Mag Loop and other info

David Cutter

This site may help a few builders.  I just came across it an hour ago and have had only a cursory look. It contains a lot of useful info on other topics as well.  You need to scroll down to section 7.

Just for amusement I built an aluminium strip loop using a 12ft x 4ft 20swg aluminium sheet forming a tube 4ft long by ~4ft diameter.  Tuning accomplished with several interleaving vanes 4ft long by 4" wide attached to the open ends of the tube. It was a monster.  Eventually I got it to work in a contest on 20m and it had a 48dB front to back ratio to null out the noisiest of Mediterranean and Russian mega-stations.  The pick up loop started life as 4ft square 20swg aluminium sheet to form a tube 4ft long by ~1ft diameter.   Then I moved house and scrapped it and I'm still using bits of aluminium from it 30 years later. Crazy days, fun and educational on several levels, ie learn by doing. 

73 David G3UNA


Like the idea of a 12 by 4 loop!

How the ell did you mount that up???got any pics????love to see!!

Interesting website you pointed out..

But need to point out below, incase someone reading and thinks wants to make a tx mag loop.

Totally disagree in his mag loop building..lots of ways in how to build an inefficient mag loop..( except for the connection to vac cap, but even that was flawed..)
Like the idea of mobile loop..though not sure about having one above my head!

Need to say why I think his loops inefficient..joins..plumbers solder. Use of ali use of copper water no..

Must be one continuous loop ( can be parallel tubed, can be twin turn on 160m.) no ali ( twice r of copper, plus one cant buy pure ali tubing ( or copper now, but one can better quality copper tubing.)
Never use copper water pipe.( cos its cheap for a not pure by along way.) .never use lead solder..( must be silver 40-55%) no joins in loop ( except for loop to vac cap.) every join removes efficiency ..
(Plus his resistance of loop measurements are flawed..loop may have 50a running though not 0.5..)

However mag loops are great!! Ok if you can do what Carlo i5jva has on 160m then dont bother.( or hannas or john vy2ww etc.) .but i cant so i love mag loops..

Still a good interesting read though!!

Mag loop Simon