[WVDXA] HFTA

[Charlie Young]

Pete:  Soon. I have been tying up loose ends ahead of Jul 31 retirement. Almost there. Looking forward to spending time on radio/antenna work. Probably August. 
 
Problem with my terrain is HFTA says low ant works best on 10/15M in some directions, and higher 50-60' works better in other.  All depends on time of day and favored vertical angles.  I would wear out a crank up!  Thus, I opted to go with stacks, but with the top antenna about 57 to 60', with the bottom one at half that. All this according to HFTA. 
I will be able to select both simultaneously in phase, both out of phase, top alone or  bottom alone. The model says going higher with the top antenna is counterproductive.       I agree, it would be simpler to just put up the ant and work DX.  Trying to avoid losing 6 to 10 DB because of a null at the needed angle. 
 
73, Charlie N8RR 



From: pstark at suddenlink.netTo: wvdxa at wvdxa.orgDate: Fri, 4 Jul 2008 21:53:50 -0400Subject: Re: [WVDXA] HFTA



Solution is to use crank up tower.
Adjust to best signal. 
Work dx.
 
When we getting started on tower, Charlie?
 
Pete K4OM

-----Original Message-----From: wvdxa-bounces at wvdxa.org [mailto:wvdxa-bounces at wvdxa.org]On Behalf Of Charlie YoungSent: Friday, July 04, 2008 9:44 PMTo: wvdxa at wvdxa.orgSubject: [WVDXA] HFTAFor those who might not be familiar with HFTA (High Frequency Terrain Analysis) software that comes bundled with the latest ARRL Antenna Book, here is a presentation the author N6BV did for the YCCCwhich describes how terrain affects the vertical takeoff angle in surroundings like we live in.  http://www.yccc.org/Articles/N6BV/N6BV%20Boxboro%202004.ppt#394,1, I have been playing with this now for about a year and using it to plan my antenna installation.  My terrain has some of the saddleback features mentioned  (undesirable) in some directions.  Not much one can do about that.  The primary usefulness, if one lives on the side of a hill or on top of the hill, is the software can give some guidance regarding how high to put the antenna above ground. It is very easy, especially on 15 and 10 meters, to be too high if the ground slope is steep.  For example, HFTA says that on 15 and 10 meters, a single yagi higher than 25' or so will be decidedly inferior than one even 40 or 50' high toward EU at my QTH.  I wish HFTA would do verticals, but it will only do horizontal antennas.  73, Charlie N8RR    

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