Of potentially more interest might be what happens to the gain at say 5 or
10 degrees elevation angle, rather than where the main lobe happens to
point. In this particular case, with "average ground" it's about 0.5 dB
difference at 10 degrees, and about the same at 5 degrees. Unfortunately
HFTA doesn't plot below 0dBi (even though that's barely 1.5 S units below
the peak), and the peak elevation angle for propagation on 40 is only 3
degrees above the horizon (I used Ohio to EU, because I don't have all the
files uncompressed)
----- Original Message -----
From: "W3YY" <w3yy@cox.net>
To: "TowerTalk List" <towertalk@contesting.com>
Sent: Saturday, October 16, 2004 12:40 AM
Subject: Re: [TowerTalk] Tower height increments
> Warren -
>
> Using HFTA and modeling a 2-el 40-m beam over flat ground, the lobe moves
> from an elevation angle of about 29 deg at 69ft to 25 deg at 79ft. It's
> probably not worth going through a lot of extra work to obtain this
change.
>
> 73, Bob - W3YY
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|