Great Hackaday Article on the Venerable LM386

I'm not crazy about chips, but I've come to like the LM386.  It is not really a little black mystery box -- as the article points out, the internal circuitry is simple and completely understandable.  So you shouldn't feel any appliance-op angst when you use one of these. 

http://hackaday.com/2016/12/07/you-can-have-my-lm386s-when-you-pry-them-from-my-cold-dead-hands/

A Charming Detail About the BITX40 Module

In the BITX20 yahoo group, Farhan responded to a question about the BFO and the crystal filter in the BITX 40 Modules.  In his response we learn more about the work of the members of the women's collective.  Uma is the name of the lady who has the job of sorting the crystals. She sorts 1000 a day:

Farhan writes:

There is a longer explanation to this. The crystals we use in the BITX are microprocessor grade. This means that they are not very precise. Uma is the crystal sorter. She takes a bunch of 1000 crystals a day and sorts them by their frequency into different bags. Each board takes its five crystals from any one bag. Hence, the central frequency of each board will be slightly different from another board.

The central frequency of the ladder filter moves down from the oscillating frequency of the same crystal. That is why, in a set of matched crystals, one can be directly used as the carrier/beat frequency oscillator without needing any trimmer : it directly sits on the higher side skirt of the filter.

The BITX40 board's BFO usually ranges from 11.990.0 to 11.997.0, though in almost all cases it is very close to 11.998.0. The best way to determine the BFO frequency is to take it another ham's shack, tune in the BFO to zero beat on USB or LSB and note the frequency. I use the Rigol scope's built-in frequency counter to measure it off the modulator transformer's primary.

So, the IF offset should ideally set to the measured BFO's frequency. These are however, very subjective choices. Given that 2.2 KHz is not an ideal passband, 3 KHz is more like it, setting the BFO will determine how you would like to hear the receiver. Setting it close to the passband will make it bassy, setting it away will make it tinny. Setting it a few hundred hertz away will make it hollow. You get to choose which way you want to make your radio sound bad (harr! harr!)

- f

Boxed-up and Looking Good: An End to "HRO Al Fresco"

The "al fresco" phase has ended for my HRO receiver project.  As has happened with homebrew projects around the world, this rig was literally pushed aside on the workbench to make room for BITX-40 Module Mania.  I began to worry that the circuitry of the HRO receiver might suffer damage from the various kinds of electronic construction mayhem that take place on our workbenches.  Also, I wanted to see what it would look like in the nice big metal box that Tim Sutton had sent me (thanks again Tim.)  And I was hoping that the box would help with the AM broadcast breakthrough that I sometimes hear with this receiver.  So, as you can see, I have good excuses for declaring Basta! on the HRO Al Fresco. 

I think it looks great.  Black on silver is very cool.  It sounds great.  I'm listening to 40 right now. Thanks to Armand WA1UQO  for the very cool HRO dial that got this all started.   

TRGHS! HB2HB! Homebrew Extravaganza on 40 Meters!

AC7M HB Amp and HB Power Supply

I was flying solo last night.  Everyone else in the house was out.  So I turned to ham radio for some company.  And I was rewarded.    

I called CQ with my BITX DIGI-TIA rig and was immediately answered by Doc AC7M in far-off Twin Peaks, Idaho.   Doc was running a K3 to a homebrew solid state full gallon amp.  And get this -- Doc had also homebrewed the 3 kw switching power supply.  I looked at my store-bought supply and felt like an appliance operator.  I hang my head in shame.

As we discussed solid state amplifiers, we were joined by another builder of silicon after-burners: Don K9AQ, who called in from a beautiful cabin in rural Wisconsin. Don's amp is based on the venerable EB-104 design.   

Both Don and Doc talked about the work of W6PQL.   He has a really amazing site devoted to homebrew solid stat amps, and he is selling lots of great boards and parts for this kind of project:
http://www.w6pql.com/  

As I finishing up with Don and Doc, I got a very welcome call from an old friend from the SolderSmoke community: Dino KL0S.  He as booming in from Williamsburg, Va.  Dino has an amazing workshop.  He is building a serious vertical antenna for 160 meters.  Dino is going for the DX.

Dino's Bench

At this point Mike WA3O in Pittsburgh called in.  And get this:  Mike heard me on his new BITX 40 Module.  The Radio Gods Have Spoken! (TRGHS!).  We switched up to 7.285 MHz where I fired up my BITX 40 Module for a BITX40-BITX40 QSO (albeit not at QRP levels).
We should definitely make more use of 7.285 for BITX40 and other HB QRP SSB QSOs.  1930 EST (0030 Z) seems like a good time.

Finally, just when I was thinking that things couldn't get any better, they did:  Armand WA1UQO called in from Richmond.  Armand and I collaborate on parts acquisition at Virginia hamfests.  We specialize in the contents of the musty cardboard boxes found under the tables.  We discussed the DISRUPTIVE influence of Farhan's BITX 40: All around the world, other homebrew projects are being literally pushed aside on workbenches to make room for that fantastic little module from Hyderabad. 

I was very pleased to hear that Armand is building an analog VFO for his module, using a coil in the 4 uH range, wound on a piece of cardboard tube from a coathanger.  The inspiration for this kind of coil (which I now have in THREE rigs) came from Farhan, who used sipping straws from fast-food restaurants as coil forms in a sig generator that he built years ago.  This week, seeing a Facebook picture of my daughter and me in a restaurant with drinking glasses in front of us, Farhan asked if I had brought home the straws. 

Pete Juliano Adds Yet Another Great Word to the Homebrew Lexicon

We've talked many times about the pleasures associated with a rig that is still just a collection of parts and boards, all still spread out on the workbench, unboxed, perhaps held together by clip leads and bits of duct tape.  They seem to sound better this way.   This is the condition under which we experience that magical moment of "First Signals"  (similar to First Light with a new telescope).

We haven't had a concise way of describing this (note my long-winded description above).  Well, this morning the Sage of Newbury Park has, on his amazing blog, provided us with the words that we have so long needed: 

Al Fresco! 

That's it!  Perfect.  When a new rig is put into operation in this way, we will henceforth say that it is being run "al fresco."  Thanks Pete!

Check out the blog post that gave us this wonderful phrase:

http://n6qw.blogspot.com/2016/11/a-little-arduino-magic-for-fpm5.html

'Tis the season... To Worry about Electrostatic Discharge

Read and heed, or you'll be sorry.  The cold weather causes us to spend more time in the shack and to work on new homebrew project.  Some of these projects may involve sensitive, delicate, solid-state components that can be instantly wiped out by that little winter spark from your finger...

Take a look:

http://soldersmoke.blogspot.com/2016/01/an-electro-static-bandaid-to-protect.html
 
I have to be especially careful this year, because Northern Virginia is now officially in a drought.  So that spark-friendly dry winter air is likely to be even dryer this year.

Moonbounce on 40

Well, we were talking about it on 40.   This just proves that there is more to 40 meter SSB than the never-ending quest for audio "brilliance," "presence," "body"  and "sparkle."   I was working at the bench yesterday when I heard Frank NC1I telling another fellow about his 35 years of experience with moonbounce.  Wow, you don't hear that kind of talk on 40 every day.  Frank also said that the contact I was listening to was one of very few HF contacts that he has made in recent years.  I just had to jump in to encourage him to get on 40 more regularly.  He seemed impressed with my BITX40 Module (which I was using).  I warned him of the buffoonery that can be found on the band, but told him not to be deterred by it -- there are a lot of FB hams on 40.

Above you can see Frank's amazing antenna farm.  The dish is for 23 cm EME. Behind the you can see his 70 cm array.  That is 48 (FORTY EIGHT!) end-mounted Yagis, aimed into space. 

Check out Frank's QRZ.com page:  http://www.qrz.com/db/NC1I  He has some great pictures of his shack.  In case you are wondering why he has so many rotator control boxes, remember that the dish and the Yagi array need two each (azimuth AND elevation).

HB2HB: Butch K0BS with a KWM2 and a Hombrew 4-1000 Amp

Wow!  Now THAT is a shack! This morning I heard Butch K0BS and his friends on 40 meter SSB.  I knew I was listening to the voices of kindred spirits when I heard them talk about a drifting VFO and the need to heat up the filaments of an ART-13.   As the group was shutting down to begin their preparations for Thanksgiving dinners, I gave Bruce a call with my BITX 40 Module. He was on a KWM-2 (the rig that had been drifting a bit) and a homebrew 4-1000 amplifier.  I told him that I think a bit of VFO drift is a sign of good character. 

You really need to check out the pictures on Bruce's QRZ.com page:  

https://www.qrz.com/db/K0BS

Happy Thanksgiving to all who are celebrating the holiday.

Ron Swanson (Nick Offerman) on Making Things and Making Mistakes

Driving home from work the other day I heard this NPR interview with the woodworking guy from the TV show "Parks and Recreation."  I've never seen the show, but I really liked the comments on the benefits of what we would call homebrewing:

MCEVERS: I feel like there are a lot of people out there listening who have spent exactly zero days being handy, like, their entire lives. Is there hope for people like this, and does your book provide it?

OFFERMAN: I think so. I mean, a lot of my own woodworking education comes from books and periodicals like Fine Woodworking and Popular Woodworking magazines. They're great teachers, but they're very somber. They're very sober. So it was important to me for this book to be really friendly and gentle and fun to let you know that whether you're getting into woodworking or making anything with your hands, it's really important to know going in that you're supposed to make mistakes. You're supposed to screw it up.

And not only do I think this is a very friendly introduction to woodworking, but I really have become a little bit of an evangelist to encourage - find something to make. If you make stuff for your house or your loved ones, you're curating your life in a way, saying, I don't have to just limit my choices to what I can buy at Amazon. I can also choose to make a table myself. And even if it looks crappy, it's still so much more charming because you've made that gesture.

You can listen to the 6 minute interview (it is funny) by clicking on the "PLAY" arrow in the upper left of this page:  

http://www.npr.org/2016/11/17/502476216/nick-offerman-shares-his-love-of-woodworking-in-good-clean-fun

HB2HB! Pete Talks to Famed SSDRA Project Builder Jeff Damm WA7MLH

Jeff "Roadkill" Damm 

Wow, THE RADIO GODS HAVE SPOKEN (TRGHS).  Pete gets on 40 with his new-old FPM5 homebrew rig and works homebrew legend Jeff Damm WA7MLH, who was also running a homebrew SSB rig.   HB2HB!   For those of you who don't know, Jeff is the guy who built many of the inspirationally ugly rigs in Solid State Design for the Radio Amateur.  Pete's second QSO was with SolderSmoke podcast listener K7ADD.  TRGHS! 

Hi Bill,

Was on 40M yesterday with the FPM5 rig and after finishing a QSO was called by WA7MLH (Jeff Damm –the road kill guy and protégé of Wes Hayward). Jeff was operating portable 7 in NW Montana running a homebrew 40 Watt SSB transceiver off of batteries being charged by a solar panel. Now that is real radio. I thanked him once again for sending me a goodie box about 5 years ago and am still using those parts.

Later after another QSO was called by K7ADD, Ben, and he couldn’t wait to tell me he was a long time SS listener and stated listening to SS made him take a whole new interest in ham radio –especially building stuff.

So you never know.

Pete

Homebrew Processor with Discrete Transistors and LEDs

I've been working with an Arduino today.  Seeing this video makes me feel like such an APPLIANCE OPERATOR.  FB OM!  No store-bought mystery boxes for him! 

Thanks to Steve N8NM for alerting us to the magnificent project.

More details here:

http://www.popsci.com/man-builds-huge-megaprocessor

Analog TO THE MAX! An Old School Readout for the BITX 40

Perhaps this was a reaction to a frustrating morning spent trying to get a 20x4 digital display to work with an Si5351 and an Arduino Uno via an I2C bus (I feel my blood pressure rising just due to the typing of those words).   After much digital fiddling, I declared a "BASTA!"  and looked around the shack for an antidote for the digital frustration.  There on the bench was my fully analog BITX40Module rig, with its homebrew L-C analog VFO.   It needed a better frequency readout. And this morning, it got one.  

The pointer is Sharpie ink on a bit of PC board.  It is held in place by superglue, suspended by a piece of wood about 1/4 inch off the chassis (to reduce dial parallax).  The numerals are in Dymo tape -- there was not enough room for the "7" but I think I will be able to remember this. 

Very therapeutic and satisfying.