October 1935 Short Wave Craft
[Table
of Contents]
Wax nostalgic about and learn from the history of early electronics. See articles
from Short Wave Craft,
published 1930 - 1936. All copyrights hereby acknowledged.
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If
MacGyver had been around in 1935, every episode would likely have included a
Fahnestock Clip as part of a scheme to get Angus (his first name - no kidding)
out of perilous situations. The handy little devices were very popular in electronics,
both for hobbyists and for commercial products, until fairly recently (within the
last two decades) because they provide a simple, reliable electrical connection
that does not require any tools for use - other than your finger. If you have never
heard of a Fahnestock clip, you will probably be surprised to learn what it is and
chances are you have seen one and maybe even used one. If you work in an electronics
prototyping lab area that has been around for a while, there are almost certainly
some in a parts bin somewhere or on some old mock-up gathering dust in the corner.
I mention Fahnestock clips because this 1935 edition of Short Wave Craft
shows them being used in two of their monthly hints and kinks page.
BTW, I never have been really comfortable referring to a 'kink' in
a discussion of a solution to a problem since Merriam-Webster defines a kink as
"a small problem or flaw." It is still done routinely today in hobby and
professional technical magazines. Oh, and the $5 prize in 1935 is equivalent to
$94.86 in 2020
per the BLS
Inflation
Calculator.
$5.00 for Best Short Wave Kink
The Editor will award a five dollar prize
each month for the best short-wave kink submitted by our readers. All other kinks
accepted and published will be awarded eight months' subscription to Short Wave
Craft. Look over these "kinks" and they will give you some idea of what the editors
are looking for. Send a typewritten or ink description, with sketch, of your favorite
short-wave kink to the "Kink" Editor, Short Wave Craft.
$5.00 Prize Winner
Ultra S-W Plug-In CoilsThis
sketch as drawn shows how I have put to good use the prongs removed from tube bases.
The advantage of being able to remove the coils (5 meter) for any necessary change
or adjustment can be seen at once.
The ICA socket was chosen because the double contact within the socket held the
coils firmly in place and practically eliminated the possibility or poor joints
and noise. One suggestion - solder the connections well, using rosin core solder.
"Tin" the ends of each coil end before inserting it into the prong. Do a thorough
job the first time! You won't have to do it over again and the results will be well
worth the additional effort.
- Harold J. Clark.
New Use for Old ToothbrushMany
short-wave "Fans" have found occasion to employ a screwdriver made of some insulating
material for adjusting trimmer condensers in antenna circuits or I.F. transformers.
By removing the brush portion of a discarded tooth brush and filing a flat edge
on the handle, an excellent non-magnetic screwdriver can be made. I trust this kink
will be of value to the readers of Shot Wave Craft magazine.
- Charles Pfleuger.
Eliminating Fringe Howl and Motorboating
Fringe howl and motorboating may be eliminated by simply placing a resistor across
the secondary of the A.F. transformer leading to the troubled stage. This method
does not give maximum results. The resistor is to drain off audio voltage, but if
it is too low a value, you will get weak signals. If it is too high, the receiver
will howl. To get best results, put a 250,000 ohm potentiometer across the secondary
of the audio transformer so that the optimum resistance may be found. This potentiometer
also acts as a smooth working volume control. I find this system very successful
and satisfactory.
- Phil Reich
Code Practice OscillatorHere is
my favorite kink and I hope that it is published in Short Wave Craft. A center tapped
push-pull input transformer may be connected as shown in the diagram and will make
an excellent code practice oscillator. The oscillation is very good and it has an
excellent tone. The tone of course, will depend a lot upon the tube and make of
transformer used. Either a 56 or a 76 tube will work very nicely; 6.3 volts are
used for the 76., while 2.5 volts are used for the heater of' the 56. The output
of this oscillator is sufficient to operate a small speaker with excellent volume.
- Vic Mountain.
Easily Adjustable Antenna Condenser
Probably many S.W. "Fans" have pondered
over the inconvenience of adjusting the antenna condensers with a screwdriver. Here
is my solution to the problem.
The small knob serves as an insulated hand adjustment and forces the movable
plate down very evenly.
- Fred Tann
Grid Leak MountingMany set builders
use grid-leak mountings and here is a stand made from two Fahnstock clips, one inch
in length. Details of how to make this two-cent G.L. stand are shown in the diagram.
This stand is very rigid and holds grid-leaks very tightly. The clip (F.C.) should
be shaped out, as shown in plan. The clips (C) should then be mounted on the strip
of bakelite (B) with screws (S) together with the soldering lugs (L). A hole should
be drilled in the center of the strip of bakelite for mounting.
- Stanley J. Kauklis.
Grinding Your Own Crystals
Here is a kink that I would like to enter
in the short-wave kink contest. In grinding crystals I used the regular method of
a piece of plate glass, grinding compound, and water.
- Edwin Cheever.
Handy Grip CapIn one of your
issues you published a kink employing a Fahnstock clip as a connection for the control-grid
or a screen-grid tube. The illustration shows a much better way to use this slip
for the same purpose. These clips are obtained from discarded "B" batteries and
are ideal for this purpose because they have exceptionally long ends.
- Frank Pulaski.
A Real Vernier
Here is a kink that has helped to bring
in many DX stations. All that is needed is a round eraser and a piece of fairly
stiff brass. The eraser is fastened to the bracket and the bracket to the panel
with small bolts. A station is tuned in with the dial and for fine adjustment a
little pressure on the eraser and a beautiful vernier is the result. If a small
dial is used the eraser may be mounted on a bracket so it touches the edge of the
dial as in B.
- Chas. R. Steegmuller.
Eliminating Hum
Here's a kink for eliminating hum, that will save a good many experimenters a
good many dollars in power supply filter. When the power supply is built, place
the power transformer in its permanent position, and then with nothing else mounted
in the power supply, turn on the transformer. Connect a pair of headphones across
the filter choke. An "induction hum" may be heard. By turning the choke at various
angles, a location will be found where no hum is audible in the headphones. Locate
the choke in that position permanently, and then wire up the power supply and filter.
Using this system, it is often possible to get complete filtering with only one
5 henry choke and two 1 mfd. condensers. The proper location for microphone transformers,
audio transformers, modulation chokes, etc., may also be found in this manner when
it is necessary to mount these units on the same base as the power supply.
- Frank E. Shopen.
Home-Made Neutralizing Condenser
A condenser that can be used as an antenna trimmer on receivers or as a neutralizing
condenser on transmitters can be made from two midget stand-off insulators and two
stator plates from an old discarded variable condenser.
The stand-off insulators used are about 1 5/16" high. A bakelite or wooden rod
that is pointed is used to adjust the rotor. When the neutralizing adjustment is
made, the rotor can be locked into place by tightening the nut indicated on the
diagram.
- Joe Balas.
E.C. Detector
Here is my kink which I hope will be given
consideration when you decide the winner for the best kink of the ones submitted.
It is a method by which a two-circuit detector using the regeneration control in
the screen-grid circuit may be converted into an electron-coupled detector. Only
a few changes need be made in the wiring, and no extra parts need be added to the
detector.
Since the electron-coupled detector is more preferable than the usual two-circuit
detector, readers of your magazine will find this kink valuable. I have enclosed
a short description and a diagram of' the kink, which I think every radio "Fan"
can easily use to his advantage.
- Seiko Yakahi.
Posted October 9, 2020 (updated from original post on 1/12/2015)
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