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Monday, October 31, 2011

Pumpkin Pi and JBOT Gremlins

Maria wanted to go with a mathematical theme for this year's Jack-0-Lantern. Pumpkin Pi!

I have been chasing some gremlins and banshees around my old Azores 17 meter DSB rig. The JBOT Amp worked fine into a dummy load, but of course things got a bit more complicated when I put it into the rig and connected it to an antenna. It would take off (like a banshee!) if the load was at all reactive. I think this is the result of inadequate shielding and inputs a bit too close to outputs. But it all settles down nicely when I put a transmatch in the antenna line and tune out the reactance. I may just leave it this way.

Output is a bit low -- only about 1 Watt. I realize that at 18 MHz output should be dropping a bit, but I think I should be getting more. I THINK I'm giving it the recommended 1 milliwatt input. At some point I think Farhan mentioned the possible need to experiment with the number of turns on the secondary of the output transformer....

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Sunday, October 30, 2011

Snow Static



Related to our post about my new (old!) all-boatanchors heating system (see below), yesterday I had some really horrendous static. I think it was caused by the snow. A Google search on "snow static" brought me to this video (which Gregg in Finland found "shocking""). I liked the tuner and the neon bulbs too.

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My New Shack Heating System: Heath, Halli, Hammarlund and Drake

Temperatures dropped over the weekend and I had to fire up my new heating system for the SolderSmoke shack. See above. Heating by Heath, Halli, Hammarlund and Drake (sounds like a law firm doesn't it?). I'm happy to report that those old filaments take the chill off quite nicely while adding a nice aroma to the room, along with some very pleasing lighting effects (I especially like the green glow from the DX-100 tuning dial).

The Azores-17 DSB JBOT project is (I think) complete. And I did include a low pass filter. In keeping with the finest of ham radio traditions, now that it is cold I will go out and work on an antenna.

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Saturday, October 29, 2011

Another Treasure Trove: The Royal Society's Archive

I'm a big fan (wanna-be really) of The Royal Society. In SolderSmoke 138 I noted that Isaac Newton (former Society president) seems to have had The Knack. And when I was in London one of the major perks of my job was that I occasionally got to visit the Society's headquarters. Bill Bryson recently edited a book about the Royal Society -- in his intro he noted that they have always been a very international group (just like us!)
Several readers wrote in with the happy news that the Society's 350 year archive has been placed on-line. Here it is:
http://royalsocietypublishing.org/site/authors/free-archive.xhtml


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Friday, October 28, 2011

Homebrew Jet Engine from Junkbox Parts!



Bob, W8SX (our man in Dayton) sent me this nice video. I really liked the friendly and enthusiastic way in which the builder described his project. I only wish he would have fired it up! Thanks Bob!

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Wednesday, October 26, 2011

Azorean Oscillator Re-build

With my JBOT amp ready for installation, it was time to go back and check out the rest of the circuitry on my old Azorean DSB/Direct Conversion 17 meter "Magic Carpet" transceiver. I was surprised to find that the oscillator, well, wouldn't oscillate. The MPF102 that I had in the main oscillator circuit was blown. I suspect voltage spikes from the T/R relay. I installed the required diode across the relay coil. (I seem to blow up a lot of MPF102s. Is it just me, or are these devices really fragile? They are junction FETs, not MOSFETS, so I thought of them as being more robust. But I seem to go through a lot of them.)

After messing around with the oscillator and buffer circuits, the nice clean Manhattan isolation pads that had been there at the start were all messed up, with big piles of solder with the ends of multiple axial leads stuck in there. I decided to start afresh. Out came the little PCB box that housed that housed the oscillator, buffer and amp stages. Off came the walls of the box. (When I built this thing the first time, I didn't realize that I would need an amp to get to the 7 dbm needed to drive the diode ring. I ran out of room on the main board and ended up building the needed amplifier on the back wall of the box!)

So I got to build this little circuit again, ten years and three countries after the original build. It was fun. I like building oscillators. There is that satisfying sense of closure and completion when, at the end of the effort, you turn on your receiver and hear the tone from your creation.

There was also a fun little bit of troubleshooting. After rebuilding the oscillator circuit I noticed that applying power to the "on the wall" amplifier caused the oscillator to shut down. At the buffer, I was seeing RF in and RF out, but the whole thing would shut down when I powered up the next stage. Obviously there wasn't a lot of BUFFERING going on! Sure enough, the MPF102 was bad. I replaced it from my dwindling supply, and all was right with the universe.

Now the amp goes in. But first I will build the low pass filter. I promise.

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Steve Jobs (age 12) calls Bill Hewlett (of HP)

"When he was in eighth grade, Steve Jobs decided to build a frequency counter for a school project and needed parts. Someone suggested that he call Bill Hewlett. Finding a William Hewlett in the telephone book, the 12-year-old Jobs called and asked, "Is this the Bill Hewlett of Hewlett-Packard?" "Yes," said Bill. Jobs made his request. Bill spent some time talking to him about his project. Several days later, Jobs went to HP and picked up a bag full of parts that Bill had put together for him."

More HP stories: http://www.hp.com/retiree/history/founders/hewlett/quotes.html

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Tuesday, October 25, 2011

Halloween Sale on SolderSmoke -- The Book

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Monday, October 24, 2011

Better Link to 1932 Yardley Beers Article

(From the November 2004 issue of QST)

I hear that picture I posted of the 1932 newspaper article was pretty much illegible. Sorry about that. Try this one from the Delaware Valley Radio Association. Scroll down a bit until you see OM Yardley in his front bedroom shack (the one with a window on the world!). On my Firefox browser I was able to click on it and get an easily read-able view.

http://photos1.blogger.com/blogger/2790/1877/1600/Yardley%20Beer%20DVRA1.jpg

Thanks DVRA!

BTW: Did you catch the name of the fellow who taught young Yardley the Morse Code? Atherton Noyes. Such good strong names!


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Sunday, October 23, 2011

More on Yardley Beers

Just click on the article and use the zoom feature of your browser to visit the teenage shack of Yardley Beers.

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

Saturday, October 22, 2011

Homebrew Hero: Yardley Beers

How's that for a beautiful homebrew rig! Prompted by our discussion of distinctive ham radio names, Harv, WA3EIB, sent us a very nice report on Yardley Beers, W0JF. The rig pictured is Yardley's "Jason" 20 meter QRP transceiver. Yardley had named the rig for his cousin. Harv met Yardley at a Colorado hamfest in 1993:

"On the table in front of Yardley was an Aluminum Box fashioned into a QRP radio named, “Jason”, 2 broken and worn head phones from the 1920’s, a few 1980’s QST and, several odd radio parts. My bulb of brilliance was not working that day. I said, “I don’t know what I’m looking for!" Somehow Yardley must have studied my eyes. I had locked my vision onto his very elaborate QRP rig. He paused for a few moments and said, “You into QRP?” By this time I felt more relaxed because he was now on my wavelength. I said, “Why yes, I would rather work with a homebrew radio that the ones with features that no one seems to know what they do!”

Harv bought the Jason (and everything else on Yardley's table) and established a lasting friendship with W0JF.

There is a nice article about OM Yardley's life in the November 2004 issue of QST.


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Friday, October 21, 2011

Steve Jobs and Heathkit

James, WL7FC/VE3ELI, sent us this clip from a Macleans article. Thanks James.

"His dad, though, was not his only early influence. In those days, the neighbourhoods of Silicon Valley were crawling with techies and engineers conducting cutting-edge work for firms like Hewlett-Packard and the Shockley Semiconductor Company. One of them was Larry Lang, who lived a few doors down from the Jobs house. Steve spent almost as much time in Lang’s garage as his own, tinkering with electronic equipment and assembling “Heathkits”: mail-order products such as amateur radios and receivers that took many hours—and much patience—to put together. Jobs would later say that those Heathkits helped him realize that everyday appliances, like the television in his living room, were not “magical” creations. “It gave [me] a tremendous level of self-confidence, that through exploration and learning one could understand seemingly very complex things in one’s environment,” he said. “My childhood was very fortunate in that way.”"


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Wednesday, October 19, 2011

Oh No! Short Circuit Danger with Anodized Heat Sinks?

Our friend Brent out in Minneapolis sent me some pre-Halloween HB frights yesterday. I'm still concerned. Am I living dangerously with my anodized but collector-connected heat sinks glued to the ground plane?
What say the HB gurus?

--- On Tue, 10/18/11, KD0GLS wrote:

From: KD0GLS Subject: Re: JBOT Amp
To: "Bill Meara"
Date: Tuesday, October 18, 2011, 9:38 PM

Bill,

Well, it is nearly Halloween, but it wasn't my intention to frighten you!

I think it's hard to argue with the fact that it works as-is. The heatsinks you bought look like common anodized aluminum to me. Out of curiosity I dug a couple of similar ones out of my parts bins and measured them. I found exactly what you did - wide open on the surface, and, not surprisingly, a dead short just underneath. I've always assumed that anodize finish was metallic and conductive, but now I know otherwise. I like to learn at least one new thing each day, so thanks for providing today's opportunity!

The clearances are no doubt small, but I think with the low voltages present in your circuit you'll probably be fine. The only potential problem might be if movement or vibration might someday break through that coating. I'd certainly recommend a fuse in the power supply line if you don't already have one.

Anyway, it looks great sitting there in the middle of your old rig. It's inspiring.

Brent


On Oct 18, 2011, at 19:42, Bill Meara wrote:

Brent: You scared me with your question but I think what I did is OK. Maybe. I looked more carefully at the clip on heat sinks I bought. They are covered with a non-conductive coating, but f I scratch them up a bit I can reach the conducting part. So i guess you just have to treat them gently if you intend (as I did) to super-glue them to the PC board. I notice that Farhan did the same thing (see his JBOT page) so I guess I'm OK. I put some heat sink compound in there too. And then there is the super glue. I have no short circuits from the collectors. I guess I could have used a Dremmel to isolate the copper just below the transistors. Or I could have put some mica between the heat sinks and the boards.

The sinks are deeper than the transistors, so there is no direct contact between the top of the transistor and the PC board.

What do you think?
--- On Tue, 10/18/11, KD0GLS wrote:

From: KD0GLS >
Subject: JBOT Amp
To: "Meara Bill" >
Date: Tuesday, October 18, 2011, 5:27 PM

Bill,

The amp looks mighty FB, and maybe I should try it as well. But I'm curious how you've insulated the collectors of all those transistors from the ground plane. From the picture, it looks like all of the metal heat sinks are sitting right on the ground plane copper.

.73,
Brent, KD0GLS, Minneapolis

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Tuesday, October 18, 2011

My JBOT 5 Watt Linear (Farhan's Design)

There it is -- my version of Farhan's JBOT 5 watt linear amplifier. JBOT stands for "Just a Bunch of Transistors." But I think Farhan is being modest. I really like the design, especially the effort to make this something that hams around the world can reproduce from readily available parts. For example, Farhan's original version used TV balun cores for the transformers. I didn't have any of those around, but I found three "mystery spec" binocular cores in my junk box. They seem to be working just fine. (I tested them a bit: Farhan had written that FT 37-43 cores would work. T1 has seven turns trifilar. Seven turns on my mystery cores yielded 13uH. On an FT 37-43 core 7 turns yields around 20 uH. Close enough -- these are, after all, broadband transformers.)

Note how closely my build follows Farhan's schematic (which you can see in the background). When building this circuit, I just kept Farhan's web page on my computer screen, and scrolled up and down from his schematic to the photo of his version.

This is the first linear amplifier that worked the first time I powered it up. It didn't release any smoke, or leave transistor burn tattoos on fingers, or try to be a 14MHz oscillator.

This version is going into my Azores-built 17 meter DSB transceiver. See how nice it fits:

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Monday, October 17, 2011

My JBOT passes the Smoke Test

Over the weekend I built my first version of Farhan's JBOT. I really enjoyed building it. I soldered in the last connections this morning and I am happy to report that it passed the smoke test. More info (and a picture) tomorrow. Thanks Farhan!

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Sunday, October 16, 2011

Bringing some Knack into Astro-Photography

I've been meaning to do this for a long time. It is a neat little project that allows for a quick and satisfying mixture of electronics and astronomy. It has been described on the web many times: Take an old web cam (preferably one of the old eyeball-looking devices) and remove the lens (I found it very cool to expose the charge coupled device).
Take a plastic 35 mm film container (hurry, while supplies last!) and chop off the bottom. Tape the container to the sans-lens webcam. Here's the fun part: Insert 35 mm container and webcam into the focuser of your telescope. Bring laptop out to the telescope and take digital pictures with your telescope.
I used Billy's old Asus eeepc and a very simple program called Cheese. (There has got to be something better for this kind of work.) But my results were very good. Last night I got images of Jupter and two of its moons. This morning I got some great shots of our moon.
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Friday, October 14, 2011

SolderSmoke: Engineering Site of the Day on EE Web!

Dilbert would be so proud! In spite of my Bachelor of Arts Degree, yesterday the SolderSmoke blog was named Engineering Site of the Day by EE Web. I'm especially pleased that the Sputnik rig of the G3XBM team was the featured photo. Check it out:

http://www.eeweb.com/websites/solder-smoke-daily-news

http://www.eeweb.com/

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Thursday, October 13, 2011

Can we put a Sputnik signal back in space for $300?

This article from Hack-a-Day caught my eye:
http://hackaday.com/2011/10/11/send-a-satellite-into-space-for-300/
We just make the antenna a bit longer and put it on 20 MHz. Or for a shorter antenna, 40 MHz.
Bert and the fellows out at UVA are going to take care of the whole SETI thing (Jerry, NR5A, was in the lead on this -- he started the SolderSmoke SETI-AT-HOME group). But we'll need some additional volunteers to cover the Low Earth Orbit portion of the SolderSmoke Space Program. And of course we have to come up with the 300 bucks.

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Wednesday, October 12, 2011

An HW-7 that Glows in the Dark

Hi Bill,

You are right, there is a lot of disdain for the HW7 out there.

While looking for a reasonable selection of do-able modifications to the HW7, I observed a sentiment that when all boiled down would sound like this: “Yea, rip out the innards and build a new transceiver in the carcass that is left.”

On the flip side, I have experienced relatively good results from my virgin HW7. Oh yea, I did add dial and meter lighting along with A nice set of Radio Shack Knobs but that is about the extent of the changes.

So Bill, I was wondering if any listeners to Solder Smoke know of a good source of reasonable modifications to the HW7 without inducing an implant? Second, is there a way of adding an S-meter to a direct conversion receiver? Are there any mods that can be lifted from the HW8 or HW9 and applied to the Old Senior HW7?

Thanks & 73’s

Harv WA3EIB Albuquerque, NM


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Tuesday, October 11, 2011

Comet Hits Sun, SFI up, Report from San Vito



The SOHO spacecraft caught some great images of a comet crashing into the sun. The YouTube clip above is from July. Here is NASA video of one that took place just last week:

http://www.nasa.gov/mission_pages/sunearth/news/comet-cme.html

Coincidentally I'm sure, the solar flux has increased significantly and the upper HF bands are working again. My 17 meter rigs still need final amps -- I am ordering parts for Farhan's JBOT circuit. (I plan to build three or four.) But because I had the 2B on 15 meters for the Sputnik event (still no Sputniks heard here) I noticed that DX was coming on that band. Using my HT-37 and a 40 meter dipole I easily worked several Europeans on 15 meter SSB. Especially nice was a long rag chew (using my rusty Italian) with Gianfranco, IZ4NPE, in beautiful Ferrara, Italy (a bicycle city).

Somehow tying this all together, I got an e-mail from Walter in San Vito, Puglia (the heel on Italy's boot). Walter has one of those "dream jobs" for a radio amateur: He tracks sunspots!

Hi Bill,

Walter here from San Vito, Italy. Just wanted to drop a note to say hi and let you know that I'm enjoying your book. Thanks for making it available as a Kindle version. While reading, it brought back similar experiences with me as a youngster. I too was fascinated by airplanes and would ride my bike to the local airport and watch for hours as the planes would take off and land. My mom gave me my first airplane ride as a birthday present when I was 11. I have to admit that I was scared when we made our first airborne turn. I didn't realize that a plane banks in the turns. I was also fascinated with shortwave radios and my best Christmas gift was a Radio Shack Globe Patrol (regenerative... hi hi) receiver kit. The gift from by grandparents was a Weller soldering gun (140 watts) to put it together with. Again, great job on the book.

The Sun has been keeping us busy at the Solar Observatory. I'm monitoring anywhere from 4 to 12 flares a day, 2 regions popped out of nowhere yesterday. The radio bands have been favorable with all the activity. I've got several projects in the works, a Genesis G3020 SDR rig is about 1/3 completed on the workbench now. It's probably me when you see Puglia show up on the website spinning globe. Take care and keep the podcast's coming. Ciao for now.
- Walter
I7/AC4IM

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