[TowerTalk] MODEL FOR TOWER

[Gedas]

Yup, I understand what you are saying and do not disagree. A 
clarification please (and this assumes there will be some interaction 
between tower and antenna worth worrying about).....were you referring 
to how we sometimes "fudge" certain simulations by selecting a Mininec 
or perfect type ground (that allows direct contact with Z=0) and then 
insert an assumed resistance for that we think are the ground losses 
etc? Or were you going to stick to a real, "high-accuracy" type ground 
that does not like a connection to ground but make a connection to Z=0 
anyway?

Also what value of R should be used ? 2 ohms, 5 ohms, 10 ohms ?  Do most 
ops really know what an accurate number to use is for our particular 
grounded towers, vertical antennas etc ?  I suspect many are taking a 
best guess at a number and assume it is close & hope for the best.

I wish I had NEC-4 but even so I am half tempted to model this darn 
situation just to see for myself what the results will be under 
different situations hi-hi.

Gedas, W8BYA

Gallery at http://w8bya.com
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On 4/26/2019 3:52 PM, jimlux wrote:
>> One thing I have not seen mentioned (maybe I missed it) is the fact 
>> that a whole lot of time & effort is going to go into generating a 
>> super accurate model for a complex tower and antenna system but then, 
>> what of the grounding of the tower itself at the base? Grounded or 
>> un-grounded or sorta grounded are all going to give different results.
>
> That's easy to test in NEC. Just put a resistor between tower and ground.