[TowerTalk] Change in Frequency As Antenna Height Rises

[Dan Maguire]

Steve G3TXQ wrote:
>>> Here are the resonant frequencies I measured of a 10m half-wave dipole on a telescopic push-up mast at various heights above ground in my back yard: 

Using a dipole model with a 1" diameter aluminum wire over "Very Good" EZNEC ground, I adjusted the length to match the G3TXQ measured resonant frequency at the 15 ft height.  That made the length 15.28 ft or ~0.47 WL.  Then I calculated the theoretical resonant frequency at other heights from 5 to 25 ft.

http://s33.postimg.org/oqqqmprhr/resonate7.png

Note that I did *not* force the almost perfect correlation at the 25 ft height.

Dan, AC6LA