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Shortened 160M Loop: inductor placement

Jul 22nd 2012, 00:08

NC8V

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
I am pondering over the use of loading coils to "shorten" two legs of a 160M horizontal full-wave loop, to make it fit my property. I would use ladder line to my transmission line matcher (Handbook design) at the operating position. Also, I am most interested in a particular part of the band, so a narrow "resonant" bandwidth at 160 is acceptable. I could use help on calculating the inductor value needed to "lengthen" two parallel physically short legs, and on determining the "best" place in those legs to place the inductors. I have done some extensive reading of 'net-accessible resources, but pointers to valued resources are always welcome. Tnx!
Jul 22nd 2012, 16:34

W1VT

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0


"Best" can vary widely, depending on what you want to get out of the antenna. Most folks don't put loading coils in full wave loops because they want to use the antenna on all bands--they want to use all of the antenna on 10 meters as well as 160 meters. Probably the most difficult challenging is deciding where to put antenna nulls--but they are inevitable if you want to put up big antennas--sort of like wanted to drive a car with a roof over your head--I've never seen one that didn't have blind spots.

I'd suggest learning how to use an antenna modeling program, so you can model different configurations and decide which one is "best" for your particular situation. I'd also suggest you compare the results against the normal recommendations for 160--an inverted L and the largest center fed dipole that will fit on your property. I'd assume that i you have four high supports for a loop, you would also have the supports necessary for a dipole or inverted-L.

Zack Lau W1VT
ARRL Senior Lab Engineer

Dec 4th 2012, 02:42

NC8V

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Somehow, I forgot that the "loading coils" would look different on other bands! ("D'oh!"). Thanks for remindIng me, and for strengthening the argument for using some more conventional techniques.

Ted Morris, NC8V

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