[Top] [All Lists]

Re: [TowerTalk] HFTA data files

To: Pete Smith <>
Subject: Re: [TowerTalk] HFTA data files
From: David Gilbert <>
Date: Fri, 26 Jun 2009 14:32:32 -0700
List-post: <">>
If there are significant changes in terrain within those increments of 
295 feet it will have a significant effect on the results, at least as 
far as HFTA is concerned.  I've proven that to myself several times by 
generating dummy terrain profiles (easy to do since they are just 
columns of text) with slightly different features and comparing the 
resulting plots.  As you might imagine that's a function of wavelength, 
so as little as ten feet difference in elevation on 20m can be significant.

Dave   AB7E

Pete Smith wrote:
> There's some question in my mind about how well 
> these data will work with HFTA.  The horizontal 
> resolution of the data appears to be 3 
> arc-seconds, which is 1/1200th of a degree of 
> latitude and longitude, or about 90 meters (295 
> feet). I don't know what effect this relatively 
> low resolution, relative to HF wavelengths, may have on HFTA.  Dean???
> 73, Pete N4ZR

TowerTalk mailing list

<Prev in Thread] Current Thread [Next in Thread>