How to make an antenna for receiving (only) broadcast AM
"no spam" wrote in message
. net...
I'm looking for plans for a simple AM antenna to connect to my stereo
to
replace the little loop antenna that came with it. In the past I have
used
long wires but they are not very directional.
I have found some fairly good plans online for what looks like wire
wound
around a box but all of them seem to have potentiometer in the mix
somewhere. It would be very little problem to build an aimable 18 to
even
48 inch frame.
I only have two AM stations I'd like to come in clearer (690 KHz and
1440
KHz). Would it be possible to make a 'box' with one 'tap' for 690 and
one
for 1440 then just connect one or the other the radio? How long would
be
wires need to be and how would I feed it into the connections on the
radio
(coax)?
Like Richard says, it's easier to find an old cap, and build the loop
around the cap. The old analog dial stereo receivers have some of
the best variables for this purpose. Most are multi gang caps, which
often can approach 1000 pf or more if you tie all the gangs together.
This can be handy for wide freq use as you can use switches and
switch gangs in or out of the circuit to change freq coverage.
Most stereo caps also had a few small gangs with low pf values,
good stuff cut)
Almost anything is easy if you know how to do it. I was looking for
something really simple w/o any electronic parts in it. I posted several
URLs with plans for building a loop like the one you are talking about. I
naively thought I might just be able to take piece of wire that was a
fraction of the wavelength of the freq and wrap it around a frame and aim
it
in the correct direction. But I didn't want to do all the work only to
find
out it wouldn't work.
OK: Start small. Identify a decent ground reasonably near the radio.
Stretch as much wire as you can on a line away from the radio. Tie off
(secure) the distant end as high and clear as possible.
At the radio wrap, the free end of the wire around the radio several times
near where the internal antenna is located. (The exact location can be
easily found by any of several clever methods, not counting taking the back
off.) Strip the insulation off the free end and attach it to the ground. I
expect you will be gratified by the increase in signal strength. Caution,
if you run this antenna near operating electrical/electronic equipment, you
may pick up interference that will negate the increase in the desired
signal. You will have to play with this. You may have to endure three or
four unimpressive performances before you have that one kick-ass success
that makes you let out a whoop. Life's like that.
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