fun with loading
"John - KD5YI" wrote in message
news:uP70g.270$_s5.47@trnddc04...
Dave wrote:
How would you guys who are stuck in an endless thread of loading coils
like to take on 'linear loading'?? are the currents the same at each end
of the loading line?? do they cancel completely along the length of the
loading line? does the loading line replace so many degrees of the
length of the elements or cause some kind of delay???
the antenna i am working on is an m-squared 40m4lldd where, for example,
the reflector is 50' tip to tip, about 10' out from the boom there is an
insulator, a rod about 9' long connects with a metal bracket on each side
of the insulator and folds back toward the boom where they are connected
with an aluminum shorting bar that then uses a piece of phillystrand that
goes to an element truss support bracket. then of course beyond the
insulator is another 15' or so of element, the tips are adjusted to tune
the elements.
What's "linear loading"? What's a "loading line"?
i probably didn't do a very good job of describing it, but basically you
take a shorter than 1/4 wave element and cut it in the middle somewhere and
put in an insulator. instead of putting in a loading coil as you would
normally expect you use a shorted piece of parallel wire line to tune it.
in the case of the 40m4lldd the parallel wire line is made of aluminum rod
and is folded back to use it as a truss for the element.
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