At 10:38 PM 8/9/04 +0000, you wrote:
OK, I hooked the loop (a cheap,
simple little plastic thing that
comes with an am/fm hifi receiver for the am part) up 1 wire to "am
antenna" and 1 wire to "ground".? I tuned to a strong
local station.?
When I rotated the loop for strong signal it sounded about like the
internal ferrite bar.? But, when I rotated to null the station
signal
I got nothing.? Does this indicate that something automatically
disconnects the internal ferrite bar when I have the loop hooked
up?????????????
Okay .... I thought you were using a tuned loop.? The loop you
describe will be an inferior antenna to your built in ferrite rod
antenna.? It is designed for receivers with relatively high gain and
no internal antenna (HiFi receiver).? It will work fine for the
purpose of picking up strong local signals.? A tuned loop is another
thing all together.? They have multi turns and are tuned with a
capacitor so they come to resonance.? When the do come to resonance
they create a strong electromagnetic field at a very narrow frequency
bandwidth.? This field can then be coupled to your receiver by
either bringing a receiver with a ferrite rod antenna into its vicinity
or if doesn't have a built in antenna you couple using a wire turn or two
as a link.? The loop you have would make an excellent link to a
tuned loop antenna.? It is in fact exactly what I use for my Hi Fi
set.
My set has the same small plastic loop (8 1/2" dia es 3 turns)?
I use it to couple to my tuned loop.? The Hi Fi set works just fine
with the plastic loop when receiving local AM stations.? However if
I want to pick up stations in say Duluth (about 160 miles away) I bring
the plastic loop close to my tuned loop, which I tune to the same
frequency.? The difference in reception is like night and day.?
The signal increases at least 20 to 30 DB.
Jim Dunstan
Thunder Bay, ON
