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Author Topic: CQ Wheel  (Read 3364 times)
DL8OV
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Posts: 789




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« Reply #15 on: January 01, 2018, 01:11:58 AM »

If you've ever seen the 'quality' of German TV then you'll know why I've been spending a lot of time in the workshop working on this.  Roll Eyes

Originally I tried a 12cm diameter wheel with segments cut from the outside edge and a microswitch for the contacts, this didn't work too well because of hysteresis in the switch mechanism. Attempt number two is a work in progress using an opto coupler to provide the switching but it doesn't look right.

Does anyone know of a microswitch type device with little or no hysteresis?

Peter DL8OV
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N3QE
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Posts: 5038




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« Reply #16 on: January 02, 2018, 09:49:08 AM »

Originally I tried a 12cm diameter wheel with segments cut from the outside edge and a microswitch for the contacts, this didn't work too well because of hysteresis in the switch mechanism. Attempt number two is a work in progress using an opto coupler to provide the switching but it doesn't look right.

Does anyone know of a microswitch type device with little or no hysteresis?

Are you using a microswitch with a roller on the end?

I think the issue you are finding, is not so much hysteresis (which would affect both on and off transitions equally if you "centered things up"), but is related to the roller being a good chunk of the size of a dit?

Tell me if this makes any sense or not.

There are different microswitches with different types of "followers" on the end. There are ones with a "V" shaped non-roller follower that might be more appropriate than a roller.

An opto coupler could have the same problem if its beam is a size comparable to a dit notch.
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AC7CW
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« Reply #17 on: January 02, 2018, 01:57:43 PM »

Interesting problem... I don't think you are going to get away from hysteresis since it's such a great way to eliminate switch bounce that it's nearly universal.
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Novice 1958, 20WPM Extra now... (and get off my lawn)
N3QE
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« Reply #18 on: January 04, 2018, 07:45:21 AM »

I also have a real Instructograph and have been playing around with my own paper tape loops for CQ'ing. https://www.youtube.com/watch?v=-7J44bDItE4

There was a real magic in the original oiled paper tapes that made them work in the mechanism very nicely.

So far the paper tapes I've created (X-Acto Knives and tape) aren't very durable but a more plasticy material might be the solution.

I'm thinking that I should hit the arts and crafts store and see what kinds of smooth ribbons they have for the artsy types.

The "contact point" on the instructograph is very small and the cam follower time distortion is not at all an issue.

What I love about this is the spring-wound hand-crank and movable pointer for speed!
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AC7CW
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Posts: 1067




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« Reply #19 on: January 04, 2018, 10:52:21 AM »

We used mylar tapes to load programs into mini-computers. Mylar won't self-destruct, not sure how it is to work with when cutting it by hand, we had computer driven punches for that.
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Novice 1958, 20WPM Extra now... (and get off my lawn)
K5SBR
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Posts: 9




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« Reply #20 on: January 04, 2018, 10:28:12 PM »

Don't confuse the CQ wheel with a "Turquoise Tail-ender". The latter was the strip gizmo. The only ones I ever heard/saw sent only the call. The variable speed of stylus drag was the way to make your call unique in a pileup. As I recall, they were even commercially produced for a while.

Most any micro-switch will require a de-bouncing circuit, just as you should use on any bug or straight key tied to a modern rig. Solid-state keying circuits are much, much faster, resulting in clicks, scratches and other trash on the signal.

73 & have fun in the shop,
Ed
K5SBR
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K1ZJH
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Posts: 3479




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« Reply #21 on: January 05, 2018, 07:17:05 AM »

Another technique was to etch the code pattern around the perimeter of a copper clad disk. A contact finger was used to sense the conductive areas to produce the dits or dahs.

Pete
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W9IQ
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Posts: 1822




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« Reply #22 on: January 05, 2018, 07:39:05 AM »

If I were to build a 'modern' version of this, I would use either a slotted or reflective opto-isolator. That would allow a simple disc construction with black marks for the CW message and no debouncing or wear problems associated with a mechanical switch.




- Glenn W9IQ
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- Glenn W9IQ

I never make a mistake. I thought I did once but I was wrong.
K5SBR
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Posts: 9




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« Reply #23 on: January 05, 2018, 07:53:00 AM »

No doubt an optical approach would be superior and MUCH more quiet. Even the best switch makes a lot of mechanical noise. Shades of a Morse Sounder.

An even more modern approach might involve programming a PIC processor? Oh, that's already been done, for less than the price of a good geared motor. What will they think of next?

K5SBR
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K1ZJH
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Posts: 3479




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« Reply #24 on: January 05, 2018, 03:04:26 PM »

Awww heck... find some RTL flip flops, make a BCD generator, get a bunch of germanium diodes and learn Boolean algebra to make a CW message matrix. K1PLP had a design in an early 1970s QST.
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K5LXP
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Posts: 5372


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« Reply #25 on: January 06, 2018, 05:05:19 AM »

If I were to build a 'modern' version of this, I would use either a slotted or reflective opto-isolator.

Old roller-type computer mice have two of these inside.

Mark K5LXP
Albuquerque, NM

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