Bill wrote:
Hello everyone I am looking for detailed plans for an AM loop. I will
be using it only for one frequency 1370AM so I dont want any tuners just a
simple AM Loop antenna for my AM radio. I will have to solder a 1/8 plug to
a 6-8 ft feedline to connect to my radio. It is a Kaito portable model
1103. I want to built this AM Loop cause I listen to talk radio alot and
the static and other distant stations sometimes make it hard. I have done
alot of looking around on google searches but have found no real detailed
plans I am not sure if I should go with edge wound or Spiral wound. Any
info you guys can give especially a detailed plan would be greatly
appreciated. or maybe there is a website I may not have seen you would like
to suggest. I am sure I have seen most of them atleast the most popular
ones. Anyways thanks in advance for any input Bill
Bill,
I have built a number of small receiving loops, and they all work very
well. The easiest way to design the loop is to use a small (and free)
program written by Reg Edwards. Go to his website
(http://www.btinternet.com/~g4fgq.reg...3.html#S301%22) and download
RJELOOP3. It will give you all the info you need, including the
approximate capacitance to resonate the loop. The basic loop consists of
about .1 wavelength of wire for the highest frequency of interest. A
larger loop with fewer turns is much more efficient than a smaller one
using more turns. You will need a variable cap to determine resonance -
the thing tunes too sharp to "cut and try". Once the cap value is
determined, have it measured and make up a fixed cap if you really don't
want to use a variable. You can use a single turn of wire around the
main loop as a low Z pickup that won't excessively load the main loop,
of come off the cap directly to a hi Z FET amp with a low Z output to
the radio. That makes tuning really sharp. These loops have very sharp
rejection, but work best during the day. At night, there are often too
many interferring stations, but it's still worth a try.

bob baldwin