Rex W1REX in England with the Original Tuna Tin 2, aka "The ASR" -- Ancient Sacred Relic. Indeed!

 

There he is, Rex W1REX, the esteemed owner of QRPme, the maker of so many great pads for Manhattan boards.  He was in the UK for the GQRP convention.  And he brought with him -- on loan from the ARRL Museum -- the original Tuna Tin 2 transmitter, the ASR (ANCIENT SACRED RELIC).  You can see it in the pictures sent to me by Charlie NJ7V. 

Way back in 2014, I met up with Rex at the Vienna Wireless Association's Winterfest Hamfest.  There too he had the original TTT with him.  I asked him to share some of the mojo from that famed rig with my homebrew BITX transceiver.  Here you can see a video of the mojo-ification ceremony: 

Thanks to Charlie NJ7V, to the GQRP club, and to Rex W1REX for all the great TTT mojo over the years! 

Rex Harper on the 50th Anniversary of the Tuna Tin 2 -- DONATIONS NEEDED!

I was really pleased to see Rex Harper W1REX on a special edition of the RedSummitRF video podcast:  

 https://www.youtube.com/watch?v=SUQE4OvkAtU

Rex provides a lot a great background info on the Tuna Tin 2.  We are approaching the 50th Anniversary of the publication in QST of the Doug DeMaw article that launched the TTT revolution.  Rex has the original TTT in his possession, and is organizing a 50th Anniversary tour. We can only hope that much Mojo will be dispensed. 

I built one in a real tuna can:  https://soldersmoke.blogspot.com/2014/05/fdim-midnight-mojo-ceremony-tuna-tin-2.html  I still have the board! 

And above you can see Rex allowing the Mojo of the original TTT to flow into my homebrew 17 meter BITX (2014).  Rex and Charlie talked about this ceremony in the video cast.  Very cool. 

Rex is making available a 50th Anniversay edition kit of the Tuna Tin 2.  Get yours here: 

https://www.qrpme.com/?p=product&id=50A

Also,  Rex needs some help in financing a Tuna Tin 2 world tour.  YOU CAN HELP!   No need to limit your donation to 1 dollar.  Donate here!  https://www.qrpme.com/?p=product&id=WWT

Thanks Rex, thanks Charlie! 

Mitch NK3H's FB SolderSmoke Direct Conversion Receiver -- "Incredibly satisfying!"

Wow, Mitch NK3H has built a really nice receiver. (He says it is not pretty, but those of us who have built one or who are in the process know that it looks great.) The SSB really sounds good also. 

Mitch writes: 

It's not pretty but it works! Incredibly satisfying. In answer to the questions, (1) though I 'd built a few small Manhattan style boards (e.g., Michigan Mighty Mite) this was more complicated. I've been using W1REX's island cutter to create isolated areas on the copper clad board, rather than pasting on pieces of circuit board. But the islands are a little small for as many as four connections on one island, as in most of the transistor bases. Inevitably a component lead would inadvertently contact the ground plane and all bets were off. Tracking down the shorts was challenging. (2) Once I got to the audio amplifier board I carefully laid out all of the components before starting to solder. But as I finished each stage and was ready for the next, I always seemed to be missing a resistor or two. I'd search the desk and the floor -- very frustrating. Turns out the speaker magnet was collecting and hiding the missing resistors. Lesson learned. (3) Next I'm hoping to build a transceiver. Still looking for the right project, probably a little more digital than this wonderful DCR.

Mitch obviously learned a lot during this project.  I had similar experiences with pads on the same level as the surrounding board -- I found that the 1 or 2 mm of elevation provided by the Manhattan pads prevented a lot of inadvertent shorts to ground.  And I too "lost" (temporarily) a lot of components to the magnet in the speaker.  

Good luck with the next projects Mitch.  With the Michigan Mighty Mite and the DCR under your belt you are ready to go.  Maybe a Double Sideband transmitter to go with the DCR? Or, as you said, perhaps something more digital.  There is a lot of good ham experience with the Si5351 digital VFOs.  Or maybe even an SDR rig.  

Thanks Mitch.  Congratulations and welcome to the Hall of Fame. 

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

Join the discussion - SolderSmoke Discord Server:

https://discord.gg/Fu6B7yGxx2

 

Documentation on Hackaday:

https://hackaday.io/project/190327-high-schoolers-build-a-radio-receiver

 

SolderSmoke YouTube channel:

https://www.youtube.com/@soldersmoke

A 40 Meter Direct Conversion Receiver from M0NTV -- With some SolderSmoke Comments

Nick's video appears above. 

First, let me say FB Nick.   It is nice to see you making use of the AGC amp designed by Wes and Bob,  using the board from Todd's Mostly DIY RF, using a mix of homebrew pads and Me-Squares  from Rex, and finally the Franklin Oscillator that we spent so much time talking about on SolderSmoke.  

But here are some comments:  

-- I still don't think you need that RF amplifier in front of the mixer. And I suspect you would be better off without it.  We did not use one in our high school 40 meter project, and never missed it.  In fact, on one version of the high school receiver I even put in a simple 10k pot as an attenuator (no RF amp).  Even up on 20 meters, I do not have an RF amplifier ahead of the diode ring mixer on either of the Mythbuster rigs I have built.  Nick,  maybe experiment a bit more and try the receiver just going from the BP filter into the mixer and see what happens.  

Note that Wes W7ZOI DID NOT have an REF amp ahead of the diode ring mixer in his original 1968 40 meter Direct Conversion receiver (the one that launched the solid-state DC recevier revolution): 

-- The Franklin oscillator is an interesting, but complicated circuit.  The gimmick is, well, gimmicky.  Here is the thing:  You can achieve similar levels of stability using simple conventional, single transistor oscillators.  We dispensed with the variable capacitors, and used PTO--style variable inductors. They worked fine.  This Franklin oscillator still does seem to drift a bit, right?   I would ground the board to the inside of the metal box.    

I would also try putting all the stages on a single ground plane.  This might help.  

Excellent New Video from Grayson KJ7UM on his Thermatron version of the Michigan Mighty Mite

Here is a really wonderful video from Grayson Evans, KJ7UM, author of Hollow-State Design for the Radio Amateur.  

I really loved this video.  Throughout we see Grayson's sense of humor.  Early on he explains the differences between a tube (what remains from a roll of paper towell), a valve (like the plumbers use) and a THERMATRON (like a 6146).  Grayson is the inventor of the word Thermatron.  We should all pledge to use it whenever possible. 

Grayson's humor also shows up when describing the parts acquistion process for the Thermatron Michigan Mighty Mite.  He puls out a coil (a huge coil) and laments that it is not -- despite its large size -- sufficiently inductive. 

There are wonderful shout outs to SolderSmoke, to Electric Radio, to the Color Burst Liberation Army, to Pete Juliano,  and to Rex Harper.  

Grayson describes the utility of Rex Harper's Thermatron ME pads.  

During the video, Grayson actually builds the Thermatron MMM.  In under 2 minutes!  He then experiences the Joy Of Oscillation, or JOO as it has come to be known.  OM needs a contact -- listen for him on 3579.  He is calling CQ.  

Grayson talks about his book, Hollow-State Design.  I have a copy with me here at SolderSmoke Shack South in the Dominican Republic.  Great stuff.   The above link takes you to Lulu, where you can order the book.  You can also get it from Electric Radio Magazine here: https://www.ermag.com/product-category/books/

Thank you Grayson for bringing us this video, and so much more over the years.  And for giving us the very useful and fun word:  THERMATRON!  

SolderSmoke Podcast #249 -- Travel, Pete's 6BA6 rig, Books!, VFOs, SDR, Computers, Spectrum Analysers, Transistor Man! MAILBAG

New VFO for 15-10 Transceiver

Schematic below

SolderSmoke Podcast #249 is available:  http://soldersmoke.com/soldersmoke249.mp3

There is also a video version of this podcast: https://youtu.be/5xyaYivtOhw

Travelogue:  

HAPPY VETERANS' DAY TO PETE AND GRAYSON AND TO ALL THE OTHER VETERANS WHO ARE LISTENING. 

Trip out to San Francisco. Sticker placed on the corner of Haight and Ashbury:  See picture below.  Note other sticker.  Really Groovy! 

Cuban Cacharreo! Andy CO2AFV's Knack Story  https://soldersmoke.blogspot.com/2023/10/a-cuban-knack-story-and-pandemic-sits.html

Bill's DXCC-100.  DONE.   

Tribal Wisdom:  W1REX on HRWB https://soldersmoke.blogspot.com/2023/11/listen-to-rex-w1rex-lots-of-tribal.html

Pete's Bench:

Pete's 6BA6 rig

Pete's 6BA6 Rig

Pete Re-invents the Shirt-pocket SSB Rig

Pete's remake of the ShirtSleeve Transceiver

Pete Builds Two Computers 

Pete Adds a Second Band to his Homebrew SDR 

 

SHAMELESS COMMERCE DIVISION:  

BEZOS BUCKS ARE BACK!  PLEASE  BUY THERE! >>>>>>>>>>>>>>>>>>>>>>>

Mostly DIY RF:  Work proceeds in the Oregon Silicon Forest on P3ST kit development. Todd is confident the P3ST will be released on December 18th.Many other kits available now:  https://mostlydiyrf.com/ 

Sign up for the newsletter:  https://mostlydiyrf.com/subscribe/ 

Bill's Bench: 

Rebuild of the 15-10 VFO (for improved Dial Spread) (with yet another QF-1 capacitor) https://soldersmoke.blogspot.com/2023/10/dial-scale-linearity-spreading-out.html

Why Building for 10 meters is harder: https://soldersmoke.blogspot.com/2023/09/why-building-for-10-meters-is-harder.html

Copper Tape shielding of 15-10 rig. 

Crushing Spurs with Better Bandpass Filters (see blog post) https://soldersmoke.blogspot.com/2023/09/crushing-17-and-12-meter-spurs-with.html

Another 15-10 rig in the works... for SSSS.   Boards are accumulating... 

More problems discovered with the Herring Aid 5 Receiver . Lots of SS blog posts  Comment from Rick WD5L.  ) https://soldersmoke.blogspot.com/2023/10/a-big-error-discovered-in-1976-qst.html   Did you try to build one?  Did you succeed or did you fail?  Please let us know. 

The Basil Mahon books (blog posts) https://soldersmoke.blogspot.com/2023/11/basil-mahon-is-author-for-us-he.html

The Sunburst and Luminary book of Don Eyles (blog posts) 

The Art of Electronics by Horowitz and Hill (blog posts) 

Spectrum Analysers:  Tiny SA Ultra https://soldersmoke.blogspot.com/2023/09/the-tinysa-ultra-spectrum-analyser-video.html  and Polarad 632C-1; George WB5OYP gave me one of these spectrum analysers  (I NEED a manual! Does anyone have a manual or a schematic? )  : 

Polarad 632C-1

Stabilizing the EB63A (with Pete recommended LP filters from e-Bay. 

MAILBAG:

TRANSISTOR MAN T-SHIRTS!  Thanks to Roy WN3F! 

Todd VE7BPO on AF amplifiers.  Thanks Todd.  

Wes W7ZOI -- Always a privilege to exchange e-mail with Wes. 

E-mail from Jay Rusgrove W1VD. About the Herring Aid 5. 

E-mail from Eamon Skelton EI9GQ!  Amazing! 

HB2HB with Denny VU2DGR https://soldersmoke.blogspot.com/2023/09/hb2hb-contact-with-denny-vu2dgr.html

Nick M0NTV on diode matching for ring mixers: https://soldersmoke.blogspot.com/2023/10/does-matching-matter-diode-matching-for.html

Paul Taylor VK3HN on the new Elecraft CW rig. 

Dean KK4DAS fixed the noise in his Hallicrafters SW receiver.  A long battle, finally won. 

Dean also in contact with G3UUR. 

Ramakrishnan VU2JXN helping me set up a backup of blog on WordPress.  

Mark KA9OOI noticed that SS podcast archive appears gone.  In fact just temporarily relocated to http://soldersmoke.com/podcastarchive.html

(SS PODCAST Archive temporarily relocated to http://soldersmoke.com/podcastarchive.html) 

Andreas DL1AJG - Crystal radio video. https://soldersmoke.blogspot.com/2023/10/building-crystal-set-videos.html

George N2APB on the Herring Aid 5

Grayson KJ7UM experimenting with Varactors and Thermatrons! 

Thomas K4SWL on Mattia's DC receiver. https://soldersmoke.blogspot.com/2023/10/mattia-zamanas-amazing-direct.html

Bob Weaver of Dial Bandspread Linearity  fame.  Electron Bunker

Mike Bryce WB8VGE QRP Hall of famer -- he too couldn't get the Herring Aid 5 working. 

Kirk NT0Z wrote about the Wayback machine.  But this former ARRL staffer he also tried and failed to get the Herring Aid 5 going.  Way back when... https://soldersmoke.blogspot.com/2015/03/kirks-herring-aid-tuna-tin-and-regen.html

New 15-10 VFO with schematic

Dial Bandspread (Before)

At corner of Haight and Ashbury

Listen to Rex. W1REX. Lots of Tribal Wisdom in this Ham Radio Workbench Interview

 

https://workbench.libsyn.com/hrwb-193-building-projects-with-rex-harper-w1rex

This week's Ham Radio Workbench podcast features an interview with Homebrew Hero Rex Harper, W1REX of QRPMe fame. (The bulk of Rex's portion starts at about 1:26:30.)

I really liked this talk with Rex.  His enthusiasm for homebrewing is really inspiring -- it is very reassuring to know that there are others like us. Rex clearly has The Knack.  

I got a kick out of Rex's story about the outhouse at Dayton.  FB OM.  

Here is the video of the mojo transfer ceremony in which shared some of the Tuna Tin 2's mojo with my BITX 17.  Thanks again Rex!  

And thanks to George and the gang out at Ham Radio Workbench. 

Update on the High-School Direct Conversion Receiver Project: Board #4 Completed

One of the receivers. (l to r) AF, PTO, Mixer, BP filter

The students continue to make great progress on their direct conversion receivers.  Yesterday they were enthusiastically sitting down to workbenches, building Manhattan-style circuits, working directly from schematic diagrams.  It was really impressive.  They are building receivers. 

This week we had two sessions of about two hours each. We introduced the final board:  the audio amplifier.  Many of the students began work on this amplifier; others were catching up with work on boards presented earlier. 

The AF amp is their most challenging board:  It used 14 Manhattan pads and about 26 components.  We warned the students that amplifiers often aspire to be oscillators.  We told them to pay attention to layout, and to keep their leads short.  

One of my builds, and a Manhattan board pattern

At first, the students just built the first stage on the AF amp board. They tested this, then moved on to build the other two stages.   

By the end of Friday, two groups had completed the build of the AF amplifier board.  

We think there are about 13 receivers in production.  Some are near completion, others will need more work.  

On Thursday of next week those teams that have completed all four boards will put the circuits together and will test the entire system.  They will then add all needed front and back panels and socketry. 

We really want the students to complete as many of these receivers as possible.  Exam season and the end of the school year is approaching, so we have to get this done.  We will remind students that they don't want to that person who ALMOST finished a project!  We will urge them to GET IT DONE!   They can tweak it and mod it later.  This kind of tweaking and modification is part of the homebrew experience. 

We have been presenting awards to the students who are first to complete each stage:  The winners of the PTO board competition got a copy of SolderSmoke:  Global Adventures in Wireless Electronics.   Those who won the mixer competition got a W1REX Hamfest Buddy transmitter.  Thanks Rex!  And this week we presented an award to the students who were the first to complete their bandpass filter.  You've heard of the Tony, the Emmy and the Grammy?  Well, we presented "The Torry"  (from Toroidal).  The trophy was made from a toroidal winding tool made in Alaska by KL7FLR.  I explained to the students who had made it.  Thanks Paul! 

"The Torry"

The SolderSmoke Team Talks to the River City Amateur Radio Communication Society (Video)

Pete and I had a great time speaking to this really nice California ham radio club (video of the event appears above).  Special thanks to club president Dr. Carol Milano, MD.  Wow, what an impressive person and ham radio operator she is:  https://www.qsl.net/kp4md/#New%20York

This club is doing a group build of a version of the famed Tuna Tin Two.    I mentioned that I had held the original TTT in my hands, and that Rex Harper had conducted a "Mojo Transfer Ceremony" that imparted TTT Mojo to my BITX17 transceiver (which was also discussed).  I promised to share the video of that momentous event.  Here it is: https://youtu.be/9RZRaFUtTcc

Thanks to Carol and the members of the RCARCS.  This was a lot of fun.  

SolderSmoke Podcast #191 RIGS! REAL RIGS!, BITX40 Module, EMRFD, MAILBAG

SolderSmoke Podcast #191 is available:

http://soldersmoke.com/soldersmoke191.mp3

TRAVELOGUE AND FAMILY DOINGS:   Pete son's wedding, Billy's Birthday, Gonzalo safely home in the Dominican Republic, MORE BEARS IN THE SHENANDOAH WOODS

BIG NEWS:  EMRFD LIVES ON!   Three cheers for Wes and for Tom Gallagher of the ARRL.

BENCH REPORTS:

PETE:   FPM Rig.  Some Halli history.  A TRUE RIG!  Working Japan. 

             WITH 600 WATT LINEAR AMPLIFIER!!!!!!!!!!!!!!!!!!!!!!

               New FEELTECH  Sig Gen.  

BILL: Farhan's BITX Module

           Built to Mod, built to get you started in homebrew

           Very impressive.  BITX in miniature.  But completely recognizable.

           REMARKABLY stable.

           Farhan personally checking each one.

           Ladies collective doing toroids.  DONATION money bought them some Diwali candies!

           VFO Drift:  Will NP0 SMD caps and lower current help enough?

           My Analog VFO -- BANDSWEEP

QRPppppppppppp  with REX's Hamfest Buddy.   Thanks Rex and Bob Crane.

HB2HB with KW4KD

MAILBAG

Jan's Netherland Mate Mighty Midget

Charlie's Kiwi DSB

Steve, Donald Fagan, and Jean Shepherd

Rob VK5RC repairs Tek Tube 'scopes

Colin M1BUU Si5351 superhet

Denis Klipa and NRL 3538

Jonathan M0JGH Wizard of Wimbledon Matchbox rig

JH8SST Simpleceiver

Peter Parker Vk3YE Reviews Book

Peter GW4ZUA Welsh LBS

Michael Rainey helping hobbyist in Germany with tuning forks.

Smoke-Free! On the Air with the W1REX Dayton Hamfest Buddy

After the Dayton Hamvention, our ace correspondent Bob Crane (W8SX) sent me the "Hamfest Buddy" kit that Rex Harper W1REX had put together and used in "The World's Biggest Build-a-Thon."

It is a single 2N2222 crystal-controlled oscillator for 20 meters.   All the parts are plug-in -- no solder smoke is released.   Mine went together in about 15 minutes and fired right up.  You can see it above.  It runs off the 9V battery. I had to hold it down with tape.   You can see the key button in the lower right.  That little inductor in the foreground is used to shift the frequency a bit.  I had to remove the 10K resistor in the emitter circuit because with my antenna the circuit was going into low-level oscillation even in key-up.  With the 10K resistor removed, this problem disappeared.

I hooked it up to my 20 meter dipole and called CQ.   With only about 60 milliwatts into a dipole under poor conditions, I really didn't think I'd get any answers.  But I figured the Reverse Beacon Network might pick me up.  It did:

Thanks Bob!  Thanks Rex!

Manhattan-style Vacuum Tubes: "An Evolution of Thermatron Homebrew Techniques" by Grayson Evans

Grayson Evans was at Dayton.  Scheduling problems prevented him from being interviewed by ace correspondent Bob Crane, but Grayson was kind enough to e-mail us the essence of his presentation.  And it is really wonderful.  He brings the advantages of the Manhattan construction technique (fast prototyping, all components on the same side of the board, easy modification) to the world of tubes (aka valves or, as Grayson prefers, thermatrons).  We also see in Grayson's work an admirable willingness to bridge the digital-analog design, to bring into his rigs the best of the old and the new.  Thanks Grayson!

Grayson writes:

An Evolution of Thermatron Homebrew Techniques

For a long time I have been trying to develop some techniques to prototype Thermatron projects as easily as the typical “Manhattan style” solid-state construction.  Thermatron projects you see now-a-days still use the traditional technique of mangling aluminum-drilling and mounting everything to a “bud” style chassis. This just takes too much time and my projects always look disappointing.

Fortunately, around two years ago, Rex Harper, W1REX, came to the rescue after hearing an earlier talk of mine and developed a set of thermatron socket pads. The MeTubes panel from QRPme consists of 10 prototype pads for thermatron sockets. The panel has v-scores for breaking the panel into single tube pads. The panel has pads for mini 7 & 9s, octal, compactrons and acorns. Awesome.

The best sockets to use with the pads are PCB style.  These provide a large pin area to bend out and solder to the pad (see photos). 

I pre-mount a dozen or so of the 7-pin and 9-pin sockets on MeTube pads so I have them ready to go when prototyping. The “crude” example below shows and 7 and 9-pin socket on one of my prototypes.  I think this was a microphone amp for my AM transmitter.  Pardon the mess.

The nice thing about the pads is that they provide plenty of room to tac solder lots of parts to a single pin–easy to add or remove parts.  This is a lot easier than using the traditional tube socket pin. 

Prototyping thermatrons in this way is FAST.  No more punching out holes to hold thermatron sockets in aluminum chassis!

But it is still nice to be able to have the thermatron on the “top” of the board and the components on the “bottom” of the board.  To do this and still use the MeTube pads, the thermatron has to be mounted on the other side.  I did this by mounting the socket through the MeTube pad.  This requires making a hole in the center of the pad to pass the socket through and then soldering the pins in the usual way.  This is way easier with PC mount thermatron sockets and make a very nice installation. 

This technique has some great advantages over using the traditional socket with pins.  The pad has a lot more room to mount components to each pin.  Normal thermatron socket pins are difficult to attach more than two wires and it’s a bit more difficult to get a good solder connection.  The pads are easy to solder to and allow components to be easily attached in any direction since the “socket” is now flat.

It is also easy to attach the socket/pad to a copper clad board.  The same hole must be made in the copper clad board to pass the top of the socket through, then the pad is superglued to the board in the regular way.  



This is another example of “right side up” thermatron mounting on a prototype test board for crystal filters.  I mounted a small “plug board” (not sure what you call these things) in the center to allow me to easily swap filter components.  Notice the acorn thermatron soldered direct to the pad.  The board works great, the filter design sucked.  I gave up.  Maybe too much distributed C.

I used this technique, combined with Roger Fell’s idea of using inverted aluminum chassis, to build my latest project, a QRP AM/CW transmitter.  I’ve been wanting to try out a few new ideas and this seemed like a good project to try them on.  I also wanted to build the transmitter in modular “blocks”, interconnected in a similar way to Rogers. It worked pretty good although I am still trying to get the thing to work right.  Even new construction techniques can’t cure my screwups.  BTW, the ANALOG VFO is ROCK SOLID.  +/- 10 Hz over 30 min.   Even I was impressed.  The Hartley oscillator is the best circuit for thermatron circuits by far.

I’ll send an update when I get it fully working on AM and CW.

73,

Grayson

TA2ZGE

HOMEBREW HERO: REX HARPER W1REX AND THE WORLD'S BIGGEST BUILD-A-THON

Rex, shortly before questioning by authorities

Wow, Rex Harper W1REX deserves some sort of big award.  I hereby grant him the coveted Brass Figlagee with Bronze Oak Leaf Palm, but that is clearly not enough.  Rex spent a month of 20 hour days putting together kits for the Four Days in May QRP event at the Dayton Hamvention.   The results were spectacular:  246 hams succeeded in building QRP transmitters, and they all did it in under 70 minutes.   

Just as impressive as the results were the ways in which Rex overcame the technical and organizational hurdles prior to the event.  You can read all about this in Rex's excellent write up:
http://www.qrpme.com/docs/FDIM%202016%20Report.pdf

The OFFICIAL SolderSmoke Correspondent at Dayton was once again our friend Bob Crane, W8SX.  Bob caught up with Rex and somehow managed to get him to stand still long enough to do this interview:

http://soldersmoke.com/W1REXDaytonInterview.mp3

And it was very nice that Rex did this as a tribute to Dave Ingram K4WTJ whose magazine articles about simple QRP rigs inspired many of us.  Years ago, right after completing a homebrew QRP transceiver, I talked to Dave on 30 meter CW and told him that his articles had helped motivate me to build. 

Finally, no SolderSmoke post about Rex would be complete without a repetition of the video showing him transferring the prodigious mojo of the original Tuna Tin Two into my BITX-17 transceiver.

Colin's Tuna Tin Mighty Mite (Video)

You will remember Colin as the builder of that beautiful BITX20 that he first used from his backyard and later used with great success from a hilltop in Northern England.  In this video we see Colin demonstrating his Michigan Mighty Mite.  Lots of soul in that little machine!   Colin notes that this rig worked well from the start.   The Radio Gods were obviously pleased by his use of a tuna tin as the chassis.  I think they also liked the MePads from W1REX and the Tek 465 'scope.   And of course the T-shirt was obviously a key element in Colin's success.  

Here is that beautiful BITX, now equipped with an internal speaker:



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

Colin's BITX

With advice and tribal knowledge from N6QW and MeSquares from W1REX, Colin M1BUU, is making excellent progress on his BITX.  I see that he has some territory on the board reserved for a DDS VFO.  That's fine, but here's and idea for Colin and other builders:  Why not build it with the standard VFO first and then add the DDS or Si570 VFO later, perhaps as an external accessory?   That way you get the experience of building an LC VFO -- the full BITX experience. 

Yea, it is hard to imagine Paul M0XPD as a newcomer to the hobby such a short time ago -- he is definitely now in the ranks of the esteemed digital Elmers.   

And yes Colin, we do hope you avoid unwanted oscillations.  Because of Farhan's great design you have a good shot at avoiding this plague.  But be prepared OM.  It happens to the best of us.  A lot.   Stiff upper lip!  Never give in!  

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

Hi Bill,
I enjoyed your video about your Arduino experiment. You bet me to it! I'm really looking forward to getting my version of an Arduino powered BITX up and running.

Steady progress is being made, yesterday I added my first bidirectional amplifier to the build. I now have the mic amp, BFO, balanced modulator and first amp completed. I tested the BFO on it's own and got a respectable looking signal out of it and with a good swing below 10MHz.

Next I need to add the crystal filter, second IF amp and mixer. Pete's video will help for the mixer! BTW, I'm using the ver3 schematic but I intend to use the ver1 band pass filter.

I set out building the circuit following the N2CQR layout diagram but I've already run short on space! I do have a good excuse though, my board is smaller than yours (10"x6").

Despite my best intentions, I'm falling back towards old habits of making my circuits physically small. I'm using MeSquares in order to try and force myself to space things out a bit. I do hope that I don't end up with any unwanted coupling!

I must try hard to leave lots of space between the next bits of circuit.

I was listening to SolderSmoke 104 today and Paul M0XPD was introduced as a new ham. Little did we know that Paul would become such a big player!

73, Colin M1BUU

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

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.     

 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

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. 

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

Thomas's Magnificent Minima

Wow, Thomas's page makes me really want to build a Minima.  Note the Manhattan style with Rex Harper's Me-Pads.  Excellent.   Thomas provides a really great stage-by-stage description of the project with the kind of candid descriptions of mistakes that SolderSmoke listeners are so fond of!  

http://www.sarfata.org/ham/minima/

Thomas himself has an interesting "international brotherhood"  personal history:

http://www.sarfata.org/about.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