[TowerTalk] [Bulk] Change in Frequency with Height above Ground

[Jim Brown]

On Fri,5/27/2016 1:18 PM, jimlux wrote:
> For dipoles, and even 3 element Yagis, they tend to be pretty 
> insensitive to surroundings. 

Not as much as you might think. Modeling showed me that a 40M dipole at 
only 40 ft would be about 75 ohms over lousy ground, but closer to 50 
ohms over average ground. When we hung it over lousy ground for CQP, it 
was an almost perfect match to 75 ohm coax as measured on my old AEA SWR 
analzyer set for 75 ohms.

Like you said, modeling can be VERY instructive.

73, Jim K9YC