On 1/10/2022 1:13 PM, Jim Brown wrote:
As usual, I agree with Rick. But I'd like to observe that an extensive
study of loaded mobile whips published in two parts in QEX about ten
years ago showed that inductive loading, especially at the base, was a
73, Jim K9YC
I wasn't clear. I assumed that the vertical has top loading wires, and
the base loading inductor is added to get resonance. According to W8JI,
once you have enough top loading to get uniform current in the vertical,
then it is OK to have a base mounted tuning inductor. For short
verticals, making the top wires extremely long to achieve resonance
without a loading coil is sub optimal because it reduces the radiation
resistance too much. I once resonated a 60 foot vertical on 160 meters
using two 100 foot top umbrella wires, because it was a temporary
antenna and I didn't want to fool with a loading coil. The drive
impedance was very low.
73
Rick N6RK
_________________
Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
|