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Friday, July 15, 2011
Cutting Edge Spectrum Analyser Video
From Alan, W2AEW. That's some great test gear! We'll have to watch our steps with Alan around -- he can ID us from the moment we hit the PTT! I hate to think what some of my creations would look like on that screen. I'd probably be immediately arrested by the FCC!
"The Early Days of SSTV" by Copthorne MaDonald
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.
Thursday, July 14, 2011
Sputnik Madness! But was it CW? or AM?
There was bad news and good news from the visit: The bad news was that the spacecraft on display was a hollow sphere. The good news is that the internal parts --including the transmitter -- might be in storage someplace, just waiting for our reverse engineering. Stay tuned (to 20 MHz!).
Speaking of which, I have a question: OK so the crafty Soviets picked 20.oo5 MHz for some good reasons: Being so close to the WWV freq, it would be easy for hams and SWLs to find it with precision. In the November/December 2007 issue of "Break In" (from NZ -- thanks Jonathan-san!) ZL3DW notes that this frequency selection would allow a receiver set to exactly 20 MHz to "produce an audio tone plus or minus the Doppler shift without ever going through zero beat." But zero beat with what? Most of the receivers out there would not have had BFOs, right? So the Soviets wouldn't have been using ordinary CW, right? Were they using AM, with the beeps produced by an audio oscillator modulating the carrier?
Here is a update from our Chief Designer, Comrade Mike, AA1TJ:
I currently have a prototype for a simple "Sputniker" transmitter on the bench using a 1sh29b in the oscillator and a 1p24b working as the PA. As in the original, the input DC PA power is 1watt. The crystal-controlled oscillator uses an inexpensive ESS 21.060kHz xtal. So far, all systems are GO.
BTW, here's an example of how inexpensively these lovely little tubes may be purchased. Oleg, RV3GM, and his pals might be able to do even better.
Although there are only so many ways one can build a two-tube, crystal-controlled MOPA transmitter, we'd still very much like to nail down the original transmitter circuitry. Bruce, KK0S and Peter, DL2FI are following up leads to that end.
Once we're a bit further along I'm hoping that someone will step-up to produce a kit. Actually, last evening someone raised their hand to ask if a kit were already available.
Dasvidania,
Mike, AA1TJ
Wednesday, July 13, 2011
Please Put Drake 2-B Serial Numbers Here!
Mine: 11976
Aramand's three (scandalous to have THREE!): 2599, 5149, and 12038
WB4NCT's: 8682
From Rogier's e-bay search: 8069
Another from Rogier: 5153
More from Rogier: 11222, 9041, 9180
From WB4HFN's web site (thanks Rogier!): 2008, 4025, 9289, 11059, 12060
WA5DJJ's: 5254
N5JKY's: 10616
Stephen NM7J / HS0ZHB 12955, 10328
Pete, VE2XPL's: 8873
WA5BDU's: 4950
Armand's 2-B (X3)
The serial numbers for these sets are
2599, 5149, and 12038
Will be neat to get an estimate for the final count. Good luck!
Also wanted to mention that I really enjoyed SolderSmoke "the book". Will there be a second volume? Enough for now.
Keep the solder flowing and the podcasts and blogs comming.
Sale on Books 20% Off!
Saturday, July 9, 2011
More on Merrill Budlong, W1MB
K1KT's recent e-mail alerted me to the interesting life story of Merrill Peckham Budlong, W1MB. Wow! What a guy! Killed a Great White Shark with a spear gun! Homebrewed his own diving gear! Insisted that the hams he was Elmering actually UNDERSTAND the circuitry! And -- most importantly -- he was obviously a very good person.
We don't run many obits here on SolderSmoke, but even though he passed away four years ago, we thought it would be a good idea to reprint W1MB's. His story can be an inspiration for us all.
Bob, W1YRC, wrote this about him: He was responsible for launching a great many Amateur Radio careers in Rhode Island. He was uncompromising in his teaching and demanded that all his students understood why a circuit performed its function or why it was essential to know how to solder correctly. He was respected and loved by hundreds of hams that knew him.
Here is a para from his obituary:
An active, athletic man, as a teenager Mr. Budlong made his own surfboards and sailing kayaks. In high school and college he was on the wrestling teams, played trumpet in dance bands, and was a lifeguard at Bonnet Shores. He graduated from Cranston High School in 1931 and from the University of Rhode Island in 1935 with a bachelor's degree in business. He was a member of Phi Mu Delta fraternity and Phi Kappa Phi honor society. During World War II, he held a second job at Kaiser Shipyard in Providence. As an avid amateur radio operator (call letters W1MB) and proficient Morse Code operator, he enjoyed contacting radio hams throughout the world. He founded the Fidelity Amateur Radio Club, which met for more than thirty years at his home. He was a Major in the R.I. Civil Air Patrol and a director of the New England Wireless and Steam Museum. Mr. Budlong was an alumnus of Fidelity Chapter DeMolay in which he was a Chevalier. He was a member of the Narragansett Bay Wheelmen and, into his 70s, participated in bicycle races and 100-mile rides. He was often seen riding his bicycle around Edgewood and Pawtuxet Village. He was a pioneer skin diving and spear fishing enthusiast. In the 1940s he built much of his own equipment before it was commercially available. In 1964 he speared a ten foot great white shark in Narragansett Bay. He was also a frostbite sailor, member of the Edgewood Yacht Club, and member of the Coast Guard Auxiliary.
Read the comments that people attached to his obituary: http://www.legacy.com/guestbook/providence/guestbook.aspx?n=merrill-budlong&pid=91256424&cid=full
Thursday, July 7, 2011
Merrill Budlong's Drake 2-B
Tuesday, July 5, 2011
Beautiful Shot of Three of Saturn's Moons
A study in contrasts, this photo captures three illuminated moons as a darkened Saturn looms in the shadows. Only the planet's rings are visible but its shape can be traced from the way it partially obscures its rings and one of its moons.
The large foreground moon is Rhea at 1528 kilometres across. Nearly a third of Rhea's size, sunny Enceladus is on the right. Dione, at 1123 kilometres wide, rounds out the trio to the left with a night-cloaked Saturn obstructing part of it.
The photo was taken by NASA's Cassini spacecraft in April. Cassini has been exploring Saturn's 62 known moons since it reached the ringed planet in 2004.
Sunday, July 3, 2011
Copthorne's Heathkit HW-8
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