[TowerTalk] Re: TowerTalk Digest, Vol 18, Issue 3

[Bill Fuqua]

At 12:00 PM 6/2/2004 -0400, towertalk-request at contesting.com wrote:
>I expect most antennas would fail by arcing limits for low
>duty cycle modes and by heating on high-duty modes like CW.
>The failure points I've found were always heat related in
>the coil. Away from coil self-resonance near the finger
>stock, otherwise in the area of maximum voltage where the
>coil is self-resonant.
>
>73 Tom


         It turns out that the shorter an antenna is relative to a 
wavelength is, the higher the Q of the resonant antenna system (antenna, 
transmission lines, coils, inductors and tuner)  must become to effectively 
radiate RF energy. And in achieving that higher Q using coils and/or 
capacitors there is a good chance of increased losses due to the higher AC 
currents and voltages involved. Also, along with that comes narrower 
antenna system bandwidth. If a electrically short antenna is broadband then 
it must have a lot of loss. Screwdriver antennas have a lot of inductance, 
I suspect that there is appreciable loss in the inductor along with high 
currents and voltages.

73
Bill wa4lav