[GreenKeys] Suggestions for telegraph demo...

[Scott Johnson]

How about  a small speaker with limited compliance, such as a cheap tweeter
or transistor radio speaker?

 

Scott W7SVJ

 

From: greenkeys-bounces at mailman.qth.net
[mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of Derek Cohn/WB0TUA
Sent: Saturday, June 08, 2013 9:10 PM
To: greenkeys at mailman.qth.net
Subject: [GreenKeys] Suggestions for telegraph demo...

 

Hi Everyone,

 

This year, I'm once again doing a demo for a large group of high school
seniors who will be entering the Univ. of Missouri - St. Louis IT program in
the fall.  There will be 33 students in this year's group.

 

After about 1 hour of my 2 hour window, I begin to lose the attention of the
students which is normal and I want to make more of my presentation
interactive with the students building their own telegraph circuit.  I have
found a source of reasonably priced hand keys (the cheapie plastic ones and
I can add a switch to serve as the circuit closer).  However, I need
something to serve as the sounder.  I'm not aware of anyone who makes
sounders anymore.

 

In the past, I have heard of people using noisy relays (not actual telegraph
relays, but automotive or other type) that will click.  It's not critical
that the device work well since the students won't know the code and won't
be able to copy a message.  I just need to demonstrate the principle of how
the technology works.  Can anyone suggest a relay or other device that the
students can use?  I looked at Tom Perera's web site where you can wind your
own sounder but I don't think that will work in the time frame I have.
Whatever I use, will have to be powered from simple batteries.

 

Any and all suggestions welcome!

 

73,

Derek Cohn
Amateur Radio Station - WBØTUA
Morse Telegraph Club - Office UD, Sine DJ

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