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Attic Loop

Attic Loop

Published on 9/28/2011, 11:44 AM by KD8BIG

Lacking outdoor space for that antenna?

Here’s what one can do:
Put as much wire in your attic as you can run in the shape of a loop. Establish the feedpoint as high as possible. Use heavy gauge wire to minimize losses. I am soon to replace my smaller gauge wire with #8 speaker wire.

Try to stand the antenna wire off from the rafters at least by a few inches. I used the longer of the two stand-offs that RS sells. I have been feeding with twin lead but will soon replace that with window line.

Use an efficient tuner.

There! Nothing unusual or tricky about it. Just the elementary stuff.

I have about 95′ of wire in the loop. It tunes easily on all frequencies above 7 MHz. I have been able to work into Central Europe and Africa on 40 meters with 3 watts. Of course, that only happens when propagation is kind.

The loop will never perform nearly as well as an outdoor antenna, high and clear of surrounding objects. It does allow me to get on the air from a location where outdoor antennas are impractical.

As is typical of loops, there are some deep nulls. To add some variety and improve coverage in general with the loop, my next step will be to insert a lamp switch at the point opposite the feed point. A long run of lamp cord coming through the same hole in the ceiling as the feed line and running down to the operating position will allow me to switch from an open to a closed loop with a gentle tug. The open loop might not be as efficient but will have a different pattern of radiation which might allow me to more effectively communicate with some areas that are in the nulls of the closed loop.
If you can get a bit more wire up in your attic than I am able to hang, the open loop might perform as a folded dipole on 80 meters or lower.

Don’t be discouraged if you are unable to put up a good outdoor antenna where you operate.

I have always wondered what attics were good for.

Now I know.

Thanks Mark for the info, De Dave G0JJR

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