Re: Poulsen Arcs

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-uswest-dot-net>" <evp-at-pacbell-dot-net>

Tesla list wrote:
> 
> Original poster: "Dr. Duncan Cadd by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <dunckx-at-freeuk-dot-com>
> 
> Hi Ed!
> 
> Date: 11 January 2001 19:26
> Subject: Re: Poulsen Arcs
> 
> >Original poster: "Ed Phillips by way of Terry Fritz
> <twftesla-at-uswest-dot-net>" <evp-at-pacbell-dot-net>
> >
> 
> Thanks for the info Ed!  The references I have are:
> 
> http://www.sfmuseum-dot-org/hist/poulsen.html
> http://www.ieee-dot-org/organizations/history_center/oral_histor
> ies/transcripts/fuller31.html
> http://hjem.get2net.dk/helthansen/poulsenarc.htm
> http://home.luna.nl/~arjan-muil/radio/poulsen.html
> http://www.geocities-dot-com/CapeCanaveral/Hangar/6160/poulsen/
> http://www.angelfire-dot-com/nc2/whitetho/1908poul.htm


	Think the one I sent you is on there.  I'm interested in the reference
to Fuller at the ieee site.  He's one of the real pioneers, of course. 
I'll look at all of them, of course.
 
> >Tesla list wrote:
> >>
> > Will try to find the URL for you.
> 
> So if it isn't one of these, I am interested!
> 
> > I've built one very small and barely successful oscillator
> here, using
> >"carbons" from AAA cells running under kerosene and
> operating at about
> >an amp at 120 VDC. No magnetic field. Thing oscillated up
> to 2 MHz. with
> >a signal which could be heard as a "gurgly" note (no
> surprise!) with RX
> >BFO on. At about 200 kHz the circulating current in the
> tank was a
> >couple of amps, but couldn't draw any power from it at all.
> 

> That's interesting.  Could it be the loaded Q was a bit low?
> Usually if the loaded Q is under 4 or 5 things get tricky
> coupling the power, but I expect I'm teaching you how to
> suck eggs on that ;-)
> 

	Almost certainly.  However, when I tried to increase the Q by raising
the impedance of the (series) tank circuit the thing wouldn't
oscillate.  By the way, the capacitance I used was about 1000 pf and the
frequency was about 200 kHz. This was a messy experiment, and I intend
to repeat it "when I have time".

> >Lousy
> >design, but just the initial experiment to see if I could
> make one work
> >at all.  What got me started on the project was a memory of
> an ad in a
> >QST from very early 20's for a "200 meter arc generator".
> Believe the
> >ad was from AMRAD, but have searched in vain for it for
> some time.
> >Pretty sure it wasn't my imagination, but ........
> >
> > If you're interested in arc generators I have a bunch of
> useful
> >references,IF you don't already have them, and at least a
> couple of old
> >construction articles.
> >
> >Ed
> 
> Always interested in stuff like this. The last of the above
> URLs has a photo of a Tesla coil inside a Poulsen station
> being used to indicate the rf output - looks like the sort
> of sparks you get from a valve coil - no surprises!

	I think that is the picture I have been thinking of.  If I remember
correctly, the thing is just sitting there with a discharge like a CW TC
and no words of explanation.  Memory may be bad on that.  By the way, we
don't have "valves" here, we have "tubes".....  I have talked to people
(audiophiles) who didn't realize the family resemblence!

 
> 
> Thanks Ed, much appreciated.
> 
> Dunckx

	It's a very interesting topic and hope that maybe someone else here
will have something to say.

Ed