UK Users of the CCW Active Loop Amplifier ++ may find my design of an aluminium loop and the use of a 9V Battery Box of interest...People in other countries may be able to source similar materials to construct the loop.

As I didn’t have a spare bicycle wheel rim (shown on the CCW website) I made a square loop from strip bought from B&Q (UK DIY Store) and have attached the drawings and photograph of the completed loop with the amplifier.

I also found at CPC (UK Farnell Group Electronics Supplier) a 9V Battery Box with switch and plug which I fitted with a 9.6V Ni-Mh rechargeable battery which is ideal for portable use as shown in the photograph attached. I accept the performance may not be the best with 9V instead of 12V but it was easy to put the battery box in my pocket when walking around with the square loop.

Enclosed 9V Battery Holder with 200mm Lead & DC Jack Plug - SBH-9VAS+DC CPC Stock Code BT06082 £1.81 Inc VAT

Thanks for posting your loop design, Chris.

That looks a lot easier to make than trying to make something circular.

It has more than a hint of cubism about it, Picasso would be proud of you!

Regards,

Chris

Here is another idea. This one is made from PVC electrical conduit tubing for the mast, and one short fibreglass rod for the horizontal spreader. Very light weight and strong. It looks like a diamond from the picture angle, but its actually square.

Sure David. Its on the back of my shed at the end of the yard. The bottom of the square is about 3m above the ground. The fibreglass cross piece is about 60 inches (1.5m) long, and each side of the square is 42 inches (about 107cm) long. The vertical tube is a length of what is called (in N. America) 1 inch PVC electrical conduit. I believe the actual diameter is closer to 1-1/4 inch. In my case I slipped that into a short length of larger PVC electrical conduit at the bottom just so the rotator clamps wouldn't crush it. I used a couple of S.S self tapping screws to bind the two tubes together so that it doesn't spin. Lugs are crimped onto the wire loop ends and then attached the amplifier. The amplifier is then attached to the vertical tube. The whole thing has very little wind resistance and weight. It has endured several 100km/h storms and hardly even wiggles in the wind.
73 Tom

The vertical tube is a length of what is called (in N. America) 1 inch PVC electrical conduit. I believe the actual diameter is closer to 1-1/4 inch.

The American pipe sizing convention refers to the INSIDE diameter, since that is what determines the flow rate in water pipes. Not the wall thickness or OUTSIDE diameter which can vary. Obviously, this does not affect the coulomb flow rate in an electrical conduit, but the pipe sizing  convention of inside measure carried over to electrical conduit sizing.

Don't get me started on the screwy measure of American construction lumber.  So-called "2x4" studs are about 1/2" less in each dimension. The dimensions refer to the rough-cut size before they are milled to the exact dimensions expected for finished lumber.  Perversely, the dimensions of plywood and other panels ARE the dimensions claimed - 4 feet x 8 feet x 3/4" thick or whatever.

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I had only a few goals. I wanted a loop that was low cost and easy to build with common materials. I wanted it to be strong enough to withstand our Canadian ice storms yet still have low weight and wind resistance for my light duty rotator. The dimensions or shape are not critical for an untuned loop. I am more interested in the lower bands and BCB so I wanted it to be on the bigger size. I happened to have a 5 ft fibreglass rod on hand that is ideal for the spreader and that was my starting point. When I built it 10m was never open so that didn't factor into the size goal. But now that it is, I am very pleasantly surprized how well it works up there. And it still shows a decent null for local noise. I wouldn't overthink the dimensions of an untuned loop. I have tried all manner of shapes and sizes including crossed parallel loops. Although there are some differences, here on a noisy suburban lot, it really comes down to what has a good noise null and still has decent sensitivity.
If you don't have any noise, then there are better antennas than loops IMO.

Nice design Tom. How did you attach the tubing and the rod together? Just drove a screw through it? 

The horizontal rod is just slipped through a snug hole drilled in the vertical PVC tube. No need for any other fasteners because it centres itself anyway due to the wire length. 

BTW, Chris G3YTU,  sorry I highjacked your topic. I should have started a new one. Tom