# Telegraph key



## cathead (Apr 2, 2022)

Today was the second day of my telegraph key build and it is beginning to take shape.  It needs contact points and some binding posts
yet as well as being mounted on a good solid hardwood board.  I picked copper because I had a bunch of 1/4 square stock left from 
the old CP200 Miller welder I junked out.  In it's annealed condition it is fairly easy to form to the desired shape.  Silver solder was used
with an acetylene torch during assembly.  Another reason for the copper and brass is that when it is done and given a high polish, it
has an attractive look to it.  Here is a photo of it in it's present condition.


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## rabler (Apr 2, 2022)

Very nice.  Are you learning morse?


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## cathead (Apr 2, 2022)

rabler said:


> Very nice.  Are you learning morse?


No, I learned it a long time ago.  It's good to keep in practice though.


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## cathead (Apr 2, 2022)

Here's another one I made a few years ago.  It's more of a machinist's version of a telegraph key.  The new one
is done without much machining to speak of.  It's more like working with jewelry I guess.


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## cathead (Apr 3, 2022)

It's taking shape.  All that is left to do is to make some binding posts and mount the key on a nice board.  
	

		
			
		

		
	





It's made of only copper and bits of brass with a gram or two of silver for the contact points, assembled using silver solder.


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## Just for fun (Apr 3, 2022)

Cool,  Are you a Ham radio operator? 

I passed my 20 WPM extra test.   But I never got good enough to do much work at that speed.   At best I was probably only good enough to hold a conversation at maybe 10 wpm.  A quick RST exchange maybe 15 if I was lucky. 

Tim
KC7EAY


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## cathead (Apr 3, 2022)

Yes, since 1961   

73,

Burt


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## addertooth (Apr 3, 2022)

I grew up around this stuff.  My dad was an amateur extra class.  He still gets on 2 meter voice.  He used to do EME (moon bounce) and Meteor Scatter (radio signal reflected off the ionized trails left by meteors during a meteor storm).  His call sign is WB5BKY. We were neighbors with K5LAD, who owned Radio Incorporated in the 60s through 80s.  Dad had QST cards (contact cards) from around the world. His first "fast" key was a Vibroplex, which moved side to side, with a long weighted springy contacts for the dots and dashes.  This was before the days of the LM555 chip which was used to make a lot of electronic keys.  His 1200 Watt P.E.P transmitter was built from scratch; it had forced air through a pair of 4CX250 tubes with a plate voltage of about 2500 volts.  The front end of the receiver was using the (then new) FET transistors.   It was a quite a rig, with a stacked Yagi array which totaled 144 elements.  The antenna was also built by hand.  As I recall the antenna rested on a Rohn 45 tower in the back yard.


I got up to 5 WPM for Novice class, but just lost interest in it because I had become an adult and was moving out of my parent's home.
It was hard for Ham radio to compete with cute girls and fast cars.

These days, REAL RF guys are getting harder to find.  One of our labs had an opening for one, which stayed open for over a year.  Very few engineers these days can speak and do RF.


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## tq60 (Apr 3, 2022)

They do not teach rf anymore.

Been in the biz since 1979, started in land mobile, went to nextel, cellular and back to land mobile.

Very hard to find folks who understand it.

Now it. Is just "boxes and wires"...

Sent from my SM-G781V using Tapatalk


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## addertooth (Apr 3, 2022)

tq60,

  Your statement makes sense.  It explains the dire shortage of people who can even do simple things, like path loss calculations, and Fresnel zone calculations.  None of the applicants could even do the basic calculations for a Yagi antenna.  They acted like tuned circuits on the input of a RF stripline circuit was the darkest of black magic.  None could calculate a PI network.  And heaven sakes, a basic Pentode circuit was far beyond them. 

  And no, I do not consider myself among those who are true masters of RF circuitry.  Perhaps it is true that Engineers eat their young.


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## cathead (Apr 4, 2022)

It started with spark gap and graduated to tubes that back then were called valves.  Triode tubes
were used in the 20s and 30s, like the O1A, 30 tube, the 27, the 45 tube in both receivers and transmitters.
Hartley and Colpitts oscillators were popular as well as tuned plate-tuned grid and TNT.  Some used
a transmitter called a MOPA which is an acronym for master oscillator power amplifier.  I have built several
of those and they are still in use today.    




This is the transmitter I will use with the new telegraph key.  It is a MOPA design using two 211 tubes(VT4C).  The coils on the left are for 160 meters, the ones in the transmitter are for 80 meters and the coils on the right are for 40 meters.  The grid current meter on the top left came from the local dump at the time and was part of the remains of an old Ritter dental X-ray machine.  It easily works from coast to coast on
ten watts of RF input power.


The world as we know it today could easily be transformed back to the stone age by an EMP (electromagnetic pulse) or an overhead
nuclear explosion.   Cell phones would become useless.  Cars wouldn't run.  Anything with solid state technology would be
destroyed.  But, tubes would not be affected!  So anyhow if things go bad, a few of us will still be able to communicate. 
Of course the receiver would have to contain tubes as well.  I'm not a doomsday person at all but it doesn't hurt to know that
things could radically change our lives in an instant.  The sunspot cycle is on the increase. A CME(coronal mass ejection) is
a real possibility in the coming 11 year cycle of old sol.


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## addertooth (Apr 4, 2022)

Cathead,
Did you use one of those old Grid Dip Meters to tune your coils, or was it just done straight from the math calculation?
Based upon your use of language, and technology, I would put your age in the range of my father.  He is almost 90. 
Those old tube rigs (like the MOPA) were laid out in a way, which was often quite artful.  I only built two tube transmitters,
one was for 11 meters, the other was the license-free range for QRP.  After that it was all transistors, as I recall with the old 
Motorola Planar transistors for some of my first "higher power" designs.


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## cathead (Apr 4, 2022)

addertooth said:


> Cathead,
> Did you use one of those old Grid Dip Meters to tune your coils, or was it just done straight from the math calculation?
> Based upon your use of language, and technology, I would put your age in the range of my father.  He is almost 90.
> Those old tube rigs (like the MOPA) were laid out in a way, which was often quite artful.  I only built two tube transmitters,
> ...



This was back in the days when RF was referred to as the "ether".  It was all trial and error back then and still can 
be if you want to play old time radio.  It's not too hard to take an educated guess on the amount of inductance and capacitance
required when building a tuned circuit.  Once it oscillates, it's easy to find it on a receiver.  If the frequency is too high, one 
needs to add more capacitance or inductance or maybe both to lower the frequency to what you need.  You don't need a
grid dip meter or even mathematics to do this.   By the way, if your dad is almost 90, you could easily be older than me.


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## cathead (Apr 6, 2022)

Here it is mounted on an oak board.  I'm pretty happy with the result and it has a good feel to it and works fine.  Maybe another
coat of varnish is in order but other than that I consider it done.


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## JPMacG (Apr 6, 2022)

Very nice Cathead.  I am a CW enthusiast and a retired RF/Antenna design engineer.   I have a small collection of Vibroplex semi-automatic keys.


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