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Old December 7th 06, 04:01 AM posted to rec.radio.shortwave
Steve Steve is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 1,324
Default Loop antenna question


Telamon wrote:
In article .com,
"Steve" wrote:

Time to liven things up in here!

My intuition is that a modest sized, untuned, unamplified loop, fed
with a matching transformer, should be quieter and yield a better S/N
ratio than an amplified loop--even when the amplifier is itself very
'clean'. However, my attempts to build an unamplifed loop that is
quieter than--or even as quiet as--my Wellbrook suggest otherwise. Why
is this? Why doesn't an unamplified loop beat an amplified loop every
time when it comes to S/N ratio, assuming of course that it's large
enough to gather a healthy amount of signal to begin with? I'm
especially puzzled by this in light of the fact that the Wellbrook
appears not to be shielded in any way (or at any rate, that's what I
gather from a previous thread on that topic).


How did you come to that intuitive conclusion? Generally an electrically
smaller loop will be less sensitive to electric fields. When you make a
larger loop so you get enough unamplified signal and it becomes
electrically larger then it becomes somewhat sensitive to electric
fields. Electrically large loops can be equally sensitive to electric
and magnetic fields.


That makes sense.


Besides size are both loops in the same location? How did you shield
your larger loop?


Not exactly the same location. Separated by about 20 ft.


How do you know that the Wellbrook is not shielded? I would have to
either ask the maker or buy one and take it apart to find out.

--
Telamon
Ventura, California


I thought someone on here did see one taken apart, but maybe my memory
is playing tricks on me.

Steve