[TowerTalk] add a 3rd el to 40-2cd

[Bob Shohet, KQ2M]

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 at 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 at bellsouth.ne ; towertalk at 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
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk

_______________________________________________



_______________________________________________
TowerTalk mailing list
TowerTalk at contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk