Does this antenna have an upper limit on the frequency it'll operate at?
I'd think some real life data on efficiency could be derived from enclosing
anantenna in a 'big enough' styrofoam cooler type enclosure. If the parts
that *I* suspect to be lossy might cause a significant temperature rise with
several hundred watts fed to the antenna.

Jerry


There is no limit on the operating frequency of any antenna. If you can feed RF
into it, it will radiate. Question is where, pattern is determined by the
electrical length of the radiator.
The real efficiency of shortened antenna should be indicated by the comparison
with full size equivalent (or any other known type) and measured field
strength, like it is done in mobile antenna shootouts.
Any RF energy lost in heat is not radiated and will show up in lower signal
levels. It is important to compare antennas with the same radiation pattern and
ground system.

Yuri, K3BU.us