Posted: 11/9/2015 2:27:54 PM EDT
| What makes the tail piece on a telegraph bug key vibrate on the "dits". Is it all springs? looking at vibroplex |
|
The tail piece is like a pendulum on a spring bar. it vibrates against the contact, and the speed is controlled with a weight that can be moved up or down the tail piece. It will eventually "run down" (so I've been told) and quit sending "dits".
You can see it "run down" in this video (around 4:50), as he makes the adjustments for the "dits". 
|
|
The "tail piece" itself is a flat spring or has a flat spring on it. I am in the process of completely tearing apart my shack and am looking for a bug to see what the hell I am talking about and not having any luck.
Vibrate really isn't a good description. It bounces back and forth, although I guess you could describe it as vibrating. How quickly it "vibrates" is determined by the length and the weight. The weight slides along the "tail piece" for adjustment. The further it is away from the finger piece end of the bug, the slower it sends. The further back toward the user, the faster. The reason I mentioned length: you can significantly slow down the bug by attaching a longer "arm" onto the flat spring "tail piece". At one time, I used a bug and I took an old transistor radio telescoping antenna; I pulled the antenna apart into sections. I then found the section that fit over the "tail piece" and slid it over the "tail piece". This slowed the bug way down. At the time, I was really active in the SKCC and a lot of people I worked (who were using straight keys) were sending far slower than the bug and I wanted to match their speed. Another option is to put a homebrew weight out on the end of the "tail piece". I have worked guys that had a piece of handgun brass stuck on the end. Yet another option is a commercial product that I believe is sold by Vibroplex called a "Vari speed". It clamps on the "tail piece" and sticks up. You can slide a weight on it as well as vary the angle it is at. |
Ha, ha. That shows how long it's been since I've looked at a bug. I would have sworn the tail piece was round (like a rod). 
Anyway, yeah, bouncing off the contacts is probably a better way to describe it. 
Some people can really work a bug well. Definitely a learned skill. |
|
The vibrating part is called the "arm" and can be either round of rectangular in cross section, depending on the model of the bug.
I have the "Vari-Speed" attachment and it's one of the best accessories ever made for a bug. You can literally change speed in a couple of seconds. I use it constantly to match my speed to that of the other station. Adjusting a bug is tricky. There needs to be enough of a gap between the dot arm and the dot lever stop screw for it to gain enough velocity to make a string of at least 8 or 10 dits without being so wide that it's difficult to operate. Vibroplex has a set-up procedure that was written by Brian Murphy (VE2AGO) and published in QST in the mid '90s. Click HERE, select your model, and print out the "adjustments" instructions. There's also a listing of serial numbers and the years they were manufactured. FWIW, three years ago I brought my vintage 1922 Original out of retirement and started using it again after about 40 years. The paddles now sit idle. |
| Mine was used on the Seaboard Airline RR in Southeastern NC. A friend of my Dad worked for them and gave him one of the old ones when I got my license. It was in pretty rough shape so Dad sent it back to the factory, had it rebuilt, and gave it to me for Christmas. I used it from the late '50s up until the mid '70s when I switched over to paddles. Three years ago I went back to it, mainly for the SKCC sprints, but found I liked it better than paddles. |
|
There's not much difference between using paddles and a bug. The dot side has to be pushed with a bit more force and the dash side has to be pushed for each dash. It's mostly about retraining one's muscle memory. After about 40 years on paddles, it took me less than an hour's practice to get back into the swing of using a bug.
Changing speed is the big problem, having to loosen the set screw on the weight, slide the weight, and then re-tighten the screw. But the Vari-Speed accessory does away with that problem. Simply pushing the Vari-Speed swing arm toward or away from you does the job in a couple of seconds. Vari-speed demo: https://www.youtube.com/watch?v=YHicOuHmarU
I have a large weight on the Vari-Speed swing arm, and two small weights on the bug arm. I can adjust between about 10 and 20 WPM with the flick of a finger. The range is even more if I shift the small weights around. YMMV, but I find it easier to jump back and forth between a straight key and bug than between a SK and paddles. I can do it mid-sentence. |
|
Quoted:
Let me know when you want one and I can hook you up. Thanks. It will probably be a while, though, as I currently have too many irons in the fire right now. Had the garage door repaired yesterday, and the roofer is supposed to come today to fix a leak. I still need to finish up my solar project, too. Maybe in a couple of months. 
|