I was fortunate to be using K6STI’s YO and TA programs to model my antennas
over my incredibly complex terrain. I found no equal program when it came to
the combination of modeling antenna stacks over terrain files that you could
easily construct and use. Of course it runs only in DOS which is one of the
reasons that I continue to maintain my two DOS based computers.
I stayed with YO and TA precisely because it did not compromise stack modeling
or terrain modeling. And it was/is amazingly accurate.
I also found the NW program to be very useful to model and build wire beam,
4-square and phased vertical antennas. It was also great for modeling and
designing phased beverages back about 15 years ago.
With the incredible advances in technology and knowledge over the past 20+
years since K6STI created his program, I’m not sure why someone hasn’t yet
designed a Windows program that can accurately model any combination of wl
phasing with any combination of antennas over any type of terrain from a
terrain file that you create yourself. Certainly the need and demand for such
a program is there especially given just how many people who “pooh-poohed” the
idea of such a program decades ago would gladly pay for such a program today!
Bob KQ2M
From: Grant Saviers
Sent: Tuesday, March 13, 2018 5:48 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] add a 3rd el to 40-2cd
One caveat for "terrain analysis" is that HFTA does not model stacks
well around 1/4 wl and less separations. So that leaves NEC/EZNEC
which does give accurate results but over flat terrain. It will also
provide better gain and elevation patterns and for the specific antenna
rather than the HFTA generic "point source" model. The ability to
model interactions with other antennas is pretty useful. I modeled my
stacks both ways.
Is somebody out there reprogramming the "dusty deck" Fortran HFTA for
the 21st century? A worthy project now that we all have beyond Cray
super-computer laptops.
Grant KZ1W
On 3/13/2018 10:12 AM, Bob Shohet, KQ2M wrote:
> I respectfully have to disagree with Steve on this.
>
> Stacking with a lower antenna is highly unlikely to produce a lower wave
> angle. So a Full-sized 3L will still be almost always superior to a 2L at
> the same height and that extra 1 – 2 db at the right angle at the right time
> with the full-sized 3L antenna could be significant. What stacking might
> give you is a higher (than the 3L) wave angle that is useful to some
> population area of contesters that you will now be louder into. And it will
> give you potentially three different wave angles to choose from if you phase
> them and have Upper, Lower or Both switching. However, you will have a less
> broadband antenna with reduced F/B and F/S which could handicap you when
> dealing with qrm and qrn.
>
> And you will have to put that 2nd antenna very low to get meaningful wave
> angle choices and those wave angles may not be very useful especially for
> working DX.
>
> Every qth is different – with different topography, terrain and other factors
> to take into consideration. Everyone should do extensive modeling with your
> own specific terrain BEFORE seriously considering stacking a 2nd antenna to
> see if it is even worth considering. And you also need to consider the
> additional wind load on the tower and whether or not what you have up in the
> way of tower and guys will support that additional “wind-sail”. :-)
>
> 73
>
> Bob KQ2M
>
> From: k7lxc--- via TowerTalk
> Sent: Tuesday, March 13, 2018 12:54 PM
> To: bmarx@bellsouth.ne ; towertalk@contesting.com
> Subject: Re: [TowerTalk] add a 3rd el to 40-2cd
>
>
>> With one antenna at 72 ft why not just add new antenna lower on the tower>?
>
> One of my all time favorite ideas. Stacked would give you similar
> performance to a full sized 3L plus you get angle and directional diversity.
> And you don't need expensive rotators! Like my old buddy Mark, AA6DX sez:
> "Worky, worky!"
>
> Cheers,
> Steve K7LXC
> _______________________________________________
>
>
>
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