Kurtz Morse Code interpreter

Contents copyright Herb Johnson 2019, except material written by Kurtz as described. Last update July 21 2019.

Summary:Online discussion suggesting a COSMAC ELF program to read Morse Code, led me to uncover a BASIC program which ran on a KIM-1 6502 computer. The program was published by the programmer, Robert Kurtz, in November 1978; The Kilobaud magazine was Web archived at archive.org. Mr Kurtz, a decorated WW II veteran, ham operator, and microcomputer developer, passed away in 2012. The article and program are available as Web links on this Web page. - Herb Johnson

Speculations on morse code

Alternatives to Tape Recorder for program storage...", from cosmacelf groups.io discussion, July 21 2019

Lee Hart posted: On the subject of brainstorming... I was a ham back in the 1970's, and know Morse code. Hams use a device called a "keyer" to quickly and easily send code. It consists of two switches; one for dot, one for dash. A mechanical device, hardware circuit, or microcomputer converts the switch closures into strings of dots or dashes. The "dot" switch sends a sequence of dots as long as it's closed. The "dash" switch sends a sequence of dashes while it's closed. Closing both at once sends an alternating sequence of dots and dashes. With a little practice, you can send code at high speeds with minimal finger motions.

So, I thought of connecting a keyer to my Elf. Use it as my input "keyboard"! It's hard to imagine a simpler hex or even ASCII input device. :-)

Alas, computers sucked me in completely. I lost interest in ham radio, and focussed on computers. Someday, I hope to get back into ham radio. Maybe I'll pursure this idea yet. - Lee Hart.

Herb Johnson (myself) responded in this post: PS: Lee Hart suggests connecting a Morse-code keyer to a COSMAC for input. Obviously a speaker would be output. Morse Code encoding is like audio-data encoding: each character is represented in dits and dahs of different periods of time, separated by longer intervals. If one has a steady "fist", a program to interpret those intervals, would be no more difficult than the cassette-data programs used to encode a byte as a start bit, eight bits, stop bit; as two audio tones (cycles) of different frequencies (periods). Such a input program, could display the resulting ASCII value on the 8-bit LED display (or hex display). An aggressive program, could "speak" a character as stored digital "voice". The program almost writes itself (ha ha). This is hardly a new idea. Radio amateurs produced and used Morse Code keyboards/displays, built upon 8-bit processors, in the late 1970's forward. I have a couple of units around me right now; "junk" sold at hamfests of the last few years. As are portable audio-cassette recorders, MP3 players, Ipods, etc. etc.

Prior work, "brass pounders"

A Web search for COSMAC Morse Code found a number of COSMAC programs, most of them in archives of "IPSO FACTO", a user paper magazine published in the 1970's ELF era. An archive of that magazine is available at cosmacelf.org

But a more general search found an an article in Kilobaud (Microcomputing) magazine, by Robert L Kurtz in November 1978. He developed a 6502 assembly language program to interpret Morse Code input, into text characters. He generalized the program into Microsoft BASIC for the KIM, and published code and details (including a hardware frequency detector) in Kilobaud.

Archive.org carries a PDF and text-OCR of the magazine. page 34-37 of this issue has "World of the Brass Pounders . . . Receive Morse Code the Easy Way" by Robert L Kurtz W6PR0. It's a busy but short BASIC program to convert Morse Code to text. It's likely a Tiny BASIC program could run this.

It's written on "9K Microsoft BASIC [for the KIM 6502 computer] which may be obtained from Micro-Z Co,Box 2426, Rolling Hills CA, for $100." Micro-Z was Mr. Kurtz' company. The program addresses peek(5558). 5888 decimal is 1700H. Bit 0 of that location is read as PA0 on the KIM-1. A NE567 circuit, described in the article, is connected which takes a keyer as input and the NE567 outputs to PA0.

This Web site by hansotten has KIM-1 manuals digitized. The Microsoft KIM-1 BASIC manual is also available there.

Here's an OCR of the text and program of the article. Contact me if there are typos or errors. The OCR was by archive.org, which I edited. I corrected the program.

Here's a PDF of the cover of Microcomputing and the article. Again, from archive.org.

Robert L Kurtz W6PR0, RIP

Mr Kurtz passed away July 6 2012. An online obituary supplies the following information and more. A WW II veteran and Bronze Star awardee for service in the Europe, his division opened the gates of Dachau concentration camp. As an EE he worked at North American Aviation (later Rockwell) on the B-1 Bomber. He started a microcomputer company called Micro-Z. He was an inventor and ham-radio operator and private pilot.

Herb Johnson
New Jersey, USA
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Copyright © 2019 Herb Johnson