
publishable data.

That's great! Then you have the background to be able to make decent
measurements, and you said you're using some of the cable. Why not just
measure the loss in a length of it and report your results?

This is not personal Roy....but it is somewhat stimulating.

I hope it's caused a few people to think a bit about how they evaluate
evidence to determine the truth of a matter. It's something which too
many people are woefully unable or unwilling to do.

Roy Lewallen, W7EL

To find ALL electrical characteristics and performance of
solid-polyethylene transmission line, use program COAXPAIR, from audio
frequencies to UHF.

Accuracy is of the same order as physical dimensions can be measured.
Use a micrometer to measure inner conductor diameter and diameter over
insulant. Or just guess at it. No need to unwind the cable off the
drum!

In a few seconds, download COAXPAIR from website below and run
immediately.
----
.................................................. ..........
Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp
.................................................. ..........

Reg Edwards wrote:
To find ALL electrical characteristics and performance of
solid-polyethylene transmission line, use program COAXPAIR, from audio
frequencies to UHF.

Accuracy is of the same order as physical dimensions can be measured.
Use a micrometer to measure inner conductor diameter and diameter over
insulant. Or just guess at it. No need to unwind the cable off the
drum!

In a few seconds, download COAXPAIR from website below and run
immediately.

Have you compared the results to any measurements of real cables?

Roy Lewallen, W7EL

Reg Edwards wrote:
To find ALL electrical characteristics and performance of
solid-polyethylene transmission line, use program COAXPAIR, from
audio
frequencies to UHF.

Accuracy is of the same order as physical dimensions can be
measured.
============================================

Have you compared the results to any measurements of real cables?

Roy Lewallen, W7EL

============================================

Yes, Roy. Countless times.

Have you any more questions?
----
Reg, G4FGQ

Reg Edwards wrote:
Reg Edwards wrote:

To find ALL electrical characteristics and performance of
solid-polyethylene transmission line, use program COAXPAIR, from

audio

frequencies to UHF.

Accuracy is of the same order as physical dimensions can be

measured.
============================================


Have you compared the results to any measurements of real cables?

Roy Lewallen, W7EL


============================================

Yes, Roy. Countless times.

Have you any more questions?
----
Reg, G4FGQ

Yes. Where can I buy some of that RG-58 that has only 2.2 dB/100 foot
loss, or RG-213 that has only 0.89 dB loss, at 50 MHz?

Roy Lewallen, W7EL

On Tue, 13 Dec 2005 00:26:25 -0800, Roy Lewallen
wrote:

Have you compared the results to any measurements of real cables?

Roy Lewallen, W7EL


============================================

Yes, Roy. Countless times.

Have you any more questions?
----
Reg, G4FGQ

Yes. Where can I buy some of that RG-58 that has only 2.2 dB/100 foot
loss, or RG-213 that has only 0.89 dB loss, at 50 MHz?

Roy Lewallen, W7EL

The silence is deafening.

Danny, K6MHE





email: k6mheatarrldotnet
http://www.k6mhe.com/