Ciprian YO6DXE Puts the Michigan Mighty Mite on AM! (video)

Excellent work Ciprian!  

Here we have a Michigan Mighty Mite being modified for AM in Romania, with input from Hungary, and inspiration from Melbourne, Australia (Peter Parker VK3YE).  With a very nice shout-out to SolderSmoke.  

I really like Ciprian's emphasis on having fun with the electronics. 

TRGHS! 

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! 

But How Does the Michigan Mighty Mite REALLY Work?

Dean KK4DAS and I were talking to Mark, a new homebrewer.  After we sang the praises of the Michigan Mighty Mite,  Mark asked us a good question:  How does it really work? 

I guess the starting point for analysis is the Barkhausen criteria (that Pete N6QW taught us):  essentially you need enough feedback to overcome losses in the circuit, and this feedback has to be in phase with the signal at the input.  The MMM is clearly oscillating, so the question becomes, "How does this very simple circuit meet the Barkhausen criteria?" 

Here goes: 

Even though it is a very simple circuit, it is worthwhile to separate out the things that it has to do: 

1) It needs to set the AMOUNT of feedback.    This is done by the tap on L1.  Too low down on the coil, and it is too close to ground through the .05 uF capacitor (not enough feedback).  Too high on the coil and you get too much feedback.  This is like an inductive voltage divider. 

2)  It needs to make sure that this feedback is in phase with the input signal. Positive feedback. Q1 is an inverting amplifier.  So it supplies 180 degrees of phase shift. As the signal at the base goes more positive, the signal at the collector goes more negative, and vice versa.  But we need an additional 180 degree shift to bring the output signal in phase with the input signal.  Here is the key:   The crystal provides the other 180 degrees of phase shift.  See

https://www.allaboutcircuits.com/technical-articles/understanding-the-operation-of-quartz-crystal-oscillators/

I tested this:  A 3.579 MHz crystal does provide the needed phase shift:  It introduces a shift of about 190 degrees.  Check out this very cool picture. The two scope probes are looking at the input and the output of the 3.579 MHz crystal with 3.580 MHz frequency coming from my HP sig gen. 

Click on the picture for a better view.

3) It needs to filter out other signals -- the 365 pf variable cap resonates with L1 at around 3.579 MHz.  This results in maximum circulating current through L1 at this frequency. 

4) It needs to match impedance to the antenna.  L2 wound over L1 forms the secondary of a transformer and efficiently moves the energy from the MMM to the antenna.  Think about the gears on your bike. 

The 10k resistor biases the base of the transistor, keeping it on.   The 27  ohm resistors limits the current through the transistor, preventing it from burning up. Note:  the 27 and 10k resistors should NOT be connected directly to each other.  There is no dot in the schematic. This causes some confusion among builders. 

The .05 uF capacitor does two things:   It grounds the L1/365pf tank circuit for RF (but not for DC).   It is less than 1 ohm at 3.579 MHz.   And it helps reduce (smooth out) key clicks (very sudden on-off changes in the oscillation). 

Sam WN5C Builds a Michigan Mighty Mite and Takes it to Lake Thunderbird

 

Sam WN5C built a Michigan Mighty Mite and then went the extra mile by putting it on the air from a field location.  And what a great name this location has for a QRP operation:  Lake Thunderbird. 

Sam wrote up his experiences for K4SWL's QRPer blog: 

https://qrper.com/2023/05/guest-post-lake-thunderbird-k-2792-with-a-homebrew-transmitter/  

Below is a picture of the rig.  NOTE THE LOW-PASS FILTER.  FB OM. We wouldn't want that rig tearing up the electromagnetic spectrum. 

Looking ahead, Sam writes: 

Next step is a DC receiver (maybe the high school receiver?) and then a more substantial transmitter married together, I think. This is all incredibly fun.

Thanks Sam! 

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. 

W2UO's Michigan Mighty Mite -- Made a Contact!

Hi Bill,

I found SolderSmoke about six months ago, and it's quickly become one of my favorite podcasts.

I've been a ham since I was 11, but never tried my hand at homebrewing anything.  I've always heard how hard it would be, and how a project like a SSB transmitter is just too far out of reach.

You and Pete are inspirational, so I set out to build a simple starter project, the venerable Michigan Mighty Mite.  However not just any mighty mite, a usable one, not just a proof of concept.  One intended to sit on a desk and look good doing it.  Complete with built in low pass filter, tx/rx switching, and an internal dummy load.

I don't know if I accomplished all that, but I did make a contact on it this afternoon.  Next logical step I suppose will be to build a DC receiver to sit next to it.

Please find pictures attached, I've learned a lot about what not to do with project, so criticism is welcome.

73!
-Jim W2UO

My response: 

Wow Jim, that is really wonderful.  Congratulations on the build.   I've built many of them, but I don't think I ever made a contact with a MMM.  FB.  

It looks great to me!   Indeed, you should do a Direct Conversion receiver next.    Maybe do a receiver for 40, then do a version of the MMM for that same band.  Then you could 

make a completely homebrew QSO.   I did this recently on 40:  https://soldersmoke.blogspot.com/2023/02/first-qso-with-high-school-receiver-100.html    It was a real hoot!  

Our friend Dean also built a MMM as his first project:  https://soldersmoke.blogspot.com/2019/12/dean-kk4das-puts-michigan-mighty-mite.html

Please keep us posted on your progress. 

Again, congratulations!   73  Bill N2CQR

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.

SolderSmoke Podcast #242 Mars, New Hams, Direct Conversion, SDR Console, Proficio, PSSST, 8 meters, A BIG MAILBAG

SolderSmoke Podcast #242 is available

Audio podcast:  http://soldersmoke.com/soldersmoke242.mp3 

Video:  (362) SolderSmoke Podcast #242 December 3, 2022 - YouTube

Travelogue: 

Mars at opposition.  Not as good as 2020 (see charts below)

SSSS Prep

Hearing aids and high frequency loss.

AirPods as hearing aids.

Out in the Shenandoah with a Baofeng.

Success among TJ High School students.

Satellite in space?

 

PARTSCANDY

 

Bill's Bench:

Direct Conversion Receiver:  IT IS ALIVE!  EVEN IN LTSPICE

PTO works very well.

Diode ring -- really needs a diplexer, Radio Marti.

AF amplifier simplicity.

But WHY can't you listen to DSB on a DC receiver? Now I know.

How does a diode detector work?  Is the envelope real?  Is it square law?

The benefits of writing... 1967 and 1966 articles on PTOs and 2Qs.

 

Shameless Commerce Division:

-- MOSTLY DIY RF!  NEWS FROM PORTLAND! Get your free Michigan Mighty Mite. 

-- YouTube Goal Reached.  Thanks! Keep watching.  Subscribe!

-- Keep buying from Bezos using the link on the right-hand column of the blog page.

-- Become a Patreon sponsor!  Left hand column of blog page.

-- I have ads on the blog page, but I have configured to avoid troublesome ads -- dating sites, etc.

 

 Pete's Bench

-- Stepper motor, LCD and Arduino for my little DC RX?

-- SDR Console

-- PSSST, BOMS, Schematics and spoon feeding...

-- Proficio SDR by Multus

-- 8 meters?

  

Mailbag

-- Alan Yates VK2ZAY now also W7ZAY PTOs, trivial motors, a broken ankle...

-- Dhaka Jack AI4SV formerly of Cyprus, Madagascar and Northern Virginia. has moved to France!

-- John WB5OAU/K5MO An old friend.  FMLA as "Glowbugs Noir"

-- Dale Parfitt W4OP on the Homebrew 2Q from 1967

-- Nick M0NTV Glue Sticks, PTOs, DC receivers and AM breakthrough testing.

-- Todd K7TFC suggests “cool” names for DC RX  PT Cruiser? PT109? PT73?

-- Levi replacing Selenium diodes in a Globe VFO.  I am not alone!

-- Juanjo EC5ACA wants to build DC RX .  FB.

-- Dave designed a discrete LM386.  Picked up by Jenny at HackaDay.  Can you build this?

-- George Zaff.  HamRadio Workbench Spiritual Brother of SolderSmoke.

-- Alain F4IET -- Still building DC receiver.  FB.  Sorry I got the call wrong.

-- Drew N7DA Building Pixies with 3D forms.

-- Toni G6XMO in Sheffield getting a 3D printer business going: https://www.whizz3dparts.co.uk/

-- Chuck KE5HPW restoring an old SW-54.  Pete is skeptical.

-- Lex and Jesse like Colin's placement of WYKSYCDS sticker on his Homebrew rig.

-- Jim KI4THZ joined the Vienna Wireless Society -- FB  on the faculty at GMU

-- Tony G4WIF suggested mechanical counter for DC RX PTO freq readout.  I have some in the junk box.

-- Our old friend Jonathan-san in W0XO now a Patreon sponsor.  Origato!

-- Thomas K4SWL sent him video of Tiny SA watching Vatican Radio sign off for the day.

-- Farhan and Chuck Penson liked blog post about Heathkit Digital Rig SS-8000 1978!

-- Ed KC8SBV working on DC receivers -- I recently used the Peppermint Bark box he sent.

-- Old friend Bob KD4EBM on the linearization of the R-390s.  Hard to homebrew one of those!

-- George from VWS trying to figure out how (if?) Marconi got his coherer to work DX...

-- Steve EI5DD sends Connaught Radio news: https://www.docdroid.net/Q1lBoyi/crnews1222-pdf#page=36

 

Won’t have another Podcast until the new year so Happy Holidays to all!  Merry Christmas, Happy New Year! 

 

SolderSmoke Podcast #241 Mars, Direct Conversion, PTOs and Glue Sticks, Anniversary of the BITX20, Multus Proficio SDR, Boatanchor Station, MAILBAG

The board I use to test DC RX circuits 

SolderSmoke Podcast #241 is available

Audio (podcast):  http://soldersmoke.com/soldersmoke241.mp3

Video (YouTube): (215) SolderSmoke Podcast #241 October 28, 2022 - YouTube

Introduction:

Back on Mars.  Opposition approaching.  I have a Mars filter.  And (like T.O.M.) a Mars globe. 

N2CQR DXCC done

SolderSmoke in the WayBack Machine

Sticker news

PARTS CANDY -- Don't Scrimp with a Crimp! 

Bill's Bench

School DC RX projects -- in Hyderabad and Northern Virginia. 

Direct Conversion Receivers -- Keeping it Simple, Learning a Lot.  A step beyond the Michigan Mighty Mite. Do we really need 100db?  Do we really need to shield VFOs?  Farhan's super-simple and stable Colpitts PTO.  Audio amps, 1000-8 transformers and rolling your own LM386

PTOs and Glue Stick PTOs.  Paul Clark WA1MAC. Brass vs. Steel bolts.  #20 thread vs. #28 thread.  Backlash Blues. The best Glue Sticks. 

2 meters and the VWS.  Bill has a Baofeng. 

SHAMELESS COMMERCE:  MOSTLY DIY RF

Pete's Bench

20th Anniversary of the BITX20   Pete's early BITX rigs. 

Computer Woes

The Multus Proficio SDR rig

Simple SSB in China  BA7LNN

Things of beauty: Tempo One, NCX-3 and a SBE-33

MAILBAG

-- NS7V is listening.

-- Graham G3MFJ sent SPRAT on a stick.

-- Nick M0NTV  FB Glue Stick and 17 Shelf videos.

-- Dino KL0S HP8640 Junior

-- Mark AA7TA   Read the SolderSmoke Book

-- Steve EI5DD Connaught (Ireland) Regional News

-- Dave K8WPE  Planting the seeds of ham radio interest

-- Peter VK3YE Ruler idea on PTO frequency readout

-- Michael AG5VG Glue Stick PTO

-- Tobias  A polymath with UK and Italy connections.  And cool tattoos.

-- Alain F4EIT   French DC receiver

-- Michael S.  was in USMC, working on PCM/TDM gear

-- Alan Yates writes up Amazon transformer problem

-- Todd VE7BPO,  Dale W4OP, Wes W7ZOI

-- Farhan VU2ESE sent me an sBITX

-- Todd K7TFC   The Revenge of Analog

-- Jim Olds    Building QRP HB gear  

The Multus SDR rig Pete discussed

The older rigs Pete mentioned

My version of DC RX that Farhan is working on

My PTO with VK3YE's ruler frequency readout

SolderSmoke Podcast #240 NIMCELS? Hex DX, CBLA RX, PTO? Solid State HT-37? Exotic caps, Benches, SBE-33, TenTec 540, KWM-1 MAILBAG

 

SolderSmoke #240 

Monday September 19, 2022

http://soldersmoke.com/soldersmoke240.mp3

Sorry, I had some technical difficulties so my audio is a bit distorted. 

NIMCELS?  Niche Internet Micro Celebrities. I dunno....  Can our listeners come up with an acronym that describes our place in the universe?  

Sponsors:  Parts Candy.  Carlos in Chicago.  Great leads.  Don't scrimp with a crimp!  You need some good quality test leads on your workbench.   Get yours from Carlos.  Click on the picture on the blog page or go to PartsCandy on e-bay.  

"Techno Wizardry"?   Our lawyers at Dewey Cheatham and Howe will be after them for that!  

Bill's Bench: 

Hex Beam has made me a DXer.  91 countries. Having fun. Mozambique (Long path), San Andres island, and Saudi Arabia, all on Friday. All homebrew SSB 100 watts. 

Put my old 20 meter CW station back on the air:  Barebones superhet and the VXO 6 watter.   WYKSYCDS. This may be one of very few CBLA Receivers in the world!

Been getting active in the Vienna Wireless Society.  Dean KK4DAS is President and a lot is happening in the Club.  Makers group. Lunch with the group on Tuesdays.  Lots of fun.

We are looking at Farhan’s Daylight Again Analog rig.  Using parts from Dean’s 3D printer, we have made PTOs. See blog post for picture.   (But are they really PTOs? Or just Variable Inductors?) 

VFO madness.  Solid stating an HT-37 VFO. Grayson: “You have clearly lost your mind.” Perhaps.  100 MHz FM broadcast RFI. This brought me to capacitors and linear tuning:

SLC, SLW, SLF and Midline/Centerline caps.  Do special caps explain why some VFOs have linear tuning while others do not?  NO, not really.  You can get linear tuning with ordinary caps.  See blog post

Working on the bench.  Reading Adam Savage’s book on workshops and tools. (link to the book in the right hand column of the blog.   Some other workbench links on the blog.  Upgrading tools and test gear.  I have a proper bench power supply. Better side cutters.  Engineering rulers.  Digital calipers. Better solder (I was talking to Ron WA6YOU – a real solder authority - about this.  Kester 60/40 ).

SHAMELESS COMMERCE DIVISION: 

mostlydiyrf.com

Currently offering seven items:

·  UDVBM-1 (in three versions)

·  PG-TIA Broadband IF Amplifier

·  TIA-AGC IF Amplifier

·  Dual-Gate MOSFETs

·  OA741D Op-Amp (discrete components)

·  8-Pole QER Crystal Filter

·  I2C Rotary Encoder

Three more are shown as coming soon:

·  GP Audio Amp (general-purpose audio amp)

·  HyCas IF Amplifier with AGC

·  M-Cubed (Michigan Mighty Mite kit)

·         Mostly DIY RF offers hardware for hardware-defined radio. That's not a comment on software-defined radio. SDR is cool and useful, and it has its place.

·         In fact, I believe in explicitly making use of technology from all eras (vacuum tubes, discrete semiconductors, and integrated circuits

·         What does "mostly" DIY mean? It means making what you want and using ready-made for the rest. Even the most fanatic DIY'ing home brewer does this without much thought. He uses components he didn't fabricate, electricity he didn't generate, and theoretical knowledge he didn't discover. One can't fight all battles, one has to choose which to fight and which to leave to others. If an appliance-operating Ham doesn't want to fight at all, that's okay, but Mostly DIY RF has nothing to offer him.

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

I need YouTube viewing hours.  So I am putting some of the best SolderSmoke podcasts up on the YouTube channel.  Please listen/watch on YouTube. Here is the playlist:  https://www.youtube.com/playlist?list=PLv9MEKq1quk-gnxog7eBqY_y7cpQadf6T   

Google feed no longer sending our e-mails.  So please follow the blog, Get yourself a blog feed reader.  I use Feedly.  It is free.   Download, search in Feedly for SolderSmoke, hit subscribe and you are done. https://feedly.com/i/discover Follow Pete’s blog too!  It is easy.

 Pete’s Bench

Resurrections: 

SBE-33!

TenTEC Model 540

KWM-1

Mailbag:

Dan KC5VPI getting into homebrewing. No longer WRONG!

Michael AG5VG built subharmonic DC receiver, put it on 40 and 20.  FB.

Mike AA9IL working on old tube stuff including a DX-100 AMD UUHF gear up to 122GHz.

Ed WA4MZS liked the SolderSmoke book. USCG vet.  As is Mike Rainey AA1TJ Semper Paratus!

Clint KA7OEI – The Music of the Beams – My Hex  does not sing!  So far!

Walter KA4KXX – The Knack started early.  Video of getting a toolbox for Christmas. And working on PTOs!  He likes them!

Phillip G4HOJ Also working with subharmonic mixers – using the more complex 4 diode version.

Peter GW4ZUA Built an amazing rig from RADCOM (1980s) Cool VFO with varactor fine tuning and a coil with a dust core that was cut in half to minimize temp effect. Box now holds 3  band version of Pete’s SimpleCeiver. FB.

Bruce KC1FSZ building 25 Watt amp for his Peppermint Bark rigs.  We won’t turn him in to the QRP authorities.

Grayson KJ7UM tested the 12BY7A from my DX-100 VFO.  It was in fact weak. Thanks Grayson.

Charles Smith KV4JT has some really interesting stuff on how to solid state tube gear.   Especially R-390s. https://soldersmoke.blogspot.com/2022/08/trigger-warning-solid-stating-old-tube.html

Gianfranco I0ZY Old friend from Rome.  Amplifier manufacturer.  FB.

Paul WA1MAC getting started again after long hiatus.

Vasily.. I mean Todd VE7BPO.  Always great tech info.  Thanks.

Mark WB8YMV building a superhet with a 455 kc IF.

I sent Farhan some comments on his Daylight Again video: He wrote back “I marvel at their stamina to watch an hour long video of a man talking with a funny accent!”  

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.

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