[TowerTalk] Tower height increments

[Dick Green WC1M]

EZNEC shows the gain increasing about half a dB from 69 to 79 feet. However,
it also shows the gain dropping back .5dB at 110 feet, where the angle is
more desirable. I suspect these minor gain differences are due to
inconsequential changes in the forward lobe.

> -----Original Message-----
> From: Jim Lux [mailto:jimlux at earthlink.net] 
> Sent: Saturday, October 16, 2004 11:31 AM
> To: W3YY; TowerTalk List
> Subject: Re: [TowerTalk] Tower height increments
> 
> 
> 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 at cox.net>
> To: "TowerTalk List" <towertalk at 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
> 
> 
> 
>