[TowerTalk] Modeling question - for the experts!

[StellarCAT]

Jim,

But as noted before I can't get a model to work! Therein lies the issue. If 
I could get a model to do something close to reality I'd feel considerably 
more comfortable - I've heard several say they'd rely on the model - I've 
not gotten that sort of comfort level comparing real world to the model and 
in a good share of cases it blows up (usually segmentation errors causing 
'negative power'). I am familiar with segmentation issues and the AGT etc 
etc ... I have the latest 6+ and AutoEZ ... and I've been working with Greg, 
W8WWV who has also run my models under NEC4 ... just don't get results that 
are similar to real world or at least published real world (manuals for 
antennas).

I'm happy to send what I have to anyone wanting to test and (try to) improve 
it.

meanwhile I believe I don't have a choice but to try to test the 40 and the 
15 together. I'm going to disconnect the coax from the 40 - leave it at the 
top of my test tower at ~37' ... hang the 6 element 15 below it at 11' up 
(trying to compromise between spacing and not having the 15 TOO low) ... 
range test the 15 for FB with the 40 turned 90 degrees to it - repeat with 
the 40 inline with it, (and of course measure the SWR in both cases), ... if 
there is a change - i.e. interaction - then bring the 40 down and install my 
sleeve on each of the 8 element halves and redo the test.

g.



-----Original Message----- 
From: Jim Brown
Sent: Thursday, June 2, 2016 8:35 PM
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Modeling question - for the experts!

On Thu,6/2/2016 5:07 PM, StellarCAT wrote:
> What I did to try to see if it would have an effect is this. I made the 
> assumption that the linear loading wires would 'breakup' the element as it 
> would probably have a complex impedance on 15 meters - thus divorcing the 
> rest of the elements - just an assumption but for starters I think a 
> reasonable one.

That may not be a good assumption. Yes, it's complex, but complex
doesn't mean that it goes away. I think you must include details of the
loading in your model.

73, Jim