Hacker with The Knack Does Well, Working for JPL

Wow.  This guy has a really inspirational Knack story.  He welded (with coat hangers!) a sidecar onto his bike when he was a kid.  He majored in Physics and Theater.  He did all kinds of hardware and software hacks. He plays a Theravin in a band.   He now flies spacecraft for the Jet Propulsion Laboratory. 

And Congratulations to Peter Parker, VK3YE, for having one of his ingenious hacks picked up by Hackaday:
http://hackaday.com/2014/10/06/dusty-junk-bin-downconverter-receives-fm-on-an-am-radio/

Thanks Hackaday! And Happy Tenth Birthday to You!  

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Edison is Off The Grid (and has been for 24 years!)

I talked to him last night on 17 meters.  He's a nice fellow.  When your first name is Edison, that's an indication that you might have THE KNACK.   

From his QRZ page: 

Ready for this?
My wife and I have lived off-the-grid for more than 24 years. Solar and wind are our main power sources on our mountain, although, we did finally add a generator to our available power sources, for those long days of "NO SUN" in Winter.  Check out the view from my home at this site:  http://mycampage.com/rosevalleycam  and also look at the other links on the page.  You might find something you like....
I've been a ham since 1967.  Started as a Novice near Sacramento, California, where I was born. But WN6FIC soon became WA6FIC, which I remained until the late 90's, when I became N7GCW.
I am a musician. Along with my wife, and Blaine Lindgren, our fiddle player, we comprise the band called "Half-way There". Click on my campage link to see more about me, and you will find all of my other links there too.  I am also a photographer. I shoot it all, but REALLY enjoy taking pictures of scenery, and live bands at Concerts we go to. I am also very fond of Sunrises, and Sunsets, and they ARE beautiful here.....

Also, check out his TREK page: 
http://n7gcwtrek.weebly.com/index.html

And I liked his description of his county in Washington state: 
"...I absolutely LOVE my world, here in our little valley.  Our friends are like family here.  People smile and wave...and mean it!  We heat exclusively with wood we cut from dead trees on our land, use propane for cooking and refrigeration, and we use solar and wind for most of our power needs, only supplemented by a generator in those long days of no-sun in Winter.  It's like living in a time warp, here in our neck-of-the-woods....  Do you know that there isn't a traffic signal in the entire county?" 
See: http://edisonshomesite.weebly.com/

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Pete's Homebrew Double Balanced Mixer Video (Part 1)

Another great video from the famed Italian Director Giovanni Manzoni!  Bravo Giovanni! 

Pete's discussion of double balanced mixers and the associated toroids has made me feel uneasy about my efforts in this area.  I wonder if my diodes were completely matched.  And I KNOW that my toroids are not as well done as Pete's.  

I recently put an SBL-1 into my old, long-evolving 20 meter ceramic resonator DSB rig. Careful with those nice little boxes! A bit too much juice and you can fry the little internal toroids (as I have done!). 

A while back I found in an RSGB Handbook a nice diagram showing how the diode ring mixer does its thing: 


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SolderSmoke Podcast 166: Getting Started in Homebrew Radio

SolderSmoke Podcast 166 is available for download: 

http://soldersmoke.com/soldersmoke166.mp3 

Bench Report:  Pete working on Direct Conversion Receivers.  
Bill on his 2B and on 20DSB rig, and an M0XPD/Kanga DDS kit, and a 140 watt amp. 

GETTING STARTED IN HOMEBREW:
Start simple:  Build an oscillator. Make it oscillate!
Gather tools, simple test gear, and books. 
Try to understand what you build. 
Build a direct conversion receiver.  
Don't fear the toroids! 
Be patient.  This is not Plug and Play. 
Build a DSB transceiver. 
Little tips: 
Protect variable caps. 
Use heat sinks. 
Use reverse polarity protection. 
Don't breathe the solder smoke! Ventilate your bench.

China Radio International Mystery Solved.  
Book Recommendation:  "International QRP Collection" by Dobbs and Telenius-Lowe
MAILBAG

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Sines, Squares, Harmonics, 'Scopes, FFTs, and Sounds

Bil Herd of Hackaday did a very nice video on Sine Waves, Square Waves and FFTs.  This is, of course, an important part of understanding how mixers mix.   I look forward to his upcoming video on Direct Digital Synthesis.  

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Hunting for Sprites

Don't let the comments about "positive lightning" and "gravity wave" cameras turn you off -- in the world of meteorology, these terms seem to make sense (but I had to do some Googling).  The New York Times article on this topic is very interesting: 

http://www.nytimes.com/2014/09/30/science/on-the-hunt-for-a-sprite-on-a-midsummers-night.html?_r=0  

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Beautiful Pictures of Mars from India's Spacecraft

Congratulations to the Indian Space Research Organization.  They put a spacecraft into Mars orbit on their first attempt, and they are getting back some spectacular images.  

I also like the banner on their web site: 

More info here: 

http://www.isro.org/pslv-c25/Imagegallery/mom-images.aspx

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Don't miss Thomas and his Minima at Pacificon!

Thanks for the kind words Thomas.  Be sure to have someone do a video of your presentation.

You truly have The Knack -- proof of this is your reaction to your wife's departure for field research in Senegal:  "IT'S SOLDER TIME!"  That's the spirit! 

Too bad about the chickens, but hey, they died for a good cause... 


Dear Bill,

I have been listening to your podcast for about a year now. I think you were right to say that one episode a month is a reasonable limit to avoid listeners getting addicted. At some point in January I was listening to you every morning and every evening in my car, a very serious case of addiction.

This is also the time that Farhan chose to announce the Minima and my wife to go to Senegal for 3 months for a field study (she is doing a PhD in Sociology). I think it took me less than a week to run to the shop, get most of the parts and start melting solder!

In two weeks from today I will present the project and my build at Pacificon. I would really appreciate if you could mention this on your blog because I am sure there are other listeners who will be there and curious for some homebrewing-materials. I hope to delight them!

For your own pleasure there are some pictures and videos on my blog: http://www.sarfata.org/ham/minima/ 

Pacificon Schedule:  http://pacificon.org/ (My talk will be at 10:45 in the Portland room)

My presentation will retrace my journey building the minima. From the first smokes on the crystal filter when I was not even sure how to test it, or what results to look for ; to the amplifier where I am still battling some oscillations (by the way, if you had not talked so much about them, I would never have understood what was going on!).

This project has taught me that radio is a lot less black magic than I thought. It bridged the gap between the maths that I can understand but not really "see" and the sound coming out of the amplifier. It made me realize that once split into stages, a radio is much better understood and testable. Without a doubt, this has been my most ham-enriching experience and I hope to convince more people to build a minima, preferably Manhattan style! 

(In this public setting, I will probably not discuss killing chickens to exorcize my amplifier but I thank you for the tip ...)

I got pulled back from homebrewing by life and work this summer but I kept the last three episodes of Soldersmoke on my phone. They were my safety parachute and I listened to them last week on the way home to give me the extra boost that gets me to melt solder or fix bugs until 3 in the morning on a tuesday. I don't think I will ever be able to express my gratitude for all that I have learnt reading the book and listening to you but I would like to start here: Thank you!

Please keep the podcast going! I have really enjoyed the new format with Pete. 

73,
thomas
kk6aht / f4hdq


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Let's Build Something! (Video) Part 1

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Radio China International Echo Mystery SOLVED!

For the past month or so I have been wondering about a strange echo that I've been hearing on the 31 meter transmissions of Radio China International.  I first noticed it on my "Kings Speech" regen receiver.  Then I heard it again on my "Off the Shelf" regen.  

For a while I thought that what I was hearing was a propagation effect:  Perhaps the very strong RCI relay station in Quivican,Cuba was sending north a signal so strong that it was travelling around the earth along the grey line and coming back to me about .133 seconds after the original reception.  

This sounded plausible (and it does happen sometimes).  But there were reasons for skepticism: Why wasn't anyone else hearing this?  Why wasn't the effect showing up on signals from Radio Havana Cuba?  

Pete Juliano had suggested that perhaps I was getting signals from TWO different RCI transmitters.  I had quickly checked the RCI schedule and didn't see them transmitting on the same frequency at the same time from multiple transmitters, so I kind of put that idea aside.  Hey, the round-the-world idea was just more appealing! 

But then I remembered something strange about the echo:  It seemed to disappear when I tuned close to the center frequency of the RCI signal, but then appeared when I tuned off to one side. Hmm.... That was an important clue. 

I've long been wary of regen receivers and for a while suspected that I was dealing with some weird regen effect.  Regen and Echo seem to go together, right?    Well, as it turns out, no.  But I was right about this being an effect of the nature of my receiver... 

Last night I was listening to RCI English service at around 0030 UTC on 9570 kHz.  Nice clear signal.  No echo. 

At 0100 UTC the program changed, and the echo started.  A very strong echo. 

I went to the RCI schedule.  Here I found the answer: 

At 0030 they were transmitting from their relay station in Cerrik, Albania on 9570 kHz. 
At 0010 they switched programs, frequencies and transmitters.  At 0100 Cerrik shut down, but the Quivican, Cuba relay came on on 9580 kHz.   At the same time the RCI transmitter in Kasi Sabagh in far-off exotic Western China, in Xinjiang, fired up on 9535 kHz.  Both transmitters were carrying the RCI English service. 

You see, my little regens are not very selective, and the RCI transmissions are quite strong.  So if I have my receiver tuned to around 9560 kHz, I'll be hearing BOTH the signal from Cuba AND the signal from Xinjiang.  That would explain the echo. 

To try to confirm this, last night I fired up my old Hammarlund HQ-100 receiver to see if I could discern the two different signals.  I could.  And the echo appeared when I tuned BETWEEN the two.  You can hear this in the video above. 

There is one remaining question here:  Is the echo caused by the RADIO path difference between the two transmitters?   Or are we just seeing the effect of the programming being transmitted at slightly different times, perhaps with this delay caused by INTERNET latency?  Anyone know how RCI gets its signals from its Beijing studio to its distant transmitters?   I calculate that the path difference is about 10,000 km.  With c at 300,000 km/second, that would yield an echo of only about .03 seconds.  The echo we are hearing sounds longer than that, so I suspect we are hearing a difference in studio-transmitter transmission time.  What say the SWL RF gurus?

BTW:  I think the same phenomenon may explain the echo on Brother Stair's "Overcomer" signal.  I see that starting at 2200 UTC he is on BOTH 7570 kHz and 7730 kHz from RMI transmitters in Florida.  Perhaps they are not synched up. 

I think this is all very cool.  Think about it:   Here I am, sitting in Virginia in 2014, listening to the Albanian, Cuban, and Xinjiang relay stations of Radio China International on a receiver first built by some guy in England during the 1930s.  And I'm trying to figure out if the echo I hear is caused by the limits imposed by the speed of light and the size of the earth,  or by the time it takes packets to move through sub-oceanic fiber optic cables.   

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Making Hardware for Mars in a Lab in New York City

I liked this video about building hardware for a Mars mission at a lab in New York City.

http://www.sciencefriday.com/video/08/10/2012/building-for-mars-sometimes-painful-always-glorious.html


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The Amazing Apollo Board from Carbon Origins

Wow, lots of possibilities here....

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Arduino Makes Music with Old Floppy Drives

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A Beautiful BITX20 from PA1ED

Edwin did a beautiful job on his BITX.  This is an excellent example of stage-by-stage construction. 
This is his THIRD BITX.  On the second one he got all the parts from an old television and a washing machine.  That's the true BITX spirit!  
I want an S Meter!  
There is more information on his blog:
http://pa1ed.blogspot.nl/

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The SWLing Post, Ears To Our World, and the HumanaLight

Thomas, K4SWL, has a really impressive shortwave listening blog.  Yesterday he was kind enough to post an article about my latest obsession:  the echoes on China Radio International: 
http://swling.com/blog/ 

Even more impressive is Thomas's work on behalf of poor people in the Third World. He is the Director of Ears to Our World, a charity group that provides innovative, simple and appropriate technologies to schools and communities in remote, rural and impoverished regions of our world.
Here they are: http://www.earstoourworld.org/

They distribute radios to people who would no other regular technological contact with the rest of the world.  They are also involved in an intriguing project called the HumanaLight:  "Dead" AA batteries power lights that can make a big difference for people living in areas that have never been on any grid.   Here it is: http://www.earstoourworld.org/humanalight/

Ears to Our World is looking for Donations to help them bring light and radios to people who really need them:   Here is where you can help: 
http://www.earstoourworld.org/donate

This is clearly a very appropriate charity for radio amateurs. 

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Inducted Into Shortwave Rogues' Gallery

Jeff Murray, K1NSS, has done me the honor of placing me in his VERY ELITE Friends of Shortwave "Rogue's Gallery."  Check it out:   http://dashtoons.com/FOSW.html

Kind of ironic that I should be recognized for my work on regens! 

Thanks Jeff! 

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"First Smoke" from Antananarivo, Madagascar

Here in Northern Virginia, it is not all that unusual to run into friends and have them say things like, "We're moving to Antananarivo."  Here is a report from Jack, AI4SV on his new location. That garage seems to have real potential as a workshop Jack.   

Greetings from Antananarivo, Madagascar!

I thought I'd turn the tables and give you a bit of travelogue and radio news.

The only radio-related item in our air freight was my toolbox, which I thought was justified. I lugged along the rest of the station in my carry on, an FT817 (with post-market Collins mechanical filter), magnetic palm paddles, a winkeyer, and the 40/20/10 end-fed LNR halfwave dipole, plus some mason line. I also brought a very compact 240V recharger that I had picked up in Sweden. 

The day after I got here, the dipole was hung using the time respected coke bottle on a string method, which greatly entertained the guard assigned to the house. A couple days later, I clambered up on the roof to raise the feed end another ten feet. Since then, I've worked about 240 stations with my QRP rig (all but three CW). I don't have any way to upload to LOTW right now, but my rough estimate is that I have worked something like 45 DXCC entities.

The location is probably not as ideal as Azores in terms of having a nearby salt water ground plane, as we're 100 miles to either east or west coast, and the local noise here can be very high in our tightly packed appliance-heavy diplomatic neighborhood. On the other hand, we're on the central highlands, almost a mile up and Madagascar is a very desirable DX location. When propagation smiles on me, I can work runs of 30+ stations before I disappear again into the ionospheric mist.

Before I got here, I talked with a bunch of US, UK, and German hams who had held 5R callsigns, and they gave me the lay of the land. Phil, G3SWH became my QSL manager and put me in touch with Albert, 5R8GZ, who has been a huge help. Prior to arrival, Albert was able to put through my paperwork with OMERT, the local equivalent of the FCC, so I could get on the air as soon as I arrived. He has similarly assisted quite a number of visiting hams and dxpeditions and is a big proponent of ham radio in scouting here. 

There's no ham club here, but there are so few active hams that in my three weeks here, I've either met or been introduced by email to about half of them.

It will be another month before our main shipment hits the docks here, and meanwhile management has given me the thumbs up to install a tower in the backyard to support a hexbeam. Between the K3 and the hexbeam, I think I'll be in good shape to do some serious operating, although I think that a couple months of operating QRP has been not only a character-building experience, but has given me a much better understanding of propagation patterns.

We have a large, empty garage and I think it's destined to become the workshop. I am curious about how dry it will stay in the rainy season and how many mosquitos will visit me there, but it has electrical power and plenty of wall space for shelving. Packing out my workshop took me about as much time as the rest of the house combined. So many little parts...

My toolbox arrived last week and the soldering iron was put to immediate use to build a dipole for six and then 15 meters. I've captured the moment of "first smoke" in the new location for your viewing pleasure.

So, please look for me on the air in future months and point your moxon over here when you can.  I'm putting updates about the station's status on its qrz page.

Keep up the podcasts! I've enjoyed the series with Pete Juliano - kind of a return to the original format. Also, I've listened to the icq podcast for years, so it was great to hear the "very special crossover episode" with you and Martin.

73,

Jack

5R8SV / AI4SV

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Kiwi Lunchbox Sideband: The Tucker Tin Two

Pete Eaton sent us links to an old article from the New Zealand magazine "Break-In."   So many good, simple rigs come to us from New Zealand!  Who can forget ZL2BMI's DSB rig?  This one is the work of Fred Johnson ZL2AMJ.  It is especially interesting and is in some ways similar to Peter Parker's "Knobless Wonder."

It uses the phasing method of sideband generation.  No crystal filters in this one.  You need TWO balanced modulators.  You have a 90 degree phase shift network for the RF (from the carrier oscillator) and a second 90 degree phase shift network for the AF from the mic amplifier.  When you combine the signals from the two balanced modulators -- viola! -- one of the sidebands disappears.  The balanced modulators take care of the carrier, and an SSB signal is launched.  That is how my old HT-37 works, and similar ideas seem to be at work in modern SDR rigs.  

G3TXQ has the complete set of Break-In articles (it includes a VFO): 
http://www.karinya.net/g3txq/temp/tucker_tin/   

Here is a Canadian article on the rig.   A "Tucker Tin" is apparently what the Kiwis call a lunch boxes (shades of Benton Harbor...).  

Thanks Pete!

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Long Delayed Echo on Radio China International

Several people have e-mailed me suggesting that the weird echo I have been hearing on shortwave broadcast stations is in fact one of the fabled "Long Delayed Echoes" that radio amateurs have been hearing intermittently since about 1927.   I was skeptical at first, but -- at least in the case of the Radio China signal -- I think LDE caused by the signal going around the globe several times does explain what I've heard.  Each trip would add a delay of about .133 seconds, and that seems to match what we hear in my recording:  

http://soldersmoke.blogspot.com/2014/08/strange-echo-on-china-radio.html 

Compare that with what K9FIK recorded on 10 meter SSB (thanks Stephen!): 

http://swling.com/blog/2013/10/hearing-the-speed-of-light-dx-double-echo/
(you can listen to the audio on this one). 

It sounds very similar. 

If this is in fact LDE, I'm lucky -- this is pretty rare.   And it is a eerie that I first heard it on on Regen receiver from the 1920s!  Above is a picture of the regen used to study the FIRST LDEs. See: http://folk.uio.no/sverre/LDE/


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SSB with Just Two Tubes

Here is the two tube SSB transmitter that Pete was telling me about.  This would be a nice companion to the "Mate for the Mighty Midget" receiver that I built a long time ago.  Another Benton Harbor Lunchbox may have to be sacrificed... 


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Eclectic Electronics: Powering Arduinos with Tube Filament Voltage

You know that you are dealing with a broad range of technology when you find yourself discussing how to power an Arduino microcontroller from the 12V AC voltage on a vacuum tube filament line. Thanks Pete. 

Hi Bill,

There is only so much that can be said in 1 hour and 19 minutes so maybe here is some stuff for the blog.

The 1st thing on the list when working with the Arduino when it is not connected to the computer is to have a proper power supply. My research as indicated that 9 VDC “raw” is a good starting point to power the Arduino boards so here are two supplies that will provide that power.

I did find that it was necessary to have an isolated supply when working with the “toob” radios and even to isolate the RF into the radio using a ferrite core transformer –some more tribal knowledge.

One supply takes an 8 VDC regulator and boosts its output to 9 VDC. The second uses a switching regulator and the beauty of the second is that the input can be either 12 V AC or DC. This is ideal for use in toob radios where you can sample the 12.6 VAC filament string.

73’s

Pete

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Regen Receivers in Cuba

Hola amigo Bill:

I was able to pick up the podcast with excellent audio quality.
It is quite true that regenerative receivers are very much in use
even today... for example many if not all of the automobile RF
keys opening and closing the cars doors rely on a superregenerative
receiver circuit !!!

The radio that you copied at the blog works very well indeed
but it would be  good idea to include a 5 kilo ohms volume
control.... Very easy to do indeed.

But let me tell you that my favorite regenerative receivers are
the classic ones, using vacuum tubes, and operating them
at voltages not higher than 50 volts... As a matter of fact many
tubes work very well at the 24 volts DC voltage level.
Using the classic Hartley circuit , there is no need for a hard to
find throttle capacitor required by the Armstrong circuit, because
the regeneration control works very well by using a potentiometer
to change the screen grid voltage of the detector.

I agree that using an RF stage ahead of the detector is always
a very good idea.... In my tubes regenerative I use a triode connected
6AK5 clone.... as a grounded grid stage....another 6AK5 clone ( the
6ZHE1P Russian tube ) is the detector and I use another 6AK5 clone
as the first audio amplifier then feeding an audio output pentode
all provided from a very simple basic 70 volts DC power supply.
BTW, using regulated DC on the filaments of the detector stage,
although a luxury by my standards is very helpful to reduce
hum .... 7805 regulator recycled from a bad motherboard, with
one 1N4007 from broken Compact Fluorescent Lightbulb inserted
in series with the regulator ground pin, produces a nice 5.7 volts
regulated DC that with a brand new tube is more than enough... with old
6ZHE1P recycled from Russian TV sets, you add another 1N4007 to obtain
6.4 volts regulated DC....

As said in the podcast, it is very important to do a very good
mechanical engineering job, place the main and bandspread tuning capacitors
away from the front panel, use isolated shafts between the capacitors
and the dial mechanism and make the front panel of a a thick steel
plate if possible.

There is a Dutch Cascode Regenerative radio that several Cuban radio
amateurs have built... it was designed with the amateur bands in mind so
the information about the tuning coils and capacitors lets you
obtain a very excellent bandspread on the ham bands.
I can send you that circuit that uses very common 12AT7-ECC81
and Russian equivalent double triodes.

Keep up the good work amigo and always tell us when the next
podcast is available. BTW it lasted for almost an hour !!!

73 and DX

Your amigo en La Habana, Cuba
Arnie Coro
CO2KK
Host of Dxers Unlimited radio hobby program
Radio Havana Cuba


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SolderSmoke Podcast #165 Arduinos!

SolderSmoke Podcast #165 is available: 

http://soldersmoke.com/soldersmoke165.mp3

September 13, 2014

Workbench Update:  Bill's "Off the Shelf" Regen,  Pete's Boatanchors
Mysterious Echos on Shortwave Signals.  Solve the Mystery.  Please. 
Microcontrollers -- What they can do for you.
Small world:  As a kid, Pete was neighbor of "Digital Dial" N3ZI 
NEWS FLASH: Arduino creator Massimo Banzi was a ham!  
Born in a bar, cheaper than pizza:  The Italian origins of Arduino
Arduino CW generators
No coding skills needed
Arduino + AD9850 = Signal Generator or VFO
Arduinos in the Minma
What the heck is a Shield?
SolderSmoke Mailbag

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Schematic for "Off the Shelf" Regen

NOTE (May 2024) The eagle eye of Walter  KA4KXX spotted an error in this schematic.  The source resistor in the MPF-102 stage should be around 2200 ohms.  Thanks Walter! 

Tony, VE7JUL, wrote in asking for a schematic on the "Off the Shelf" regen.  Here you go Tony.  Nothing fancy or new here.  All the credit goes to Howard Armstrong, Charles Kitchin and Jay Rusgrove! 

Even though they seem much simpler than other receivers, I think regens are in fact more of a challenge than, say, a Direct Conversion receiver.  Be prepared to do a lot of fiddling around with the coil and the tuning and regen capacitors.  Think of that detector stage as a VFO, a VFO that you want to be able to smoothly take out of oscillation. 

Here's a tip on regen debugging:  Once you have it built, hang a high impedance 'scope probe off the drain of the FET and watch the scope/counter as you move the main tuning cap and the regen control.  This will give you a visible indication of where (on the regen control) the stage is going into oscillation.  A freq counter (I have one inside my Rigol 'scope) will let you know what frequency range you are operating on.  You may end up having to make adjustments to the coil, adding or taking away turns to get into the proper frequency range, or to the desired level of feedback.  Pay attention to the phasing of the coil turns.  You may also find yourself adding capacitance in series with the regen and main tuning controls (to reduce their tuning range) or adding capacitance in parallel with the main tuning cap (to lower the entire tuning range if necessary).  

Build it solid and strong!  It is, after all, an oscillator.  Be prepared to do a lot of "noodling"   

Hi Bill,

This receiver with just 4 transistors and no chips looks really interesting to me.  Do you have a schematic that you could either flip to me or point me to?  Getting my hands on some air variable caps may be a challenge, but I can 'noodle' something out on that.

Love the podcast, blog and really enjoyed the SolderSmoke book - thanks for your continuing efforts to share with the amateur radio community.

73/72
Tony

VE7JUL

the little red dot at Coquitlam, British Columbia on what used to be the Clustr map (but is now a Revolver map)

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Shortwave Echo Mystery on Yet Another SW Station. What is this?

A few weeks ago I noticed a strange echo on Radio China International's signal.  If you scroll down a bit you can see my YouTube recording of the problem.  On one of the SWL lists, there was speculation that this problem was the result of a flaw in the RCI digital studio gear.  But then a few days ago I heard it again on RCI -- surely the tech-savvy Chinese would not have let this kind of problem persist for weeks.  

Today I heard the same effect on a very different SW station -- this one an the 24/7 fire and brimstone broadcast that appears at many points on the dial.  The effect is very similar to what I heard on RCI.  

So OK all your shortwave gurus:  What is going on here?

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"Off the Shelf" Regenerative Receiver

I call it the "Off the Shelf" Regen because the base on which it is built is scrap lumber from a recent shelf building project.  Also, all the parts came out of the junk box.  

6-10 MHz, AM, CW, SSB, Data.   4 transistors, no chips.   


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SolderSmoke Interview on ICQ Podcast

Colin and Martin of the ICQ Podcast were kind enough to invite me in for an interview.  I really enjoyed our talk.  We covered a lot of ground, everything from podcast history, to regens and BITXs and Arduinos.  I think SolderSmoke podcast listeners will enjoy this.  Thanks Martin!  Thanks Colin!  Here it is:

http://icqpodcast.com/download-the-show/2014/9/7/series-seven-episode-eighteen-bill-meara-n2cqr-07-september-2014


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Ed's Awesome Workshop

Wow, there is a lot of workshop wisdom in this video.   This is also a reminder that there are a lot of very cool people in the FDNY.   Ed is an EMT/Firefighter.  

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

Arduino CW Sender by KK6FUT and N6QW

The next time Pete and I get together on SolderSmoke, we'll talk about Arduino.

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Sometimes the Receivers Seem to Almost Self-Assemble

I've been building shelves for my wife.  So I end up with all these nice pieces of pine, just the right size for the base of a breadboard receiver and a very sturdy cabinet to surround it.   Then I find in the junk box two nice variable caps and this old pill bottle coil (with tickler!) that I wound in 1998; I figure they will resonate from around 5 - 15 MHz.  Then Jeff Murray, K1NSS does that poster about Dave Richards, AA7EE (scroll down) in which he mentions the virtues of a National Velvet Vernier reduction drive -- I have one of those too.  And then there is the copper-clad board (from AL7RV/W8NSA) that would be perfect for the front panel.  You see where this is going, right? My friends, I am once again on the road to shortwave regeneration.  It will have an Armstrong detector with throttle cap.   

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Youth, Short Waves, and the Invigorating Properties of Regen Receivers

Oh man, when I saw this I just had to put it on the blog.  The artist is Jeff Murray,  K1NSS, the genius behind Dashtoons.   Dave Richards AA7EE is, well, the OC!  

So not only have we learned that regen receivers are NOT demonic, we now see that they have health enhancing properties!  Like all that antioxidant stuff!  This is great.  I'm feeling younger already.  

Regen on my friends!     

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Cutting Edge Regens! No, really.

Bill - 

Thanks so much for featuring The Sproutie on your blog. I heard through my friend Jason NT7S on Twitter that you had built a regen and we both did a double-take. Bill from Soldersmoke building a regen - and enjoying the experience? I was frantically pinching myself, as it just didn't seem likely, given your past bad karma with them but there it was - a lovely old set with that great brushed aluminum finish with the swirls on the front panel - and being worked on by Bill N2CQR. Wonderful!  I have been meaning to either e-mail you, or comment, perhaps below the post in which you featured the letter from Todd VE7BPO. I discovered recently that although we think of regens as being an established, and now stagnant technology, there are still people doing cutting edge research on them.  Some of the discussion was in the Yahoo regenrx Group, and much of the research is being done by a fellow from NJ with the username vladn. Concerning the phenomenon that we notice with our regens that, as we get close to the threshold of oscillation, the bandwidth narrows, and then as we advance into oscillation (as we do to receive SSB and CW), the bandwidth broadens out somewhat, I am going to quote verbatim a comment that was left on my blog by user qrp.gaijin,

This phenomenon has been deeply analyzed and explained (by user “vladn”) here:http://theradioboard.com/rb/viewtopic.php?f=1&t=4680&start=0 . It is, in fact, possible to completely eliminate this phenomenon; bandwidth can be controlled independently of oscillation amplitude (to choose a desired amount of selectivity), and oscillation amplitude can be controlled independently of bandwidth (to control how easy it is for the regen to lock on to the incoming signal: we want a low oscillation amplitude and easy locking for synchronous AM reception, whereas we want a high oscillation amplitude and no locking behavior when listening to SSB). Eliminating this phenomenon, i.e., separating control of bandwidth and oscillation amplitude, can be done by using an explicit amplitude limiter (i.e. a separate transistor/tube stage as part of the oscillator’s explicit amplitude stabilization control loop) that exhibits scale-independent gain compression. In other words, regardless of the oscillation amplitude, if the oscillator’s gain compression (amplitude limiting) behavior is scale-independent, then the final result of the repeated selective amplification (that defines the final regenerated Q and bandwidth) will be the same, regardless of the oscillation amplitude. See this video (by vladn) for a demonstration of independent control of oscillation amplitude and bandwidth: http://www.youtube.com/watch?v=UyqD99WGlss .

The fellow in NJ whose username is vladn has built a regen to test the above theory, and it works! You can see it in the video that is linked in the above quote. vladn has done other equally cutting edge research into regens, but I wanted to let you know that these little receivers are still being developed and improved by a few intrepid experimenters. Howard Armstrong would be so proud!

Best of luck building your regen Steve. With Bill Meara now a regen fan, the radio Gods are on your side!

73,

Dave
AA7EE

****************

Hi Bill and Dave,

The Soldersmoke blog post about the Sproutie super-regen radio by Dave got my soldering iron warm without even turning it on!  That National N Velvet Vernier dial really got my homebrew and radio nostalgia juices flowing with that beautiful nickel plating and the big shiny Bakelite knob.  Plus the use of modern semiconductors along with an Octal socket for the plug-in coils was almost too much to bare.

I immediately bought the National dial and the two variable caps on eBay and from the link Dave suggested in his post for the dial.  That custom chassis company, while in Nova Scotia, is quite close to me here in Maine, and I just might have to visit them to talk about the details of my proposed chassis. 

The obvious next step is a real PCB, but Dave's beautiful technique using the ME squares and pads is hard to argue with.  Those solder-friendly squares and pads are local to me too from good ol' Rex Harper.

Bill, many thanks for your post and link. Dave, thanks for the great design and implementation, as well as the amazing details and photos on your blog.  I think I see a HB super regen project in my immediate future. The parts are piling up!  Gary sold out of the N dials almost immediately.

73

Steve Silverman  KB3SII ... .. ..

**************

I'm really glad that Steve wrote in because his e-mail reminded me that I need to thank him again for the multiband dipole that he sent me a couple of years ago.  For a number of reasons I couldn't really use it in its original configuration, but the wire has been used in almost all my recent antenna projects, including the magnificent Moxon.  The black insulation was just what I needed for that essential stealth effect.  Thanks Steve. 

  

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Some Inspiration on Receiver Building

As a result of all the recent toob talk with Pete Juliano I've been going to work with old copies of Electric Radio in my backpack.  Yesterday, somewhere in the tunnel under the Potomac River, I read these inspiring words from master receiver builder Bob Dennison, W2HBE (SK): 

"Part of the fun in the radio building hobby is tearing up a set after a short period of use so its parts can be used again in a bigger and better set. Another order is sent to Allied Radio for an audio transformer, an RF choke, a vernier dial and some of those exquisitely beautiful Hammarlund variable condensers.  Oh what a joy it is! You just haven't lived until you've built a whole series of progressively more exotic receivers.  Give it a try!"  (ER, March 1993) 

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Regen Madness

Dave, AA7EE, has a really nice blog article about his experiences with regen receivers.  He writes about a regen kit he built as a kid (pictured above) and goes on to describe in beautiful detail a regen he built recently using a combination of old tech and new tech:
http://aa7ee.wordpress.com/2014/08/21/the-sproutie-a-general-coverage-regen-receiver-with-plug-in-coils/

I agree with Dave when he notes that regens are unfairly thought of as mere novelties. My old "King's Speech" regen (below) is a very useful shortwave listening  receiver and could easily be used for 40 meter CW contacts.  It is even stable enough for SSB.   

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Seized up Variable Capacitor -- Any ideas?

Perhaps in retaliation for all the bad things I've said about regens over the years, the main tuning cap in the old regen I've been working on suddenly went from completely loose to totally stiff.  I can turn it, but it is too tight for the old vernier drive in the regen.  I have replaced it with another cap, but this part was kind of the star of the show, situated as it was several inches above the chassis, connected to the tuning control by a long shaft.   I've tried squirting WD-40 in there -- no joy.  I can't even figure out how to open up the part of the cap where the ball bearings should be. It is an OLD Eddystone from England.   Any ideas? 

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Strange Echo on China Radio International

Last night I was doing some shortwave listening on my new (OLD!) regen.   As always, China Radio International was booming in on multiple frequencies. But as I tuned them in, I noted something strange:  a very distinct echo on the signal (you can hear it in the video above).  Very strange.  Kind of like the Long Delayed Echos we've all heard about.  I started thinking of explanations.  Might this be some weird regen reverb effect?   (You see -- I'm still wary of these regens!)  But no, I checked -- the echo was there when I listened with my superhet HQ-100.  Could it be that this was some strange multipath effect, perhaps involving multiple powerful transmitters in different locations?   I was listening to the 0100-0200 UTC (20 Aug 2014) CRI English language service. (The echo continued when they switched to Chinese at 0200)  I think the frequency was 9580 kHz.   An SWL website says the transmitter was a relay station in Quivican, Cuba.

What do you guys think?  These fellows might have an explanation: 
http://swling.com/blog/2014/07/china-radio-international-warbling-on-daves-home-brew-receiver/

I really like shortwave listening with this old homebrew 1930s radio.  There are still a lot of interesting signals out there.  Recently heard:  Voice of Vietnam,  Radio Turkey, Radio Romania, WWV, WWVH, CHU, W1AW,  transatlantic aircraft,  Radio Australia, Radio New Zealand... and the mysterious numbers. 

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Happy Birthday Philo Farnsworth!

Thanks to Bob Crane (and Garrison Keillor):  

It's the birthday of Philo Taylor Farnsworth, the inventor of the television, born in a log cabin in Beaver, Utah, in 1906. He conceived of the basic elements necessary to transmit a visual image while he was still in high school; later, at Brigham Young University, he began his research in earnest. He co-founded Crocker Research Laboratories in San Francisco when he was just 20 years old, and the following year, in 1927, he transmitted his first image: a straight line. Investors wanted to know when they would see financial returns, so at his first demonstration for the press in 1928, he transmitted the image of a dollar sign. This earned him the first of about 165 patents.
Farnsworth appeared only once on his invention: He was the mystery guest "Dr. X" on the game show I've Got a Secret in July 1957.
.......

I liked Paul Schatzkin's book on Philo:  "The Boy who Invented Television": Here you can read chapter one for free: 
http://soldersmoke.blogspot.com/2008/08/philo-t-farsnworth-radio-hero.html

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Alan Wolke Looks at Diode Ring Mixers

Bill,   I remember in your Soldersmoke book that you had difficulty for a long time trying to understand how a mixer created the sum and difference frequencies, and how this was accomplished in a diode ring mixer.  I know that you've got it all sorted out now, but I thought this was a good topic for a video anyway.  

Here's my video on the subject:

https://www.youtube.com/watch?v=junuEwmQVQ8

73,

Alan

Alan:  Thanks.  Great stuff. Yea, I've been looking at the innards of mixers for a long time. In my book, I try to explain how I have come to understand the physics of the mixing action -- how the use of a non-linear element causes two signals to "multiply" and how this "multiplication" results in sum and difference frequencies.  I tried to go beyond the trig functions because for me the trig didn't really explain anything. 

In the book I was looking at the classic two diode mixer (beloved of Doug DeMaw!).  A few years later, on the blog, I was looking at the action of the diode ring.  I concluded that there is a big difference between how the diode ring works and how the two diode mixer works.    RSGB provided a great diagram: 

http://soldersmoke.blogspot.com/2009/04/are-diode-ring-mixers-fundamentally.html

73   Bill 

-----

I guess one way of describing the difference between a two diode mixer and a diode ring would be to say that the more simple mixer multiplies the signal by 0 and 1 (if it is operating in "switching mode), while the diode ring multiplies by 1 and -1.   

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SolderSmoke Podcast #164 Ancient Tribal Knowledge: Tube and Tube-like Radios

SolderSmoke Podcast #164 is available:

August 16, 2014

http://soldersmoke.com/soldersmoke164.mp3

ANCIENT TRIBAL KNOWLEDGE -- TUBE AND TUBE-LIKE RADIOS

Workbench Updates: 
-- Pete's Arduino Keyer Project
-- Bill Builds (and LIKES!)  a REGENERATIVE RECEIVER
-- The Joys of Regen Shortwave Listening
-- Grayson Evan's Tube (Thermatron) Book
-- Book review:  "The Joy of X"  (It's about math).
-- Shameless Commerce:   A Plug for Bill's Book
-- Pete discusses tube projects
-- Making your own enclosures from Home Depot flashing
-- Amplitude Modulation
-- Compactrons, Nuvistors and other unusual tubes
-- BANDSWEEP:   Radio Havana on Bill's new regen 


Bill's Mate for the Mighty Midget Receiver
3 6U8 Tubes on a Benton Harbor Lunch Box Chassis


Nuvistor 2 meter down converter


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Voice of Vietnam on Old (New!) Regen Receiver

I'm having a lot of fun shortwave listening with the reborn British regen.  This is the Voice of Vietnam. 

I rebuilt the regen using the old Eddystone variable capacitors, the original coil form, the original wooden chassis (now covered with copper flashing) and the original front panel and knobs.  But the old triode was replaced by an  MPF-102 JFET.  And the AF amp tube was replaced by an LM386. Something old, something new... The circuit is the old Armstrong circuit, with a tickler coil and throttle cap.  Thanks to Charles Kitchin for all the regen wisdom in his Nov/Dec 1998 QEX article (available on-line). 

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Some Progress on the Old Regen

That's Radio Havana Cuba.

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