Fw: [Elecraft] Flagpole antenna

[Vic Rosenthal]

Hans W�est wrote:
> 
> > I need a vertical antenna on my lot for a few ....
> 
> See also the all band "Sommer T-25/S Vertical Antenna" at
> 
> http://www.sommerantennas.com/t25s.html

I've tried this one and I emphatically do NOT recommend it.  It depends on a
loading resistor to smooth out SWR variations, and if the antenna is detuned by
the presence of nearby objects, the resistor simply dissipates more power.  I
was unable to get claimed efficiency (I measured the power going into the
resistor) on any band, and SWR was unacceptable on other bands.  I spent a lot
of time on this and talked to Herr Sommer himself and even he admits that it
must be mounted at least half-wavelength from large metal objects, masts, etc.  

Although it is supposed to work in a less efficient fashion on 80/160 meters, it
was entirely worthless on these bands.  

Even if you can guarantee that the antenna will be clear of conductors that
might detune it, it will still be less efficient than an antenna that is not
resistor-loaded.  And it has a counterpoise which makes it impractical for
stealth antenna applications.

Vic K2VCO