Hello
spiney
I found this group a few weeks ago and decided to sign up even though
it doesn't seem to have alot of activity.
I have a loop skywire up about 25 feet. 40 Meters.
It works well so far. I have made contacts mostly to the north of
California, Oregon and into Washington state. Probably due to my
location. I have some hills blocking my eastward and southern
directions.
I was intrigued by the posting of the loop drawing, the one that is
parallel tuned. Does that loop have the same radiation pattern as a
regular non tuned horizontal loop? I ask because if you research small
transmitting loops made mostly out of copper (the ones using a
capacitor for tuning) they radiate off the plane of the loop where the
skywire loops radiate off the broadside. I wonder if that parallel
tuned loop radiates off the plane of the loop?
I think that image was posted by KE6YNH, Tom.
Tom, if that is you, are you the guy who we helped last year when
there was a missing person in your neighborhood? (I'm in Bay Ho).
GReg
N7USR
Andy
> parallel tuned. Does that loop have the same radiation pattern as a
> I wonder if that parallel
> tuned loop radiates off the plane of the loop?
I'll jump in here, and hopefully what I say is correct...
As far as I know, the radiation from an antenna doesn't depend at all on
what you may connect to its feedpoint which might make it tuned. If you
build a loop antenna, how it radiates is how it radiates and you can't
change that. (I think this doesn't include the case where you make a loop,
fed at one end, open the FAR end and insert a tuning capacitor there, which
makes it a different animal.)
The general pattern for loops, as I understand it, is:
(1) A full wave loop radiates broadside to the loop, with a null in the
plane of the loop.
(2) A small loop, which includes both physically small loops, as well as
building a full wave loop for some band but then using it at lower
frequencies, tends to radiate more in the plane of the loop, eventually
having nulls broadside to the loop, for small loops. (Of course ground
might intervene and change this pattern somewhat.)
(3) Using a full size loop at higher frequencies, such that it is multiple
wavelengths long, developes nodes in its pattern and also tends to radiate
more in the plane of the loop, than broadside.
In the figure you mentioned, adding the tuning capacitor and transformer
doesn't change the relative distribution of currents along the sides of the
loop, so the pattern will be unchanged. It just helps you create a better
match for the feedline and/or rig.
Andy