Hi Mike,
I make the Hi-Z Antennas receiving arrays and I am always looking for ways
to make them work better. Attention to detail has been the key to success in my
endeavors. I had made some early tests on this cable going on 15 years ago when
I did not have as good equipment. As I design or redesign things I find modern
technology has paved the way for even better performance. Here is the
situation. The 8 element all active array whose model shows 13.48 dB RDF
remains the top of the list as far as I know for that performance. What I do
know about that also is mathematically those 8 elements theoretically can
produce an RDF of right at 16 dB. The rub is the element amplitudes and phasing
has to be controlled to some remarkable unobtainable accuracies to do that.
Just maintaining 2% amplitude accuracy and 1 or 2 degrees phase stability 10
years ago when the 8 array was put into production was all I thought I could
squeak out with the then current components and measuring ability I could a
fford. Buying 1% resistors and capacitors in surface mount is now common which
has helped available accuracies and my test equipment is much better than I had
at the time. Chasing these things is part of what I do trying to push the
barriers of low band Receiving.
It has always been in the back of my mind that not knowing accurately the
stability of the delay cable was one of the error terms greatly affecting how
the array could match the model. Just something that had to be done in my mind.
Here is some more shocking cable data I took several years ago
https://www.k7tjr.com/coaxial_tests.htm
Cheers,
Lee K7TJR OR
-----Original Message-----
From: Topband <topband-bounces+k7tjr=msn.com@contesting.com> On Behalf Of Mike
Smith VE9AA
Sent: Wednesday, April 8, 2020 11:49 AM
To: topband@contesting.com
Subject: Re: Topband: RG-6 Delay cables
Interesting Lee. I guess I never thought anything about delay lines in our
weather here. I have RG-6-like cables on all my 4-squares.
I was unaware electrons cared whether it was +35*C or -35*C (or general temp
range here in NB)
What prompted you to do such testing?
Thanks
Mike VE9AA
<big snip>
".My bottom line conclusion is that for our purposes on the top-bands I no
longer
wonder if the cable delay and attenuation remained constant with winter
deployed arrays.
Incidentally, T&B Snap and Seal have been the best connectors here for
repeatability.
Lee Strahan
K7TJR."
Mike VE9AA
Mike, Coreen & Corey
Keswick Ridge, NB
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