Posts Tagged ‘CW’
Simple keyer complete
At last, I finally got the QRP keyer using KD1JV’s Simple Keyer Chip boxed and working.
The completed keyer |
As usual, nothing went according to plan. There must be some relative to Murphy’s Law that states for any homebrew project the case will be just too small for comfort. A related rule is the one which guarantees that after you have drilled the case, the position of one of the switches or sockets will be in just the place where it fouls one of the components.
After my first attempt at getting it into the box the keyer was dead as a dodo. This turned out to be because I had forgotten to break one of the tracks on the Veroboard.
After the second attempt the keyer responded to the function button but there was no keying. That turned out to be because one of the connecting wires had broken at just the point where it was soldered. With my eyes as they currently are that took a while to spot.
When I had resoldered the connection and put the board into the case for a third time I noticed that another connecting wire was hanging on by one strand of copper. Lesson: don’t use hookup wire from China, it is made from inferior grade copper.
View from the front |
View from the back |
This had taken me a day, so I decided to put the project aside until I felt calmer. The next day I re-made all the connections using new wire, put the board into the case one last time and it actually worked! But Murphy had one last laugh: Now I couldn’t find the four screws for the Hammond case I was using. We searched everywhere. Fortunately my parts box had another Hammond case which sacrificed its screws for the benefit of the keyer. Later, Olga and I managed to find suitable replacements in the local DIY emporium so the other case won’t be wasted.
This Simple Keyer is just what I need for the simple QRP rigs that only work with a straight key. The code speed is easily adjustable and there are two memories, one of which can be repeated as a beacon. I don’t need more sophistication than that for QRP work.
Trials and tribulations
I’m sorry if you are one of the many people who have sent me email expecting a reply, but unfortunately answering emails is one of the things I very often never get around to. Although it might seem from the blog that I am getting back to normal, everything I do still takes me a lot longer than it did when I was fit and well and I’m more prone to making stupid errors. I’m happy that I’m still able to do some of my ham radio activities but what I achieve is often accomplished only after a lot of frustration.
Today the Simple Keyer Chip from Steve Weber arrived in the post. I verified the behaviour of the chip I’d programmed, then replaced it with the new one. I was pleased to find that it now operated at the correct speed – the sidetone was now audible to humans rather than bats and the default speed was rather more sensible. Obviously I’d messed up some setting of the programmer – but the keyer still ignored the dot paddle. I began to suspect that this meant there was something wrong with my wiring, but between my limited field of focus and my shaky hands it took the entire morning – culminating in a lot of bad language – before it eventually dawned on me what was the trouble.
To cut a long story short, the cause of the problem was the 3.5mm socket I was using for a key jack. It had three terminals which I thought were for tip, ring and sleeve, dash, dot and ground. But it was a mono socket! There was no ring connection. One of the three terminals was linked to the other and disconnected when the plug was pushed in, intended to silence a speaker when phones were plugged in. It took me an entire morning including checking the wiring of two morse keys before I discovered my stupidity.
I hunted in my parts drawers and eventually discovered a proper 3.5mm stereo socket. After connecting that in place of the other one I confirmed that the keyer worked as expected. But the frustrating search for the solution had made me tired so I decided to leave the task of drilling the box and finishing the keyer for another day, thereby adding to the list of unfinished tasks alongside the unanswered emails.
Another thing that annoys me is my Rapid Electronics HY3003D bench power supply. It has a rather inconvenient fault for a power supply that is used in a radio shack. The voltage regulation circuit suffers from RFI. If any of my radios transmits, the voltage increases. In some cases it could increase to a level that could damage the circuit I am testing, though fortunately that hasn’t happened yet.
I don’t always remember to put my APRS gateway or the WSPR (or Opera, which I have been testing today) beacon into receive-only mode whenever I’m working on something. (I’ve tried clamp-on RFI suppression ferrites on the mains lead and they made no difference.)
Anniversary of Vail’s First Demonstration of the Telegraph
Over at “This Day in History,” the lead story today is “Morse demonstrates telegraph.” It leads off, “On this day in 1838, Samuel Morse’s telegraph system is demonstrated for the first time at the Speedwell Iron Works in Morristown, New Jersey.” Well, I thought, surely this is worthy of a blog post, so I poked around on the web to learn more.
It turns out that this first demonstration was put on by Morse’s partner, Alfred Vail. Vail had first become involved three months earlier when visiting his alma mater, the University of the City of New York. He stumbled upon Samuel Morse demonstrating his “electro-magnetic telegraph” with over one-third of a mile of wire coiled around a room. Vail was hooked. He convinced his brother George and father Stephen to support further development of the telegraph at the Speedwell Iron Works, and he signed an agreement with Morse to turn Morse’s crude prototype into a market-ready model — at his own expense — by January 1, 1838, in return for a minor share.
The challenge was to get the thing to work with a length of wire much longer than Morse had managed to use. Alfred Vail recruited an apprentice at Speedwell, William Baxter, and got to work. After many frustrations, they finally succeeded in getting their model to work:
At last on January 6, 1838, the machine was ready to be demonstrated. The cotton-covered hat wire was coiled around the room on nails to equal a distance of two miles. Alfred sent Baxter to “invite Father to come down and see the ‘Telegraph’ machine work,” which sent the eager lad plunging into the cold afternoon without stopping to throw a coat over his shop clothes.
The machine that sent Stephen’s message, “A patient waiter is no loser,” was still far from perfect. A few days later [January 11] several hundred men and women crowded into Speedwell to witness the first public demonstration. The message this time had a practical cast: “Railroad cars just arrived, 345 passengers.”
I’m not sure how these messages were formatted, but most likely they were not sent letter-by-letter. In those early days messages were laboriously sent using numbers that were assigned to commonly-used words. Eventually the “Morse Code” alphabet would replace this system, though great debate rages over who invented it.
Vail himself gives credit to Morse for the alphabetical system on p. 30 of his book, The American electro magnetic telegraph: with the reports of Congress, and a description of all telegraphs known, employing electricity or galvanism (available online for free), though some doubt the truth of this statement. Many years after his death, someone even sneaked in and engraved on Vail’s tombstone, “INVENTOR OF THE TELEGRAPHIC DOT AND DASH ALPHABET.”
Whoever invented the alphabet, what does seem clear is that Vail was the one who invented the straight key, an elegant improvement upon the cumbersome machines first used to encode messages. Today, you can even purchase a replica of Vail’s “spring key” from Kent Morse Keys!
Alfred Vail became increasingly frustrated by Samuel Morse’s lack of involvement in the development of the telegraph while publicly taking all the credit. Vail stuck with it for ten years before finally leaving the telegraph behind.
Simple keyer trouble
It should have been simple. I needed a basic CW keyer that would allow me to use a paddle with my homebrew QRP / QRPP rigs because my shaky hands make sending Morse with a straight key too difficult at the moment. I also needed to be able to record a message and play it once or repeatedly until I heard someone reply or was spotted on the reverse beacon network.
A couple of years ago I built a DC20B QRP transceiver. I didn’t like it very much and eventually sold it on eBay but I did like the keyer built into it which used an ATTiny13 microcontroller. One day, I thought, I would build a keyer using this chip. I got two of the Atmel chips and Steve Weber KD1JV sent me the hex file so I could program them but I never got around to doing anything more until a couple of days ago.
The simple keyer circuit uses only a handful of components but due to my condition it took a lot longer than it would have done pre-tumour to work out a perf board layout and build it. So you can imagine that I was a bit upset when after all that effort the keyer didn’t work. It responded to the dash key and the function button, but not the dot key. Also the sidetone was very high pitched and the Morse speed was about 100wpm!
Thinking I had made a mistake programming the clock setting in the chip I tried programming the other one. This ended up just the same. Unfortunately with the simple keyer program you have to disable the reset pin that is used by the programmer so you only get one chance to write the code to the EPROM. But as I don’t have the source code and so can’t try modifying it that shouldn’t have been a problem. If I hadn’t sold the DC20B I could have tried the keyer chip from that, but now I am now stuck with no idea what to try next.
I have the code for another keyer that uses a PIC12F509A – the K9 from K1EL’s freeware page. But I’d have to start over with the circuit board as the pinouts of the Atmel and Microchip microcontrollers are not compatible. The functionality of the K1EL keyer program is not what I was after either, so I don’t feel much like trying it at the moment.
Stubby Index Finger
For some reason around the Christmas season every year, I think of one of my favorite films… Evil Roy Slade. This year, I had planned to do some serious kit and homebrewing on my days off. But I managed to cut my stubby index finger while trying to fix our dishwasher. Somehow some broken glass was in the drain basket when I went feeling around. OUCH… ever try to solder and handle small parts with a wounded finger? How about operating a straight key like I do?
So I share a clip from my buddy Mickey Rooney and his character in the movie. Hope you have a Happy Holiday!
Contest Point Giving for Christmas
The weather was too nice to sit inside. In the low 70′s with a very slight breeze so after church and a short nap I headed out to try my hand at giving out points in the QRP ARCI Homebrew Sprint. My startup was delayed by curious folks in the lakeside park wondering what in the world I was doing and how I got that string and wire so high up in the nice tall pine trees!
I checked 40m first with an inverted L end fed half wave and my trusty Stuner (KI6S Stu’s kit) and decided to change to 20m after not hearing much activity. 20m was decent and there were a few of the big gun qrp contest regulars shooting it out. N4BP, K4BAI, K0ZK and a few other were running stations while the little guys like me were mostly doing Search and Pounce. Hey it is fun even if you cannot run a frequency, right?
Sun went down about 1745 local and the mosquitos were quick to find the hole in my hat and attack. This time I remembered the repellant and after a few bites I took time to spray my hat and hair and the backs of my hands. The temperature dropped fast and my hands got a bit stiff pounding out the morse code on my J-47 straight key. 50 degrees is cold for a Florida evening. The darkness also brought out the raccoon family and it was fun to shine my flashlight on them and watch them stand on their hind legs and stare into the night wondering what the funny guy was doing in the dark.
40m came to life after sunset and I finished with a respectable 20 contacts for about 3 hours of operation and was able to give some Christmas contacts to the needy fellow contesters who were chasing another certificate. What a great way to spend the afternoon… by the lake in the sun and outdoors playing radio.