I have a couple questions for the list regarding magnetic loop antennas.
Firstly, has anyone used them on HF?   I'm speaking of the small 
transmitting loops that are made in a square and use a capacitor on one side 
to tune to resonance.
And, if so, what sort of results has anyone found with them?
Also, has anyone on list built one using a coaxial stub capacitor?
Check out this website:
HTTP://www.standpipe.com/w2bri/

he's got a very straight forward, step by step description of how to build a 
magnetic loop antenna from copper plumming supplies, and using a piece of 
coax as a capacitive stub.
The antenna looks exceedingly easy to build, and his claims, as well as 
others, say the 3.5 foot square loop will perform as well as a half wave 
dipole on whatever band you tune it for...of course, as long as the loop's 
circumphrence is something less than a quarter wave on that band...for 
instance, this loop is 14 feet all around and therefore is less than a 
quarter wave on 20M.  I've heard allot of great things about the magnetic 
loop type antenna...of course it's only draw back is that it has an 
extremely narrow band width...something like 20 to 30KHZ.

anyway, check out that website and tell me what you guys think.

73
Colin, V A6BKX