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Wednesday, March 18, 2015

Software Advice From the Brainwagon (Mark, K6HX)

I was really happy to get this encouraging message from Mark, K6HX.  Mark is a real wizard -- he has been deeply involved in the production of many of Pixar's wonderful animated films.  And his blog -- Brainwagon -- is always a good read.   Mark offers good advice for software and hardware troubleshooting. Thanks Mark!

Hey Bill and Pete:

Just finished listening to your latest SolderSmoke on my commute
yesterday, and thought I'd drop you a line to let you know that I'm
really enjoying the "dynamic duo" format that you've adopted.  Having
different ideas and different perspectives on the show, but with both
of you showing such great enthusiasm really makes the show a pleasure
to listen to.  (Incidently, your audio for this last podcast seemed
much better to me, a couple of episodes seemed to be plagued with much
different levels between Pete, who was booming, and Bill, who
frequently seemed to be quite low.  Whatever you did, keep it up!)

As a guy who does mostly computer/software engineering, I'm especially
liking Pete's continual, good natured prodding of Bill to get with the
program and use more gadgets like the Arduino, the AD9850 and the
Si5351.  :-)  But what's most valuable to me is when you guys engage
in the back and forth of debugging problems like your recent amplifier
feedback issues.  And what I realized (and might come as some comfort
to Bill) is that most of the skills which you guys have developed to
understand and debug radio projects apply equally well to software.

Stop me if this seems familiar:

If you want to learn to program, you do it by programming.  Pick a
simple project and try to get it working, then build on your success.

Don't try to learn it all at once.  Making a computer blink an LED is
a good start.

Make use of the resources of the Internet community.  Look at what
other people are doing, look at their designs, and enlist their help
when necessary.

Keep notes about what works and doesn't.  Make an archive of all the
code you write.  Examples that work can be helpful to create new code
that works.

Don't just poke the program with a stick, hoping it will work if you
prod it the right way.  Develop a theory of why it works, and test
that theory.  If the theory is not born out in practice, then don't
leave that code lying around in your program.

Don't get too wedded to your idea about why a program may not work.
Test your assumptions, even the ones that you are sure of.  Often
those hide the worst bugs.

Think about modularity.  Build simple routines/modules that you can
reuse to build bigger programs.

Build on the shoulders of giants: using tested modules of other people
isn't cheating.  But eventually you may need to understand what is
inside these black boxes, so keep working on developing your skills.

Share your enthusiasm with others, via the Internet, Youtube or social media.

-------------------------------------------------------------------------------------------
See Bill, you've already learned a lot of the lessons you need to be a
programmer, you just learned them all with respect to radios.  They
will serve you well if you decide to take the plunge into tinkering
with programming.  :-)

On some of the ham radio related Facebook pages, I've been a little
annoyed lately that so many hams seem to lament that "nobody builds
anything anymore".  Ironically, I suspect these are the same sort of
people who decided to pile onto Bill's amplifier project and skewer
him for its audio quality.  If we want more experimentation in ham
radio, we are going to have to tolerate a little more failed (or at
least, not totally successful) experiments.  But even beyond that, I
supect that there is quite likely more people (in absolute numbers)
doing homebrew now than in any time in decades.  It's an incredible
golden age for homebrew.  We have great books out like EMRFD, great
mailing lists, vendors to sell us amazing parts at incredibly low
prices, and the Internet to share and learn.  People like you two are
part of this.  What are all these complainers doing to get people to
build stuff?

I have to really thank you, Bill in particular.  While I've still not
gotten all the way to building my own transceiver, you got me back
into amateur radio, fueled my interest in beacons, QRSS, WSPR and
homebrew in general.  And Pete's approach to radio seems to be the
wedding of electronics and software that I find in sync with my own
ideas.  I look forward to doing more projects, and hearing about
yours in the weeks and months to come.

Well done, sirs.

Mark (K6HX)

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Tuesday, March 17, 2015

Tony's Mighty Mite (Escape from the DARK SIDE!)



Hi Bill,

Thanks for the crystal for the mighty mite. I have been pretty busy of
late, but got a few minutes to take a first stab at a build. I am an
electronics neophyte, but learning every day. I am a convert from the
software darkside - software engineer by trade - and enjoying every time
I succeed in getting something to work! I am glad that the circuit is
forgiving because I grabbed what I had at hand to make it and it ain't
pretty by any means, but I have included a photo of the build as was the
deal and also a snapshot of proof of oscillation from my oscilloscope.
I'll do it up right soon and try connecting it to my arduino to send
some morse code out to the ether. Send you more pics when I make it
pretty :)

Thanks again - 73, AK4ZF
Tony Cekolin



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Sunday, March 15, 2015

Hank's New Rig



   
Pete, Bill:
Applied power to the 6C4 / 5763 transmitter for the first time today. I made RF. No smoke was released to the wild. Only issue is the load air variable cap is fully meshed at full capacitance and still not getting the dip on it. Need to root in the junque box for a 220 or 330pF silver mica and wire that in across the load cap. 
    As it is its putting out 2w. Listening on a general coverage receiver I'm not hearing any chirp or drift. Will build a low pass filter and have to interface in the power supply. Still have a few details to do such as labeling the controls but for the most part I just built a transmitter from scratch. Happy day at the workbench.
    Another fix is to redo the coax from the RX / TX switch. Didn't have any RG174 so I just grabbed a clipping of RG8X had laying around. Ugly but got the job done.   
    Thanks for all the help and encouragement. 
Till later
Hank Ellis K5HDE

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Saturday, March 14, 2015

Happy Pi Day! Scottish Moonbounce in 1965, Eddystone Dials



Somehow this seems appropriate for Pi Day (3-14).  I guess it is because the antenna is circular.
Thanks to David GM4JJJ for sending this to us.  There is no audio. Kind of fun to watch the lads struggle with the big antenna while wearing coats and ties! 
 
David writes:
 
Hi Bill,
    Just watched the video of the progressive receiver and immediately noticed the old Eddystone drive and dial. 
    My first general coverage receiver was an Eddystone 840C in about 1969 I guess, so it brought back fond memories. 
    I also had (much later) an Eddystone 770R VHF receiver, which I used to listen to transatlantic 50MHz on during the sunspot peak a couple of cycles ago now. That was before we were allowed to transmit on 6m over here. 
    Incidentally if you saw the recent film "The Imitation Game" about Alan Turing, you might have spotted the 770R in it, which was actually a mistake as the receiver was not produced until after the war. 
Now something to break your heart, and mine actually:


    This old rig which was given to me sometime in the 70's by another ham, was stored the attic of my previous house now used by my brother, and a couple of years ago I had to clear the attic of the "junk" that I had left when I moved out. I didn't have any more room to store quite a lot of things and I made the decision to take a few things that I never thought I, or anyone else, would need. They went to landfill. :-(
    As you can probably see there is an Eddystone drive and dial driving a VFO which originally had insulation material around it for thermal stability. I think it may have been mixed or multiplied up to 144MHz judging by the scale on the dial. Looking back now I should have tried to save it, but I just felt at the time it would just probably lie in my new attic until I departed and then someone else would have to throw it out.
    I don't know exactly who made it, I was given it by Andy GM3IQL(SK), but I vaguely recall him telling me that it was made by Fraser Shepherd GM3EGW(SK) who I did not know as he died tragically young, but was a brilliant constructor. It could equally possibly have been made by Jimmy Priddy GM3CIG, and I could contact him as he is still around in his 80's now. At least I had the sense to take some photos.
  Now a couple of semi related video material that I put up on YouTube.
This is a (silent 8mm) film made in the 1965s about the first moonbounce attempts from Scotland and Jimmy CIG made the film. My Elmer Harry GM3FYB(SK) is in it. 
Another one this time 1965 field day!
    Bill, I really enjoy SolderSmoke podcasts etc, I am returning to ham radio after about a decade, got the bug again....
    The KX3 is in the shack, and I have the parts here now to build a QRP WSPR beacon by Hans Summers also.
    I like QRP, having previously worked with George GM3OXX back in the 70's when we went out portable with wideband FM QRP 10GHz (3cm) gear using Gunn diode oscillators. Just a few mW and we could work several hundred miles with small 2 foot dish antennas in the right conditions over water by super refraction. The receivers were just mixers, no active RF amplifiers in those days.
I think the best I did was 322km with my 10mW from Scotland to Wales on 10GHz. A couple of decades I built up a real SSB transverter with surplus MOSFETs for 10GHz and with greater power (250mW) and SSB bandwidths I could work non line of sight paths on that band from home. 
    I also like QRO for such things as 2m EME (moonbounce) and am in the course of replacing my old 8877 W6PO design 1500W amp for 144MHz with an Italian manufactured LDMOS 1kW amp that is a fraction of the size and weight, who would have imagined a single solid state device would be able to do that at a price amateurs could afford?
   Anyway enough of my ramblings. 
   Hope you don't mind me taking up so much of your time, I will let you get back to whatever you have on your workbench!
73
David Anderson GM4JJJ
 
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Friday, March 13, 2015

Final Integraton And On-Air Test of the LBS Transceiver (Video) (FB!)



Very nice.  A beautiful and educational project from Pete and Ben.   I have to start putting "tune switches" in my rigs and ammeters in the bias circuits of my finals. 

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Thursday, March 12, 2015

Pete Juliano: Homebrewing With Transistors SINCE 1953!


I knew Pete had a lot of experience with transistors, but I didn't realize just how far back this experience reaches.  Pete writes, "The March 2015 issue of QST  had an article about a 1953 transistor transmitter project which was really advanced technology since the transistor was only invented about 5 years before that time...  About 1953 at the age of 11, I built my first solid state audio amplifier using the venerable CK722 from Raytheon. The transistor did look a bit strange in that cool blue cube shape with a red dot on the side to identify the collector. What a joy and surprise to me that it worked the first time power was applied...  It  was the CK722 that in large measure started me on a life’s work and engagement in a wonderful hobby. That CK722 path also led me to designing and building a QRP solid state version of the Collins KWM2 which I call the KWM-4."  I asked Pete why an 11 year-old kid in 1953 felt compelled to build a solid state audio amp.   The answer is very cool:  Pete's father had introduced him to crystal radios at age 8.  Pete wanted an amplifier for his crystal set, but his dad was worried about him building high voltage tube gear.  So that's how Pete got his VERY early start with transistors.

We are really lucky to have Pete Juliano sharing his vast tribal knowledge with us.


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Wednesday, March 11, 2015

N9IZ's Steam-Rollered Indy Mighty Mite (Video)



Not even the U.S. Postal Service's Anti-Crystal Steam Roller can stop an intrepid homebrewer.  OM N9IZ got his Mighty Mite working and produced a really nice video and blog post on the project.  You can just feel the enthusiasm:  On the blog he writes:   "Everything was assembled on a bread board for trial.  I must admit to being overjoyed when I saw the visual waveform on the PowerSDR panafall display of my Flex-5000A main shack radio.  So much so, that I ran through the house calling for my YL, KC9TAH.  She was in the shower and thought I’d cut off a finger or something while in the mad scientist lair.  Much to her dismay, it was only a nasty CW signal emanating from the Flex speaker.  She did humor me by going out to see the marvelous project before asking me what I was going to fix for lunch."  FB OM!   
  
Bill
 
I thought you might like to hear that another MMM has been brought into the fold.  You might remember that the crystal you sent me was steamrolled by the USPS.  Believe it or not, it works!  Not sure the frequency is exactly spot-on, but who cares...it works!  I enjoyed it very much and made a youtube video of the testing process.  I also took pictures and posted it all to my webpage.  Most of my other projects have been more QRO in nature so I'm treading in uncharted territory.  We'll see how far that goes, but right now I'm loving it.  I have my issue of QRP Quarterly and plan to follow along in constructing the LBS project.  All for now from Hoosierland.  Hope you enjoy the blog post on my webpage.  73 OM.

DE N9IZ


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Tuesday, March 10, 2015

Shep on Parasitics and Troubleshooting: "That way madness lies"


You guys really have to listen to this.  This is culturally important.   And it is a great follow-up to SolderSmoke 173.
 
In this 1965 radio broadcast, Jean Shepherd describes his teenage struggles with parasitics and other technical problems in his homebrew 160 meter transmitter.

He describes the sound of parasitics on a signal, saying that they sound as if the signal is being attacked by "debauched erotic locusts."

He really nails it in describing the scornful, dismissive tone that many hams use in telling their fellow radio amateur that there are problems with his signal. ( I have recently been on the receiving end of this kind of treatment.)

He observes that no one is more worried, "than a man who has built something and can't get it to work." Indeed.

During a date with a girl from his high school, he is so obviously pre-occupied with his transmitter trouble that she tells him that something is wrong with him and that his mother "should take him to a doctor."

And he describes the joy that comes when you figure out the problem and get the thing to work.

The REALLY good stuff begins at about the 25 minute point.

http://ia310115.us.archive.org/2/items/JeanShepherd1965Pt1/1965_01_29_Ham_Radio.mp3

Shep was quoting from King Lear: "O, that way madness lies; let me shun that; No more of that."  In other words: "BASTA!"  That is what I have said about my 40 meter troubles.  My BITX 20/40 is now a BITX 20. 

EXCELSIOR!



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Monday, March 9, 2015

The Original BITX 20 -- Designed at 35,000 Feet in 6 hours, Built in India in 3 Days


 I came across what appears to be an early version of Farhan's description of the design and initial construction of the BITX 20  (see below); this version has some interesting information on the origins of this important rig.  The picture below shows the designer himself working on that first BITX20.  It is from a CNN video.  I know Farhan is sick of seeing this old video, so I present here only the shot of the designer's hands at work on the original transceiver.
 

Some thoughts from the designer, Ashhar Farhan, VU2ESE: 

    This transceiver was designed during a six hour flight from Europe with paper, pencil and the basic calculator built into my cell phone. It was soldered in three sittings over three days. Very little went wrong during the construction. It was one of those easy designs. The only mistake that I made during construction was that I soldered one of transistors in reverse. The design worked as ‘advertised’. I guess that extensively using feed back amplifiers provides designers with greater repeatability. Also, I realized, a little late in life though, that detailed forethought and ‘mental’ home-brewing is important for a clean design.
    The linear chain was initially unstable. It tended to oscillate in the 14MHz band as well as around 500 KHz. I traced the 14MHz oscillations to a choke that I was using at the output of the balanced modulator. It has been removed. The 500 KHz oscillations were because of excessive gain in the driver and pre-driver stages. From 5 ohms, the emitter degeneration has been increased to 10 ohms and better bypassing on the power rail has eliminated the oscillations.The receiver is as hot as I need it to be on 20 meters. Signals from USA, Europe, South Africa and of course India were heard with clarity reminiscent of a clean Direct-conversion receiver on the first evening. The transmitter is powerful enough for local rag chew and it is a modest challenge for DX. VU2PEP has an excellent two element beam at 20 meters at about 40 feet height. DX is easy for OM Paddy who uses the rig regularly. We netted LA2FKA within the first 20 minutes of firing up the rig.
    No, I don't offer PCBs. I don't repair rigs. I don't offer kits. I might do a PCB for this rig (I hate PCBs, they hamper experimentation).
    This transceiver is dedicated to the memory of OM Juggie, SK (VU2JH) who was a great organizer of India hams, he wrote technical articles in Electronics For You magazine about amateur radio, spurring many to take on ham radio as a hobby. He organized the Millennium Ham Meet in the year 2000. He was always searching for a good and simple homebrew SSB transceiver. He died young. He gave me my first morse key.

Jagdish, VU2JH




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Saturday, March 7, 2015

SolderSmoke Podcast 173: Pete's LBS Triumph and Bill's Tale of QRO Woe

SolderSmoke Podcast #173 is available:

http://soldersmoke.com/soldersmoke173.mp3

7 March 2015

Bench Report:   Pete's Progress on the Let's Build Something Rig:
http://www.jessystems.com/LBS_Detail.html
Ben's cool case for his LBS rig
Bill's Tale of Woe:  QRO troubles with the BITX 40
    -- QRO amplifier taking off on 40 (but not 17)
    -- Criticism and public humiliation on 40
    -- Troubleshooting
    -- Suggestions from Allison
    -- A sad realization about my VFO frequency selection
    -- Exorcism needed
    -- Pete suggests a digital solution
    -- Wow, my 'scope has an FFT!  Almost a spectrum analyzer!
    -- Some thoughts on trouble shooting
    -- On the meaning of "BASTA!"
The Spring 2015 Issue of Hot Iron http://www.walfords.net
More on Pete's KX3
Encouraging other hams to build
 
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Wednesday, March 4, 2015

Video of The Moment Colin Made his First Homebrew Contact With Australia



Our British cousins are not a wildly emotional people.  The word "phlegmatic" is sometimes used when describing them.  Stiff upper lip and all that. But as you can see at the 51 second mark in this short video, contacting Australia whilst using a new scratch-built homebrew BITX20 on battery power from a windy English hilltop WILL get those English fists pumping and those thumbs up.  The wind drowns out Colin's voice, but his gestures say it all.  Well done Colin!  Brilliant!  

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Tuesday, March 3, 2015

Colin's BITX DX From the Field


That has to be one of the best-looking scratch-built homebrew BITX20s.  Pete and I agreed that it looks almost too good to take out into the field.   But that is where Colin took it.  His BITX was designed for Summits on the Air, and the radio gods rewarded him for his efforts with VK DX.  Well done Colin! 
 
 
Hi Bill and Pete.
Well it just worked out that weather was going to be bearable this morning but getting worse through the weekend. I'm really want to ramp up my SOTA score so I'm trying to get out as much as I can. I switched my plans to an early morning activation on one of the local hills. The hill, called Sharp Haw, is a little lump on the edge of the Yorkshire Dales, it's not very high at all, but it is worth 1pt for SOTA.
The early morning time window brought the possibility of VK QSOs via long path on 20m. I looked at the VOACAP prediction for propagation and it suggested a peak at 0800utc.
I was actually late getting up, my alarm clock batteries have decided they've had enough. Despite the late start, I still managed to get on the air by 0725, hearing a strong Australian accent on the power up frequency of the BITX, 14.200, was a good sign.
At 0737, I was called by VK1DI. I had to turn the AF gain up, but sure enough, the signal was workable and we exchanged reports, 55 for him, 33 for me. Within the space of less than 20 minutes, I had 4 VKs logged, the strongest being VK3DET, giving me a 56. The other two stations were VK3CAT and VK2IO. I also worked an Asiatic Russian station amongst others.
I'm over the moon, I might even apply for my SSB thousand miles per watt wallpaper!
I still find it magical that 25 volts into a bit of 7/0.2 wire can transport your voice across 15,000 miles! Amazing!
73, Colin, M1BUU

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