Re: Simple radio signal

[Gary Karshner <karshner@STMARYTX.EDU>]

Owen,
        I remember making a radio demonstration like you are describing when I was
in grade school. I took a model T Ford coil (induction coil) with a simple
spark gap across the terminals and built two identical flat coils. Both
made from a pair of crossed sticks with groves cut about a centimeter apart
into each leg of the cross. Into the groves I wound a "flat square" coil of
about 20 turns. The purpose of the cm spacing between the turns was to
prevent arc over as one of the coils is connected across the spark gap. The
leads of the other coil were connected to an NE-2 Neon pilot lamp. As the
sparks jumped the gap of the coil, the NE-2 would light even when the
antennae coils were meters apart. This is a very noisy transmitter and
should not be run too often. Ne-2's make a good indicator for high voltages
and static electric experiments were you expect to see a feeble spark, as
they are quit bright.
        It this the sort of thing you were asking about?

Gary

At 10:30 AM 3/9/00 -0500, you wrote:
> I want to create a simple demo of transmission & reception of radio signals.
> Any ideas?  The spark from a VanDeGraf generator should send a signal that
> can produce a small spark at a receiver (simple antenna with gap).  How might
> I construct this "receiver?
>
> Thanks in advance.
> Owen
Gary Karshner

St. Mary's University
San Antonio, Texas
KARSHNER@STMARYTX.EDU