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Author Topic: Home-made morsekey: ideas?  (Read 1044 times)
PE1RLN
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Posts: 24


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« on: June 20, 2001, 08:04:40 AM »

Has anybody info about how to make your own morse-key? I want to build them myslef but have no idea about how to do it.

Please, rpely here.

73 de Thijs, PE1RLN
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WB6BYU
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Posts: 13151




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« Reply #1 on: June 20, 2001, 03:53:30 PM »

There are many different ways to build a morse key, depending on
the materials and tools available.  A key is simply a high-speed
switch, generally (but not necessarily) having a vertical motion.

Here is a simple home-made key, with a discussion of the factors
to consider in developing your own design.

Start with a piece of PCB board for the base, about 10mm x 15mm.
You may want to mount the PCB on a a piece of wood, to allow you
to countersink mounting holes on the bottom.  Some rubber feet
will help to prevent it from sliding around on your desk.

Attach a block of wood or plastic about 2mm high and 4 or 5mm
square to one end of the base.  Lay the handle of a metal soup
spoon on top of this block (so the bowl of the spoon is over the
PCB), then place a similar block on top of the handle and screw
the two blocks together, clamping the handle of the spoon between
them.  Attach one wire to the PCB and the other to the spoon
handle.  When the bowl of the spoon is pressed against the PCB it
completes the circuit, keying the transmitter.

There are several types of adjustments you want to be able to make
on your key:

THROW:  the distance the knob travels to close the contact.  Bend
the spoon handle so that the bowl is close to the PCB, but not
quite touching.   Often this is adjusted by using a screw for one or
both of the contact points, or as a mechanical stop on the lever
arm, allowing the spacing to be adjusted by turning the screw
(which should have a lock nut to keep it in place.)
The contacts may be on either side of the pivot point on the key,
but the basic design is that pressing down on the knob closes the
contacts, and the contacts generally provide a mechanical stop
for the key travel.

TENSION:  the pressure required to press the key (and, generally,
also the force applied to open the contacts when you stop pressing
the knob.)  Loosen the clamp blocks and slide the handle of the
spoon in or out to adjust the distance between the blocks and the
bowl.  With a shorter handle, more force will be required to close
the key.  Most hand keys generally have an adjustable spring to set
the tension, though some use a torsion bar (as does the spoon) or
even magnets.

Both of these will interact, and will depend on personal preference
and the speed at which you are sending.  This is why they are
made to be adjustable in all good keys.

Some other factors to consider:

The size and shape of the knob.  You may like holding the bowl of
the spoon, or you may prefer a different shape.  American knobs
tend to be flat, like a large coat button, and are held with the tips
of the fingers.  European knobs tend to be taller, and are sometimes
held more inside a closed fist.

The weight of the key.  Some people prefer a heavy base to keep
the key in place.  This is particularly important when using a key
with a horizontal action (such as a "bug" or a set of paddles) so
that it does not move sideways when the paddles are pushed.

The ease of cleaning the contacts.  I usually close the key on a
piece of paper, then pull out the paper to clean the dust from the
contacts.

Protection from high voltages.  The spoon key is not suitable for
use with a cathode-keyed valve transmitter, which may have
200V across the key contacts.  (It is too easy to complete the
circuit through your finger by accident.)  For tube equipment, it is
safest to have all exposed metal parts be at earth potential, with
one insulated contact for the keyed wire.

This will give you a simple key, and some ideas of what to look for
in other designs.  I'm sure there are some web sites with photos of
key collections, which will give you more ideas.

Good luck! - Dale WB6BYU
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PE1RLN
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Posts: 24


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« Reply #2 on: June 21, 2001, 02:42:18 AM »

Thanks, but I-ve seen many "professional" keys that were not very difficult to build. I am actually looking for a site or something that has the info.

Your info was good too because I didn't know it was called throw and stuff like that, so I know a little more now.

Thanks an see you again. Keep up the HAM-spirit!

Thijs, PE1RLN

73!
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KP4HE
Member

Posts: 22




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« Reply #3 on: July 03, 2001, 11:58:03 PM »

Unless you have a way to crome or electroplate metals.  The cheapest materials are aluminum and plastic which can be found at any sulpurs stores. I constructed one about 11 yreas ago out of alum. and plex. glass. Some screws and springs. I still have and use.
To avoid corotion I just WAXED the alum and this has mad it last.  Aluminum is easy to wok with (tap and die).Have also in mind that the better the material you have for contacts the better your key will perform.  I use Automoble point contacks and only have to solder them to the tips of the screws which act as contact adjusters.  Wood can be used for the bass but it needs more time to work it for a nice look.(sanding and painting) It must be heavy to hold the key in place. I use plastic which also cleans better.
Look at the comercial models and try to figure one out that you like and just fab a similar with the nuts and bolts you can find to biuld the key.  
After you'r done, if it looks good just SHOW/OFF what you did.  It's a great satisfaction when you get the complements.  The 1st one is alway the hardest to built.  Then it's a ride in the park. Hope this can help.  
HAVE FUN....... 73
KP4HE
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PE1OBG
Member

Posts: 20




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« Reply #4 on: July 09, 2001, 04:10:11 AM »

check out this month's Electron -magazine of the Veron, Dutch hamclub- Thijs, it contains an article on building a key with readily available parts such as waterpipe and it's fittings.

I'm working on a Phelps replica at the moment, not really a simple project, but i got good drawings from Tom Parrera, i'm not sure about the name but the drawings are very detailed.

73'Leo.
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KD5MSY
Member

Posts: 34




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« Reply #5 on: July 28, 2001, 01:00:13 AM »

I would like to say that these are all great ideas and that it is always great when hams come to the help of some one who has a question. Also the ideas of "Waxing" the contacts is a good point to keep in mind, How ever if you have the extra pocket change go down to your local electrical suply house and get some "no ox." I know the spelling is not corect but they will know what your talking about.  It is used mainly on copper conections and will not let it oxidize and has little or no resistance, altho it does have a tendency to collect dust and dirt, but should not require that much cleaning. Best of luck.

KD5MSY
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