Visualizing Harmonics and Square Waves

Very illuminating.  Very cool.   We want more!  Show us how a mixer works! 

From:
http://hackaday.com/2015/09/17/visualizing-the-fourier-transform/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+hackaday%2FLgoM+%28Hack+a+Day%29&utm_content=Netvibes


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AA7EE's Beautiful Sproutie MK II

 

This is almost too much.  Sensory overload is a real risk here.  Go check out AA7EE's amazingly beautiful regen receiver.  On his site he has a masterpiece of a write up, along  with schematics and build photos.  I love the plug-in toroids.    Great work Dave.  Thanks for sharing this with the homebrew community. 

 

Here it is: https://aa7ee.wordpress.com/2015/09/14/the-sproutie-mk-ii-hf-regen-receiver/

 

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Alan Re-Caps His Drake 2-B

That Drake 2-B is a beautiful thing.   Every time I look at an older tube rig I'm reminded of the three dimensionality of these old machines.   Solid-state rigs are in Flatland, but tube rigs are in three dimensions.

Alan makes a very cool use of the I-pad in this repair.  And I'm jealous of his Hayseed Hamfest Electrolytic (I opted for the multiple caps hanging below the chassis).  Excellent management of the solder-sucker by Alan.  And I was impressed by the disciplined way he pulls solder from the reel -- he has the reel right next tot he rig and dispenses it directly.  I tend to hack off small lengths of solder and end up with lots of little bits of solder on the bench. 

Glad to hear that the other caps on the Drake are standing the test of time.  I wish the same could be said for all the caps in my Heath HW-101.

One thing caught my eye in Alan's video:  The dial cord.   You know you have become a true 2-B aficionado when you have actually gotten good at replacing the dial cord.  It is something of a rite of passage.   Perhaps this will serve as the basis for a future video by W2AEW,

Thanks Alan!  And congrats on passing 4 MILLION YouTube views.  People watch because your videos are so good.   

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Inspiring Stuff on "QSO Today"

Eric 4Z1UG is doing some really great interviews on his "QSO Today" podcast.   I found the last three to be especially informative and inspirational.

Chuck Adams K7QO dispensed a lot of useful information about Muppet boards and construction techniques, but more importantly he put out a lot of wisdom about the hobby, especially on the importance of teaching and sharing knowledge.

The interview with Glenn Elmore N6GN presented many interesting technical ideas, including using WSPR on VHF and UHF, and using aircraft reflections as a Sporadic-E like propagation mode.  He also mentioned "wing vortex" propagation.  Glenn talked about how to use a drone and a special light-weight transmission line to get your VHF/UHF (or cell phone) antenna above the trees.  (See above).

I found the conversation with Gerald Youngblood K5SDR both fascinating and a bit worrisome.  Gerald is obviously a great guy, and he does a wonderful job of describing the technology behind SDR radios, linking it to the phasing techniques that hams have been using since the dawn of single sideband.  He makes a strong case for the new SDR rigs, noting the absence of receiver-produced noise, the advantage of band-wide visual waterfall displays (even while noting that they tend to "make every ham an Official Observer"), and "brick wall filters that don't ring."  But I got and uneasy feeling when he referred to non-SDR rigs as "legacy rigs."  I found myself wondering how long it will be before all our rigs are required to be noise-less and all our filters skirt-less. Will there come a time when our beloved legacy rigs will be deemed unacceptable? (You can already hear this sentiment on the bands.)  And how much room is there in this SDR world for the kind of homebrewing we do? ( I know, I know.  I admit to feeling the presence of Ned Lud as I type these words.)

Great job Eric! And thanks to all the interviewees.   We look forward to the interview with Pete N6QW. 

Eric's QSO Today podcast can be found here:  http://www.qsotoday.com/

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Claude Shannon had The Knack (video)

From Wikipedia:
Shannon showed an inclination towards mechanical and electrical things. His best subjects were science and mathematics, and at home he constructed such devices as models of planes, a radio-controlled model boat and a wireless telegraph system to a friend's house a half-mile away. While growing up, he also worked as a messenger for the Western Union company.
His childhood hero was Thomas Edison, whom he later learned was a distant cousin. Both were descendants of John Ogden (1609–1682), a colonial leader and an ancestor of many distinguished people. 

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

And he he was part of a scheme to beat Vegas at the roulette wheel through the use of what may have been the first wearable computer: 
http://www.engadget.com/2013/09/18/edward-thorp-father-of-wearable-computing/

An excerpt from that site: 

After their initial meeting, Thorp says, "we got right to it," and he spent about half his time for the next eight months working away with Shannon in that basement lab in Shannon's house, on one of Massachusetts' Mystic Lakes. In his paper, Thorp described the lab as a "gadgeteer's paradise," with what he estimated to be about a hundred thousand dollars' worth of electronic, electrical and mechanical items. The regulation roulette wheel, ordered from Reno for $1,500, was set up on an old slate billiard table.

Thorp describes Shannon as the "ultimate gadgeteer," and recalled in his paper that the man he met in that office was a "thinnish alert man of middle height and build, somewhat sharp-featured," and that "his eyes had a genial crinkle and the brows suggested puckish incisive humor." That humor would become evident as the two worked together at the house on the lake. Thorp wrote that Shannon taught him to juggle three balls, and that he rode a unicycle on a steel cable strung between two tree stumps. "He later reached his goal," he wrote, "which was to juggle the balls while riding the unicycle on the tightrope."

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Kids Homebrewing in Japan in the 1920s

 

Michael Rainey, AA1TJ, Poet Laureate of QRP and Wizard of the Vermont Hobbit Hole found this drawing and put it on his face book page.  It is clearly supportive of the "International Brotherhood of Electronic Wizards" theme of this blog, so I have shamelessly expropriated it.  All for the cause Michael!   I hope this indicates that OM AA1TJ is emerging from a too-long spate of radio-inactivity. 

 

Michael says the drawing is from the 1920's children’s magazine, "Kodomo No Kuni" by Kiichi Okamoto.  David Cowhig, WA1LBP, provides this translation:

 

Title "Ni-chan,  I can hear it!"

The radio kid is saying something like:

-- Wait, no I lost it.

-- uhhhh

-- I can hear it, I can hear it, I've got it!

 

David notes: Sometimes Japanese use the katakana syllabary to add emphasis like we might with italics or exclamation points. 

 

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

Kon-Tiki and the Gibson Girl

Back in July we shared a very nice video sent to us by Rupert G6HVY on the radios used by the Kon-Tiki expedition.  Many of us had questions about the device used by the intrepid radio operator to generate hydrogen gas (for the antenna balloon) while on the high seas.   Mike Herr WA6ARA supplied the answer:   1200 grams of Calcium Hydride crystals.  This was part of the WWII rescue  radio set CRT-3 (aka the Gibson Girl). 

Fair Radio Sales occasionally sells this intriguing device: 
https://www.fairradio.com/catalog.php?mode=search&keywords=hydrogen&submit.x=21&submit.y=8

And here is great site with more details on the other antenna supports in the Gibson Girl set, including a ROCKET LAUNCHED KITE! 

https://billboyheritagesurvey.wordpress.com/2012/01/17/war-kite-the-gibson-girl-kites/

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Speaking of Breadboards...

Clint KA7OEI sent us these inspiring photos of his 10 GHz transverters.  FB Clint!  The one on the top was built in 2005 and STILL looks like this.  Note "CAT" component in the version pictured in the second photo.


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Si5351 and the Spectral Purity Mask

I was thinking about spectral purity standards and the Si5351 chip. I realized that I didn't even know what the FCC standards for "close in" noise are.   The standards for spurious emissions ARE well known, but these are for harmonics and parasitic emissions relatively far from the desired signal.  What about unwanted signals CLOSE to the desired signal? 

My old 2002 ARRL handbook indicates that the FCC has not established firm standards for this "close in" noise.  (They call it "out of band" noise, but are clearly referring to noise that is close to the desired signal but spreading out beyond the desired bandwidth.  Phase noise would be in their category.)

In the course of my Googling, I found the above spectral purity mask.   I don't know where it comes from, but I think it is the kind of graph that would be very useful to us as we evaluate the merits and shortcomings of various frequency synthesizers.  Would our DDS or PLL rigs fit in this mask?   I think an Si5351 rig WOULD.  According to KE5FX's measurements, at a mere 100 Hz from the center frequency, the Si5351 phase noise is already -90 db.

Does anyone have a similar mask showing current standards?

I still don't understand why so many folks believe that the Si570 is a useful part for homebrew rigs, but the Si5351 is not.  Look at the numbers:

Si570
Clifton Labs  measuring at 30 MHz carrier. At 10kHz from carrier:   -109.6 dbc/Hz
Silicon Labs web site (carrier freq not specified) At 10 kHz from carrier:  -116 dbc/Hz

Si5351
KE5FX measuring at 19.99 MHz. At 10kHz from carrier:  -127 dbc/Hz
Silicon Labs  measuring at 156.2 MHz. At 10 kHz from carrier   -112 dbc/Hz.

Can anyone out there explain the technical basis for the belief that the Si570 is a useful part while the Si5351 is not?   

It is important to keep things in perspective.  ALL of these noise numbers represent VERY small noise levels.   Let's keep is simple and assume a 100 watt carrier signal and a phase noise of -100 dbc/Hz.   That means the phase noise per hertz would be .00000001 watts.  That's watts/hertz.  How much "noise power" would that represent in a typical SSB passband?  Multiply by 2500 Hz and you get 25 microwatts.  That's really low noise levels. Not enough to worry about.  And as we've noted, we've happily used rigs with LC VFOs and crystal oscillators for all these years without every once measuring their phase noise.

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Alan Wolke's Drake 2-B (video)

Alan's video inspired me to do a little work with my Drake 2-B.  Nothing major -- I was just making sure that the passband knob is in the right setting.  I've complained that the Drake 2-B doesn't sound great on AM.  I recently noticed that my BITX40 DIGI-TIA sounds surprisingly good with AM signals -- I just treat them as SSB signals and zero-beat the carrier with my Si5351 VFO.  I wanted to try doing the same thing with the 2-B, and then make some comparisons.  I only heard a few AM signals this morning, so I will try again later today and will report results here.   

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SolderSmoke Book Now Free on Amazon Kindle

http://www.amazon.com/SolderSmoke-Global-Adventures-Wireless-Electronics-ebook/dp/B004V9FIVW/ref=la_B001JOYVM4_1_1_title_1_kin?s=books&ie=UTF8&qid=1441406675&sr=1-1

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

Breadboarding and Mountaintopping

We needed an illustration today.  I was having trouble finding something suitable.  Then the Radio Gods (along with Joe Peltola and the artist N0UJR) provided this.  Obviously I can relate to the breadboard operation. I'm sure Pete can too.  As for the mountain topping, that made me think of Colin, M1BUU.  And of Wes, W7ZOI.

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