SolderSmoke #92

The latest SolderSmoke podcast:

http://www.soldersmoke.com

September 28, 2008
TOPICS:
The Flea at Trastevere
QRSS 2N2222 goes toes up. Why?
Da Vinci Code MEPT Frequency Standard
Wind Powered QRSS
QRSS Whispers reflecting off airplanes
Transformer troubles at CERN
Arnie's cool Cuban hack
Woodpecker update
A SolderSmoke charity project
Another engineer joke
Kanga USA BACK IN BUSINESS!
The Joy of Fixing Things
Jim Severns - KNACK VICTIM
A Homebrew Italian Space Program
MAILBAG: G0FUW in Gibraltar
VU3RDD in Southern India
KB1QVO on laser comms
K4BVL likes our audio
VK3PB on Italy's "Space Hackers"
W0DAB on free online MIT courses
DL4MGJ on fixing 2B parallax
WB6NTL on transistor failure mode
AF6C on crystal ovens
G3ZTB likes Shep

A Homebrew Italian Space Program

Peter, VK3PB, alerted me to the six YouTube videos about the Judica Cordiglia brothers of Turin, Italy. These guys were young and enthusiastic amateurs when the space race began in the late 1950s. They quickly developed some very impressive monitoring facilities that allowed them to listen to both US and Soviet space missions.

Watch these videos and you will not only get a look at the technical work of these intrepid and skilled amateurs, but you will also get a sense of the many intangible things that make Italy such a special place. You'll get a sense of the human warmth, the friendship, the enthusiasm and fun that characterize life here.

They had the foresight to film a lot of their youthful technical adventures. The videos take us back to the Italy of the late '50s and early 60's. (That roof that they built their antenna on looks EXACTLY like mine!)

Don't miss these videos. They are really wonderful. Here are the links (if you have trouble, just search YouTube for "Space Hackers 1/6" "Space Hackers 2/6" etc.

http://www.youtube.com/watch?v=1F_67UAaG70
http://www.youtube.com/watch?v=N-y2DuYNxm4
http://www.youtube.com/watch?v=s8sElZpvzRU
http://www.youtube.com/watch?v=wcGPXZPYHNs
http://www.youtube.com/watch?v=A9kiSMcrqRg
http://www.youtube.com/watch?v=WUT-eZH0860

Rudy Severns

Allan, WA9IRS, sent me the link to a really interesting article about guy who is obviously one of us, a victim of The Knack. Here is how the article begins:

An innovator in power-supply design who anticipated the trend toward higher frequency switching, an illuminator of power-supply topologies, and one who introduced many engineers to the promise and perils of power MOSFETs, Rudy Severns has made diverse contributions to the power electronics field in a career spanning five decades as an engineer, author, instructor and consultant.

On the 50th anniversary of his first jump from a biplane, Rudy Severns went skydiving yet again, pushing his lifetime total to somewhere in the vicinity of 500 jumps. Throughout his career, he took breaks for months-long sailing voyages, which usually necessitated a job change on his return. When it was time to fulfill his military obligation, a young Severns parlayed his experience as a radio operator into a stint with the Army's Special Forces, where he learned the skills of unconventional warfare.

Here's the link to the article: Rudy Severns

IZ1KXQ's Wind-Powered QRSS Beacon

Paolo, IZ1KXQ, is the fellow who brought us the 5 mw QRSS MEPT beacon powered by small solar cells (see an earlier blog entry). He is now experimenting with wind power. FB Paolo! We hope to see your windy signals soon.

Cool Cuban Hack

Arnie posted this on QRP-L. I thought it was a pretty ingenious way to work around
an unavailable part. FB Arnie!

My TS820 non QRP, but capable of QRP operation transceiver. ... has a similar type of female 9 pin socket to connect or not connect the external VFO. I needed a plug when not using the external VFO, and it was made using a Russian 6H2P dual triode that had a bad filament... I very carefully broke down the glass using nichrome wire at red hot temperature and then a thermal shock. The glass bulb broke nicely in a rounded even circle !!! Then I proceeded to remove the soldered connections to the two triodes... removed them , and soldered the wires required for the jumpers as specified by TS 820 manual... After checking that all was OK, then I poured Araldite epoxy to fill the glass ... It worked very well, and the only cost was the small amount of valuable epoxy ( not easy to find locally, and extremely useful for repair jobs and pasting the islands of the Manhattan style homebrew printed-nonprinted circuits !!! 73 and DX Arnie Coro CO2KK

Beacon Final Amp Goes Bad

All of a sudden the power output meter on my 30 meter beacon (MEPT) transmitter stopped jumping up and down. The oscillator was still running, and the keyer was working, but output had obviously dropped considerably. I started troubleshooting and my attention started focusing on the 2N2222A in the final. The stage runs Class A, with long QRSS key down periods. The emitter resistors get a bit warm. I replaced the transistor with a new 2N3904 and -- BINGO -- output was back up in the tens of milliwatts.

I did some tests on the 2n2222A. With a VOM I looked at forward and reverse bias resistance across both junctions, comparing the part from the rig with a new part from the same batch. In the transistor that went bad there is a lot more reverse bias current across the base-collector junction.

So, what happened? Any ideas?

This was one of those very satisfying repairs in which you quickly zero in on the problem, change one part, and then put the gear back into action. The victory was made even sweeter, when, a few minutes after I put the rig back on the air, I noticed my QRSS CW signal on I2NDT's online grabber.

I'm almost finished with my 10.140070 frequency standard. Armed with that, I'll be free to experiment with FSK keying (without fear of being unable to find my way back to the 100 Hz -wide QRSS frequency band). 73 from Rome

SolderSmoke #91 STEREO SPECIAL

Be sure to listen to episode 91 of the SolderSmoke podcast:

http://www.soldersmoke.com

September 14, 2008

TOPICS:

Sardinia!
ON5EX's QRSS MEPT leads us back to bike riding
Watching Jupiter, listening for Jupiter
KF6KYI's I-tunes QRSS
Stan, 9H1LO's new grabber
Laptop motion detectors as earthquake detectors
Nuclear fusion in the shack
Philo T. Farnsworth
Building a QRSS freq standard
SPRAT CD
Forget about stocks: SSDRA now selling at $399.89
SolderJokes
QST articles on-line! FB!
Jim Williams and the joy of fixing things
STEREO SPECIAL: Roger Hayward's new binaural DSB project
Antenna woes
MAILBAG:
G0WAT on HOGCON 2008 (21 Sept in Herts.)
AJ8T on Russian rovers with laser reflectors
KA9OOI on language and low pass audio filtering
WB6TNL says NO to rat neurons in QRP gear
KB6QR "beknacked" vice "knackered" ?????
NR5A has a Drake 2A
7J1AWL on the air from Vietnam
KC0PET goes solar
OZ1CJX Bad case of Knack, may need professional help
K8WPR says Knack keeping him away from wild women, bars
AJ8T on CK722 museum
AG5RS works Texas balloon from Dubai (via net)
KI4SGU POW radio parts
N8WQ on schematic drawing program
KF4LMZ has QRSS-itis, finds 10.140 rock in CB rig

The Joy of Fixing Broken Gear

Alan, WA9IRS, sent in this really great link about Jim Williams, an engineer who writes for EDN. In his article Jim captures better than anyone the joy of repair.

Those taking up an engineering degree online can use the tips included in his book.

Check out his article: "Try Fixing it Yourself."
And if you like the article, check out Jim's book: Another Look at Analog Circuit Design

N2CQR in Sardinia

There was no SolderSmoke podcast last Sunday because at our normal
broadcast time we were on an overnight ferry from Rome to Sardinia.
Beautiful island! I have a little SW rx with me, and this
Blackberry. And SSDRA.... But not much radio work this week.

Stars are beautiful here. Milky Way is BRIGHT! View was especially
good from the ship when we were way out in the Med. 73 from Sardinia!

Bill

--
Sent from Gmail for mobile

Large Hadron Rap

We don't really cover rap music here at SolderSmoke, but we make an exception for this one. More than 400,000 downloads so far.

Shooting Lasers at the Moon

Ron Sparks, AG5RS, sent us this very cool picture. My kids take great delight in shooting those tiny red laser pointers out the window, and as described in SolderSmoke we actually built a simple laser communications system. But so far we haven't achieved the kind of "beam shooting into the sky" effect pictured here.

Here are Ron's comments.:

"It was interesting for you to mention the lunar laser reflector. It had a very special impact on my life. You see, I grew up in Texas at about the midpoint of the 600 mile line between NASA Clear Lake and the McDonald Observatory in the Davis mountains and was in High School when Neil Armstrong walked on the moon. I had the pleasure to visit both NASA and McDonald at that time and had direct contact with some of the people responsible. I have actually put my hands on the controls for the laser in the attached photo. More importantly, the control box was opened up for me so I could see all the gizmos inside."

Check out the website: The Lunar and Planetary Institute

The website has some interesting info on the width of the laser beam when it reaches the moon, and how they use the data to measure the distance. Sounds vaguely QRSS-ish:

"Laser beams are used because they remain tightly focused for large distances. Nevertheless, there is enough dispersion of the beam that it is about 7 kilometers in diameter when it reaches the Moon and 20 kilometers in diameter when it returns to Earth. Because of this very weak signal, observations are made for several hours at a time. By averaging the signal for this period, the distance to the Moon can be measured to an accuracy of about 3 centimeters (the average distance from Earth to the Moon is about 385,000 kilometers). "

CLASSIC GERMANIUM

Ted, AJ8T, alerted me to this very interesting page.

"The CK722 holds a unique place in the history of the transistor. Introduced by Raytheon in early 1953, the CK722 was the first low cost junction transistor available to the general public. It was an instant success. Countless "build it yourself" articles were published in the popular electronics press and electronics/hobbyist magazines describing how to use the CK722 to build all types of devices such as radios, oscillators, electronic voltmeters, photoelectric alarms and hearing aids. Eager to learn about the exciting new transistor technology, the public responded enthusiastically to the CK722 - hundreds of thousands of these transistors were bought by experimenters, radio hams, engineers and others interested in this technology over the next few years. In addition, there is a sentimental aspect to this device. Many of the talented and dedicated professionals and amateurs who have been responsible for the tremendous rise of the electronics industry over the past four decades can still remember the time when, as a young hobbyist, they were able to scrape together enough money (maybe through saving allowance or cutting the neighbor's grass) to buy that first CK722 - can you still recall the smell of solder and the absolute delight of hearing a local radio station coming through "loud and clear" on the newly constructed one transistor radio powered by, of course, a gleaming, bright blue CK722? This webpage and book have been constructed to help preserve the special legacy of the Raytheon CK722."

Check it out:

http://www.ck722museum.com/