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  

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

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

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

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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