[TowerTalk] 160M Inverted Vee

[ersmar at comcast.net]

Gary:

     Your description of your DX-A antenna as two slopers seems accurate to me.  (Sounds like N4KG's broadbanded sloper design, too.)  If that is the case, then you might get better performance on 160M simply by replacing that entire contraption with a single 1/4 WL sloper wire on 160M and getting rid of the lossy trap.  

     You would connect the sloper to the coax the same way (sloper wire to center conductor) but you would have to run the shield attachment point up and down along the tower to locate the spot that gives you the best match for 1.830 MHz, or wherever your favorite freq might be.  I'm guessing that the DX-A instructions didn't tell you to move the tap along the length of the tower to find the best match.  Did I guess right?

     All this assumes you have somne sort of HF Yagi atop the same tower that will provide some capacitive loading, and serve as the <other half> of your sloper antenna.  (Your 3L 40 is on the same tower, yes?)  

     For a very cogent discussion of sloper design and installation, please check out this posting on TT:  http://lists.contesting.com/archives//html/Towertalk/2002-01/msg00186.html .  I learned quite a bit from it and based my 80M sloper's design on this info.

Just remember to keep the end of the sloper wire way off the ground - maybe something like 20 feet or more.  This is a very cheap alternative for you to test out and report back to us all.  

GL es 73 de
Gene Smar  AD3F


 -------------- Original message ----------------------
From: "Stone, Gary R." <Gary.Stone at va.gov>
> Let me throw in a few comments and a question or two.  I have the Alpha
> Delta DX-A.  It is essentially a sloper with both sides active antennas.
> One side is for 80 meters and the other side is for 40 and 160 - which
> has 1/4 wave for 40 meters and then a loading coil to make up for 160.
> (Each side is connected to the center conductor of the coax. The shield
> is grounded to the tower and I have a separate ground wire going down to
> a ground rod). 
> 
> Well, I have worked about 56 DXCC (including all continents) on 160 but
> can't seem to hear anything active lately that I don't have in the log.
> The antenna seems very poor on 80 meters but that has not been a focus.
> I did work WAS on 160 mtrs with this antenna and it seems to do ok with
> close in contacts (I live in Texas and the 50 states were somewhat close
> in - with Alaska and Hawaii being a bit harder).
> 
> The question is that I am wondering if I could modify this antenna to
> make it more optimized for 160 meters - and if it sacrifices 40 and 80
> that is fine as I now use a 3 ele on 40 and 80 is not a concern that I
> have DXCC on that band.  My initial goal is DXCC on 10-160 and have done
> that except for 160.  So, any ideas about optimizing this AlphaDelta
> antenna for 160 would be appreciated.  
> 
> Gary, N5PHT
>