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Author Topic: how to adjust a mechanical bug  (Read 480 times)
KC6PLP
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Posts: 3




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« on: June 05, 2001, 12:32:41 PM »

I have an old vibroplex bug - I have adjusted it, but find that I get some "dit" bounce.  I have tried putting a little damper behind the u-shaped spring, but it hasn't helped.

I have the dit and dah lever spacing set evenly at about 1/8 inch - but, the spacing at the contacts is not even - the dah contact is about 1/8 of inch, the dit somewhat larger. To set the dit contact spacing,I pressed the dit lever and then brought the dit contacts together.

Any help, etc., is appreciated.

Robert
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WB2WIK
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Posts: 20574




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« Reply #1 on: June 05, 2001, 01:29:57 PM »

This is REALLY hard to describe in words; a "bug" adjustment is very much a "feely" thing.  The good news is, there's not much that can actually go wrong with a Vibroplex bug design.  Unless a spring breaks or is lost, or the bounce "dit" contact (u-shaped spring, as you say) is damaged, they just keep on working for decades.

Since you're in Beaverton, which is not exactly a remote location (!), I'd recommend you try to get a local "Elmer" who is a proficient bug operator to stop by (or you visit him) and help you.

I used Vibroplex bugs for a long time (no more!) and after making thousands and thousands of contacts using them, I don't even know what you mean by "dit bounce."  The dit contact's supposed to bounce, that's why it makes more than one "dit."  I guess you mean something else!  There's interplay between the travel distance to the stop (of the keying lever on the "dit" side, which is normally the right thumb side), the sliding weight on the end of the bounce lever, the spring tension on the dit lever (which adjusts tension to the "stop"), and the hardness of the u-shaped spring containing the dit contact...they all interact and it's common to have to adjust all three adjustable elements a few times to get the right "feel."  After having done this a few zillion times, I can do it blindfolded -- literally -- as almost any proficient bug operator can.

However, unless you're already good at it, I'd recommend spending some "off the air" time practicing with an oscillator or sidetone.  Then have an experienced CW operator listen to you "live," and when they tell you "you sound great!", that's the time to start making contacts.  

I operate CW about 90% of the time, and about 90% of the ops I hear using bugs can't send worth a darn, and are very hard to copy...which is why I use electronic keyers -- I don't want to sound as bad as "they" do!

73 de Steve WB2WIK/6



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W4PM
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Posts: 11




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« Reply #2 on: June 05, 2001, 03:14:16 PM »

"Dit bounce" is something you hear novice bug users talk about.  Once a bug is set up properly and the user has practiced enough to get his timing correct it is no longer an issue.  Dirty contacts on the other hand can cause scratchy dits and/or dahs so we must make sure our contacts are clean!

The first thing to adust is the lever rest screw.  This is the adjustment on the right side of the bug frame.  It should be adjusted so that the lever at rest just contacts the damper.  This assures that once the lever is released after sending dits it returns to rest against the damper and the vibrations are stopped or "dampened".  It this is not set correctly it can cause "dit bounce".

The next thing to set is the lever stop screw and the adjustable  dit contact.  The stop screw is on the left side of the frame and it's purpose is to stop the travel of the lever when the lever is pushed to the dit side. This sudden stop sets the pendulum into vibration causing the dits to be sent.  You must have enough travel of the lever to set up a strong vibration which yields clean, well formed dits.  The amount of travel here is a personal preference thing but I've found about 1/8" yields cleans dits which will be sustained for 10 to 20 dits or more before the vibrations die out.  Don't set this too close!
The adjustable dit contact is then adjusted to properly weight the dits. The dits and the spaces between them should be of similiar length.  This can be measured on a meter or you can simply listen to a string of dits sent by an electronic keyer and make your dits sound the same.

The setting of the spacing of the dah contacts and the tension adjustments of both dits and dahs is a matter of personal preference but don't go too light on the tension or you will find yourself sending mushy or heavy code.  I set my dah contacts about 1/16" with a fair amount of tension.  Practice sending a string of dahs until they sound uniform. Adjust the spacing and tension until they feel right for you.

When setting the speed weights make sure you set your dit speed to match the rate at which you plan on sending.  You may have heard guys sending with a dit rate of 30 WPM and a dah rate of 15 WPM. That's a bit tough to copy until you get into their swing!

I mentioned timing in the first sentence.  The timing of the transition from dits to dahs can give a beginner a fit.  Bad timing will yield your "dit bounce". If you change from dits to dahs too soon you cut the last dit short. If you wait too long your moving dit contact is on the way back and may throw in a short dit you don't want.  Don't despair! With practice the proper timing comes naturally.

Also, remember that bug sending is done with the wrist and arm and not just the fingers like a paddle/keyer.  If you try to send with a bug with only your fingers you will quickly throw in the towel because it's real tough to send good sounding code like that. Get that arm and wrist moving back and forth!

Bug sending is fun. Good luck.


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AC5E
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Posts: 3585




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« Reply #3 on: June 05, 2001, 03:22:41 PM »

  Howdy: First, let's go over the nomenclenture for a moment. Looking down the center from the paddle end the last item is the damper. Then you should have one or more speed adjusting weights on the weight arm. Then there is the dit contact on the left. Next, there are two "centering stops" to keep the weight arm centered. Then, again on the left is the spring tension adjustment. Then the weight arm pivot assembly. And hard up against the paddles are the dah contacts.
  Now - everything on a bug is subjective. A bug someone else has set up is about as annoying as riding a borrowed saddle. The thing just does not feel right. So you are going to have to play with it until if feels right to you.
   So anything I tell you is subject to your interpretation. And anything I or anyone else tells you will only get you in the ballpark.
  In general, you should adjust the centering stops so the weight arm just barely rests against the damper when it's just sitting there looking pretty.
  I keep my dit contact at between .060 and .080 inches open at rest. I keep my dah contacts at close to 0.100 at rest.
  I keep the return spring adjustment screw around three turns out from even with the pivot assembly arm.
  I generally use one weight, about half way out on the wieght arm. More weight or further out is slower. Forget faster until you get plenty of practice.
   And then, since every bug is a law unto itself, I adjust things until it works to suit me.
   Now, one more piece of advice. Find a code reader. Set it up and send to it until the code reader can read your code. Then get on the air. Practice makes perfect, and you will be very glad you practiced first.

  73  Pete Allen  AC5E
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K6RAS
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Posts: 78




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« Reply #4 on: June 05, 2001, 09:18:01 PM »

Well, you've gotten some very good advice on the mechanics for adjusting your "bug".  I can neither disagree nor add much to what has been offered as adjustment advice.  I would like to share some suggestions for actually using your "bug" in such a way which makes it comfortable to use and allows you to send well.  Never slap, punch, or press the paddles.  Always caress them.  That is, I usually demonstrate a technique which applies the index and middle finger of the sending hand to the dah side and the thumb to the dit side.  The middle and index fingers should touch the dah side gently (I recommend allowing the gently rub the paddle) during the dah cycle.  Likewise, the thumb should glide over the dit paddle with an even gentle pressure (I typically allow the thumb to slide from the font of the paddle toward the rear during a dit cycle) for the duration of the cycle.  With practice, this method allows the operator to develop a rhythm of smooth and even dits and dahs.  The result is purely musical.
Have fun.  Listening to CW from a good speed key operator can be better than hearing any philharmonic orchestra.
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KD7MTI
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Posts: 20




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« Reply #5 on: June 08, 2001, 12:14:00 AM »

Thanks for all the advice - I went through the various recommendations, etc., I also found that I had the dit spring tension quite loose - now, my dit bounce is gone and I removed the damper I added.

My only problem now is waiting for 40 m to open.

Thanks.
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KL7IPV
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Posts: 984




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« Reply #6 on: June 20, 2001, 01:19:34 AM »

You can also access the Vibroplex site at www.vibroplex.com for lots of info.
73,
Frank
KL7IPV
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KD5XB
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Posts: 30




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« Reply #7 on: June 26, 2006, 09:03:57 AM »

I'm going to reopen this thread, as I recently acquired a bug -- see http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7766003092 -- and I have a question on it.

Do you normally need to adjust the damper screw almost daily?  I have not noticed this, but I read somebody's post somewhere and they made that statement.  Am I just fortunate, or was that statement indicative of a further problem?

Also, I haven't used CW in the 24 years since I got my General Class ticket in 1982, but I got back into it for Field Day this past weekend.  And it was FUN!  But I felt a little "pushed" at the slowest speed my bug would send.  I've already added the Vari-Speed, and it helps a lot, but I guess  need more practice.

Tnx es 7 3
Earl
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KD5XB
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Posts: 30




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« Reply #8 on: July 22, 2006, 08:50:42 AM »

Gee, that didn't get any replies...

Earl
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W4PM
Member

Posts: 11




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« Reply #9 on: July 22, 2006, 05:36:04 PM »

By "damper screw" I assume you mean the screw on the right side of the frame which sets the position of the lever at rest.  One you have it set so the lever at rest just contacts the damper and have tightened down the lock nut it should hold its adjustment.  No need to adjust it daily!  The only thing that I can think of that might cause a need for daily adjustment is if somehow the bearings are too loose and the lever rocks around in them. They should be tight enough to prevent the lever from rocking up and down or rolling side to side.  If the bearings are too tight the lever will bind and if way too tight the "jeweled" bearings on your Presentation will BREAK.  I hope this helps.
Puck  
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KD5XB
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Posts: 30




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« Reply #10 on: July 22, 2006, 06:57:39 PM »

No, I meant the damper at the far end of the frame -- the L-shaped item the end of the rod gets against when all is at rest.  I think I've read somewhere about the mounting bolt for this damper getting loose with a lot of use?

Earl
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W4PM
Member

Posts: 11




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« Reply #11 on: July 22, 2006, 09:49:55 PM »

Accorging to your e-mail you're talking about the screw that holds the damper to the damper arm.

I've never seen that happen unless it wasn't tight in the first place.  If it is properly tightened it would take years to work loose.  I've got bugs
from the 1910's and 20's on which the screw holding the damper disk was still tight.
Puck
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