SEMI-AUTOMATIC KEY ADJUSTMENT
byBRIAN MURPHY, VEZAGO
originally published in QST MAGAZINE
Although the use of electronic keyers is increasing, many C.W. operators would prefer to keep their “bugs”, especially if they
could make them perform as well as, or better than, keyers. The performance one gets with a bug depends greatly on the adjusmrent, andno amount of skill can make up for a poorly adjusted bug. It has been my experience that there is a tremendous lack of understanding
among amateurs over the maze of adjustments found on most bugs. There is also the belief that the adjustments are solely for one’sindividuality, and we therefore hear a lot of signals with choppy dots, poor ratio of dot length to dash length, and poorly timed spacing
between dot groups and dashes (e.g. “0 l ---I’for the number ‘two’).
The following will describe some techniques to use in adjusting your own bug, together with some hints on good character
formation and better, error free sending.
GENERAL
Although different manufacturers have a few more or a few less adjustments on their bugs, most have the ones shown in thediagram in Fig. 1, together with various types of spring tension controls. Admittedly, some of these adjustments have to be made by trial
and error according to instinctive feel, but we will outline the general objectives:

142.13.)
4.)
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To make dots of correct length with correct ratio of dot to space length.
To prevent high frequency vibrations of the moving dot contact F with resultant scratchy dots.
To prevent any other undue motion (unwanted bouncing) of the dot contact (F).
To keep the time between dot groups and dashes down to its proper level (the length of one dot).
Proper mating of contacts.

PROCEDURE
The first adjustments to play with are C, D, and G on the diagram. The damper arm, G, may be non-adjustable on some
Vibroplex@ bugs, in which case D should be adjusted as follows: clear D, C, and E away so that the arm comes completely to rest against
the damper arm G. Then advance D so that it slightly pushes away the lever, but not enough to clear the arm away from the damper arm.
The result is correct if, when the arm springs to rest against the damper arm G and D, there is absolutely no visible bounce. This is toensure that when another group of dots is started, the arm is not still vibrating. If G is also adjustable, there is just this much more latitude
in making the alignment.
With E still clear, adjust C for optimum distance between D and C. This is probably the most difficult adjustment to makebecause some experimenting is required. When the paddle is pushed for dots, the lever butts up against C, which sets up the oscillations ofthe arm. Moving the lever from D to C takes time, so that transforming from dashes to dots is faster, and therefore smoother, if thedistance is kept small; but then, unfortunately, the arm does not gain enough momentum to make long slow dots. This is where manyhams fail to make the best compromise, and end up with very poor dots at speeds below 25 w.p.m.
Since there is seldom any problem getting fast dots on a bug, it is best to start with the D to C distance quite large. This will feelawkward, but try it with the weigh set for the slowest possible speed after setting up the dot contacts. The moveable contact F on the arm
should mate evenly with its counterpart E. After checking this, adjust so that E and F just barely short together after making a string ofdots. Lock E, and now connect an ohm-meter across the bug terminals. While making a string of dots, the average deflection of the metershould be mid-scale = 10% for both slow and fast speed settings. The reading should be taken for the first five or ten dots only, because
after that it will start to change, depending on the E setting. It is typical to have too low a reading and, hence, have choppy dots. Too higha reading will probably result in mushy dots. Of course, adjust the screw E closer or farther as required. In case your meter has a poortransient response, a good ear is the final check for this test.
Now if the arm oscillations die out too quickly with slow dots, C has to be adjusted to increase the D to C distance and, hence,
the lever momentum. This is also true if the dots cannot be made slow enough, say 20-25, words per minute.
If C is changed, E must be re-set before further testing; and so these compromise the bulk of the adjustments which affect yourfist. If D to C is too large, one will find it too difficult to switch from dots to dashes smoothly and vice-versa.
At this point another problem occurs with many bugs: contact D is usually mounted on a hairpin spring which sometimes has ahigh-frequency vibration visible after some dots are made when the arm comes to rest. This vibration will make the next dot scratchy, agood cure for this problem is to cut out a small cubicle of fine grain, soft, synthetic sponge and fit it snugly - but not too tightly - inside thehairpin behind the contact, so that the vibrations are damped out. Use a small dab of glue on the back side to hold it in place.

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The dash contact spacing B can be set to personal preference. Too wide a spacing and too much spring tension will result injerky dashes, while small spacing and low tension may cause an occasional joining of what was intended to be two dashes. Contacts
should mate perfectly for maximum life and may be cleaned with good silver polish; or they may be lightly scuffed with the very slightly
abrasive material used to clean relay contacts, if they have become pitted. DO NOT use emery paper or sandpaper, as these leave an
unwanted residue on the surfaces and can also excessively wear down the surface.
OPERATING
When using a bug, it is essential that it be firmly mounted, even if it is heavy and has rubber feet. It is sometimes inconvenient toattach it directly to the table top. If the table top is smooth, suction cups with protruding studs are available at hardware stores that can bestuck on the table around the sides of the bug, so that the studs keep the bug from sliding sideways.
The following will describe some ideas on how to send, at the risk of fiery disagreement from Al operators across the land.
Most surely, this is not the only way; but the basic ideas might lead one to recognize a weakness in his own method.
The hand should rest on the table, with the paddle located between the print of the thumb and the side of the index finger. Using
the tip or the print of the index finger is all right provided the wrist action, not finger action, is maintained on dashes. Dashes should bemade by rocking the wrist with the fore-arm resting on the table. No part of the hand, wrist or arm should feel constricted. When a row ofdashes is made, the side of the index finger should remain in contact with the paddle, while the wrist is rocked back and forth, with noslipping on the table. This helps the continuity of the row, rather than hold the remaining fingers outstretched in midair, curl them underso that they may rest on the table. Most of this comes naturally; but it is mentioned to prevent beginners from starting off completelywrong.
There is a great tendency to set the dot speed too fast. Concentrate on sending good code at the slowest dot setting possible
which should be a least down to 20-25 w.p.m.. A technique which produces amazing results is to send as slow as absolutely possible for
one QSO, then, a fast as you are able for the next QSO. The effect of sending slow engrains good ration, spacing and general good form,
while sending fast gives practice in timing and muscle control. I would strongly discourage leaving the speed control always set to thefavorite spot, because this seems to lead to the freezing of bad habits, and definitely results in poor ratio when trying to vary the speed byvarying the dashes only. On a bug, or keyer, variation of speed is the key to learning control.
For good practice, open up the telephone book as some page other than Smith, an send the names, addresses and phone numbers
at slow, fast, slow, fast, . . speeds. Ten sets at 15 w.p.m. and 30 w.p.m. without one error is excellent. Those numbers are terrific practicefor dashes!

- A R MABCDE

Main Pivot
Dash Contact
Dot Lever Stop
Dash Lever Stop
Dot Contact

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Dot Spring
Damper Arm
Dot Lever Tension
Dash Lever Tension
Dash Lever

Illustration Copyright 1996 The Vibroplex Co., Inc.
BUGADU DOC