[Elecraft] Vibroplex

[Ron D'Eau Claire]

As Fred knows, I have Les' old bug that is shown in the photo whose link he
posted, and the cable clamp weight. 

It makes for a very smooth feel, but H-E-A-V-Y. Les must have had a wrist
like Popeye's arm. But the guys in commercial service like Les worked at KPH
often had to send for long periods of time under 20 wpm - sometimes as low
as 10 wpm. For them, matching the other station's speed wasn't just a
courtesy; it was required. The cable clamp kept the dit speed slow enough
for those stations. 

My favorite weight was simply a large alligator clip that I attached to the
end of the pendulum (the alligator clip jaws don't interfere with the damper
if you place them on the top and bottom of the end of the pendulum). I also
wrapped some solder around the end of the alligator clip for extra weight.
Lengthening the pendulum has a huge effect on the speed for minimal weight
added. 

I bought a set of the heaviest weights the Vibroplex makes and was
disappointed. They are the same diameter as the original weights and simply
longer - the most inefficient way to add weight since it's distributed over
a long part of the pendulum. Even two of them has only a small effect on the
speed of a "fast" Vibroplex. 

I also have a Speed-X bug with a large diameter weight (about the size of a
2 euro coin or an American quarter dollar) with a very nifty squeeze lock
instead of a set screw. It slowed down the Vibroplex quite nicely, since it
concentrated the weight over a small section of the pendulum for maximum
effect, especially when it was out near the end. 

The squeeze lock on the weight lets me change dit speed as quickly as
turning the knob on a keyer from about 18 wpm to >35 wpm. 

73, Ron AC7AC



-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Fred Jensen
Sent: Friday, December 14, 2012 11:25 AM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] Vibroplex

My crew mates at the coastal marine station all had shiny Vibroplex bugs
they carried around in velvet lined wood boxes.  They were all lightning
fast on the dot side, and various "methods" were used to slow them down. 
  See

http://www.radiomarine.org/gallery/show?keyword=kphhistory&panel=pab1_1#pab1
_1

scroll down to Les Burger on the right for an example.  My beat up J-36 by
Lionel [$5 at Surplus Sams] that I carried in my backpack would easily slow
to 10 WPM, the leaf spring was about half as thick as a Vibroplex.  Putting
more weight on the armature will slow a Vibroplex, but it's also additional
weight you have to slap around, and can lead to an "interesting" fist.

[If the URL above line wraps, you'll have to copy it into your browser]

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2013 Cal QSO Party 5-6 Oct 2013
- www.cqp.org