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My Experience with the Bug         <German colloquial: Schlackertaste>
Dedicated to my friend Alex Pringle, GM3MAS, who made me familiar with the Bug

When I received my first amateur radio license in 1966, I already had gained some experience during a slightly longer period with a home-built 0-V-1 as a SWL in CW. It was clear to me, that the Morse code would become my preferred mode of operation. Accordingly my first QSO took place in CW. Initially I used only straight mechanical keys, which had some limits in speed. I felt happy as a lark, when I got a single-lever paddle from an OM for nothing. It was a FM-32 made by Jablonski, a GDR company. Such a key is called also a Sideswiper. With a super simple electronic, made with only one transistor and a telegraph relay, I built an elbug, which at least produced a fairly balanced dot-dash-space ratio at a particular speed. In 1969 I earned with this paddle my HSC Membership (# 627) with this paddle.

From time to time I noticed QSOs sent in a very special way by some operators, who had no fixed dot-dash ratio, but varied something within a character, resulting in a sound, that was somehow beguiling. The characters did not sound as uniform and sterile like a machine encoder or an elbug. It sounded more like music with a non-random rhythm. Despite none standardized characters, reading a text made no problems. On the contrary, there was even an additional joy. I asked in the QSO for the key they used and got the same answer over-and-over: Bug or Schlackertaste. My desire grew, once to be able to use a bug this way. Unfortunately for many years, I was just viewing photos of such keys.



I have never lost completely sight of my desire. In 2009, a long time after the political change, a close-friend OM bought a Japanese Bug BK-100 at a flea market for me. However, my initial euphoria settled down quickly when I realized how difficult it was to elicit this key such rhythmic characters. I never had used such a bug before and had probably to learn the adjustment procedure. In the Internet-age it was no problem to find a lot of instructions as literature or video clip. Despite of many attempts, I soon gave up and accounted my failure to material fatigue on the parts of the already somewhat older bug, that no longer allows to type a clean character. Almost like in the fairy tale I had no choice but to consider this key as "Snow White's Coffin" in the following period with sad eyes only.




Japanese Bug BK-100


A year later, in 2010, I bought a brand new and factory packaged Vibroplex Original Standard Bug. Whether it was already preset or not, I can not say. The first character I wanted to elicit the key, was anything but hopeful. First haphazard turning of the adjustment screws was not successful, as any experienced friend of bugs may know.

Nevertheless, it was clear this new bug had to work. If it for some reason still does not work, it could only be a problem of the operator.


Bug from the USA:

Vibroplex Original Standard



Again, I looked at the video clips and literature on the adjustment of such bugs and began purposefully and in a strict sequential order with the setting. Also, I found in my toolbox a  valve tappet feeler gauge, so nothing was left to chance. If I would just be able to produce a sufficiently long sequence of dots with a dot-to-space ratio of 1:1, I would know that the setting has been successful.




Valve tappet feeler gauge




Although the weight was fixed at the end of the lever for the lowest speed, the first characters I get out of the key were miserable and rather daunting. Now it become clear that this was just the start of a long ordeal of excercise for me, but I really wanted to walk the line. Instead of jumpimg into a QSO, I practiced behind closed doors several times a day. Fortunately, I am retired from QRL, so I was able to spend more time for my hobby. For over a year I had regular skeds with my friend Alex GM3MAS. It seemed to me he had dealt with nothing but bugs his whole life. His way of using the key was and remains for me the reference of all. From him I received tips and further adjustment procedures. I do not remember how many weeks it took until I finally dared to directly contact Alex with my bug.


Again and again it happened that after a lot of good characters some characters sounded scratchy. First, I assessed this phenomenon as a mechanical problem of the bug. Other ops on the band confirmed that the scratchy sound is heard quite often with this type of bug. Particularly vulnerable should be the contact point at  the spring. Finally, I found  that fewer characters scratched when I stuck a piece of soft foam inside this spring. I proudly told Alex of this finding in the next sked. However, Alex seemed not to be impressed that much. He just told me "you do not need it". Another OM, which also began to play with bug, even built an electronic debouncing system that should prevent the scratchy noises.


Since now I was more often on the move with the bug on the bands, the way of my keying improved slowly. It remained almost unnoticed, that it hardly scratched. Now I remembered Alex's words and removed the foam. And lo and behold, there was no longer any difference. The number of scratched characters remained minimal, even without foam. What had happened? How can this be explained?



A piece of soft foam inside the spring for "debouncing"



                             Undoubtedly frequent keying improves the skills. When pressing the key lever one will notice unconsciously,  that scratchy characters will occur at a certain timing, and also unconsciously one will respond. That means, the OP improves constantly and unconsciously this timing.                                      


To confirm this effect, I looked for characters, in which scratch effects occurred relatively often. These were mainly characters with transitions from dot to dash,  especially when a dash follows a number of dots. One of such characters, for example, was the "3". Ironically, Alex has this number in his call sign!


                            So I sent a series of "3's" and found that from time to time there was an unclean 3 dot-dash  transition. So it seems logical that this inadequacy is only a inadequacy of the OP.  Therefore I began to add a barely noticeable break at these dot-dash transitions, and the charakter became clean.                                                                                                                                                                       


Now I took special attension to Alex`transmitting style when he was sending his call sign and noticed with some amusement, that I could guess some slightly extended intervals in his "3". Of course this small extension of time was done unconsciously like a motorist when pushing the clutch pedal while shifting gears.


After I realized all of my shortcomings and accepted the main mistake to be my operation style,  I turned back to the japanese BK-100 and repeated all settings the same way as I had done before with the Vibroplex bug. It happened exactly what I already suspected: Now also the BK-100 functioned as it should.


From the previous facts one should draw the following conclusions:


  • Strictly adjust the bug by the rules!

  • Unclean characters are caused by the operator.




     How I setup my bug:








 Please click on the picture to enlarge it






Experienced telegraphers manage to adjust a bug without tools and only by ear to a dot-to-space ratio of 1:1. Very useful is also the use of an audio editor, for instance WavePad (tnx Ron, DL5CL, for this tip). This Freeware can be downloaded  for example from




A previously recorded audio file (such as MP3) with a self-given text will be loaded in the audio editor. Then you can measured very well all mark- and space lengths and correct the setting of the bug easily (step 4 of instructions).


As already mentioned, especially Alex (GM3MAS) impressed me with how he mastered his bug. Listening to him is always a pleasure. He constantly encouraged me in my efforts, so I've never lost courage.

Here is an MP3-sequence from a QSO on 30m in 2009:


Helpful links:


BUG page by Ron, DL5CL:


CW page by LudwigDK5KE: 



Denice Stoops, a professional radio operator (also KI6BBR) with a bug:




With this experience report, I would like to encourage other interested OM's not to give up at the first road block, but stubbornly stick to learn and master the bug.


73 cwfe

Lothar, DL1DXL

Translation: DL9NL and DL2RMM


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