Thoughts on DSB PSK-31

To QRP-L: 

I have a JUMA TRX-1 cw and dsb transceiver. It seems to me that if I transmit an psk signal there would be two signals generated, one on usb and another on lsb. Is this correct? It does not seem like a good thing to do to me.
Thoughts?
73 Larry WB4HLX
-----------------------------

Larry: 

I've been experimenting with DSB PSK for the last few weeks.  Sure, you are using twice the needed bandwidth,  but in this mode that means you are using only an additional 31 HERTZ! That's not a lot.  Also, if (as I am) you are using a Direct Conversion receiver, in your waterfall you will also be looking at two sets of frequencies -- those going about 2 kHz above center AND 2kHz below.  This helps you avoid causing interference:  If the frequency looks clear on your screen, you can be reasonably sure you won't be bothering anyone with your extra sideband.

This is similar to the AM question: there too you are using additional spectrum.  But it is allowed.

Doug DeMaw and other esteemed technical gurus have promoted DSB as a useful mode that -- through its relative circuit simplicity -- encourages the building of homebrew gear.  DeMaw wisely advised against using high power when running DSB.

I've been having fun with PSK DSB.  I've had many contacts.  I'm running less than one watt to a dipole.   One curious thing that I've noticed:  PSK seems to be sideband independent:  When I tune in a PSK signal on my FLDIGI waterfall, the software will decode it even if I have the FLDIGI set for LSB or USB. 

You might also want to try JT-65.

Good luck. 

Glad to hear that I'm not alone.           Center             Glad to hear that I'm not alone.

73   Bill N2CQRhttp://soldersmoke.blogspot.com

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

Ontario Knack Story

Bill:

I think I’ve finally earned the right to contact you.  I have a really severe case of the knack.  I did not realize it until I discovered amateur radio.  My thinking is that there is no hope for those afflicted with the knack.  I believe that amateur radio helps those afflicted to deal with the condition.  It alleviates the symptoms.   

For years I wandered through the technical wilderness dabbling in physics (I have a M.Sc. in Nuclear Physics), aircraft (I was a tow pilot at a gliding club for several years), high power rockets (www.napas.net), electronics and amateur radio.  The most enjoyable part of radio is not the QSOs it’s the building and the satisfaction of a working device. 

I am relatively new to amateur radio but I’ve always had a passion for all things electronic (and technical).  I am a self-taught electronics geek and have been playing around with digital electronics (PIC microcontroller) for some time know. I starting building altimeters for high power rockets that has the capability of setting off onboard charges  to separate the rocket.  When your rocket reaches 10,000 feet, you cannot open a chute at apogee because it’s going to drift too far and you need to open the rocket at apogee (no chute) and then open the main chute at about 1000 feet to minimize drift. I routinely travel to the US to attend LDRS (large dangerous rocket ships). 

Anyway I had to get my amateur ticket for onboard video camera and trackers (beacons).  Once I got my license and got into radio, it was like a drug!! 

I am now  home brewing everything in my shack.   

When I came across Soldersmoke that was like a super drug.  I downloaded and listened to EVERY episode (seriously!).  I followed you and Mike’s journey and I learned soooo much.  I was devastated when I found out about Mike.   

You inspired me to build my own transmitter.  Earlier this year I built a 20m CW transmitter for my rocket that will eventually send telemetry (in CW from a PIC microcontroller) completely from scratch – no kits – no one’s design. Your early episodes also pushed me to learn LTSpice which I used extensively to model transmitter design of others as well as my own. I’m thinking of calling the transmitter “kaputnik”. 

My design is based on a Chinese AD9850 DDS module which generates a square wave followed by a class E amp (with a tuned circuit).  Puts out 1 watt of power with harmonics down by about 40db.  The reason I used this module with that I can easily change frequency (with mod to tuned circuit)  – after all the DDS module is programmable.  All I need to do now is clean up key clicks because the carrier is turning on too fast.  I playing around with slowly increasing the bias on the mosfet to allow the power output to increase slowly.  Any advice/tips/tricks would be appreciated. 

Next project is a remote antenna switch.   However, you have me close to tackling a SSB transceiver.

Anyway, keep up the great work and I’m looking forward to listening to another 150 episodes!! 

Take care and “stay thirsty” my friend. 

73
Dave Rajnauth, VE3OOI

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

Building an Arduino Shield

No, an Arduino shield is not something that will protect you from Arduinos.  Resistance IS futile! In the world of microcontrollers, "shields" are, in essence, PC boards with headers that allow you to stack them atop the main microcontroller board.  So instead of the digital rat's nest of wires that you see in my proto-board version of the DDS signal generator, we'll have the AD9850 board mounted above the Arduino on its shield.  But take heart, my fellow luddites:  I have left a lot of space on the board for the construction of a DISCRETE COMPONENT, ANALOG, NON-DIGITAL amplifier.  I'd like to get the output from the 9850 up to around 7 dbm.

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

SolderSmoke Podcast #152 Special Digital Edition

SolderSmoke Podcast #152 is available at

http://soldersmoke.com/soldersmoke152.mp3

May 18, 2013

-- SolderSmoke's WWV Advertising Campaign! 
-- Bands Better -- Working DX!
-- Shack and Shed reorganization
-- Arduino Madness!  CW Beacon Machine!  DDS Sig Generator! (see video above)
-- Breaking and Fixing an Arduino
-- Reverse Beacon Network
-- The Cult of Arduino: QRP Computing with Italian Charm
-- PSK-31 and JT65 with Homebrew DSB Rig
-- SolderSmoke Book Corner:  Hollow-State Design!  Getting Started With Arduino!
-- Massimo Banzi has THE KNACK!
-- MAILBAG:  AA1TJ, G3RJV, AL7RV (now W8NSA), others...  

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 Adventures: LCD screen added

Pretty impressive for a guy whose previous project was a crystal controlled DSB transceiver, don't you think?  They say that variety is the spice of life, and the Arduino board has been adding quite a bit of spice to my tech life lately.  That tiny board up above the proto board is the six dollar DDS-9850 board -- it arrived in an envelope from Shenzhen, China last week. I hope to connect it to the Arduino and the LCD to make a sig generator or VFO. 

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

Earth-Moon-Earth!

I think the really cool thing about this is the "self echo."  Listen carefully when the operator in the video turns it over to the G station.  At first I thought they were doubling, or perhaps another station was on frequency.  But then I realized that when he releases the push to talk, the first signal he hears is his own signal, bouncing back from the Moon! c is real!

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

DSB Digital Success!

It's ugly but it gets you there.  I finally got the little 30 meter DSB/Direct Conversion transceiver that I built in Rome working on PSK-31 and JT-65.  It features a VXO circuit from George Dobbs, an AF amplifier designed by Roger Hayward, and an RF amp chain designed by Peter Parker.  It produces about 1 watt of RF.  At first I was manually switching the rig from transmit to receive, but this got old real fast, so I built a little VOX circuit -- the AF from the sound card does the switching.  Last night I fired it up on PSK-31 and stations were calling me (including one fellow in Cuba).   Then I went to JT-65 and had a complete QSO with KT1B. Another this morning with K0ASK.  It is kind of fun to combine the simple (this rig) with the complex (the computer and these digi modes).   I find that I can work both JT65 and PSK 31 while keeping the VXO at 10.139 MHz.   

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

Drone Dudes

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

Homebrew Adventures with JT65

My six dollar DDS board hasn't arrived yet, so this weekend I worked on the re-build of the 30 meter Direct Conversion/DSB transmitter that I built in Rome (originally for WSPR use).  I was hoping to use this rig to make at least a few PSK-31 contacts.   But I started seeing these strange looking sigs in the waterfall.  I found out they are JT65 (JT for Joe Taylor).  So I downloaded the program JT65-HF.  I got the receiver going very quickly (it is a 40675 dual gate MOSFET followed by the audio amplifier out of Roger Hayward's Ugly Weekender RX).  The transmitter is just a two diode singly balanced modulator followed by the RF chain from Peter Parker's Beach 40 Rig.   QSOs seem imminent.


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

Now That's A Radio Shack! JH0JDV

I was at the workbench this morning, working on a 30 meter DC/DSB transceiver.  I had the Barebones superhet tuned to white noise on 17 meters.  Then I heard a strong CQ that sounded like DX.  It was Ely, JH0JDV.   He was the only signal on the band.  We had a very nice contact, no problems at all.  I was running my normal 10 watts to a dipole.  Afterwards I Googled him.  Wow, he has a REAL radio shack!  FB Ely!

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

Making the World's Smallest Movie

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

WA0RBR's Fun-Rig

Last night I called CQ on 20 CW (with my Arduino keying the homebrew transmitter!) and was answered by Mark, WA0RBR.   I Googled the call and found that Mark is quite a homebrewer.  He wrote a nice series of articles for 73 magazine in the early 80's.   Here they are:

http://mikeyancey.com/73mag/listauthor.php?Author=WA0RBR


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

Save 20% on "Hollow-State Design" and "SolderSmoke"!

http://www.lulu.com/shop/grayson-evans/hollow-state-design/paperback/product-20987562.html


http://www.lulu.com/spotlight/soldersmoke

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 Economist" on Raspberry Pi

http://www.economist.com/node/21576780

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

Direct Digital Synthesis

I just bought one of these.   I hope to hook it up to an Arduino and turn it into a VFO.  Or a signal generator.  Six bucks!

http://www.amazon.com/dp/B009I7DR7E/ref=pe_175190_21431760_3p_M3T1_ST1_dp_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

A simpler DC motor

A few years ago Alan, VK2ZAY, showed Billy and me how to make a very simple DC motor.  This one looks even simpler.  I'm guessing that the bottom of the coil is making intermittent contact, setting up flux lines that get torqued by the magnets' field.  

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

Grayson's New Book

Our friend Grayson's book about hollow-state radio is now available.  It looks like a great addition to the radio art.  Available from Lulu:

http://www.lulu.com/shop/grayson-evans/hollow-state-design/paperback/product-20987562.html  


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

King of the Nerds

Are you a super fan of STAR WARS, STAR TREK, GAME OF THRONES, LORD OF THE RINGS, or BATTLESTAR GALACTICA? Are you a GAMER who owns every console and maxes out trophies and achievements? Do you have an outrageous collection of TOYS and/or COMIC BOOKS? Are you passionate about MATHEMATICS, PHYSICS, or BIOLOGY? Do you build ROBOTS or PROGRAMS for fun? Are you obsessed with SUPER HEROES? Are you a D&D or WoW fanatic? Do you love everything SCI-FI? Are you ARDUINO proficient? Do you know at least 100 digits of Pi?Is your IQ at least two standard deviation above the mean? Do you consider yourself a GEEK or a NERD?

Submit a tape and possibly win 100K.

http://nerdking.net/
 
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

McGyver

Mike, KL7R, was a fan of McGyver.  Mike would have liked this:

http://blog.makezine.com/2013/04/22/5-4-3-2-1-things-about-lee-zlotoff/


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

AA1TJ Crosses the Pond using an Electric Razor!

Take a look at Michael's Razor Rig, made from parts salvaged from his electric razor.   I was thinking that perhaps on the receive side a fox-hole receiver made with a rusty Gillette blade would fit in nicely with the shaving theme.   Very glad to see the AA1TJ blog getting more active. 

http://aa1tj.blogspot.com/2013/04/talking-to-france-via-my-electric-razor.html


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, K6HX's code, and an RBN (minimum) speed limit?

 

Hello Mark:  I've been using your code.  Very nice.   Easy to use and modify, even for a digital dunce like me. 

 

I've been using an Arduino and your code to key my 20 meter QRP transmitter.  I watch the Reverse Beacon Network to see how I'm getting out.  I think  your code let me discover something about RBN:  there may be a lower "speed limit" on the skimmers.  I noticed that when I left your code at the default 12 wpm, I was not picked up by the skimmers.  When I called CQ the old fashioned way (with my hand!) at 15 wpm I got plenty of spots.  This morning I changed the speed setting on your code to 15 wpm and -- sure enough -- immediately got picked up by an RBN station. 

 

Anyway, thanks for the code and for your Brainwagon blog. 

 

73  Bill  

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

MIT's Hobby Shop

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Yellowstone, Smoke-jumpers, and SolderSmoke on 20 CW

Bill,

It has been a long time since I have written to you.  I’m the ex-smokejumper up here in the great winter wonderland known as Montana.  I thought I’d drop a quick note to say howdy and fill you in on the crazy string of events that happened this afternoon.

To refresh your memory…. I stopped jumping fire in ‘09, I have continued to be employed with the US Forest Service as a radio technician.  Part of my duties is to do annual maintenance on all of the Gallatin National Forest VHF handheld radios.  So every winter I update the programming and check the VCOs, RX specs, modulation, and TX power on about 250 handheld radios (luckily the USFS provides me with a handy Aeroflex 3500 service monitor that speeds up this task, but I digress). 

Anyhow I had finished programming and tuning a large batch of radios and today I was making my rounds to deliver them to the various offices.  My route was from Bozeman (where my shop is) to West Yellowstone (where I used to jump out of) … through the North side of Yellowstone Park to Gardiner), then  following the Yellowstone river north up the Paradise Valley (where I grew up as kid) to Livingston (where I live now).  I must say it’s an absolutely beautiful drive that took me to 6 of my delivery points.  This time of year Yellowstone Park is closed to normal traffic, but official Gov’t use is permitted, so you see very few other vehicles, it’s a pretty neat time of year to be in the Park.

Continuing….I stopped at the smokejumper base to deliver their radios and visited with some of the “bros” for a bit then headed on my way.  As I drove off I was thinking of my very last fire jump in Yellowstone and it reminded me that I had written to you back in ’08 about my last jump and listening to “Soldersmoke” while waiting for my ride home.  So today as I drove on through the Park I turned on the old Yaesu FT-747 that I installed in my work truck to accompany me on some of these long drives.  I did not have the mic or key with me, so I was “voiceless”, but I put the 20m stick on my hustler antenna and turned it on anyway.  I enjoy tuning in to some CW while driving and just listening to random QSOs to make use of my drive time by honing my CW skills.  Just after I turned on the radio I heard some a W7 station calling CQ and listened for a while in hopes that it might be W7ZOI, I always am listening for the callsigns of the QRP gurus out there, no luck though it was not Wes.  I continued listening for quite a while.  On the final leg of my trip from Gardiner to Livingston, I was just north of Yankee Jim canyon in Paradise Valley when I heard a very rhythmic CW pattern.  It was almost musical sounding, so I tuned it in good, put the narrow filter on and listened.  It sounded like the OP was using a Vibroplex bug key, due to the long dash patterns, but the way he keyed it was almost like CW R&B..it was a little tough to copy but fun to listen to none the less.  Anyhow as I continued listening, his callsign was KC0MTC in Des Moines, IA and you can guess who he was talking to…none other than yourself, N2CQR!!  I couldn’t believe I had just been thinking about “Soldersmoke”, in fact I had even checked the podcast on my iPhone before leaving West Yellowstone to see if a new podcast was posted yet.   Then a hour or so later, I hear you live on 14.058500 MHz.  What are the chances.  I was frantically thinking of a way to jury rig a cable of some sort to plug into my key jack.  I was hoping you would make another contact so  I could pull over, take a 15min safety break,  rig up a key out of headphone cable or something and give you a call by touching the wires together.  Unfortunately, you disappeared right after the QSO with KC0MTC.  I think you went QRT after that.  I tuned all around the CW portion of 20 searching but no luck. 

Either which way, I got a big kick out of it and thought it was quite a coincidence.  I figured you would appreciate the story.  So here is your signal report into Montana …

You were just above the noise this evening, which is quite high S3-4 due to the engine noise in my mobile. You were readable most of the time but dipping into the noise occasionally.   I heard you tell him you were QRP but missed the power level you were using.  I’d give you an RST of 549, this was about 1730 MDT.  Not bad at all for QRP and 1800 miles or so….KC0MTC was booming in a solid 599.

Anyhow 73’s,

Kevin – AA7YQ

"The New Cool"

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 Repaired (well, sort of)

Thanks to info from Leif, KC8RWR, about the purpose of the chip that was heating up on my Arduino board (an LM386 used to determine which socket was supplying voltage for the board) I decided to try just taking the hot chip off the board.  This afternoon I fired up my reflow station and blew some 466 degree F air on that chip.  It came right off and the Arduino appears to work just fine without it.  

This was only a semi-satisfying repair.  It would have been much better if I'd really known what I was doing, and if I'd really known what was going on with that chip.  

The removed chip is up by the tip of the pen (TOO SMALL!).  The transistor and the relay that keys the transmitter are on a piece of PC board above the Arduino. 

That Arduino called CQ for me on 20 meters tonight -- Mel, K4JFF,  in Georgia responded.  Thanks Leif! And thanks again to Mark, K6HX, for the code.

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

Adventures with Small Computers

 
I've succumbed to the lure of the tiny computers and microprocessors.  This weekend I was playing with the Arduino that I bought (supposedly) for Billy.   You see, I have a little microprocessor-based keyer in my ten meter beacon rig (Demaw's "Lil'Slugger") .   It works fine once you get the desired Morse sequence into it, but getting that done is difficult and frustrating for someone (like me) unaccustomed to an iambic keyer.   So I was thinking that this would be easier just to replace the keyer with  an Arduino.  I was right.    With some help and advice from Billy, I got the Arduino going, and got the little LED blinking.   Then I took some code from Mark K6HX, modified it for my call-sign, and loaded it into the Arduino.  No problem at all.  Kind of fun.  And it opens your eyes to all the possible applications of this little board. 
 
Unfortunately, in the course of fooling around with the interface between the board and my rig I think I did damage to my Arduino.  I managed to blow out the blinking (pin 13) LED on the board.  I could live without that, but now the ICs get very hot (especially the little surface mount chip just below the 16 MHz crystal).   Anyone hope of fixing this?  (I've already ordered a replacement board,  but I feel guilty about this.)
 
Here's a good article describing the pros and cons of Arduino, Raspberry Pi and Beagle Bone:
 
http://blog.makezine.com/2013/04/15/arduino-uno-vs-beaglebone-vs-raspberry-pi/ 

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

French Knack: F8ATA, F8KE, F8CKH, and K3DY

Hello Bill, It has been a while! I don't know if you remember but I emailed you back in September 2010, introducing myself as a fellow amateur listening to your podcasts. I had just moved from France and received back then my FCC vanity callsign K3DY.

It took me a while to get my ham shack back together but finally I was on the bands again! Recently, I started re reading your book, very inspirational. Since my very first license (as F8CKH) at 16, my interests have always been into the design / homebrew as well as QRP & CW. Why on earth would a teenager do that? I think I have the knack. My motto is: "Don't turn it on, take it apart!!!".

Anyway, it has been a lot of fun to work on some various projects (the one in progress now is a LC meter using a LCD display and a PIC 16F627). It took longer than expected to get to that point as I had to work on a PIC programmer interface as well as refresh my C language programming skills! I recently discovered that mouser is offering some nice project enclosures. In the past, my finished products were kind of "ugly" (to the average Joe not us of course!) so I am trying to work on that.

Oh also, last time I emailed you, I talked about my grand father EF8ETA, F8ATA then F8KE in the late 20s and how seeing his electronic lab and radios when I was 7 or 8 inevitably changed my life! After all this, I - had - to get my license and get involved! My father, also a ham, emailed me a picture of F8KE's shack in 1929/1930. My grand father was at the time 19 years old. Also attached to the email are two scans of his QSL cards dated as well 1929 or so. He was using a classic design for the era, based on a Hartley Oscillator. I am trying to imagine how it was to get the knowledge back then on how to build a station (TX, RX, antenna) but also how to get the parts! When people now complain that they can't finish up a homebrew project because they can't find a FT50-3 core, well they should think of how it must have been almost 100 years ago.

Have a great weekend! 73, K3DY Antoine

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

Happy World Cosmonautics Day!

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 and Bugs (real bugs! billions of them!)

http://blog.makezine.com/2013/04/10/swarmageddon-cicadas-helping-crowdsource-citizen-science/

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

Imaging Across the EM Spectrum

Amazing images here:

http://blog.makezine.com/2013/04/09/somewhere-outside-the-rainbow-imaging-across-the-em-spectrum/

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A Nice Workshop in Germany

Wannabe-Choppers from Thorsten Indra on Vimeo.

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

Sputnik Schematic Found!



We were searching for this last year.  Oleg, RV3GM, finally found the schematic for the transmitter in the Sputnik satellite. 

ftp://ftp.radio.ru/pub/2013/04/55.pdf


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SolderSmoke Podcast #151

SolderSmoke Podcast #151 is available.

http://soldersmoke.com/soldersmoke151.mp3

April 1, 2013

Topics:
-- Spring not yet sprung
-- Dominican nostalgia wave hits SolderSmoke HQ
-- Rebuild of my first transmitter
-- Dusting off the Barebones Superhet
-- SolderSmoke Book Corner:
      Ben Franklin by Walter Issacson
      How Arthur C. Clarke handled his Mailbag
      "The New Cool"  Dean Kamen's house/shack
      Transistor Radios by Ronald Quan
-- New SolderSmoke Advertising Campaign
-- QRP vs. QRO:
      Put 40 milliwatt "Shark Fin" QRSS rig on the air
      Being lured into QRO amp construction projects
-- Reverse Beacon Network
-- Looking for my Elmer (or his son)
-- MAILBAG

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

An update from Yi Yao, VA3YAO

We did a short article on Yi Yao a while back, noting that he definitely has The Knack.   His homebrew frequency counter (above) confirms that he does.   In a recent  e-mail from him I also detect an inclination toward poetry.  April is Poetry Month, so I thought I should share the latest from Yi:

Hi Bill,

I haven't gotten around to making my first rig yet. But, after
listening to SolderSmoke since the beginning, it seems like the universal rule
of homebrewing has been to avoid regens!

I've been focusing on mechanical design for the last while. Having
spent 2 years in a heavily electrical engineering oriented
environment, I decided to try something new. Most of the smoke that
 I inhale these days is from cutting oil vaporizing as I turn something
on the lathe. Chips mean bits of metal that are created from cutting
metal. Soldering is done with a torch. The common thread with
electronics is the knackish pursuit of elegant design and beautiful
construction.

I've been thinking about getting myself a copy of SSDRA, but even
looking at online used book stores, this is costing in the
neighbourhood of some of my university textbooks. There's no shortage
of good information and ideas for homebrewing online though. I think
that's what I will use.

Cheers,
Yi


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

Wow! Great Article on the Wow SETI Signal

Thanks to David Umbaugh (and his son!) for alerting me to this really great article in The Atlantic on one intrepid amateur who has chosen to follow-up on the famous (and possibly extraterrestrial) "Wow" signal.   You will like this article. 

http://m.theatlantic.com/technology/archive/2012/02/the-wow-signal-one-mans-search-for-setis-most-tantalizing-trace-of-alien-life/253093/

Robert Gray's book is available here:

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

Good time to Buy Book: 20% off at Lulu

http://www.lulu.com/spotlight/soldersmoke

Use Coupon Code VERNUM through March 31 and get 20% off.

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

Edgy Skimmer Antenna

For the last few days I've been hanging out on 20 meter CW, 14.050 - 14.060 MHz, using my re-built W1VD/Barbados rig.   I've had some great contacts, but almost as  much fun is watching the Reverse Beacon Network to see who is hearing my calls.   WA7LNW is one of the "skimmers" that most consistently picks up my signal.  One look at the picture above explains this.  The receive antenna for his skimmer rig IS ON THE EDGE OF THIS CLIFF!   Jack has one of those dream jobs for a radio amateur:  he works at that amazing location, testing ejection seats for jet aircraft.  More great pictures here: 

http://www.dxwatch.com/qrz/lookup.php?c=rbn/WA7LNW

Thanks for the reports Jack!

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AA1TJ's Latest QRPp Rig

 

From Mike, AA1TJ:

I called CQ on 20m CW for a couple of hours yesterday afternoon with no response. With the cadence of my own Morse tugging at my eyelids, I was suddenly shaken awake by a brisk signal returning my call and signing CU2BV. I snapped out a 579 report and turned it over. The dits and dahs in my headphones told me it was Fernando; operating from São Miguel island in the Azores. He reported a weak but solid copy (529) of my fifty milliwatt signal.

Here's the radio that I used yesterday. The one-transistor transmitter is to the left of the red relay on the top board. The single transistor is a germanium surface-barrier device made by Philco in August of 1958. To the right of the relay is a two-transistor time-delay circuit used to switch the antenna between the transmitter and the receiver. My receiver on the lower proto-board is a reproduction of my first shortwave receiver: a $7 Japanese kit that I bought at Radio Shack when I was 13 years-old.

Fifty milliwatts is some twenty-four times less power than was used by an old double D-cell flashlight. I later learned that my signal was nearly simultaneously picked up by an automated receiver located just west of Dusseldorf, Germany.

Snowy Vermont to the lush Azores - some 1500miles off the coast of Portugal - with less power than is consumed by a beeswax candle...is it any wonder that I love radio? ;-)

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

Sunblock! Earth-Sun-Mars Alignment Affects Communications

Something to be considered by those hoping to win the Elser-Mathes Cup.

http://www.jpl.nasa.gov/news/news.php?release=2013-108

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

Video of my Barebones Superhet

I literally blew the dust off this thing last week.  I posted the schematic a few days ago (scroll down).   This morning I finished re-building the CW transmitter that went with it.   I am running out of rigs to re-build, so I suppose I will now have to start building some new ones.  Maybe a BITX-20?  Or a BITX-75/20? 

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 Southern Appalachian Radio Museum

Chris, KD4PBJ, of SMT Solutions, sent us a thumb drive with pictures and videos of his visit to the Southern Appalachian Radio Museum.   What a great collection of radios!   I saw many old friends on those shelves.

There is a lot of radio history in that museum, and much of it is conveyed by the photos and videos that Chris took.   Here they are, all 111 files:

https://picasaweb.google.com/116927941005026017464/SARM#

The museum is in Asheville, N.C.  http://www.saradiomuseum.org 

Thanks Chris.  And thanks to the curators of this fine museum.

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

A Beautiful Receiver by W1DN

I wish my prototypes (or final products!) looked this good.    I like the way Lee puts the switches onto the prototype board.  Very nice.

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

Wow! Raspberry Pi as an RF Transmitter

https://github.com/threeme3/WsprryPi

This site shows you how to use a $35 Raspberry Pi Computer as an RF transmitter for the WSPR (Weak Signal Propagation Reporting) System.  All you need is a simple low pass filter and an antenna. (Oh yea, and a ham radio license.)  The site says you can get 10 milliwatts out.  That's enough for WSPR!   Very cool. 

This looks like a real international effort:

Credits goes to Oliver Mattos and Oskar Weigl who implemented PiFM [1]  based on the idea of exploiting RPi DPLL as FM transmitter. Dan MD1CLV combined this effort with WSPR encoding algorithm from F8CHK, resulting  in WsprryPi a WSPR beacon for LF and MF bands. Guido PE1NNZ extended this effort with DMA based PWM modulation of fractional divider that was  part of PiFM, allowing to operate the WSPR beacon also on HF and VHF bands.

For more info on WSPR:  http://soldersmoke.blogspot.com/search/label/WSPR

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Podcast Noise Explained; Mic advice from Germany

Hello Bill,

This might be down the drain for you, but I only listen to your podcast very few months:

The background hiss you mentioned in Soldersmoke 148 definitely was a crosstalk from the switching voltage converters for the CPU in your laptop. The CPUs these days are operated with voltages in the .7 V to  2 V range,with currents from several Amperes up. A high-performance CPU may dissipate150 W which can easily mean supply currents of 100 A an more. The CPU operating voltage, especially in a laptop, might change several 100 times a second. I think you can imagine the rest.

Why is that voltage adaption so important? This is within your domain: The biggest heat source in digital electronics these days is charging and discharging capacitors. Unless you use a resonant circuit (which you cannot do on a chip) you dissipate P = 1/2 C U^2 with every discharge. Yes: Power depends on the square of the supply voltage. And at a clock frequency in the 2 GHz range you charge and discharge all those capacitors quite often. Each of these has a capacity in the fF (.001 pF) range, but you have billions of these...

Over the time you had quite some complaints about your whistling s. In former times this was definitely made worse by some technical problems. But this is a problem long gone. An Soldersmoke 149 I believe the remaining problem simply was the tooth gap you described a few years back.

BTW: You could easily reduce the file sizes of your podcasts by at least 50% with a few simple measures:

- You should record the podcast as you do now, with a 44 or 48 kHz sampling rate, that's fine. I would even record in wave format.

- Afterwards downsample your recording to a sampling rate of 12 or 16 kHz. This provides ample audio bandwidth for this purpose. See e.g.http://forum.audacityteam.org/viewtopic.php?f=28&t=19705

- Then create the MP3 file with a signal rate of 48 or 64 kbit/s.


BTW: Last weekend at a ham flea market I got a variable transformer. Now I can try to revitalize my Drake TR4C that has not seen any electricity for some 30 years. I bought it when I got my shortwave license in 1975. At that time I lived with my parents. Then I could operate it during my military service. But after that I got an electronics engineer and lost all possibilities to erect any kind of SW antenna. Only three years ago I got my own house near Munich. But I'm hardly at home and I nearly exclusively operate from my car. I will not try this with any kind of boatanchor :-)

vy 73
Alexander
DL4NO

------------------------------------
Von: solder smoke [mailto:soldersmoke@yahoo.com]
Gesendet: Dienstag, 19. März 2013 09:49
An: DL4NOAlexander
Betreff: Re: Soldersmoke 148: Background Hiss

Thank you Alexander.  That is very useful information.   I have switched to a new computer and I think the hiss  problem is gone.   The gap in my teeth remains however!    I am thinking about getting a better microphone.  Any advice on this?   I am glad to  hear that you are back into ham radio.  My Elmer (the guy who helped me get started as a novice) was an immigrant from Germany (Hilmar,  WN2NEC).  He was an excellent technician.   I still use some of the things he made for me.   73  Bill ------------------------------------------------ Hello Bill,   about a microphone: Think about a headset, possibly a wireless one. I would search forums about dictation software for advice.   A headset fixes the position of the microphone relative to your mouth. At the same time the microphone is near your mouth so any ambient noise is suppressed. A wireless [Bluetooth] headset would allow you to move around freely. Unless you come near a larger hard or soft surface or leave the room the sound should not change much. You could arrange the materials for your next podcast around the room and move from "chapter" to "chapter". And as the digitizing happens in the headset all weak analog signals are safe away from any voltage converters and digital electronics.   I had never left ham radio, I just reduced and modified my activities. 2m or 70cm FM were always possible. Here in Germany we have more than 1,000 repeaters. Many of these repeaters have Echolink capabilities. For the last 15 years I have more or less exclusively worked from my car while driving. In my car I have a FT-857D. For shortwave I use monoband antennas on a PL mount at on the roof of my car. For pictures see http://www.dl4no.de/thema/amateur1.htm. The schematic in http://www.dl4no.de/thema/mobil-st.htm shows how I ensure that my TRX gets its 22 A peak from the 12V outlet in the trunk of my car: I buffer it with a 1 F capacitor - really 1,000,000 µF! The mean supply current during SSB transmit is less than 5 A.   A quite important role in my ham life play the local chapters of our German ham radio society DARC. There are more than 1,000 of them, each with its own DOK. So wherever my customers are, at least one local ham meeting a month is not far away. I participate in their activities, give a lecture from time to time. This is a big help as I mostly work at my customers and these are scattered all over southern Germany.   Just a short story with some local connection for you: Peter, DL5NC, spent quite a few years in the Washington, DC area. He has a US call, but please don't ask. He was born some 50 km from my home town. Formally this area, Franconia, has been part of Bavaria since 1806. Nevertheless we believe that the Bavarians have no clue how to brew beer.   One Friday morning (your time) he was on his way into Washington, DC. Through Echolink he connected to a Munich repeater while I was in the afternoon rush hour on my way to a beer garden. I told him that this was one of the few places in Munich where you could get a decent beer. And otherwise I had my own beer at home imported from Franconia. He threatened to never again talk to me because of mental cruelty. In the meantime he returned to Germany and got a neighbor. We drank a few Franconican beers together in the meantime :-) vy 73 Alexander DL4NO

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DeMaw's Barebones Superhet

A recent e-mail got me thinking about Doug DeMaw's Barebones Superhet.  June 1982 QST.  Mostly 40673 Dual Gate MOSFETS (this one's for you Dino!).  Barebones indeed.  Check out the schematic.

I literally blew the dust off my version and fired it up on Sunday.  It sounds really great.   I had lowered the values of the caps in the ladder filter to widen it out for phone.   Also, I see that I used LM386 instead of the op amp AF Amp prescribed by W1FB.   I notice that my version has much better audio than another version of this RX (with the op amp) that I'm using on 17 meters.  Could the difference be the LM386 vs. op amp?  There is a lot more audio with the 386, and the AF response seems wider.  

I feel the urge to put this receiver to use.  I am rehabilitating the W1VD CW transmitter that used with it during the late nineties, but I'm a phone guy now, and I feel compelled to use this RX as part of an SSB rig.  Of course, I could build a standalone SSB TX, but how about a diode switching scheme to make use of the Barebones' filter, the VXO and the BFO in a transceiver?

Here is my article on the original build of this receiver: http://www.gadgeteer.us/HBHOME.HTM

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A Beautiful Workshop in Scotland

A nasty Coronal Mass Ejection hit our magnetic field at around 0600 UTC today.  The HF bands are now in poor shape.  What better time to visit a really impressive workshop in Scotland? 

Ian has an interesting site: http://www.ianjohnston.com/

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

Vanguard!

Wow, Vanguard even looks like a QRPp satellite. 

I suspected that something was up:  I noticed that Mike Rainey, AA1TJ has recently been crossing pond with a QRPp Germanium rig...  Then Steve "Snort Rosin" Smith clued me in: The next period of  Vanguard QRPp Activity Days begins tomorrow.  "Club 72" has a nice write up, and a nice collection of pictures of the Vanguard rigs that have been built around the world:

http://www.club72.su/vanguard.html

Go Germanium!  Go Vanguard!

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QRP SSB with a New Rig

Kelly, WB0WQS, was trying out a new KX3 that his wife had given him as a present.  The radio gods must like that low-power rig because, in what seems like a deliberate demonstration of the awesome power of QRP phone, Kelly's first QSO was with another QRP operator:  me!  The sun was going down and taking 17 meters with it, but neither of us missed a word.  We talked about SolderSmoke and our mutual friend, Jerry, NR5A -- Kelly had known Jerry when they were teenage hams. Good luck with the new rig Kelly!

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