Ham Radio QRP Low Power

• Training for Sending Code - on the Web

  Be Kind - Send Good Code

  I have created a number of training aids to help me recognize morse code letters and words over the years, and I've used CW decoding apps on my phone to help me check if I'm sending copyable code. But I wanted to create a computerized coach that anyone could access to work on their sending skills and make it fun to use by tracking progress.

  
  

  I've heard first hand that folks think they are sending copyable code when they are not.  Last week I was on 30m and someone was repeatedly calling CQ, but try as I might I could not decode their call.  Every time they'd send it there would be an unrecognizable character or two.  On each subsequent call it would sound like a different set of characters or non characters.  I tried to copy them to respond for about 3 minutes and gave up.  I kept seeing them call CQ on the waterfall but were never answered.  They needed to work on their sending.

  
  

  The Web App

  It not only shows if your sending the characters you think you are, it gauges whether your inter-character and word spacing is good.  It gauges your overall timing accuracy and in QSO mode, those measurements work toward unlocking virtual rigs and badges.  For straight key mode it measures your DIT to DAH ratio and gives you real time feedback on what your ratio is through the gauges under the decode window (hint: you want them to all be as close to straight up and down as possible).

  
  

  How does it work ?

  You are sending Morse with your selected keyboard input of straight key or emulated paddles. You are not typing letters, but working to send well timed code.

  
  

  You can also use a VBand USB Paddle / Straight key interface from https://hamradio.solutions/vband/

  
  

  The QSO simulator alternates turns: it sends a line ending in K or BK, then it’s your turn. When you’re ready to hand the conversation back, send K (or BK) as a standalone word.

  
  

  Decode window

  You (decoded) shows what the app decoded from your keying. Use Clear to wipe it.

  
  

  Progress per user

  Progress is stored per-browser. Use Reset progress if you want to wipe skill points, unlocks, badges, and calibration.

  
  

  

  
  
  

  

  
  
  

  

  
  
  

  

  Link to the web app - Morse Buddy

  
  

  Be Kind

  This is definitely still a work in progress and completely free. I'd appreciate constructive criticism, feature requests and bug reports in the comments.  Software bugs, not Vibroplex bugs; but if you can leave a Vibroplex bug in the comments that would be awesome as well.

  
  

  That's all for now, so clean up your sending and keep folks from spinning the dial when they hear your call.

  
  

• Do you need the newest test equipment?

  Tektronix 475 - The Beats Keep Coming

  A friend recently gifted me a Rigol spectrum analyzer and I've been having fun with it diagnosing and fixing problems with one of my antennas and looking for RF interference in the house, but that's for a future post. While that Rigol is nearly a decade old, it's far newer than my other test equipment, in some cases by more than 40 years.  Much of my test equipment is from the era of bell bottom jeans and Starsky and Hutch, because A) I'm generally cheap, and B) I just don't have that much disposable income to dispose on a hobby.  My experimenter board and oscilloscope are from the glorious 1970s, and my vacuum tube voltage meter is from the 1960s.  Summers were longer, Spring was greener, young adults were strung out.  Ah, the good old days.  

  
  

  I restored the non-functioning multi-meter a few years back, but the experimenters board and oscilloscope are living on with what they were born with.

  
  

  That new shiny spectrum analyzer with its digital goodness and assumed accuracy got me to wondering if my old "Craigslist find" oscilloscope is still accurate enough for my amateur uses.  I figured that the Tek 475 had probably drifted in accuracy, but when I was measuring the output of the function generator on my equally old Heathkit Electronic Design Experimenter Model ET-3100, the max frequency reported was nearly 65% higher than what the ET-3100 was supposed to be generate.  

  
  

  That Heathkit experimenter board's signal generator was never intended to be accurate but 65% is a huge deviation from the expectation. So I decided to measure the accuracy of my oscilloscope.  

  
  

  
  

  

  
  

  How to test?

  Not having an actual signal generator I thought, well what can I trust to generate a  known frequency that I can measure?  The Tek 475 has a bandwidth of 200 MHz.  So testing a signal near the top of that range should prove challenging for the old scope and give me an idea of accuracy on the time scale side of things because that will push it to the limit of its abilities.  Regarding voltage measurements, I'd already compared it using a few stable voltage sources (batteries) against my multi-meter. They both measured exactly the same.

  
  

  So, back to time-domain accuracy.  The 2m simplex calling frequency is 146.520 MHz.  That's pretty near the top of the scope's bandwidth.  If you key a FM transmitter with no input (no modulation) it will generate a carrier at that frequency. There will be harmonics but they are well away from the primary frequency. To measure that on the oscilloscope I need to know the time it takes a wavelength at that frequency to complete. A 146.52 MHz signal has a period of 6.83 nanoseconds (ns). That sounds difficult to measure.

  
  

  The scope's fastest native setting is 10 ns/div (labeled as .01µs)

  A singlecycle of this signal (6.83 ns) will occupy roughly 0.68 divisions on the CRT, so less than one division, which may make it difficult to assess.  But if we engage the X10 Magnifier Switch we get an effective time division of 1 ns/div.  With the magnifier on, one full wave cycle will now stretch across 6.83 divisions (the little squares), creating a waveform that's relatively easy to measure.

  
  

  I keyed the HT into a dummy load at its lowest power setting next to the oscilloscopes' probe and saw...

  
  

  

  
  

  
  

  Note the time division at 0.1µs and the X10 magnification is pressed

   

  

  
  

  Ladies and gentlemen that is 6 full divisions and crossing midway past the 4th hatch mark of the next division (representing 8) giving us very close to 6.83.  I don't have the start of the waveform exactly on the zero crossing so if that were a nudge to the left it would be crossing the 6.83 at the correct location.

  
  

  I'd venture to say they don't make'em like they used to

  
  

  Conclusions

  Is an oscilloscope from the 70's as easy to use as a digital scope that has markers? No. 

  Does a digital scope make you think about the actual length of a waveform? No.

  Were engineers smarter in the 60's and 70's? Who knows.  They certainly had to work harder to get an answer to a question, but then they weren't being interrupted by messages and alerts on their phone every... hold on I got a message... 

  
  

  The Tektronix 475 was a professional piece of equipment back in its day.  It likely was used in a lab that kept it calibrated until it became obsolete, probably sometime toward the end of the 80's. When I picked it up, it was pretty much as you see. The panel wasn't very dirty, the screen was clean and unmarked, there were no scratches on the case and there were still plastic caps over the rear connectors.  It seems to have lived a pampered life.

  
  

  But, for the past decade the poor thing has been abused by someone (me) who doesn't know how to properly use it.  It serves as my silent electronics Elmer as I fumble around with it trying to confirm or deny my little hypotheses as I build equipment and alternatively let the smoke out of equipment (did I tell the story of how much kinetic energy a power transistor on a 1-watt transmitter can produce?)

  
  

  So, if you are a nascent electronics experimenter looking to get some test equipment on the cheap, and you want to actually have to learn what your measuring, and you like to have a potential 50-70 year old fire hazard on your desk, keep an eye out for an old Tektronix scope from the good old days.