> -----Original Message----- > From: [email protected] [mailto:Repeater- > [EMAIL PROTECTED] On Behalf Of Dave Gomberg > Sent: Monday, August 11, 2008 8:37 AM > To: [email protected] > Subject: Re: [Repeater-Builder] Height Gain figure > > At 16:42 8/10/2008, Dick wrote: > >An antenna's gain is what it is and it doesn't change with elevation. > > I am assuming you mean elevation over the surrounding terrain?? > > This is not true. For example, a dipole has an energy distribution > pattern that changes markedly with height above ground. Just try > using a NVIS for DX! And verticals become ineffective at very high > installation points unless special steps are taken to compensate (by > improving the counterpoise). Anyway, that's my opinion and I'm stickin' > to it.
Once the antenna is several wavelengths above ground (as it will be with any reasonable height at VHF and above) the pattern is going to be the same no matter how much higher it is raised. The ground will have insignificant effects on the radiation pattern. 73 Gary K4FMX
