DDS amplifier

Tony, G4WIF, asked about an amplifier to boost the output of the AD9850 chip.  Here is Dr. Juliano's prescription: 

You might find that once you plug that DDS into a circuit you may not quite get 1 V pk to pk  and in fact after about 10 MHz it really starts to sag. See the attached drawing as you can put this “afterburner’ on the output of the DDS. The isolated output is good if you are interfacing with “toob” type equipment –it can be left off if you are doing SS or just left in place. This is the output from the amp and as you can see fairly clean.

 

73’s

Pete N6QW

 

 

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Digitizing my BITX17 with an Arduino and an AD9850 chip

This is only temporary!  My analog, discrete, hardware-defined BITX17 was NOT harmed or even modified for this little experiment. 

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Background on the use of Si5351 -- code and integration with Arduino Nano (video)

I somehow missed this one.  Here Pete talks about how the use of the Si5351 in ham radio has been evolving, who has been working on it, etc.  

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Pete Goes Superhet with the Si5351 generating BOTH VFO and BFO (video)

Congrats to Pete for his amazingly fast development of a 40 meter superhet receiver using a single Adafruit Si5351 paired with an Arduino Nano for ALL of the frequency generation.   No more VFOs, no more crystals.  It sounds great!   Amazing stuff.  

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BIG Amplifiers with SMALL Microcontrollers and LOTS of Tribal Knowledge

Hi Bill,

I wanted to forward to you a slightly edited email I sent to one of our podcast listener’s as I think this is a really good example of some “Tribal Knowledge”.

-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Hi OM,

Ham radio publications are much like the Internet –all that is published must be scrutinized. One such publication had a beautiful QRP to QRO amp using a 3CX800A7. A few watts in and 800 Watts out. My daughter was in FM radio broadcasting and I told her to introduce herself to the station engineer and to look out for any pulls – then the floodgates opened –about a week later I had a 3CX800A7.

So I started to work on the amp. The circuits just didn’t make sense and parts were missing that would make it work correctly. I contacted the author and here is what he shared. He built the amp but never did get to proof the final article. In fact he sent me his notes and sketches which were correct. Thus I could have never built that amp using just the article. I built it for one band, 20 Meters. It has a tuned input and a Pi-L output so is quite excellent on harmonic reduction.

Oh BTW this amp caused me to learn about PIC Microcontrollers. You cannot hit the 3CX800A7 with HV voltage until the cathode is warmed up (must be a female tube). That time delay is 3 minutes. I could not find a suitable time delay relay with a 3 minute delay that didn’t cost an arm and a leg. So that is when I thought about using the PIC16F84 as a time delay relay. Later I ported that over to a 12F675. The cost was less than $10. In the 3CX1500A7 amp ( another free tube)  I have two microcontrollers in there. One is used for a three second step start on the filaments (don’t want to shock the filaments with inrush current) and the second for the 3 minute delay before starting the HV step start sequence.

You can see the “Big AMP” on my website at http://www.jessystems.com.

There was only one problem – I was worried about the cooling of the tube so I made sure there was plenty of air which I dump into a very small sub-chassis and the exhaust is out through the tube. Well “Dah” large volume in and small port for exhaust and you have a jet engine sitting on the desk top. Man it was loud – I would wear headphones when it was working.  When I built the 3CX1500A7 amp I used a larger plenum so not as loud.

There are several key points I want to make about tribal knowledge:

1. Turn off the soldering iron and spend a good deal of time “noodling” over the circuit so that it is clear what each function will do and that all the wires connect to something.
2. Contact the author and ask lots of questions and you might be surprised to find out the published design is not what was designed!
3. Look for uncommon solutions to build problems. Many times parts used in the articles are so unique that only one exists in the whole world and it is installed in the authors unit.
4. The amp was built in 2000 and the use of the PIC16F84 as a time delay for an amp was a bit leading edge but don’t be afraid to employ some advanced technology into your projects. [Today an Arduino built into the amp could do time delay, temperature control of blowers, SWR sensing, grid trip protection and even warm your coffee.]
5. In the Big AMP I figured out how to keep the blower going for about 1 minute after the amp is turned off to “cool down” the tube. The point here is to think about not just the amp itself but refinements to make that $600 tube last for a very long time thus filament current inrush protection and tube cool down.
6. Don’t forget SAFETY – there is 2000 Volts @ 1 amp running around chassis–it is an electric chair sitting on your desk top. I included a microswitch that when the top cover is off it de-energizes the HV circuits. See if you can spot it in the photos.

73’s

Pete N6QW

PS The amp really does exist –see below.

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Pete's Boards Come Alive as a Direct Conversion Receiver (video)

I love it when a new rig is spread out on the workbench like this, pulling in its first signals.  Like First Light on on a new telescope.   These are the same boards you have been seeing in Pete's previous videos:   The Si board, the mixer, and the AF amp.   Now they are linked together in the form of a Direct Conversion receiver.  

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Pete's "Let's Build Something" Audio Amplifier (video)

Who needs LM386 ICs?  Pete goes discrete!   Love the MePads.   And I knew Pete was going to test it with his finger!  He's just taking stray hum from the power lines and coupling it to the input through that Exacto knife.   

Seems to me like these boards is getting close to actually receiving signals.     

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Pete's Mixer (Pictures)

Hi Guys,

 

Just finished building the PD/BM that will be used in the final circuit of the LBS Part I. I will also upload a video of the build.

 

The W1REX MeSquares really work very well and greatly facilitate the build. So the newbie builder -- will have one leg up by using the squares method.

 

73’s

Pete N6QW

Pete's video on this circuit appears below -- just scroll down a few. 

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Bandpass Filter Construction by Pete Juliano (video) TFMS!!!

MePads!   Arduinos!   Breadboards!  SuperGlue!   Graph paper!  Noodling!   Room for Relays!  
TFMS (TUNE FOR MAXIMUM SMOKE!) 

Another great video from N6QW.  Thunder power! 

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Pete Builds a Doubly Balanced Modulator (Video -- Part 3)

Another beautiful piece of cinema from Giovanni Manzoni's Newbury Park Studios.  Bravo Giovanni! 

Pete is obviously a doubly balanced kind of guy.   I liked his use of the W1REX MePads and the breadboard.  Also, the balance pot and the un-balance switch are very handy innovations. 
Most of all I like the way Pete's video takes you from schematic to actual circuit.  

Thanks Pete! 

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SolderSmoke Podcast #167: Arduinos, Amplifiers, Books, and Tribal Knowledge

SolderSmoke Podcast #167 is available: 

http://soldersmoke.com/soldersmoke167.mp3

3 November 2014
Who the heck is Giovanni Manzoni? 
Pete's Bench Report: 
     "Let's Build Something"  Project 
      Arduinos and Si5351s
Bill's Bench Report:  140 watt Amplifier Completed! 
      Low Pass Filter Design with the ELSIE Program
      Samlex Power Supply
     How I almost blew it up! 
     The new amp and the lids in the FT4TA pileup
Tribal Knowledge!
"Nature abhors a vacuum (tube)!"  "The Innovators" by Walter Isaacson. 
Carter, WA9DNF, REALLY knows which end of the soldering iron to grab! 
Meeting with Thomas, KK6AHT.  The two electronic cultures. 
Interviews by Chris, KD4PBJ, at Two Days in Huntsville: 
     Glen Popiel, KW5GP, Author of "Arduino for Ham Radio" 
     John Henry of TenTec
     Steve, WG0AT  

                                               Giovanni Manzoni
Giovanni Manzoni b. circa 1950 Civatavecchia, Lazio, Italy is a noted videographer specializing in the avante garde use of YouTube in ham radio homebrew settings.   Long noted for his insistence on the use of completely home-made video equipment, Manzoni went so far as to demand that his cameras and recorders only use discrete components -- he claimed that integrated circuits "freaked him out."  Manzoni's collaborators have long been puzzled by his claim that all his videos are filmed "on location."  What he means by this remains unclear, however, in a 1997 interview in QST-Italia, he was quoted as saying "No matter where you go, there you are!" 


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OH NO! SolderSmoke Goes QRO! Bill's Amplifier Project (video)

I got the Communications Concepts Inc. EB-63A amplifier working today.  Yea!
Kind of ironic that the highest power amp I have ever built gave me the LEAST trouble.  This just goes to show that circuit layout is very important.  This amp is a proven design, with a proven layout and board.  That's why it didn't turn into a 140 watt solid state oscillator!

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"Science Friday" Interviews Author of "The Innovators" (listen)

Michael Rainey alerted me to Ira Flatow's Science Friday interview with author Walter Isaacson.  I'm reading Isaacson's new book "The Innovators"  (appropriately, on my Iphone 5). The book is very good, with surprisingly frequent references to ham radio.  Flatow's interview with Isaacson is also quite good, and will give you a better idea of what the book is about.  Here it is.  It is worth a listen:
http://www.sciencefriday.com/segment/10/24/2014/meet-the-innovators-who-made-the-digital-revolution.html

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Mailbag: Coils Wound Backwards, Last QSO 1981, Visions of Transistors Keeping Him Awake. Paul has THE KNACK

http://www.pan-tex.net/usr/r/receivers/ra01000a.htm

Hi Bill

I'm just getting back into ham radio after 33 years (last QSO: 1981),
want to do it all through homebrew, seem to have the same mindset as
guys like you and Frank K0IYE, bought your book [love it and Frank's],
and just "discovered" the Soldersmoke podcasts.  I've been listening to
them with one ear as I bike to and from work (about 40 minutes each way, so it's almost perfect).  I'm employed as a digital geek, but yearn for the days of DeMaw's prime (worked him once when he was W1CER), when the 40673 ruled.  I'm very glad that, 40 years later, people like Farhan can weave discrete analog wonders, even if they later choose to use digital *control* (NOT DSP! No!).

I had to start somewhere with your podcasts archive, so I started with
2014 and really enjoyed your struggles with the Herring-Aid 5. My 1st
receiver  was the "DC 80-10" by DeMaw from somewhere around 1970 in QST or the Handbook -- used a CA3028 as the product detector -- and I had similar struggles.  While listening to it, I immediately thought "you wound the feedback coil backwards, you idiot!"

I got my license back in March 2014 and want very badly to get back on
the air with a homebrewed, or at least minimally-kitted, station.  I've
built the receiver:  David White's (WN5Y) Beginner's and Experimenters
receiver[1] heavily modified, have a long wire antenna up, a decent RF
ground, and all the parts I need for QRP z-match tuner, swr meter, T/R
switch, sidetone, and IRF510-based transmitter.  Target:  40m CW by the middle of December, 30m in the couple of months after that with a
fully-Manhattan-style Barebones Superhet and another IRF510
transmitter.  Then one of these BitX things.  It's been a couple of
decades since I felt that there weren't enough hours in the day.  Some
nights I can't sleep, what with all these transistors and simple analog
ICs whirling around...

Anyway, keep it up, I'll be listening.

-- Paul Lender, AD0HQ

[1] I built an Arduino/AD9850 DDS -- a la AD7C -- and used it to tune a
4-crystal filter (10-cent crystals from Tayda!) for the receiver with
the same Rigol scope that you use.  I tried, really tried, to do it with
an analog RF signal generator.  Change is good.  Change is good.

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Dear Santa: I want a Knack Watch. The one with real tubes...

This is what all the cool homebrewers will be wearing next year.   Just be careful at airport security -- they might not understand! 

Check it out:  http://www.johngineer.com/blog/?p=1595

We received some comments from some noted Thermatron authorities: 

Hi Guys,

This will cause all of the bells, whistles and sirens to go off all it once.

Now all that is needed is a logo on the watch that says

EBOLA ( Electronic Bi-state Operational Long Arithmetic) and this will cause you to go to jail without passing Go or collecting $200.

Pete

---------------------

Wow, I love this thing!…even though it uses little black plastic things to work.  Have no idea what they are. (johngineer has knack squared)

Reminds me of a project I am trying with fellow ham.  We picked up an old HP nixie tube freq counter at junk yard.  We were going to strip out the nixie tubes to make a clock, but decided we could make it as clock as is.  Want to program an Arduino thing into generating a frequency that is the time and feeding it into the counter.

For example 3:45:25 would be 34,525 Hz.  

But my Italian is terrible so haven’t been able to get the Arduino to work.  Just learning it.  Project a bit over my head. picked up one of those online language courses on Italian. Hard, but not as hard as Turkish!

Grayson

TA2ZGE - Ankara, Turkey

KJ7UM

Follow the Hollow-State Design Blog

hollowstatedesign.tumblr.com

-----------------------

 I'm wondering if I  could do it Manhattan style, with discrete components... 

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Spark Forever! Pete's First Transmitter

The SolderSmoke legal team (we too use Dewey, Cheetham & Howe!) has advised us to be very careful about divulging the details on this rig.  They are not sure about the statute of limitations.   Beyond what he said on the podcast, all Pete will say is that TOOBs were involved: 1S4, 3S4, 3Q4, 3Q5, 3V4s.  He says power out was ALWAYS less than 100 mw ERP.  That's  his story and he's stinking to it. 

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Smart-Phone Cosmic Ray Detector

http://hackaday.com/2014/10/17/detect-cosmic-rays-with-your-smartphone-using-crayfis/
I find this cosmic ray project very appealing.



Also, Adam Fabio over on Hackaday recently posted a Hack-let on ham radio:
http://hackaday.com/2014/10/17/hacklet-19-ham-radio/ 


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"Two guys and a Minima walk into a bar..."

Thomas, KK6AHT, was in Washington this week.  He and I got together for a beer and a look at his Minima. 

I'd seen pictures of it, but it was much more impressive in person.  Thomas did a great job on this rig.  It is a really nice mixture of digital and analog.  I liked the fact that he built the analog portion Manhattan style using MePads.  He and I agreed that while it would make sense to produce a PC board for the Arduino/Si570/LCD portion of the rig, builders should be encouraged to do the rest Manhattan style. 

Showing true homebrew dedication,  Thomas was unhappy with the level of audio output when we turned it on.  He started to trouble-shoot right there in the Ruby Tuesday bar! 

It turns out that we were in a very Knack-ish location.  We were on the site where they created ARPANET. 

Thomas very kindly left me with a nice package of Minima digi-parts including the Arduino chip loaded with the software and an SI570.    So now I have no excuse.  

Thanks Thomas! 

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Arduino Hell!

Hi Bill,

 

I am a long time listener of SolderSmoke and a big fan! Since your last podcast was on the use of Arduino’s for ham radio, my Arduino Hellschrieber project may be of interest to you and your listeners. I am using the $15 dollar RadioShack color display they are closing out and a simple circuit with our favorite transistor!

 

I have a video in my second blogpost and all the details with code below.

 

http://wa6pzb.blogspot.com/2014/10/arduino-hellschrieber.html

 

http://wa6pzb.blogspot.com/2014/10/arduino-hellschrieber-ii.html

 

Keep up the great work, I have your book both in print and Kindle!

 

73, Dan WA6PZB

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Has AA1TJ Joined the FMLA?

I have learned that esteemed homebrewer Michael Rainey, AA1TJ, recently whipped up a 56 MHz, quarter-wave, helical coaxial resonator (BTW: the spoon is also homebrew).  Hmm, 56 Mhz.  Or perhaps we should say MegaCYCLES?  Michael claims this device is for a low phase- noise VFO, but I find the frequency selection highly suspicious.   The last time I heard of that frequency it had to do with an underground group set up by the late (or not so late) Frank Jones.  
Here is all the info on Frank's Five Meter Liberation Army.  

http://www.sunflower.com/~brainbol/frank/

A man of the '30s awakens one night in the '90s (episode 13) with a new mission: recapture 56-60 mc. He forms a Five Meter Liberation Army from his mobile home in a Barrio trailer park run by Tom Joad of Steinback's Grapes of Wrath (episode 9), and soon draws a decidedly uncolorful bodyguard (episode 7). A six foot tall half Mexican stockbroker named for Ayn Rand makes him rich and a demonic white ferret and a half-siamese cat become his familiars. (episodes 10 and 9). The leader of all this, called only "Frank," settles down in the narrator's basement to be joined by Maj. Armstrong (episode 8), Hiram Maxim (episode 23) and one-time pals Carl and Jerry from the 1950s Popular Electronics (episode 25). His huge 1940s sedan, with contemporary plates, is immune from police (episode 13 et seq) and his breadboarded electronic creations recall those distant days when a ham built his own rig and could "fix a radio." Of course all this is crazy. No one builds anything anymore and the other things Frank stands for, like self- reliance, tolerance and a generally Boy Scout viewpoint are simply out of step. Frank knows that too (episode 20), but he does not care. If you're standing in the middle of the road and see a big brown Frazer coming at you, you better jump - one way or the other.

VIVA EL FMLA!  VIVA!


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