On 16/03/2005 12:02 PM, Jack Painter wrote:
"clvrmnky" wrote

[...]

I get a bit of a boost in signal running off the wall-wart, but it is
actually more convenient for me to run off batteries. I end up moving
the receiver around quite a bit. I can pick the big blowtorches and the
relays from Sackville quite nicely off the whip, so I often listen to
them in the kitchen or when doing chores around the house. For "DXing"
I settle in near the door where I've got my antenna experiments going.

That's interesting OM, as it implies you are seeing a counterpoise effect of
rf-coupling across the windings of the dc transformer, or perhaps just the
secondary side? If a wal-wart helps complete an antenna, it would seem
there may be a design component missing from the antenna somewhere ;-)

I realized that my nomenclature was wrong. I should have said "bit of a
boost in amplitude" because this is what I'm /really/ hearing. I'm
guessing here that when running of the wall-wart we just have more
available current to draw on for RF and AF amplification, heterodyning
&etc. I have no proof that the signal coming into the set is any
better/stronger or that my antenna is more sensitive or selective.

That is, I don't recall the signal meter changing much when I switch
back and forth between battery and wall-wart. Although, quieter signals
will be uniformly attenuated (along with the noise) slightly when I
switch to battery.

Currently (with a random-wire antenna) the radio seems to not care what
is on the "ground" side. This is hardly scientific, but when I attach a
good number of feet (i.e., more than the length of the antenna) of
copper wire to the ground side of the antenna input (or touch it with my
hand) I get no noticeable change to tuned stations or between-station
noise. I may hear the slightest bit "tick" of noise when my finger
makes first contact with the case of the plug that goes to chassis
ground. Nothing obvious, however.

"clvrmnky" wrote
Currently (with a random-wire antenna) the radio seems to not care what
is on the "ground" side. This is hardly scientific, but when I attach a
good number of feet (i.e., more than the length of the antenna) of
copper wire to the ground side of the antenna input (or touch it with my
hand) I get no noticeable change to tuned stations or between-station
noise. I may hear the slightest bit "tick" of noise when my finger
makes first contact with the case of the plug that goes to chassis
ground. Nothing obvious, however.

that's normal - wait until you discover "the paper clip principle"...

Or, "when a paper clip attached to the back of the radio receives as much as
your just erected antenna", LOL. Stranger things happen, and it helps if you
record in a log what your antenna experiments have yielded. If you use the
S-meter to help relate signal strength (including noise levels), remember to
measure it against at least three frequencies in your intended listening
range (lowest, mid-range, and highest). No antenna treats the whole hf
spectrum the same and you may develop favorite arrangements for particular
listening desires.

Good luck,

Jack Painter
Virginia Beach, Virginia