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Thursday, October 30, 2008

Arduino -- Italian Open Source Hardware

Scott Haley in Tulsa alerted me to this very interesting article in Wired magazine. How do you say Knack in Italian? Check it out: Wired article on Arduino

Sunday, October 26, 2008

Aliens on 80 meters!

Graham, G3ZOD, was looking at the 80 meter band using the on-line SDR receiver in the Netherlands (http://websdr.ewi.utwente.nl) This is what appeared on the screen. Looks like you can work some real DX on 80 these days. The big issue will, of course, be DXCC credit. And I imagine getting a QSL card might be a bit tricky.

Friday, October 24, 2008

The Flea: Minimalist QRP from Catalonia

Here is a really interesting little rig from Joan, Ea3FXF, and Eduardo, EA3GHS. They have a very nice web site with more info, including SPICE simulation files and SPICE waveform results.
Check it out: http://ea3fxf.googlepages.com/flea

Thursday, October 23, 2008

Lasers, LEDs, Tin-foil Hats, and QRP

Yesterday I got a very interesting message from Rye, K9LCJ. The map of Tasmania comes from the Modulated Light DX portion of the KA7AOI site (below).

Hi Bill:

I really enjoy your Solder Smoke show and news feeds. Great stuff that has got me back into ham radio again. Your note about optical comms got me fired up enough to add some notes that you might not be aware of.

There is a substantial worldwide community playing with optical communications and they have achieved some amazing records using simple off the shelf components – mostly big Luxeon LEDs which have some (debatable) advantages over Lasers. The most sophisticated component in typical systems is the Fresnel lens – which can be obtained at office supply stores or ebay as “page magnifiers” for a couple of bucks.

There seem to be about four major groups:

The Radio and Electronics Association of Southern Tasmania has an active bunch and they have achieved some great distance records with (QRP) LEDs. They have also been bouncing signals off of geographic features to establish communications paths. They are also doing some cloud/sky bounce things that are quite amazing. The REAST web site has lots of well documented test data that’s really interesting to read.

K3PGP has an exceptional web page full of test reports and construction details. His K3PGP preamp/receiver (and variants) are the basic building block for most systems. It uses a $1.00 pin diode, a MPF103 FET and a handful of common parts to get some almost fantastic performance.

Yves, F1AVY has a strong theoretical background and has been doing interesting stuff in France for quite a while and his web page has lots of interesting technical details.

Clint, KA7AOI has a very comprehensive web page. Clint holds the record for long distance communications (173 miles) and describes much of his equipment and testing. There is also a bunch of historical material that is very interesting.

There are probably a bunch of folks I have forgotten, but all of them are noted in the many and varied links found on these web sites.

I think that the most interesting thing about the activities is how the teams have adapted available technology to an interesting problem. Much of the work resembles current amateur weak signal activities. In fact, Spectran and WSJT are part of almost every activity. Much of the work is unique outside of the academic community and might even be called groundbreaking in some areas.

We have a small group here in the Raleigh North Carolina area, but so far we haven’t done anything of note other than build equipment and play in the local park. The fact that this sort of thing must be done outside at night draws all kinds of attention – some of which is not necessarily good. …a bunch of strange looking guys running around in the dark with strange flashing red lights…. I have a special cap that I wear for the occasions.

Hat.JPG

Keep up the good work.

Rye Gewalt

K9LCJ

Monday, October 20, 2008

Laser QSO and Visual EME with laser!


Bob, Kd4EBM, sent me some really good info on laser safety. Bottom line: For the time being anyway, Billy will be limited to the <5mw href="http://www.earthsignals.com/Collins/0036/index.htm">http://www.earthsignals.com/Collins/0036/index.htm
Their rig is pictured above.

And here is one that is really mind blowing: A while back we discussed the laser reflectors left on the moon by the Apollo astronauts. Well, apparently there is an intrepid amateur out there who has been shooting his own lasers at the Sea of Tranquility, and seeing reflections come back. Visual EME. Check it out:
http://www.k3pgp.org/viseme.htm

Thanks Bob!

Wednesday, October 15, 2008

SolderSmoke #93

Oops, forgot to put this on the blog on Sunday:

http://www.soldersmoke.com

SolderSmoke #93

October 12, 2008
HB Pi Network Tuna (with mystery)
Hamfest report from Belgium
Space Hackers removed from YouTube
Verdict on Judica Cordiglia brothers
FB Italian ham magazines
I shift to FSK on 30 meters
Gimmick capacitors
QRSS QSY woes
SolderJoke
MAILBOX:
Jerry NR5A Back in action
Scott KD5NJR on Space Hacker controversy
Steve WB6TNL on the different flavors of solder smoke!
Paul WA1MAC labled PC boards with SSDRA page numbers
Ramakrishnan VU3RDD getting back on the air
Jim K9JM had 60 POUNDS of 2N2222
Jim AL7R listening from Yuma
Wes W7ZOI on plumbing washer toroids
Paul WA5WCP on laser safety
Terry G4GHU also went to KSC on honeymoon

Tuesday, October 14, 2008

The Da Vinci QRSS Code

Here is my 30 meter QRSS frequency standard using paper for insulation.

Sunday, October 5, 2008

I SHIFT TO FSK ON 30 METER QRSS

The online grabber of Johan, ON5EX, provided instant gratification this morning. Right after I finished some modifications that I hoped would result in a Frequency Shift Keying signal on the 30 meter visual QRSS band, looked at the grabbers and found this. That's me. It is a kind of "upside down" FSK. Look along the bottom of the square wave and you can read the CW.

I used a fairly standard approach to get the FSK, but with a twist: I added the usual LED and a cap to the oscillator circuit. Now, on key down, the positive voltage from the keyer causes the LED to conduct, putting the additional cap into the circuit. But here is the twist: for the capacitor, I just used some of that twisted-up two conductor insulated wire that often comes with cheap old (mono) ear phones. In the old days this would have been called a "gimmick" capacitor. I started out with 3 or four inches. Using Spectran to monitor the amount of shift, I just cut off bits of the wire until the shift was at the desired 5 Hertz. I just clipped away at the wire until the shift looked about right.

The rig is now key down all the time, and even though power out is still only about 20 miliwatts, I have the final in Class A, so I actually had to put a heat sink on it. But there is still no need for a muffin fan, or liquid cooling or anything like that!

Five hertz isn't much of a shift. I think I can hear it, but barely. Shows up nicely on the grabber screens.

It was a lot of fun to start out with a vision of what I wanted the signal to look like, then actually make it happen.

Friday, October 3, 2008

Flea Market Find -- Pi Net Tuner -- With a Mystery



Last Sunday's "Flea at Trastevere" (I'm the only one who calls it that) was a huge success for me. Minutes after arriving, amidst all the junk, Billy and I found this homebrew Pi network antenna tuner. The guy who sold it to me told me he had built it himself. The workmanship is top-notch. The quality of the parts is superb. There's a built in SWR meter and a 10 db attenuator.

When I started drawing out the schematic I noticed something weird: As the front panel indicates, it is a Pi -network, but for some reason the builder has the input variable cap floating. The physical connection to the chassis is via insulators. The other variable cap has the standard mechanical and electrical connection to chassis ground. That input cap needs to be grounded too, correct? Why would this builder -- who obviously knows his way around a soldering iron -- go to the trouble of allowing that input cap to float?

"Space Hackers" removed from YouTube

They say the videos were taken down because of some Intellectual Property issue. That's their story, but I've seen the X-Files, and know that something more sinister is probably at work here. Kay, WD0BDK, suspects the Russians -- the thinks they are mad at us for making fun of the Woodpecker!

(Note to lawyers: I did not post the videos on YouTube.)

Wednesday, October 1, 2008

Skepticism about "Space Hackers"

Many of us really enjoyed those videos about the two Italian brothers from Turin and their homebrew space monitoring program. But there is some controversy about some of their claims:

http://www.svengrahn.pp.se/trackind/Torre/TorreB.html

Controversy or no controversy, I still liked the videos and admire the efforts of the two intrepid brothers from Torino.

Sunday, September 28, 2008

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

Saturday, September 27, 2008

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

Thursday, September 25, 2008

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.

Wednesday, September 17, 2008

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

Sunday, September 14, 2008

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

Saturday, September 13, 2008

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

Wednesday, September 3, 2008

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

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