Portuguese Knack: Balloon Launch May 30

I don't think they are radio amateurs, but these guys seem to have The Knack. That's an edge-of-space balloon payload they built. They plan to launch on May 31. You will be able to follow the event live, on-line. They have a very interesting web site: http://spacebits.eu/

DaVinci Milliwatt Beacon Crosses the Pond

We were out in the country this weekend and I brought along the little DaVinci 10 milliwatt QRSS beacon. I was hoping that it would do better with the big dipole that I have out there (vs. the sub-optimal end-fed wire I use here in Rome). Success! Bill, W4HBK, saw the above image on his screen in Pensacola, Florida on Saturday evening. My signal is the little bumpy line just below the Morse signal. Joachim, PA1GSJ, also saw it, and passed along this image:

Better than EE text books! With Free Shipping and 10 % off

I was feeling kind of bad about the fact that while free shipping for the book is available for readers in the U.S., people from other countries are not eligible. But Lulu came through! During May readers everywhere can get 10 percent off by using the coupon code FLOWERS. Lulu won't let you combine free shipping AND the 10 percent off; U.S. customers are probably better off sticking with the free shipping. Customers from other countries can use the 10% discount during May.

Steve, KC2VNI, sent in some nice comments on the book:
---------------------------

I am an electrical engineer and I will say that the way Bill explains things is far, far, better than what I've seen in most books dealing with either communications theory or with communications electronics.

Not to go on a rant, but the college level electrical engineering text books are very poorly thought out and are really not written for the beginner (even an undergraduate electrical engineering student) who does not share the author's years of insight.

I would recommend that people who read the book should post comments about it where hams will find it. I posted comments on E-Ham. I will probably post to Ham Radio nation.

Several tweaks to the book (with the understanding that my comments are NOT meant as a slam on the book nor am I an electronics expert):

1) Give me a more detailed troubleshooting methodology- The literature associated with testing and troubleshooting is very,very limited.
A flow chart or diagram of some sort would be very helpful. I get the impression that Bill's efforts in this area were "cut and try" because of his obvious enthusiasm. Having said this, the beginning home-brewer has NO IDEA as to what he needs in the way of test equipment, what he should look for when testing a circuit, what the wave forms should look like, etc. (Note from Bill: A detailed discussion on troubleshooting methodology would be very helpful to students taking electrical engineering online.)

2)Very little discussions about the more mundane things like power supplies, connectors and the like. These trivial items can cause you hours of frustration if you don't think this through. If you want to string things together on a bench, I suppose it does not make difference. However, if you want to operate say QRP mobile in the woods then you need something that has a little bit of thought.

3) Very little discussion about heat sinks and thermal management- This is one of the most neglected areas for most people in electronics (and not just the homebrewer of radio equipment). Here, I recommend the ASME text "Hot Air Rises and Heat Sinks: Everything You Know About Cooling Electronics is Wrong". When I read the discussion about a transistor running hot and extra heat sink compound being applied in the book, I wanted to scream!

One other thing-is there any way I can get an autographed copy of the text?

Thank You very much for this very fun book

73

Steve KC2VNI

Muntzing with Michael

Snappy title, don't you think? I think it could become a TV series, maybe if the Discovery channel someday gets into QRP and homebrew. In his QRP-L message about his latest rig, Michael, AA1TJ, said that he had "spent the morning 'Muntzing' G3XBM's, fine little XBM80-2
transceiver for the MAS (Minimal Arts Session) event." For those of you who don't recognize the verb "to Muntz", Michael is referring to one of the early manufacturers of TV sets, who, in an effort to reduce costs, ruthlessly went through his engineers' designs, throwing out every component that wasn't absolutely necessary. So I think Michael -- who I often refer to as the "Poet Laureate of QRP" -- has given us a new and very useful verb: To Muntz! (This comes in a month in which another very useful word was given to us: G3RJV's "socketry.")

Michael said, "I felt like the guy in the movies yesterday; throwing everything overboard that's not absolutely necessary in order to keep the Zeppelin/balloon aloft long enough to make landfall. :o)" The results speak for themselves. The schematic above and the picture below show Michael's entire transceiver. And he made a bunch of contacts with it.

One word of caution: Minimalist radio is not for the faint of heart. As the parts counts go down, the degree of difficulty for successful contacts goes up.

Check out Michael's page: http://www.aa1tj.com/Menos es MAS.html

Here's a picture of the rig:

YET ANOTHER HB DSB QRP WSPR Station! And more "inverted FSK"!

Paul, M0XPD, reports that he has joined the DSB revolution and has put a homebrew DOUBLE Sideband WSPR signal on the air. The rig is pictured above. So I can no longer claim to be the ONLY DSB WSPR station in the world. FB Paul. For more details go to Paul's site:
http://m0xpd.blogspot.com/2010/05/homebrewed-whispers.html

This was the second time in a week that I've found someone else doing the same nutty thing that I've been doing. The first incident involved G0XAR. I found him transmitting upside down FSK on 30 meters. Again, I am no longer alone...
Note that both of my colleagues in radio eccentricity are from Britain, a land that takes justifiable pride in its eccentric boffins!

"It's all your fault!"

Lulu just announced free shipping on the book (to U.S. addresses only) for the whole summer. Starting now. But before you order, consider these words of warning from one reader:

Bill,

I just finished your Soldersmoke book. I really enjoyed it - but...

I got the radio and electronics bug a bit late and was 23 years old before I got my ham license. I was truly fascinated by it all. Then I started wanting to learn why it all worked. It was truly a challenge to start figuring out how electronic circuits work with nothing more than my average intellect and a few books. I strained my gray matter over the electrons and P and N type material. Finally I decided to ignore it and move on - just put the 'trons into the black box and pick them up on the other side. I eventually became proficient enough to build kits and do some basic troubleshooting. I had SSDRA and a bunch of stuff by Doug DeMaw, but never could get too deep into it. Eventually I had what I believe was a neat miss from lightning and station KC4GIA went silent for a number of years.
Then I found your podcast. I've really enjoyed it. I've slowly started getting back on the air. I've bought my old dream rigs (Drake Twins, B line) and built an ATS3B. But the urge to learn more and progress to the true homebrewer level has taken hold. It's all your fault. I blame you completely. I now have a copy of EMRFD, the latest ARRL Handbook, and even have started trying to figure out LTSpice. Ok, that's also the fault of the Hands On column in QST.
I do have to thank you for the excellent descriptions of the electrons moving through P and N material. I actually think I've got it now. Now if I can figure out all this biasing, and impedance matching, etc. I might get somewhere. Your description of how you have to match impedance through different stages makes sense, but I'm still fuzzy on how to determine the impedance in the 1st place, etc. I'm truly excited by the possibility of learning how to design circuits on my own rather than building by rote. Again - it's all your fault.
Back to the book. I really enjoyed the story of the 17M DSB rig you built in the Azores. It was like an adventure story. Very cool. I'm still a bit vague on why DSB, but you seem to like it, so whatever moves you my friend. I am also intrigued by the satellite contacts. I had always thought you had to spend a small fortune on an az-el rotating antenna array. I'm looking forward to trying it out with normal antennas. My only satellite contacts have been through RS-12 (I think that's the right number) using the 15 and 10 meter bands. I don't think there is anything out there using that mode any more.
I also find it fascinating that a guy who used to live a little over an hour from my QTH in Winchester, VA and is now halfway around the world has had such an impact on my enjoyment of the hobby. If you do end up back in the DC cesspool, I hope to get the chance to meet you.

Final thought - Audio Book! I'm used to you talking to me. There ought to be a way to sell a download or something. I think the book is awesome, and may even become a scribbled in resource at some point, but an audio version would be a good companion to the print version. Just a thought...

Thanks for the motivation. You've brought me back to what's fun in Amateur Radio - learning!

Mark
KC4GIA

Physics, Math, and Futurama

My kids watch this show. Here's an interesting article about the writers and their science/math backgrounds:
http://www.aps.org/publications/apsnews/201005/profiles.cfm

The Death of a 2N3904: Captured on Grabber Video!

On Sunday I was working on my little DaVinci QRSS transmitter. I had it on, happily generating FSK on 30 meters. Then all of a sudden I noticed that power out had dropped to zero. I suspected a blown final transistor -- this was before the installation of my elegant Altoids smoke-stack heat sink, and the little 2N3904 I was using in the final was getting quite hot (it runs Class A). Almost instinctively, I turned to the ON5EX grabber. The image from Johan's receive system captured the final moment of that transistor. See that bright spot where the square wave ends? That's when the transistor blew. I tested the 2N3904 out of circuit: the base-collector junction is now completely open (no current in either direction). The death of this transistor may also have been related to the intermittently bad 4700 ohm resistor in the bias circuit. The 2n3904 has been replaced by a more robust 2N3053 sent to me by AA1TJ. It is protected by the Altoids smoke-stack heat sink (scroll down for schematics and an image).

Hope everyone is having fun at Dayton. I caught G3RJV's talk yesterday via streaming video. As always, inspiring stuff! And I really liked a word he used: socketry. You know, "the PC board, and the box will all the associated SOCKETRY."

Schematic for QRSS Transmitter

Here is the schematic for the little QRSS (visual) transmitter that is currently rockin' Europe's 30 meter band with an AWESOME 20 milliwatts of SLOOOW FSK. (As I type, it is 0415 UTC, 0615 local, and the first signs of my signal have just appeared on the ON5EX grabber up in Belgium.) The FSK modulation comes from Hans Summers' multivibrator circuit (see earlier posts).

It was a lot of fun to take this thing very quickly from LTSpice, to the workbench, then to the antenna, with Johan's grabber providing instant feedback. This started out as a one-stage Colpitts oscillator transmitter. But I needed more stability. Indeed, the separate oscillator with the source-follower buffer makes it much more stable. Before, any adjustment to the antenna tuner shifted the frequency. At one point I even suspected that wind blowing the antenna was shifting the frequency -- we are talking about a band that is 100 HERTZ wide, so even a few hz of instability is noticeable. But I find that crystal ovens and other extraordinary measures are not really necessary.

I had one unusual problem with this little rig: As I was doing my initial tests, I noticed that the output signal was sort of jumping up and down. The problem was in the PA. I isolated the problem to the base circuit. At first I thought that some small blob of solder was intermittently messing up the bias voltage (that's quite possible here in the N2CQR lab!). But no! It was that 4700 ohm resistor. It was bad, and kind of intermittently bad! I never had a resistor go south on me like this. It is an ordinary 1/4 resistor. It is not dissipating a lot of power.

I'll keep it around 10140010 today. Check it out on Johan's grabber:
http://www.on5ex.be/grabber/grabber.html
Look for a horizontal lines with little bumps (about 4-5 per minute). That's me.

The DaVinci Altoids LED 30 Meter Multi-vibrator MEPT Transmitter

Hey, check out the Altoids heat sink for the PA in my little 30 meter MEPT rig. Is this a new use for our beloved Altoids tins? I like the smoke-stack look.

This rig has evolved quite a bit. It started out as a frequency standard for QRSS and was mounted inside a paperback copy of Dan Brown's book. Then I matched the oscillator up with the multi-vibrator pattern generator from one of Hans Summers' rigs. This week I decided that I really needed a buffer and a PA -- I needed a bit more stability. I'll try to post a schematic tomorrow. In the meantime, watch for my little signal on the ON5EX grabber (off to the right). The pattern is small (3 Hz) bumps, about 4-5 per minute.

First Transatlantic Transistorized QSO

1956. 80 mW on 20 meters. U.S. to Denmark. Above, the rig that did it.
The online Transistor Museum has a wonderful new article about this historic event, with details on the rig and the operators. Check it out:
http://semiconductormuseum.com/HistoricProfiles/Raytheon_TransAtlantic_Transmitter_Profile_Index.htm
Thanks to AA1TJ for alerting us to this.

The Limerick Revolution

On the last podcast I mentioned a new PC board technique being pioneered by Rex, W1REX, out of Limerick, Maine. The Limerick technique uses cool-looking black PC boards with pads for the components. (The picture above is the kit version of AA1TJ's famed Reggie receiver.) Connections between the pads are via PC board traces within the board. I like it because it seems to provide the big advantage of our beloved Manhattan technique: you have all the parts and connections topside. Check out Rex's fine line of kits: http://www.qrpme.com/

Today G-QRP club announced the release of a Limerick kit version of G3RJV's Sudden receiver.
Take a look at the final product and the boards:

Very nice. Read more about this wonderful kit here: http://www.gqrp.com/sudden.htm

Go Limerick! Go Sudden!