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Showing posts with label Macdonald -- Copthorne. Show all posts
Showing posts with label Macdonald -- Copthorne. Show all posts

Thursday, August 11, 2011

Alarm from Space

So I was sitting in the shack yesterday morning, drinking coffee and listening to IGY by Donald Fagen on Pandora, when I heard what I thought was an alarm. I thought it might have been a smoke detector going off (always a real possibility in the N2CQR shack!). It took me a moment to realize that what I was hearing was the device pictured above. I'd left my 2 meter HT tuned to 145.950 MHz, and Arissat-1 was breaking squelch with SSTV tones. Very cool.

Later, I was thinking about this as I pedaled along on my bike. I remembered our recent discussion of Copthorne MacDonald, inventor of SSTV. Way to go Cop!

It is easy to join in the fun. Just tune you two meter gear to 145.950 and leave it there. You'll soon be alarmed just as I was.

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics"http://soldersmoke.com/book.htmOur coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmokeOur Book Store: http://astore.amazon.com/contracross-20

Friday, July 15, 2011

"The Early Days of SSTV" by Copthorne MaDonald

The Early Days of Amateur Radio Slow-Scan TV

by Copthorne Macdonald

I got my ham license in 1951 at age 15, and like many hams of that era, the bug hit hard. I worked my way through the University of Kentucky's engineering school, taking 5 years to go through, working nights and weekends out at the transmitter of a local 5 kW AM station. Naturally, I was hamming on the way to and from work in my oil-guzzling 1948 Chrysler. The rig was a 15 watt surplus WWII AM rig that took up most of the leg room under the dash.

One day in 1957 I was in the engineering school's library, thumbing through the Bell System Technical Journal, when I came across an article on some Bell Labs signature transmission experiments using ordinary phone lines. For the first time I realized that picture transmission didn't necessarily mean extremely wide bandwidth. And being the ardent ham I was, I instantly wondered if some sort of practical SSTV system could be worked out for ham radio.

I spent my spare time during the next few months looking into the feasibility of the idea. What sort of display tubes were available? (Ans: P7 phosphor.) How did you get frequency response down to DC if ham rig audio response cut off at 300 Hz? (Ans: Modulate an audio subcarrier.) I kept waiting for the fatal flaw to appear, but I saw none. The idea looked feasible.

I took my paper feasibility study to the head of the EE Department, and asked him if I could design and build such a system as part of an independent problem course. (This would give me a few credits as well as legitimize my use of school facilities for the project.) He agreed, and I ordered surplus CRTs and power transformers and such from surplus houses like Fair Radio Sales in Lima, Ohio. During the next 6 months I designed the unit stage by stage, built a "tank" of a flying-spot scanner in the school's machine shop, and put it all together. I still kept waiting for the fatal flaw to appear, but it never did. The system worked!

What is now the Citizen's Band was at that time the 11 meter ham band. All sorts of strange emissions were allowed on 11 meters then, and the first on-air tests were conducted on that band. Since only one set of SSTV equipment existed, audio tape recordings of the SSTV signal were transmitted on the air by one ham station. At the receiving station we listened to this weird sound coming out of the receiver's loudspeaker as we watched the transmitted pictures being painted in light on the screen of the P7 (long-persistence phosphor, radar-type) cathode ray tube.

I wrote a paper describing the system, and entered it in the American Institute of Electrical Engineers (now IEEE) student paper competition in 1958. It won national first prize that year. The ham community first heard about the system in articles that appeared in the August and September 1958 issues of QST magazine.

Shortly thereafter we hams lost the 11 meter band to CB, and had no long-distance HF frequencies on which to use SSTV. I spent the next 10 years working with hams like Don Miller, W9NTP, and Robert Gervenack, W7FEN in specially authorized on-air tests to convince the FCC that slow-scan would cause no problems to regular ham activities and should be permitted in the 75- to 10-meter voice bands as a regular operating activity. In 1968 the FCC finally authorized SSTV operation on a regular basis in the HF bands. In the 1970s my interests shifted to the USES of ham radio -- to "New Directions Radio" -- ham radio for personal growth and social change. Since 1985, I've been spending most of my time writing -- some of it for rent and food money, some on dear-to-my-heart subjects like the development of wisdom, and strategies for living the most effective life possible.

Sunday, July 3, 2011

Copthorne's Heathkit HW-8

Here's evidence that I am moving ever further along the ham radio hippie trail: This week as I was browsing through the 1970's era columns of Copthorne MacDonald, I came across this gem about our beloved Heathkit HW-8. (The photo is of Cop's rig.)

http://infoark.org/InfoArk/Sustainability/Mother%20Earth%20News/70/MEN_CD/mendemo/dcd/047/047-040-01.htm

Inspired, I connected mine to my salvaged and solar-charged gel-cell battery and made a number of contacts on 40 meters. It was all really groovy.

Peace, Bill

Friday, July 1, 2011

Copthorne MacDonald and New Directions Radio

I mentioned in SolderSmoke 135 that somehow I feel myself becoming a bit of a hippie. I'm riding a bike to work. I now have a compost pile and a vegetable garden. I'm enthusiastically helping Billy fix his electric guitar... Mike, KC7IT, wrote in to let me know of an important ham-hippie connection that I'd been completely unaware of.

Starting around 1973, a fellow name Copthorne MacDonald (what a great name!) wrote a ham radio column for Mother Earth News. (Further evidence of my drift: I've recently been buying this magazine!) It is an interesting mix of radio technology (much of it homebrew and QRP) and what at the time was called "alternative lifestyles" (communes and all that). Lots of info about sustainable and eco-friendly living, solar power, etc. Here's a good example:
http://www.motherearthnews.com/Nature-Community/1975-07-01/A-Low-Cost-Start-Ham-Radio.aspx

Copthorne MacDonald is the inventor of Slow Scan Television.

I really like Copthorne's writing and I was really pleased to find out that much of it has survived and is available on the internet. Mike KC7IT points us to more of the articles:
http://www.motherearthnews.com/search.aspx?search=new%20directions%20radio&sorting=oldest

Cop's writing constitutes another treasure trove of ham radio literature for all of us!

I found an archive (infoark) that seems to have his "New Directions Radio" newsletters:
http://infoark.org/InfoArk/Sustainability/Mother%20Earth%20News/70/MEN_CD/mendemo/dcd/027/027-022-01.htm

I was please to find that OM Copthorne is alive and well. He posted this on eham.net back in November:

« Reply #9 on: November 09, 2010, 11:01:41 AM »


Hello all. This is from Cop Macdonald, now VY2CM, his very self.

Many thanks to Benn Kobb AK4AV for alerting me to this page, and thanks for the supportive comments above from a number of you.

A brief summary. I'm not currently on the air, but as Benn noted I was at the 2009 Dayton Hamvention where I gave the talk he mentioned and received that year's Technical Excellence Award for the SSTV development work I did some 50+ years ago as an engineering student at the University of Kentucky. While doing some Googling for Hamvention info I discovered that in 2007 I had been inducted into CQ Magazine's Ham Radio Hall of Fame. Perhaps CQ, too, had trouble tracking me down, as this was news to me. If anyone is interested in the details of that initial SSTV system, the Kentucky Engineer article on the subject is online at http://www.copmacdonald.com/KYEngineeerSSTVArticle.pdf. The QST articles on that first gear appeared in the August and September 1958 issues, and are available online from the ARRL digital archives.

The Mother Earth News column ended in 1983 when the magazine changed hands for the second time. I continued to do much writing after that. A lot of it dealt with energy conservation and energy alternatives --- some examples at http://www.wisdompage.com/SEUhtmDOCS/conservation.htm. In the late 1980s I developed an interest in wisdom, and have written three books on aspects of that subject. Connected with this, in 1995 I started a website called The Wisdom Page to make wisdom-related resources available to people worldwide. It has become quite popular. Last month the site had 14417 visits by people from 149 countries who viewed or downloaded documents, podcasts, and videos some 36159 times. And if you Google the word wisdom, http://www.wisdompage.com
consistently comes up on the first page of the search returns — out of some 75 million+ pages containing the term. Anything else you might want to learn about my doings over the years is probably at http://www.wisdompage.com/aboutcop.html
Best wishes to you all. Cop

Thanks Cop!
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