Magnetic Loop Antenna

I was handed a leftover roll of 7/8" Cellflex cable from which I'm building a Magnetic Loop Antenna for 80 and 40 meters.

As often the Internet provided the wanted information, this time in the form of the web-page of HB9MTN.

He build his Antenna in the attic of his house. I decided to put mine on the roof of the garden shed.

The loop is made using  the 7/8" Coax cable. wound in two turns at a diameter of 160 cm. This gives about 10 m of radiator and the spacing between the two turns is 15 cm. The High Voltage Capacitor was ordered from HB9TJX . A backlash free 100:1 worm drive was taken from a BC221 frequency meter obtained from the Dutch Ham Amateur museum. (There was very thick rust and oxide inside everywhere so it did not break my heart too much.) The worm drive itself is driven by a small DC motor with a 100:1 gearbox attached.

The coupling loop is made from roughly 200 cm of 2.5 square mm ordinary installation wire.

Once that was in place it was time to adjust the antenna.  An unexpected surprise was found but a workaround was not too far away.

Next subject was the remote control of the Capacitor and a readout of it's position.

A word of thanks is appropriate to Anton PA0AVS. His skills and workshop were used several times to get this far.

I'm not done yet but here are some pictures. 

Image Gallery