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

Swedish Mighty Mite

A thing of beauty!  Check out the key! 

What a great diagram.  Schematic included! 

http://www.sm7ucz.se/MMM/MMM.htm

Remnants of mine

Steve "Snort Rosin" Smith's 

More on all this: 

http://soldersmoke.blogspot.com/search?q=michigan+mighty+Mite

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

WB9IWT's Quarantine Mighty Mite and N3FJZ's "Hiram Percy Maxim Recognition Factor"

Leif WB9IWT has, during the emergency, been working on a Michigan Mighty Mite (See pictures above and below).  FB Leif.  

But also check out the very astute comment from Rick N3FJZ (below) .  I am, of course, all in favor of the HPMR Factor.  Almost all of my rigs would score quite high.    Others, I know, would seek a low score.  To each his own.  This is all for fun.  

Leif,

Great work.  If a ham from the 1920's were to see this rig, they
probably wouldn't recognize the actual components right away (but
knowing hams, they would no doubt figure it out), but the breadboard
layout circuit flow would be immediately recognizable; e.g. the plug-in
crystal, the coil, binding post.  The transistor and variable capacitor
may baffle them at first, but seeing there are three leads on the
transistor would start to give them clues.

That's the cool part about analog discrete component radio, no matter
how many years go by, and the appearance and size of the actual
components change, the physics of what's going on at the electron level
stays the same (SDR not withstanding).

I guess this could be a litmus test for us analog radio builders.  It
could be called the "Hiram Percy Maxim Recognition Factor" or "HPMR
Factor" with a range of 0 to 1.  After you  build your rig, take a look
at it and pretend that you could present it to Mr. Maxim and the more he
could understand the circuits, components and circuit flow on his own,
the closer to a factor of 1 your radio would achieve.  For example, an
SDR might only achieve a factor of .1 or even maybe 0, where as your rig
may achieve a factor of .8, and one of your crystal receivers would
definitely get a 1.

Someone could even workout a check list or formula where you would add
or subtract some fractional numeric values for each component you used;
e.g. you would subtract some value for every IC chip, microprocessor or
LCD display you use, and add some fractional value for each hand wound
coil, vacuum tube/valve or open air variable capacitor, et cetera.

Fun to think about.

Keep building.

Rick - N3FJZ

KB8M's Mighty Mite -- Beware the Treacherous P2N2222!

Doug KB8M did a beautiful job with his Michigan Mighty Mite.  But, as often happens, it still didn't work. He turned to us for advice.  I gave him a long list of things to check, but Pete brought the power of superior tribal knowledge to the problem and spotted the defect immediately: The transistor was in backwards.  It is a P2N2222.  That means the pin out it C-B-E  not the usual E-B-C.  I had fallen into this trap with one of my BITX rigs and had to pull out and reverse many of those transistors.  Fortunately for Doug he had used a socket for the transistor.  TRGHS!!!!!!!!!!!!!  JOO!!!!!!!!!!!

My Mate for the Mighty Midget Thermatron Receiver

A few days ago I received an e-mail from Jan PA3GSV -- Jan is working on a receiver similar to my old Mate for the Might Midget and had some questions about how I'd handled the filter portion of the circuit.  Then on Sunday, while listening to Eric's interview with Farhan on the QSO Today podcast, I got so enthused that I felt compelled to work on a homebrew receiver.   So out came the old Mate for the Mighty Midget.  I built this thing in 1997-1998.  It is described here:

http://soldersmoke.blogspot.com/search?q=Mighty+Midget

In the above  video  I was listening on 75 meters to a very congenial early morning roundtable featuring W4CH, K5KBZ and others.  I know, I know, this is the third or fourth video that I've made of this thing.   This is almost as bad as 2B-mania. Or the Michigan Mighty Mite thing.   I blame Jan.  And Eric.  And Farhan.  And Grayson.  And Lew McCoy!

Here is my e-mail exchange with Jan:

Bill:

I recently build the W1TS two tube xtal controlled transmitter, and am looking for a 80/40m companion for this that has a crystal filter.

At first, I wanted to build the “Simplex Super” and finally got hold of the 1700 kc crystals, but then they got lost in the mail…

Only part of a two box shipment arrived, with 455 kc fundamental frequency FT-241 crystals, so now I am looking for a diagram using a 455 kc IF. Jan

Jan:   In this link you will find the schematic for the receiver I built. 

 http://jvgavila.com/mmrx_3.gif

 I was not able to build the filter with the two 455 kc crystals.  I could not obtain the needed crystals.  I used two 455 kc IF transformers as described in my article.   This resulted in a very broad frequency response but it was OK and quite good for AM. 

 Last year I put in a Toyo 455 kc SSB filter, but I did not match the impedances, so the results were not good.  Your e-mail makes me want to work on this again! 

 Let me know how your receiver turns out. 

 73  Bill  N2CQR

Thanks for your reply.

It is a neat looking little receiver.

And yes, I also have a cardboard box labeled “good junk” which is filled with stuff from ham fests J

Finally it will be put to good use!

I printed the article for some evening reading this week.

It will take me some time building this receiver, as there is some metalwork and mechanics involved.

I will let you know how the receiver turns out, and I am also curious what improvements you make on yours.

 Thanks again, and I will let you know.

 73  Jan PA3GSV

Wow, Jan has the Knack!   Check out his station:

That's the W1TS rig on the left.  More pictures from Jan on his QRZ.com site.  He too uses wood cabinets!  I'm not alone!  Here's Jan, PA3GSV

 

Bill Talking about Homebrew Radio with L’Anse Creuse Amateur Radio Club (Michigan) -- February 2, 2022 (Video)

This was a very nice meeting.  We just talked homebrewing and why it is such an important part of ham radio.  Video above

Topics included:

-- Jean Shepherd

-- Being "Electrically Inclined" 

-- The Herring Aid 5

-- Radio Clubs around the world

-- The Shame Shelf

-- Making mistakes, releasing smoke

-- Errors in ham radio magazines and schematics

-- The importance of understanding the circuit

-- The Michigan Mighty Mite

-- Building a power supply for the HW-32A

-- The origins of the SolderSmoke podcast

-- Knack stories, the IBEW and what we all have in common

-- The importance of books

Thanks to The L'Anse Creuse ARC for the invitation. 

N5AB's Mighty Midget 40

Bill & Pete,

Your recent podcast on the Michigan Mighty Mite got me excited about hooking up

the one I built a few months ago.

The wattmeter claims it’s putting out 700 mW into a dummy load.

The old crystal I’m using is 7.108 mHz

The shack receiver verifies I’m on 7.108

The receiver also says I’m very strong on 14.216

I added a low-pass filter kit (now apparently discontinued) from kitsandparts.com

Even with the filter, I’m still hearing a strong signal on 14.216.

I’m not sure what’s going on here. Perhaps the transmitter coil is radiating the harmonic I’m

hearing on the shack reciever.

You guys are putting out some great podcasts! keep up the good work.

Bill N5AB

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 #238 -- SolderSmoke Shack South, Cycle 25, Chiquita Banana Radio, RCA, HQ-100, Mate Mighty Midget, Sony SWL RX , Mailbag

SolderSmoke Podcast #238 is available:  http://soldersmoke.com/soldersmoke238.mp3

TRAVELOGUE:  

Cathartic decluttering:  Bill preparing for future winter travel to Dominican Republic.  Will build SolderSmoke Shack South.  Dividing everything up:  Rigs, parts, tools, supplies, antennas, test gear.  Everything.  

OUR SPONSOR:  Parts Candy.  

https://www.ebay.com/usr/partscandy  Premium quality test leads! Hand cut, hand crimped, hand soldered, these will become your new favorite test leads GUARANTEED!

PETE'S BENCH:

-- Cycle 25 better? – Out here on the left coast – it is not evident

-- Chiquita Banana and the US Navy in early ‘wireless” operations.  Why RCA was created by the US Navy in 1919.

-- Update on the MAX2870 –someone has written the code to make it work with the Raspberry Pi and the QUISK SDR software

-- Field Day prep

SHAMELESS COMMERCE DIVISION:

 

Bill needs your help:  

-- Please watch his YouTube videos.  The longer the better!  Success based on hours watched. Great to have on while you are working in the shack. Just go to YouTube and search for the SolderSmoke channel. Or:  SolderSmoke - YouTube

-- Please put links to the SolderSmoke blog on your websites and blogs. 

-- How to USE the SolderSmoke Blog: Propagation, shopping, other sites... 

-- Please put comments under the articles on the SolderSmoke blog.  We like comments and dialogue. 

BILL'S BENCH:

-- Repair of the Sony ICF SW1 shortwave receiver.  Bad electrolytics.  Number Station receiving device? 

-- HQ-100   Q-Multiplier. BFO Switch. AVC.  Noise Limiter limitations.  Dave K8WPE: Old Radio Lessons.

-- MMMRX: Detector circuit. Alignment. Muting. On the air (40 AM with DX-100) 

MAILBAG: 

-- Bob Crane W8SX -- Great interviews at FDIM. On the SolderSmoke Blog. Thanks Bob! 

-- Dave Bamford W2DAB -- Stickers on the Upper East Side of Manhattan.  FB Dave! 

-- Farhan VU2ESE:  LADPAC software now available through W7ZOI' site.  

-- Lex PH2LB: Stickers in a Netherlands pub.  

-- Dave K8WPE Michigan Mighty Mite links.  Old Smoke idea. On the SolderSmoke blog. 

-- Rich WB4TLM was in the electronics class of CF Rockey W9SCH. FB. 

-- Dean KK4DAS Working on  his dad's HQ-170A. VWS maker group on mixers. 

-- Grayson KJ7UM -- Mixology article in ER. 

-- Pete Eaton -- Farhan's new analog rig: Daylight again!  Standby for more info from Farhan. 

-- Will KI4POV New HB Al Fresco single conversion superhet.  FB. 

-- Alvin N5VZH. Shep's "I Libertine."  Yes.  I laughed, I cried,  It changed me. 

-- Chuck KF8TI.  Mr. Wizard!  

-- Steve N8NM on the mend after some routine maintenance. 

-- Ben AB4EN is listening and likes the podcast -- Thanks Ben. 

May 1939 QST

Dean KK4DAS Puts Michigan Mighty Mite on the air! And is heard in Falls Church, Virginia! (video)

QRZ.com says we are 5.9 miles away.   The U.S. Postal Service almost prevented this from happening -- they objected to my just putting the crystal in an envelope and mailing it.  Dean's wife had to pay postage due.   

The rig didn't work at first, but Pete N6QW provided sage advice and tribal knowledge.  Adjustments were made and Dean experienced the Joy of Oscillation.  Then, he connected an antenna and was heard at the SolderSmoke East Coast HQ. 

Obviously the beret was the key to Dean's success: 

This was a lot of fun.   And it is a reminder of the power of the MMM.   Dust off those Mighty Mites!  Call CQ and see if you can be picked up by the Reverse Beacon Network.  Let us know if you succeed.   

Getting ready

Done!  Dean's MMM

Mike Caughran KL7R's Last Podcast

 

Mike KL7R (SK) during a visit to the AL7FS shack.

This was Mike Caughran KL7R's last podcast. He died in a car accident shortly after we made this program. January 13, 2007. Mike's oscillator work. Michigan Mighty Mite. Lasers, diodes, and Einstein. Laser communication experiment. W7ZOI-KL7R QSO on SKN.M0HBR's feedback amps.The new comet. Saturn, Jupiter and calculation of c. 17 meter QSOs. New SPRAT CD. MAILBAG: China enigma, VE4KEH, M0DAD, GU0SUP, M1CNK, K4AHU, KD4EDM, KG9DK, AA6KI, VA7AT ON5EX

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

Mike's Obituary from the February 2007 ARRL Letter:

Mike Caughran, KL7R, SK: Well-known low-power (QRP) and homebrewing
enthusiast Michael S. "Mike" Caughran, KL7R, of Juneau, Alaska, died January
22 of injuries suffered in an automobile accident in Hawaii. He was 51.
Caughran may be best known as one-half of the team -- with Bill Meara,
N2CQR/M0HBR -- that created and produced the weekly SolderSmoke podcast
<http://www.soldersmoke.com/>. "I think people were drawn in by Mike's
friendly voice and manner," Meara commented on a memorial page for KL7R
<https://kiwi.state.ak.us/display/mc/Home>. A member of ARRL and the Juneau
Amateur Radio Club, Caughran also wrote articles for the Michigan QRP Club's
T5W newsletter and he was an active ham radio contester. "Mike was one of
those people who you instantly like because of his honest, straightforward
and humble way of talking and expressing ideas," said Mike Hall, WB8ICN, who
edits T5W. "His co-hosting of SolderSmoke provided me hours and hours of
enjoyment." Caughran was an IT professional with the State of Alaska.
Survivors include his wife and son.

Retro QRP Rigs of the 1960's, 70's, and 80's -- Video by Mike WU2D

It is time to put aside (again!) all of the heated ideological arguments about the power level that defines "low power."  Just sit back and enjoy this wonderful trip down QRP memory lane. 

Mike's description of the simple, single-transistor QRP transmitter was really nice.   I recently made something similar: https://soldersmoke.blogspot.com/2023/02/first-qso-with-high-school-receiver-100.html  And Mike does a nice plug for our beloved Michigan Mighty Mite.  Go CBLA! 

The modular idea:  words to live by my friends. 

40673!  TT2!  And G3RJV's PW Severn - indeed, bow your heads!

Wow, the Ten Tec Power Mite (or Might!) -- I still want one.  Same for the Argonaut -- what a great name (sounds like a "magic carpet), and with SSB to boot!  I want to join the Argonaut cult! 

I have both the HW-7 and HW-8 (the HW-8 is heading to the Dominican Republic).  This video makes me want to fire up the HW-7.  Maybe on 40.  

My 40 meter homebrew rig (Digi-Tia) has in it the filter from that old Yaesu FT-7 rig.  The filter was given to me by Steve "Snort Rosin" Smith.  https://soldersmoke.blogspot.com/2015/05/bitx-digi-tia-build-update-2-installing.html  

Thanks to Mike for including me in the credit roll at the end.  What a great group of people -- it is a real honor to be listed with those folks. 

Vienna Wireless Winterfest Hamfest 2022

After a two-year pandemic hiatus, yesterday the Vienna (Virginia) Wireless Society's annual "Winterfest" hamfest was back.  And the weather was in fact COLD -- it definitely felt like Winterfests of years-gone-by. 

Club President Dean KK4DAS kindly invited me to participate in a forum on homebrewing.  You can watch the presentation STARTING AT 2:04:06 (hours:minute:seconds) here: 

https://www.youtube.com/watch?v=s48of3uS9tM

It was especially cool to be able to tell the audience about Pete N6QW and Farhan VU2ESE. We talked about Pete's Simple SSB transceiver, the Michigan Mighty Mite and the BITX rigs. 

Some observations on the hamfest scene: 

-- There are lots of boatanchor radios out there, and it seems like a buyer's market.  These old rigs do not seem to be selling nearly as fast as they did a few years ago. 

-- There is a lot of older analog test gear on sale too, and it too seems to no longer be as in demand as it was a few years ago.  Perhaps the availability of cheap, small, and very effective digital oscilloscopes is affecting the sale of these once sought-after items. 

My purchases: 

-- A really old beat-up (crashed?) ARC-5 R-23 receiver.  I have already extracted the variable capacitor. 

-- A nice box of smaller variable caps. 

-- 100 feet of 550 parachute cord. 

-- Two nice metal chassis/boxes 

-- A bag of shaft adapters/connectors

With Armand WA1UQO (left) and Steve Boles W4SB (center)

With Charles AI4OT 

Thanks to Dean KK4DAS and the entire VWS team for a great event. 

SolderSmoke Podcast #248 -- Back from the Summer -- Spurs and Filters, S-meters, 6BA6 mania, Shirtpocket rigs, MAILBAG

The PsssT Kit, coming soon from Mostly DIY RF

SolderSmoke Podcast #248 is available for download: 

Audio: http://soldersmoke.com/soldersmoke248.mp3

Video: (800) SolderSmoke Podcast #238 -- Spurs and Filters, S-meters, 6BA6 mania, Shirt-pocket rigs, Mailbag - YouTube

Travelogue:  Trip to the Dominican Republic 3-9 August.  Thinking about the M0NTV video on mixers...  

Solder Smoke Shack South is almost done.   I am thinking about workbenches, operating tables and antennas.  How high should an electronics workbench be?   Table height?  Or workbench (woodwork) height?  

My son and I went to see "Oppenheimer"  Trinity test scene very cool.  They wanted to see if the gadget would work! 

Is the SolderSmoke blog completely archived on the WayBack Machine?  Please check and let me know.  Thanks. 

Bill's Bench: 

-- I've been working a lot of DX with the homebrew rigs:  Indonesia, Australia, Japan, Hawaii.  Lots of fun.  15 meters has been especially good. But the rigs still need work: 

-- M0NTV's video got me to put TinySA to work.  I found that output from dual banders could be improved.  Spurs and harmonics. Yuck.  I need more TinySA -- ordered the TinySA Ultra. 

-- Allison KB1GMX helped a lot.  EB63A amp was unstable, especially on 10 meters.  Higher frequencies are harder!  Tightened up shielding, negative feedback, and bypassing.  This all helped, but I found that I needed to take the higher frequency LP filters out of the amplifier box.  W3NQN filters are better, with steeper skirts and better 2nd harmonic rejections. NanoVNA proving very useful. https://www.gqrp.com/Datasheet_W3NQN.pdf

-- Also worked on the Bandpass filters for these rigs.  Farhan's comments on skirts of different filter configurations.  Some are "LSB" filters (with steeper skirt at the highest freq) and some are "USB" filters (with the steeper skirt at the lower frequency)  See diagrams on the blog page. So I built USB new filters for 12 meters and for 10 meters. 

-- Danger that my unshielded wooden box rigs might be inviting feedback.  So I shielded the 1510 rig with copper guitar amp tape (conductive adhesive).  Good stuff.  

-- Phase Noise rears its ugly head again.  See blog posts. 

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

SHAMELESS COMMERCE DIVISION:  

Mostly DIY RF getting ready to release PsssT kits.  Target date:  December 18, 2023 (E Howard Armstrong's birthday).  https://mostlydiyrf.com/

Amazon Search box seems to have died.  I can't get it back.  Can anyone tell me what happened?  (There seems to be "explanations" from Amazon about this, but they are written in a strange language that I cannot follow.)  Something similar happened with the Google Ads on this blog page.  Apparently you can't have ads both on YouTube and blogger.  

But hey, there is Patreon for those who want to support the podcast and blog. 

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

Pete's Bench

An S-meter for Bill? 

6BA6 Mania! 

QRP SSB with 6BA6

Shirtpocket rig re-build

Mailbag: 

Walter KA4KXX has a great article about homebrewing in the September 2023 QCWA Journal.  

 Steve KC1QAY -- Has joined the CBLA.  I sent him a 3579 crystal.  He built a MMM and experienced JOO.  And Allison KB1GMX is in his local radio club.  TRGHS. 

Ajay VU2TGG in Pune, India -- launching a high school receiver effort. 

Denny VU2DGR The Wizard of Kerala: https://soldersmoke.blogspot.com/2023/08/the-wizard-of-kerala-india-denny-vu2dgr.html

Joe VK4BYER working with kids a remote Australian community.  FB. 

Todd K7ZF -- Wants to get into homebrewing. Advised him to start small. 

Dean KK4DAS:  Fixing Hallicrafters Worldwide RX. Ciudad Trujillo!  Got question from Mark in the VWS Makers Group:  HOW DOES Michigan Mighty Mite REALLY Work.  See blog. 

Trevor Woods -- Info on Super Islander Mark IV made in Cuba from old CFL bulbs.  FB. 

Bob KD4EBM sent me some great stuff:  Sony SW receiver,  QCX Mini.  Made a CW contact with the QCX.  Felt virtuous -- it is going to the DR.  Thanks Bob. 

Peter KD2OMV:    One of the guys I worked with the ET-2 transceiver.  Great to hear from him. 

Armand WA1UQO   Richmond area radio museum? https://www.youtube.com/watch?v=BSCmljje1p8

Mike WN2A -- Sent me a great care package with lots of toroids.  A lifetime supply!  Thanks Mike!

Nate KA1MUQ got his Doug DeMaw receiver going after 38 years!  FB.  Been there, done that! 

Tony: G4WIF Liked Valveman video about Gerald Wells.  He visited him! https://soldersmoke.blogspot.com/2023/08/valveman-story-of-gerald-wells.html 

Dean KL7MA  Bill talked to him on 15 SSB.  He had worked Wes W7ZOI!  FB! 

The Return of Pete's Simple-ceiver Plus (and a possible analog option)

Winter is approaching ladies and gentlemen, and it is time to think about radio projects.   Bob N7SUR suggested a direct conversion receiver project.  I think this is a great idea.   As a kid, I had fallen victim to the idea that building receivers was "too hard" for radio amateurs. Not true!  DC receivers to the rescue!  Carry on with the DC revolution first launched by Wes W7ZOI in 1968.

Pete N6QW is providing guidance and tribal knowledge via his blog.  For those of you who want to join the ranks of those who have defied the conventional wisdom and have broken through the "receivers are too hard" barrier.  I say build yourself a DC receiver.  Build it from scratch.  Many of you already got your feet wet in homebrewing with the Michigan Mighty Mite project.  Now it is time to jump into a DC receiver project.  

You folks already know what kind of VFO Pete will prefer:  It will be an Si5351.  That's fine.   But I will try to keep the banner of discrete component analog ludite-ism flying high.  This morning I ordered a batch of 7.37 MHz ceramic resonators.  I hope to pull them down into a significant portion of the 40 meter phone band.  If this works, I will share the batch with anyone who wants to joining my Analog Army (remember the CBLA?).   Note (above) that Pete has magnanimously left open the possibility of using a non-digital VFO. What a guy!    

Check out Pete's project here: 

http://n6qw.blogspot.com/2017/08/a-new-line-of-transceivers-difx_19.html

Brazilian Minimalism: The Curruira Transmitter

Miguel PY2OHH is the Wizard of Sao Paulo. This morning I was looking at his wonderful web site and came across this little rig.  It seems a bit simpler than our beloved Michigan Mighty Mite.  And the folks down in Brazil had several of these on the air and made contacts with them.  FB.  Miguel hints they may turn this rig into a transceiver. 

Here is the Curruira:

http://py2ohh.w2c.com.br/trx/curruira/curruira.htm

 

 

The rig is named for this little bird: 

 

 

Meeting up with ARRL CEO Tom Gallagher, NY2RF

On April 12, Tom Gallagher NY2RF was in DC and was kind enough to make some time in his schedule for us to get together and talk about radio.  As we mentioned on a recent podcast, Tom, who has recently taken over as Chief Executive Officer of the American Radio Relay League, is a true FB ham.  He has a restored Drake station that he keeps on the air, and was recently talking up the Michigan Mighty Mite during his interview with Eric 4Z1UG in the "QSO Today" podcast.  And he is a SolderSmoke listener.  It was great to finally meet Tom.  We are all lucky to have him at the ARRL.

Dean KK4DAS Builds SSB rig, Makes First Contact.

You can almost see the excitement in the notes (al fresco!)  of Dean KK4DAS.   He made his first QSO with a homebrew transceiver this week.   Not long ago Dean was taking his first tentative homebrew steps with a Michigan Mighty Mite.  Wow, he has made great progress.   

Read all about it on Dean's blog:  https://kk4das.blogspot.com/2020/04/furlough-40-first-contact.html

Congratulations Dean! 

SolderSmoke Podcast #245: Cuban DSB, DC Receiver?, Can you spot the AI? (Prize), Winterfest Loot, Gina's Podcast, 6BA6 buy, MAILBAG

 

DC RX Example by KK4DAS

SolderSmoke Podcast #245 is available for download: 

Audio Podcast:  http://soldersmoke.com/soldersmoke245.mp3  

Video:  (68) SolderSmoke #245: Cuban DSB, DC Receiver?, AI, Winterfest Loot, Gina's Podcast, 6BA6 buy, MAILBAG - YouTube

Travelogue: Cuba DSB and AM. Jose CO6EC and the Islander. We need more info, especially on the solid state Jaguey rig.

Bill’s bench:

Will the High School DC receivers get finished? Future uncertain. But the project was technically interesting. Great working with Dean KK4DAS. Battling AM breakthrough from Radio Marti. We joked that Dean has been listening to Radio Marti so much that even though he doesn’t speak Spanish, he has noticed an increased urge to liberate Havana.

Audio amps: Harder than we thought. Lots of variation in Hfe of 2n3904s. Oscillations.
Not using feedback amps nor LM386s, nor push-pull. Simplicity is a design goal.

Fixing the tuning (bandspread) problem on the VFO was fun.

Antennas? A quarter wave with ground or counterpoise works well. We tried it. (59) An Antenna for the TJ 40 Direct Conversion Receiver - YouTube
----
Back to work on the uBITX. I chickened out on replacing the predriver with a BFR-106, but then – Just in time Todd K7TFC and his Mostly DIYRF came out with BFR106 boards! TRGHS. I will do the mods on two uBITX transceivers. I even bought a solder-sucking iron for the second job.

Winterfest Hamfest. Big success. Thanks VWS. HERRING AID FIVE! Simpson 260! QF-1, Another Radio Shack DMM, Eamon Skelton’s Homebrew Cookbook, Knobs, SWR meter.
----

SHAMELESS COMMERCE: 

-- Todd’s Mostly DIY RF and the BFR106 boards, and much more: https://mostlydiyrf.com/

-- Become a Patreon sponsor of SolderSmoke: https://www.patreon.com/join/4785634/checkout?ru=undefined

----

Pete's Bench: 

Technical Note: Skype problems. Pete's Skype kept dropping out. Bad in the last podcast (#244). Three minute gap. I was ready to scrap the whole podcast when Dean KK4DAS offered to help. And he is obviously well qualified: https://potomacofficersclub.com/speakers/dean-souleles/ Dean went to work with AI. And he was able to fill the audio and the video gaps. Can you spot the three minutes of AI? Send me an e-mail with the time segment of the AI/Deep Fake portion of SolderSmoke 244. The first one with the correct answer will win a prize. 

SolderSmoke #244:

https://soldersmoke.blogspot.com/2023/03/soldersmoke-podcast-244-pete-is-back-tr.html 

Thanks Dean!

----Interview on his Pete's daughter’s podcast. https://soldersmoke.blogspot.com/2023/03/listen-to-pete-juliano-on-his-daughter.html

-- 6BA6 e-bay buy. Will we see an all 6BA6 rig from Pete?

-- The NCX-5 on e-bay

PETE’S NEW BLOG: https://hamradiogenius.blogspot.com/

Mailbag:

-- A New SPRAT arrived in the mail. PH2LB’s Gluestick on the cover.
-- Will KI4POV – Awesome homebrew – on the blog.
-- Sands, VK9WX listening to SolderSmoke on Willis Island! Wow. 
-- Andreas DL1AJG in Germany continues with the Electronics for Biologists DC RX build.
-- Dean KK4DAS and his homebrew 10 meter DSB rig.
-- Jim W2UO built a Michigan Mighty Mite and made a contact.
-- Dave K8WPE and the E in IBEW. We need new stickers.
-- Bob KC4LB – Surface Mount is SMALL.
-- Bruce KK0S on the Herring Aid 5 Board.
-- Chuck WB9KZY on Nuclear Monopole Resonance very cool video – on the blog.
-- Alan WA9IRS wants a CW editor for his phone. Really.
-- Vic WA4THR also working on uBITX power out improvement.
-- Tobias weighs in on Kludge. As in Fudge.
-- Tony G4WIF notes that when he changes his oil he often removes sludge, not slooge.
-- Consultations with Lexicographer Steve KB3SII.
-- Walt AJ6T says CW operating declined after FCC ruling in 1970s about callsigns.
-- Ramakrishnan VU3RDD now VU2JXN has joined the VWS. An old friend of SolderSmoke. Urged us to launch a blog back in 2008. We announced his daughter’s birth - - now Ram is getting ready to build a DC receiver with her.

My Hodgepodged Morse: Audio Tone into the Mic Jack Creates J2A not A1A. BASTA!

In SolderSmoke podcast #229 Pete and I were discussing my rather flaky effort to turn the Hodgepodge BITX40 Module into a CW rig by injecting keyed 700 Hz audio into the mic jack (see video below). We got some very helpful responses from ND6T and VK2EMU:  

Hi Bill,

You mentioned generating CW by modulating SSB: Collins did that in their

first SSB transceivers, I believe, as did SGC, but the results were less

than optimal. The problem is that you are involving the audio chain and

modulator. You know from experience how difficult it is to maintain low

intermod there and the tone is no exception. So we end up with lots of

spurs within the filter passband and then also have the opposite

sideband suppression less than perfect. If you check your transmitted

signal with a spectrum analyzer or SDR you can easily see the nasties.

Listening to a CW signal thus generated makes it obvious unless it is

buried way down in the noise. It IS a valid CW signal (not MCW) since it

is (almost) a single signal. However, in actual operation it doesn't

work very well.

I know because I have done that. I bought one of Farhan's original

BITX40 boards and wanted to put it on CW. I ended up injecting a keyed

signal from one of the spare clocks on the Si5351 into the RF amplifier

chain (thus avoiding the above stated problems) but still had garbage

from the audio and IF stages. I fixed that by shorting out that signal

during transmit by a transistor to ground. That was documented on your

BITXhacks website: http://bitxhacks.blogspot.com/2017/02/ and on my

website: http://www.nd6t.com/bitx/CW.htm . It has been a while, eh?

...

Don, ND6T

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

Hi Bill and Pete,

With putting an audio oscillator into you hodgepodge radio, your transmission is not the same as a standard CW rig.

If we have a transmitter as described in the ARRL handbooks from the 1940's or 1950's, (or even the Michigan Mighty Mite) it is a crystal oscillator and maybe a PA tube. By keying either the oscillator and/or the final PA on and off, then we can send Morse code as ICW Interrupted Continues Wave. If we check the list of emission designators, we have A1A.

However, if we feed a tone into a SSB transmitter, then we have J2A.

At the other end it may sound the same, but because it is created in a different way, it has a different designation. 

A quick look at Part 97 shows that J2A and J2B are classed as CW, so you are in the clear. However, if you put a tone oscillator into an AM signal to send CW, then that would be classed as A2A and not classed as CW, but as MCW. MCW can be used on 6 meters and above, but not HF.

SITS.

73 de Peter VK2EMU

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

So I say BASTA with the J2A!  If I want to go CW, it's all A1A for me.  I dusted off my Fish Soup 10 and am now back on 40 CW with 200 mW.... A1A all the way! 

 

Building a Better Diode Ring Balanced Modulator (with Knack Karma)

So yesterday Pete and I were talking about Dave W2DAB's Michigan Mighty Mite malady. Dave is tantalizingly close to the joy of oscillation.  Wizard that he is, I think Pete diagnosed the problem with his eyes closed from 3000 miles away.  I sent Dr. Juliano's prescription to Dave this morning and expect the concrete canyons of Upper Manhattan to be ringing with pure 800 Hz tones as soon as Dave fires up his soldering iron. 

Anyway, I then told Pete that I'd been looking through my bookshelf for something suitable for my 11 year-old nephew Sebastian.  I found something for him, but I also came across a book that was too advanced for the young fellow:   "The Master Handbook of Ham Radio Circuits." TAB Books, 1977.  By "The Editors of 73 Magazine."   Between turkey sandwiches I started looking through this book.  I immmediately found an article of interest:  "A Better Balanced Modulator."   The author (unnamed) looks closely at the performance of our beloved and much-used diode ring mixer with dual trifilar transformers.  He concludes that the unbalanced input and output coils (in the traditional configuration) detracts from the balance needed for optimum carrier suppression.  He suggest the use of baluns at input and output (see above) and claims significant improvement in carrier suppression.   Very interesting. (If anyone wants to dig into this, e-mail me.)  There is also a very simple solid-state VFO circuit that promises phenomenal stability.   

Anyway,  I found myself trying to remember where this great book came from.  Then I remembered someone sending it to me.  A quick check of my e-mail revealed the source:  Dave W2DAB sent it to me three years ago.  Thanks again Dave!  


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