[TowerTalk] Antenna Modeling

[Edward Mccann]

Wes:
Standing by for your observations on and experiences with balanced tuners.
Ed McCann
AG6CX


Sent from my iPhone

> On Jul 12, 2018, at 6:12 AM, Wes Stewart <wes_n7ws at triconet.org> wrote:
> 
> I been reading this thread with interest and for no particular reason I'll jump in here.
> 
> I've been modeling antennas since the ELNEC days. (I used Touchstone running under DOS for circuit analysis forever ago.) But I've built antennas longer than that, obviously without modeling. So I'm comfortable with both methods and I believe there is a place for both.
> 
> "Trial and error" should probably be "trial and adjustment."  A simple dipole, hung inverted-vee style in my case, installed in an available space, is more quickly made operational by estimating length by formula, adding a few inches (or feet depending on band) hanging it up, measuring the match and shortening it appropriately. When you're done, you're done.  Was this a "learning experience"?  Maybe a little to a beginner, but otherwise, not particularly.  But so what, everything doesn't have to be a science project.
> 
> I've used the same method to build one of those antennas that according to some, doesn't work; the parallel wire (fan), fed in the middle with coax+CMC, inverted-vee style, 80 and 40 meter dipole, apex at 45'.  As some have noted, it takes special care to model this and in my experience, it's hard to account for every other variable, such as proximity to (unknown) ground, support structures, other antennas, etc.
> 
> So, not realizing that it won't work, I did it anyway.  Seemed pretty simple to me and while I am normally not a fan of anecdotal evidence, with years of experience with this antenna, I'm okay with it.  My main activity is working DX but with no obsession toward working every country on every band. One hundred entities on each band suits me as success, more are just gravy.  That said, using this, it can't possibly work antenna, in casual operation, I have over 1,000 80-meter and 2,000 40-meter contacts with DX stations.
> 
> I'll address the balanced line feeder in another thread.
> 
> Wes  N7WS
> 
>> On 7/11/2018 9:29 PM, David Gilbert wrote:
>> 
>> 
>> Same here.  Trial and error may eventually work, but most likely you won't know why.  Modeling, especially if you investigate the currents and their phasing, will help you learn and understand why something might work or not work.  "Ham" radio doesn't mean being ignorant of the stuff behind what we do.
>> 
>> There are pitfalls with modeling of course, but doing things like a running a sensitivity analysis (tweaking dimensions to see if the changes make sense) can minimize that.  I learned more about antennas from playing around with EZNEC+ than I ever did from any other source.
>> 
>> 73,
>> Dave   AB7E
>> 
>> 
>> 
>>> On 7/11/2018 5:19 PM, Jim Brown wrote:
>>>> On 7/11/2018 5:08 PM, Dan Bookwalter via TowerTalk wrote:
>>>> I know everyone is onto modeling everything,  I am in the camp of , put it up , give it a try , dont like it , try again ...
>>>> We have lost so much of the "ham" part of ham radio... I used to , and still do , throw a wire out and see what you can do ... other than 160 and probably 80 , you can work a suprising amount of stuff ..
>>> 
>>> My view is completely the opposite -- to me, ham radio is studying the fundamentals and using that knowledge to build our stations, including antennas, that work better. Wandering around in the dark is not part of my view of ham radio.
>>> 
>>> 73, Jim K9YC
>>> 
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