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Magloop Height?
"Dave Oldridge" wrote in message 9... "Lee" wrote in o.uk: Is there any optimum height for a 3ft dia magloop, or is it dependent on frequency??. I have mine planted in the lawn with the top about 6ft from the ground (on a rotator!) and was curious whether to work it against ground or put it at the top of the tower, or have i completely lost the plot???, Heh heh........ Surprising how cheaply a magloop can be built for and after 12 months it still works well!!. What band is yours on? I have a 55-inch diameter coax loop that I'm using on 75, but I'm seriously thinking of working up a multiband design in soft- drawn 3/4" copper pipe. It would be six feet in diameter (mainly due to space considerations). Dave Oldridge+ ICQ 1800667 ======================================== Dave, Magloops with copper pipes are the most efficient of all small antennas. They should be rotateable through about 45 degrees. Changing from coax loop to 3/4" or 1" copper pipe loop will be a considerable improvement on both transmit and receive. Especially if it is not too low above ground and is not in a cluttered environment. The idea is to keep ground loss less than conductor loss. For multi-band operation you will be best with a motor-driven vaccuum tuning capacitor. With a 1000pF capacitor and a small loop the 160, 80 and 40m bands can be covered. It depends on the minimum capacitor setting and loop perimeter. There is no noticeable difference between aluminium alloy and copper pipe. Aluminium alloy is lighter in weight and stands up to the weather better but is more difficult to bend. A square loop is not noticeably worse in performance than a circular loop and may be easier to construct. Download program MAGLOOP4 from my website. It may provide food for thought. ---- Reg, G4FGQ. |
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