[TenTec] Loop/open wire/AH3?

[joel hallas]

Bill,

It sounds like a good system and I expect it will work well on all bands 
at which the loop is a full wave or longer. That being said, at the full 
wave band, it will be mostly a NVIS antenna, with most radiation skyward 
(see Dean Straw's article in Dec QST and the article by the Dutch group 
in Jan), and provide good medium distance coverage. On the higher bands 
it will be great for low angle communication, if you have reasonable height.

Two observations:

1. The AH-3 tuner is intended to feed a single wire antenna. It will 
also feed your configuration but (based on my experience with the 
comparable SGC tuners) there will be impedances that it doesn't like. 
What I've done is just add a short length of the open wire feeder to the 
antenna connection until I get a total length that works on all bands.

2. You may have currents running toward the radio on the coax shield and 
power supply wires going to the tuner. Try to leave enough wire of both 
types to make a coil, perhaps half a dozen turns, 6 or 8 inches in diam 
of both cables together. If there's evidence of RF on the radio, do 
another coil16 or so feet further back from the tuner, or try a differnt 
coil arrangement.

GL & 73, Joel
Joel Hallas, W1ZR
 
William wrote:

>I have been following the discussions re open wire feeders and invite
>comment on my planned new antenna.  I will be installing a loop around my
>residential yard thanks to a fortunate arrangement of fir and cedar trees
>here on the West (Wet) coast of Vancouver Island.
>
>I will feed this with ladder line-when it arrives---and feed it with my Icom
>AH3 tuner by connecting the main output of this tuner (generally used for
>long wires and whips) to one side of the ladder line and then connecting the
>ground terminal of the tuner to the other side.
>
>Coax should then run through the wall of my shack to the Argonaut V.
>Suggestions/comments/improvements?
>
>Bill
>VE7BER
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