[600MRG] Loop antennas

[Dave Riley]

The list has been very quiet here lately but here goes:

After trying all known antenna configs here I have settled on a 4 turn litz wire loop of 8' diameter for 630m.

I believe that I have tried everything but lower the atmospheric background noise and line QRN.
This loop beats the long wire, inverted L, and e-probes by far. 

The center tap of the loop sees a local ground and it does help.

Toroid coupling at both ends of the feed are really necessary.

The feed line is 72 ohm KW twin lead and is just laying on the ground.

An LNA made by Nooelect  is quiet and has good gain. ( Amazon )
Now they have a 10khz and up version, so am waiting to try. SAQ and Navy freqs.

Did I miss anything? Am using W1FRV ( first radio voice ) call sign to commemorate Reggie Fessenden who did a lot of loop work here in town way back.

The new loop on 160 ( W1NMF ) commemorates USCG COMM STA Marshfield and it just had a very good first night showing.  It is 4' plus diameter of one turn of 1/2" copper tubing.
It uses 3 #75 toroids at the feed point to increase 'L', improve Q with a two turn wire coupling secondary which gives near 30db of return loss. The variable vacuum cap is tuned for the WSPR-160 band.

Any comments greatfully accepted..

Dave, AA1A








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