Loose Ends (1)

Here's a few things going on: 

1) Frequency Synthesizer.  I've been struggling with the code for the KY-040 rotary encoder in the frequency synthesizer.  I was trying to add switch debounce into the code, but this is much easier said than done.  The encoder is very noisy electrically, hence the need to debounce. But time for the fall of the CLK signal and the change of the DT signal is often just a couple of milliseconds... The DT line really needs to be sampled at the fall of CLK...   I'm running some experiments to characterize the problem, and will write a white paper on it later. 

2)  QRP LABS 10W amp.  I ordered a 10W linear amp from QRP Labs.  It apparently ships from Turkey.  It finally arrived yesterday.  The other QRP brother, KA5VZE, has promised to put the kit together for me.  We're going to drive the 10W amp with the frequency synthesizer to make a transmitter.  More on this later.  See photo below. 

3) The "Morris" Morse straight key:  I picked up the homemade "Morris" KA5VZE straight key yesterday.  It's awesome!  Now I just need a transmitter to plug it into...  

I want to customize it even more.  Maybe some idealized nose flames, or a mud flaps girl silhouette.. 

4)  Computer oscilloscope.  My bench oscilloscope is a Tek TDS2014.  It's fairly nice. 100 MHz bandwidth digital scope with 4 channels. The frustrating thing is that it doesn't have any way to offload digital data or even jpegs of the display.   I have an old TiePie Handscope HS4 lying around that I got from somewhere.  It's about 10 years old.  I'm going to try to get this going for the encoder study I'm planning.  This scope is displayed and controlled from a Windows computer.  The software is still available and I've downloaded it. Let's see if it works.  As I recall the scope had 100 ns, 12 bit sampling, and some huge buffer size. 

"Morris" key (6): qso with KD4RAX

 

Trying out Steve's "Morris" key on the 40 Mtr band with Mike @ KD4RAX.

"Morris" key (5): Boring the return spring recess with homebrew faceplate

In order to turn the recess that seats the return spring I had to devise a way of mounting the base onto the lathe in order to bore it out.  I drilled four holes in the back of a 3/4" thick disc for the 4-jaw chuck to have a purchase on it.  Once it was mounted on the lathe I leveled off the faceplate with a couple of passes of the cutting tool.  

 I then screwed the base onto the faceplate after centering it to the boring tool.  The streak across the base is where I forgot to manually turn the chuck to see it it interfered with anything.  And sure enough it did.  The carriage caught one of the screws used to mount the base and subsequently pulled the tool into the work.  Now it has a decorative element that is quite lovely,... Don't you think? It should buff out. :)

"Morris" key (4): machining the rocker arm

 Test #1 & #2: Using a depthing guage to test the trueness of the rocker arm.  The pointer is brought up to one side of the rocker arm where it barely touches as is shown in the video.  NOTE:  The depthing guage is used by watch and clockmakers to find the correct depthing of gears and mark to plates where the bearings are to be placed.  

TEST #2:  The rocker arm is flipped over and the other side of the arm is tested for alignment.  This test clearly shows the rocker arm is bent and will need straightening.

ADJ:  Using a cross peen punch on the underside of the rocker arm to straighten it.

TEST #3:  After adjusting the rocker arm is tested again to demonstrate that it is in alignment.

"Morris" key (3): machining the base

 

I finished out the base and installed the bases for the trunnion assemblies.  I have had these miniature pillow blocks for about 30 yrs sitting in a jar.  Just could not throw them away.  I got these at an estate sale where a retired engineer's machine shop was being sold off after he passed away.  I missed out on the machinery but bought all the fasteners...took 2 van loads to get it to my clock shop.  I never regretted spending the $30.00.  Along with the fasteners came bearings, bushings, and other machine shop bits and pieces.  

"Morris" key (2): base pattern cutout

 

Pattern copied from base to AL plate using fine permanent marker.

outline drilled out and rough base cut out using jeweler's scroll saw.

Switch components for tuning traced onto cold rolled steel sheet metal.

Progress so far.  The rough parts on the base are smoothed out using a cylindrical burr driven by a Foredom flex shaft.  

Radio Shack Morse Code Keys

 Radio Shack, in my experience, sold two straight Morse keys in the last quarter of the 20th century.  The photo below, from Page 166 of the 1979 Radio Shack catalog shows the cheap plastic key, Cat No. 20-185, priced at \$1.99. That's \$8.17 in in 2022 money.   The more expensive brass hand key, Cat No 20-1084 sold for  \$4.49 then ($18.43 in 2022 dollars).  I got the image from a very wonderful site at https://radioshackcatalogs.com .

I bought a key in the early '80s and being practical and poor, I bought the  cheap plastic version and used it for a decade or so.  Later, as I picked up old timer buddies and bought a silent key's estate, I picked up several different vintage keys.  My favorite was a military J-38 key,  it was "poetry in motion."... 

Mike apparently has a brass key which hopefully he'll maybe feature in some future posts.  I'm going to discuss the cheap plastic key here, because it was "for the masses" and did the job well. 

    I'm borrowing the nomenclature of the key from KD2UJ's "Parts of a Telegraph" page.   The actual photos are taken from a completed Ebay.com auction. The auction ended on 11/30/2022 and sold for \$12.95.   A labelled photo is shown below.

Construction:  The key was cheaply constructed, but that was the whole point: 

• The frame and knob were black plastic. Not particularly bullet proof, but sturdy enough
• The lever and trunnion were stamped plated steel or stainless steel.
• Binding posts, gap adjust and sprint tension screws were simple knurled knob screws. I don't know if they were inch or metric.
• The key had no ball bearing in the trunnion.  The lever simply snapped into the trunnion at opposing holes and was held by the tension of the trunnion. Electrical continuity to the lever was through the trunnion bearing. 
• The wiring was done through stamped metal straps on the underside of the plastic base as shown in the photo below.

Operation: 

• I mounted the key on a 1X4 piece of wood that was 6 inches long.  I put rubber feet on the wood.  The key was in a fairly natural position. 
• The key gave a definite tactile stop when it hit the contact going down and also a nice tactile feel coming back up as it hit the travel limit.  This felt natural and I could do maybe 15 wpm comfortably without a lot of strain.  

For comparison to the "good old days" I searched around for cheap, utilitarian hand keys on Ebay.com, Amazon.com, and Aliexpress.com.  I couldn't find any straight, traditionally contructed hand keys for less than about \$35 on any of the three sites.  Amazon.com did have very cheap keys for about \$6.  An example is shown below.

I don't really like this style of key and I wouldn't recommend it as a beginner's key. It would have a very mushy feel, and given the lack of a limit stop, it would only be suitable for very slow keying.  Additionally, a beginner would have to "unlearn" the feel of this key to move on to a traditional key. 

"Morris" key (1): A replica Morse straight key

 I'm going to build a replica of my old "Morris" key that I have had since a novice in the 80's.  I believe I bought it at Radio Shack.  It was discontinued in 2010.  You can still get some of the parts for it.  I'm only going to purchase the knob.  I hold my key close to my body and tap on it sideways.  

Straight key build (2): First 3D print.

Note: 11/29/22.  I am going to put this project on hold while I order some springs.  I plan to redesign it, preferably using OnShape.   -Steve 

Below is how the key goes together after fitting the parts in TinkerCad

This is the first print of the morse key: 

Unfortunately it's a no go.  I forgot to add support underthe the key platform and the printer to fail construct the underside of the platform 

You can se in the photo above that the bottom of the elevated part of the key platform is just loose filaments. 

The above photo shows my conception of how its supposed to fit together.  There is no assembly drawing or BOM included.  It needs a spring and various screws.  There is also some sort of shaft and bearing that go where lever connects to the key base...  It's a mystery!  I'm going to investigate how the parts fit together before printing the next try, with the support added. 
 

Straight key build (1)

 Mike sent me a link to a TinkerCad design for a straight key.  I'm going to print out the parts and see how it goes together.  I'll have to or some bearings and a pivot rod.  Here's a screen capture of the TinkerCad model:

Looks like key knob on the left in red, along with low contact holder. In grey is the cradle and key arm. 

Original link is: https://www.tinkercad.com/things/hjTDqVf2n0u