alford loop

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After using a round loopantenna for long period I was not happy with the performance and that is the reason for this experiment

I build a Alford Loop antenna and found very much improved performance compared to the round loop


In the Alford loop the loop is symmetrical fed on two opposite corners. Though relative large compared to the wavelength the Alford loop behaves like a very small loop.

Originally (as with the K6STI loop also) an open line feeder is used. By adapting a slightly different layout the resulting capacitance can be reduced. This shifts the resonance frequency back up to about the same frequency as shown by the normal loop. When the circumference is about 0.5īl the loop resonates.

The resulting radiation pattern in the YZ-plane (horizontal polarization) shows very deep nulls all the way

The antenna is build on PVC pipe
 for the middle part I use a PVC pipe of 2 mtr long with 5 cm diameter.
for the horizontal support I use a 19 mm diameter pipe which I mounted in the middle pipe by drilling a hole in the 5 cm pipe and gluing the 1.9 cm pipe into the 5 cm pipe.
On the side of the horizontal support I mounted a 20 cm long small pipe vertically glued to the horizontal pipe.
I made this extra strong with a small hole in the horizontal pipe and a tyre wrap.

The antenna wire is attached to the pipes using  tyre wraps.


For active amplifier I am using the LZ1AQ active amplifier.

From the antenna I have two wires to the input of the amplifier. The two connections on the antenna are 7 cm apart.

This antenna gives me best performance I have had from an active antenna.


Here some feedback I received from someone about the performance of my antenna

Hallo Hans,

your KIWI-receiver has good results.   Can you tell me something  about the

used amplifier for your Alford-Loop ?

I'm testing also some antennas (active) for my KIWI...

Quite pleased with this feedback.