Topband: RG-6 Delay cables

[Lee STRAHAN]

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 afford. 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 at contesting.com> On Behalf Of Mike Smith VE9AA
Sent: Wednesday, April 8, 2020 11:49 AM
To: topband at 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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