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.

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

Five Lessons from Pluto for Homebrewers

http://www.edn.com/electronics-blogs/embedded-basics/4440230/5-Engineering-Lessons-from-Pluto?_mc=NL_EDN_EDT_EDN_today_20150901&cid=NL_EDN_EDT_EDN_today_20150901&elq=3e27f3c4018844db9381c8a508867555&elqCampaignId=24586&elqaid=27842&elqat=1&elqTrackId=06ba9f8cc21140c1ae477df75c36dd65

Thanks to Bob Crane, W8SX, for the link to this article.   Those of us who are reading "The Martian" will find the mention of RTG power interesting (but hey, let's not try to put any plutonium in our rigs, OK?) 

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

Interview with Paul Horowitz (W1HFA) -- A Giant In Radio Electronics (Video)

I've been hearing about this book for years, but until I watched this interview, I knew nothing about the author.  Thanks Lady Ada.  (And thanks to Farhan for the alert.) 

As a native New Yorker, I'm pleased to include in the blog yet another reminder that the Big Apple is not all fashion and finance -- a lot of solder has been melted in my home town. 

Paul Horowitz has a truly awesome bio.   He got his ham license at age eight.  QST tells us that lots of little kids do this, but unlike some of the youngsters we see in the magazine I suspect young Paul really mastered the theory.  Paul Horowitz has "The Knack."  Big time.

PhD from Harvard.   Author of "The Art of Electronics."  Pioneer in the Search for Extraterrestrial Intelligence.  Carl Sagan is believed to have  modeled the main character in "Contact" partly on Paul.  Check out the wiki  page:

https://en.wikipedia.org/wiki/Paul_Horowitz

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

"The Soul of a New Machine"

 

We talk a lot about putting soul in our new machines.  The phrase comes from a book by Tracy Kidder.   Ira Flatow of NPR's Science Friday recently took a new look at this book.  There are TWO recordings in this link.  Both are worth listening to.  The second is an interview with the author, conducted at Google HQ in New York City.  Woz chimes in. 

http://www.sciencefriday.com/segment/08/28/2015/the-scifri-book-club-talks-the-soul-of-a-new-machine.html

At about 6:43 in the second interview, Ira Flatow and Tracy Kidder get into a little argument about how to pronounce the word "kludge."  I'm with Ira -- the fact that he pronounces it this way makes me think that we are using a New York, or at least and East Coast pronunciation. 

I am a big fan of Tracy Kidder.  His "Mountains Beyond Mountains"  is about Dr. Paul Farmer, a heroic physician who has dedicated his life to treating the poor people of Haiti.  "My Detachment" is about Kidder's stint as an army officer in Vietnam.   Kidder and his editor wrote a nice book about the crafts of writing and editing: "Good Prose."  "Strength in What Remains" is about the genocide in Burundi. 

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

Awesome Kits from Austin Texas

http://www.qsl.net/k5bcq/Kits/Kits.html

If this is the kind of great stuff that results, then I agree with the bumper sticker:

KEEP AUSTIN WEIRD!

Scroll down to kit #25 for more details on the device pictured above.

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

Adam Savage (Myth Busters) Interviews Andy Weir (Author of "The Martian")

I liked this interview a lot, and I am sure SolderSmoke listeners will like it too.
Weir admits to NOT having the Knack, but Mark Watney clearly does have it.

Also, check this out: http://www.cannonade.net/mars.php#map

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

Knack Movie and Book -- SolderSmoke on Mars -- "The Martian"

I realize I'm very late in reading this book.  Billy read it last winter.  The movie is already coming out.  I guess I didn't see the Knack element in this story until I saw the movie trailer.  Wow.  This is a book and movie for us.    Dude is stranded on Mars and has to fix the radio  (with Hendrix playing in the background).  I'm reading the book now (appropriately, on my I-phone).  I find myself thinking about the Elser-Mathes Cup.   

More on the book here: https://en.wikipedia.org/wiki/The_Martian_(Weir_novel)

From the Wiki article:
Andy Weir, the son of a particle physicist, has a background in computer science. He began writing the book in 2009, researching related material so that it would be as realistic as possible and based on existing technology.^[4] Weir studied orbital mechanics, astronomy, and the history of manned spaceflight.^[6] He said he knows the exact date of each day in the book.^[7]
Having been rebuffed by literary agents when trying to get prior books published, Weir decided to put the book online in serial format one chapter at a time for free at his website.^[4] At the request of fans, he made an Amazon Kindle version available at 99 cents (the minimum he could set the price).^[4] The Kindle edition rose to the top of Amazon's list of best-selling science-fiction titles, where it sold 35,000 copies in three months, more than had been previously downloaded free.^[4][7] This garnered the attention of publishers: Podium Publishing, an audiobook publisher, signed for the audiobook rights in January 2013. Weir sold the print rights to Crown in March 2013 for over a hundred thousand dollars.^[4]
The book debuted on the New York Times Best Seller list on March 2, 2014 in the hardcover fiction category at twelfth position.^[



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