On Tuesday 21 June 2005 03:13, Ron D'Eau Claire wrote: > The difference between mode A and B lies in what the keyer does when both
Thanks Ron for your clear description of the keyer logic. I passed my 12 wpm test at the General Post Office headquarters in London in 1979 'by the skin of my teeth'. There was just one examiner who gave the session to four of us. He had us do the sending test (part of it back then) to get it out of the way, as he said - everyone can do this part. As a warm up, he sent the required three minute passage, manually with a straight key. When two of us had a good copy (less than three errors), he wrote out their pass slips, sent them on their way, and told the other chap and me, "All right, this is the real test." The other chap passed and I had four receive errors. "Hmm .. better get it right this time - I'm going to give you one more chance." Third time lucky, or I had warmed up to his style of sending (over 12 wpm if you ask me). He wrote out my pass slip (really, I must frame it), and practically begged me to use Morse and not just regard it as a necessary evil to get on the HF bands. That was on the 6th of April, 1979. Three or four months later with practice on the radio, (G4ICV in the post three weeks later) I needed something faster than a straight key. I made a dual paddle keyer with logic chips on Veroboard from a design in the RSGB's Radio Communication, February 1980, "The 'ultimate' Keyer (Mk2) - with automatic intercharacter spacing - C.I.B. Trusson, MSC, CEng, MIEE, G3RVM." I had 30 wpm contacts with that. It's the only iambic keyer I can use accurately and it's still a magician's logic design that can generate Morse from two paddles. In G3RVM's design, he uses two 4011s, a 4023, 4001, 4002 and a 4013. A low priority task for me is to decode this logic and enshrine it in a microcontroller. I regret dismantling my original mechanical design of this to connect a Bencher paddle system. Now, I don't trust myself not to send a character short or an extra dit or dah. I have given up completely with iambic keyers. I prefer a straight key. But for faster sending, I have programmed a PIC16F624 that lives inside a standard PC keyboard that receives the incredible gibberish from its data and clock lines and translates it to Morse using the three keyboard LEDs for feedback. I had interest from the people at ARRL to publish this design - but one chip and an optional resistor and output transistor isn't much of a hardware project. They suggested I write a tutorial on PIC programming. I never completed the suggested ARRL article. I have rewritten the firmware for a Freescale (Motorola) 908. That's a processor, something I am really happy to programme. See www.njqrp.org somewhere for a description about why a linear address space 908 is nicer and more powerful than a PIC chip. For now, I have a unique keyboard keyer for whenever I rarely need to go faster than I can send using my straight key. Ian, G4ICV, AB2GR. -- _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
