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Re: Simple radio signal



HI!


I question whether the scope receiver is detecting EM radiation, more likely
mag. induction in the case of 60 Hz. Of course in the case of higher frequencies
it's EM.

This reminds me of an intercom I built while a 6th grader. It consisted of two
large coils of wire ~ one m diameter (may be a 100 T. I used the wire from the
primary of an auto. spk. coil.). One was connected to the receiver of an old
candle stick 'phone (I had > a dozen of them then.) The other was connected to a
couple of # 6 cells and the carbon transmitter (all in series). One coil was on
the wall of the garage (my bed room and work shop, and the other about ten? yards
away in the living room (not permanently!). Obviously coplanar. I doubt that
this was a "radio."

bc



Could one determine which by finding the intensity WRT distance (far and near
field?)?



Bob Muir wrote:

Folks,
We are immersed in the em signals from many, many sources, albeit,
not all in the rf part of the spectrum.

A simple receiver found in most departments is the oscilloscope.
Simply let a wire (about 1 m long)(= antenna) dangle from the input.
You'll see on the o'scope 60 Hz emitted from the house wiring and
light fixtures. Crank up the sweep rate and you'll probably see the
carrier of an AM radio station. This morning, I had a strong signal
of about 1600 Hz.

I haven't it, but I bet if you ran a crummy (like a demonstration)
electric motor near the "antenna", you'd "see" the noise radiated
from the brushes.

A cheap AM radio would supplement this nicely.

"Keeping my ears on!"
bob

On Fri, 10 Mar 2000 13:56:06 -0700 "Daniel L. MacIsaac"
<Dan.MacIsaac@NAU.EDU> wrote:

The easiest way to get a simple radio reciever is to buy the cheapest
transistor AM receiver.
ck


DEFINITELY. Now how to we get a cheap transmitter that will send a
resonably polarized signal and how to we make a cheap AM receiver
into a polarized receiver?

Dan M

Dan MacIsaac, Assistant Professor of Physics and Astronomy, Northern AZ Univ
danmac@nau.edu http://purcell.phy.nau.edu PHYS-L list owner

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Bob Muir muirrob@uncg.edu
Physics & Astronomy 336-334-3255
UNC Greensboro, NC 27402-6170
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