G-QRP 2025 G2NJ Trophy

Thanks to G-QRP for selecting us for this prestigious award.  This was for our efforts with the SolderSmoke Direct Conversion Receiver.  

Audio Amplifier Stage Template and Handout: SolderSmoke Direct Conversion Receiver by N7HPR

 

Above is Steve N7HPR's template for the audio amplifier board, the board that gave a lot of people a lot of trouble.  But it SHOULD have caused a lot of trouble!  It is the only gain stage in the receiver -- it provides at least 80 db of gain.  It deliberately uses no feedback -- we did it this way to keep the circuit simple.  So if you let too much of the output find its way to the input, this amplifier will turn into an oscillator.  Then you will have to tame it. And almost all builders did. This was a valuable lesson:  All amplifiers aspire to be oscillators.  They have to be denied the Barkhausen criteria. 

Above we see the placement of Rex's Me pads, and the transformer. (Note that Steve DOES ground one of the output pads.)  I think that Steve's layout was really good -- it sounds like they did not have a lot of the feedback and motorboating problems that were reported by others.  This is a good reminder of the importance of careful layout. 

Here is Steve's handout: 

Steve's messages have caused me to reflect a bit on this project.  I will try to write about this in the days ahead.  

Thanks Steve. And thanks to all the builders. 

SolderSmoke Direct Conversion Receiver: TOROIDS! Steve N7HPR's Handouts on the BP Filter and the Mixer/Diplexer

 

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

Winding the trifilar toroids was the hardest part of building the mixer board, and with the high school students, I admit to chickening out.   Instead I prepared about 17 of them using a batch from Hyderabad (wound by the seamstresses!) that Farhan left me.  Here is  how we did it: https://soldersmoke.blogspot.com/2023/02/progress-report-high-school-students_25.html Steve's use of wires of different colors is a good idea.  It helps to keep track of the different wires.  

We often hear that winding toroids is a show-stopper for many would-be homebrewers.  This should not be the case.   Winding the coils is not difficult.  

The Diplexer came from Roy Lewellan W7EL's optimized QRP Transceiver.  Dean and I were struggling with the suppression of signal from Radio Marti on 7335 kHz.  When we added Roy's diplexer, it seemed to help knock down Radio Marti.  

We too used the NanoVNA to tune the BP filter.  I remember this as one of the more pleasing moments for the students. 

SolderSmoke Direct Conversion Receiver-- N7HPR Handout #1 -- The VFO

 

I like the way Steve N7HPR did this:  First, that he had a working receiver on display to serve as a prototype.  Second, that he asked the students to come up with their own Manhattan board designs and third, he provided templates that would allow them to properly place their Me Pads. 

We did some of these things with the high school students.  We definitely had a prototype on display, and they looked at it a lot.  We did ask them to deisgn their own Manhattan boards -- as I recall, the response to this was uneven at best.   The templates are a good idea that we did not try with our group build.  

One big advantage of building the VFO first -- the students get something of the Michigan Mighty Mite sensation.  They have successfully built a source of RF, a transmitter!  We had one of the students move around the room with his oscillator (battery powered) turning it on and off as he listened to the tones from a DX-390 receiver.  This is very similar to the demonstration that Marconi did with the very first radios.  

More tomorrow.   

Thanks again Steve.

Steve N7HPR Describes the Group Build of 10 SolderSmoke Direct Conversion Receivers

Group Build of the SolderSmoke Direct Conversion Receiver Challenge

By Steven Bible, N7HPR

Andrew Johnson Amateur Radio Club and Greene County Makers, Greene County Tennessee

The main goal for the group build is hands-on learning. Each of the students are working on their amateur license. Three are working on their Technician, one General, and the remainder on their Extra. The extra exam has a great deal of detailed technical knowledge and the SolderSmoke Direct Conversion Receiver Challenge is a great vehicle for teaching many of these technical details.

Several in the group have experience soldering thru-hole components on a printed circuit board. However, Manhattan style construction was new to them. It would add a valuable skill to their toolbox. The question, from an instructor’s point of view, was how to ease them into this skill before taking on a much larger project? The answer was to first build a smaller project to introduce the students to this unique construction style. I chose Allen Wolke’s W2AEW YouTube video on building a buffered Colpitts crystal oscillator. The added benefit was teaching the oscillator questions on the amateur exams.

#123: Build a crystal oscillator from schematic thru prototype construction and

testing – DIY [https://www.youtube.com/watch?v=blalAktxFoI]

In the video, Allen shows how to identify the nodes on a schematic and use them as the

pads on the PCB. From this I came up with a teaching method where the students study

the schematic and sketch on a handout how they plan to assemble the board. I

designed and 3D printed a template for the student to trace onto the PCB with a pencil.

They would superglue MeSqares onto the squares of the template, and the circles were

suggestions of where to ground components to the PCB. This gave them the mental

exercise to reason how to take a schematic and turn it into a prototype. Building the

oscillator was an excellent introduction and helped lead the students into the larger

DCR Challenge.

PCB Template. Students sketch the template onto the PCB.

Over the course of eight weeks of 2-hour classes, the students built the four blocks of

the Direct Conversion Receiver. I designed and laser cut a baseboard from 1/8-inch (3

mm) Baltic Burch plywood where the students could mount the four blocks of the

receiver. This provided the students some structure in assembling the receiver.

We started with the VFO block first. The most challenging thing was winding the PTO

form. But everyone managed. Other challenges were poor solder joints and missing

connections, which were easy to remedy. They became excellent teaching points.

I also noticed that students would look at the (what I called) the prototype Direct

Conversion Receiver that I built to show everyone what it would look like in the end. As

it turned out, this was a valuable part of the group build. Students would take photos of

the prototype so that they could gain a better understanding of the construction of the

receiver.

As students completed their VFO, I would test it using an oscilloscope demonstrating to

them what and how an oscilloscope works and the signals coming from their VFO.

The second block was the Band Pass Filter. This block had easier transformers to wind

compared to the mixer. This allowed a gentler introduction to toroid winding. To aid in

the identification of the windings, I purchased red and green enameled wire that had a

poly-coat that was easy to remove using a blob of solder on the soldering iron. Overall,

this was a simple block for the students to assemble. As students completed their Band

Pass Filter, I connected it to a nanoVNA and allowed them to tune the filter. Another

great teaching moment introducing them to filters and vector network analyzers (VNA),

all if which are on the General and Extra exams.

The third block to be assembled was the Mixer. This had a little more challenging

transformer with the trifler windings. I purchased enameled wire in three colors: copper,

red, and green. The copper-colored wire was coated with enamel which required

scraping to remove. The red and green was the poly-coating the students were familiar

with from building the Band Pass Filter.

The three colors allowed the students to identify the primary (indicated with a dot on the

schematic) and secondary sides. The schematic showed the location of the colors and

the MeSquares they were to be attached to. This alleviated much of the confusion that

can occur with connecting trifler windings (see DCR Mixer Handout.docx).

The forth block was to assemble the Audio Amplifier. By this time the students have

developed their knowledge and skills to assemble the one block that had the most

components. Assembly went smoothly; however, we would have the occasional

misplaced component, bad solder joint, etc. This was the case throughout the build, but

they were welcomed as excellent teaching moments.

When the entire Direct Conversion Receiver was assembled, we would test them first

using a tinySA in signal generator mode and inject a 7.1 MHz carrier. We would tune the

PTO to tune down to 7.0 MHz and up to 7.3 MHz. We had to add an inductance in

series with the PTO to accomplish this range. This took some trial and error. There was

some troubleshooting to be done to find an error or two. Finally, we connected the

receivers to a loop antenna and listened to on-the-air signals. It was not the best

antenna setup, but it gave the students confidence that their receivers were working.

The amateurs in the group took theirs home and hooked them up to their station

antennas to listen further. Each reported good reception.

The Soldersmoke Direct Conversion Receiver Challenge was an excellent group

project. The students learned a great deal from the hands-on experience. W2AEW’s

buffered Colpitts crystal oscillator video was perfect for introducing Manhattan style

construction. Creating a kit of parts, 3D printed templates, handouts, and laser cut base

gave structure to the group build and minimized construction errors. Having a fully built

receiver (that I called the prototype) for students to refer to proved extremely valuable.

Building as a group provided an encouraging environment where the students would

assist each other and share teaching moments (what to do, what not to do). Finally,

there were many teaching moments that helped solidify knowledge and skills and there

were many direct references to the questions on the Technician, General, and Extra

exams. The goal of the group build was met!

Many thanks to the SolderSmoke team for an excellent project!

73, Steve N7HPR

Thanks Steve!  More to follow -- Steve's handouts on the construction of each stage are really great. 

 Stay tuned!

SolderSmoke Homebrew Direct Conversion Receiver Hall of Fame Update: 126 Completed, 119 + 7 Honorable Mentions: (As of March 9, 2026, 1827Z)

N7HPR's Group

One of the 10 Receivers They Built

Please let us know if you spot any errors, or if we have inadvertently missed anyone.  Don't worry about being late to the game -- the challenge continues.  All of the info is still available. 

As of March 9, 2026 1827Z:

So far Total Receivers Built: 126. 119 plus 7 honorable mentions.  Total Count:  126.  Receivers built in 17 countries.   

NE3U (KY4EOD)  Matt 

KQ4AOP       First ham signals ever heard! 

N9TD             Derek

AC3NG          Ryan

VK3TPM       Peter Marks  

W4KAC         Ken 

W4KAC         Ken built a second one! 

N2EPE           Erik

VA3NCA        Wayde    

KI5SRY         Mark -- Gears on PTO screw

 

KA1MUQ       Frying pan receiver

AA1N              Adam

ZL1AUN         Aaron -- Using SSB transmitter -- New Zealand

W8UC             Never before homebrewed. 

VK4PG           Phil -- Nice case, "really pleased"

G7LQX           Working well, video of CW and SSB.  -- England

KE2AMP        John     Spring on PTO screw -- great

N9SZ              Steve  nice receiver

KD9NHZ        Piotr  Nice one

KE8ICE          Calvin, Very cool receiver. 

 

WV3V              Jayson!  Got it done!

GM5JDG         Martin.   -- Scotland 

KF8BOG          Jim:  A long struggle, but success.  

Chris Wales    Fantastic video.  -- Wales

YD9BAX         Wayan! Homebrew transformer!  Indonesia

N0NQD         Jeff 

WN3F              Roy -- Made new stickers! 

AB5XQ            Bill  

KB7ZUT          Andy  

AA1OF            Jer

VictorKees        Holland

KC9OJV           John -- Manhattan-style convert

WZ5M              1, 2 or maybe even 3 receivers!

K1KJW             Jim in Vermont

KC5DI              Dallas -- friend of WZ5M

Gary                 Australian -- Wooden PTO form

LU2VJM          Juan in Argentina  -- Argentina

K1OA               Scott "Most fun in 50 years"

KC9DLM         Ben -- Had EFHW problems

PH2LB             Lex  Yellow, Glue Stick -- Netherlands

AI6WR             David

G6GEV            Dave (It was a blast!) 

KC1ONM        Wayne  MakerLabs NH

KB1OIQ          Andy    MakerLabs NH

KA1PQK         Jay       MakerLabs NH

W1TKO           Mike    MakerLabs NH

K5KHK            Karl

SM0TPW         Mikael  -- Sweden

KI7LKB           Brian (coat hanger tube)

M6CRD            Chris

W2DAB           Dave in NYC

W4JYK            Wes of VWS

KA4CDN          Mike of VWS

M7EFO             Adrian 

VK5RC             Rob

KD8KHP          Dave

VK1CHW         Chris

KA0PHJ           Brian

W0IT                Louis

W1PJE             Phil

W2AEW           Alan

KN6FVK          John (Barkhausen-Be-Gone Spray) 

VU2JXN           Ramakrishnan -- India

AA0MS            Doug 

9V1/KM7ABZ   Paul  --  Singapore

VK2BLQ          Stephen -- Australia

N3FJZ              Rick

Daniel               VE5DLD  -- Canada

Student 1          Student of VE5DLD

Student 2          Student of VE5DLD

Student 3         Student of VE5DLD

K7WXW          Bill 

NK3H               Mitch

KN4ZXG         Ted

WA1MAC        Paul

N4AVC             Chuck 

K3IY                 Kevin

N6ASD             Ashish in Bangalore

W1DSP             Rick

WD4CFN         Steve

KM5Z             Mike

KF5DAN         Dan

Fritz                 Fritz

N9OK              Joe

WA5DSS         Bill 

K0GDB           Grant

G0JNR            Shane Glow-in-Dark Coil Form

KK7BCO        Tobias

K2BVR            Bob

Robert              Sutton

K5YFO           Dave (Texas) 

KD4PBJ          Chris

KN4GAH        Chris -- EE perspective

F1GMA           Philippe  -- France

W2TEF            Todd

EI9ITB            Karl  -- Ireland

VU2TUM         Puneit Singh

AA7EE             Dave Richards

KI5VIR            Jay

CT7AXD       Graham -- Promoted from Honorable Mention!

G3MOT           Josh

KW4H             Steve

NJ7V                Charlie (RedSummit)

N2ETZ            Denny

AB9LM           James

W9XT              Gary

G0PJT             Alex

KF8FZZ         Tyler

N7HPR           Steve (Instructor) (N7HPR Group)

Clark               (N7HPR Group)

KQ4ZHO        Kurt (N7HPR Group)

KQ4OBR        Brian (N7HPR Group)

KR4CUF         Justin (N7HPR Group)

Amanda          (N7HPR Group)

David               (N7HPR Group)

KM4AED       Jamey (N7HPR Group)

KN4MVH      Larry (N7HPR Group)

N5GVW          Dick (N7HPR Group)

W7KAL          Kal

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

Honorable Mentions: 

*AA7U            Steve No PTO

*VK7IAN        Ian -- No Manhattan boards -- Tasmania

*KC1FSZ        Bruce's build on a PC board

* DL1AJG      Andreas -- Germany

* Matthew      Student of DL1AJG

* Arash           Student of DL1AJG 

*KA4KXX     Walter -- FB 20 Meter version

SolderSmoke Podcast 263: DR-PR, UM, DCRX, SKN, Design, PSSST, W7ZOI, FT-101, HW32A, VK, HST, AMP, MAILBAG

Pete Juliano N6QW

February 23, 2026

SolderSmoke Podcast #263 is available for download: 

Audio:  http://soldersmoke.com/soldersmoke263.mp3

Video:  https://www.youtube.com/watch?v=Fn164glxQ6s

Opening 

May 26, 2014, coming up on 12 years! That was the 1^st podcast where Pete N6QW was interviewed by Bill in Podcast #161,  which means 102 podcasts ago. 12 Years of Julian-ismo.  Thanks Pete!  

What to build?  Question faced by VWS Makers Group and by Charlie of RedSummit RF.   Regen?  Test Gear?  Simple oscillator?  

But did you DESIGN it yourself?  What does that even really mean? Barrie Gilbert in Jim Williams' book:  https://soldersmoke.blogspot.com/2025/12/homebrew-you-say-but-did-you-design-it.html

Grayson KJ7UM on a podcast -- Make it your own way.  Copper Clad and Glue!  Manhattan style! "BUILD SOMETHING!:  Tube testers not necessary.  OK to call thermatrons "vacuum tubes."  No ruling on calling them "valves" yet. 

Pete:  

-- When hams were hams -- Turning a Heath monobander into a tribander

-- Simple SSB

-- W7ZOI rigs

-- The Yaesu FT-101

SHAMELESS COMMERCE DIVISION:   Mostly DIY RF!   Patreon!   But no more Amazon.  We do not want to help Bezos make more money. Even if this will cost us.   So please,  consider a donation or a Patreon sponsorship instead.  But no more Amazon through SolderSmoke.  

Bill:   

-- Dominican Republic to Puerto Rico on 2 meters -- status report. 

-- Working Australia on 20 meter SSB in the morning. 

-- The SpiderWeb net. 

-- The Hubble Space Telescope -- an old friend

-- One contact on Straight Key Night (Dean reminded me).  I worked NB1U on 20 meters with QCX from KD4EBM. 

Dean: 

-- The University of Michigan ant the Direct Conversion receiver project.  

-- Boxing up the amplifier.  A tale of woe.  Identifying oscillations.  A QSO with the Dominican Republic: https://soldersmoke.blogspot.com/2026/02/a-qso-with-dean-kk4das-northern.html 

 Travails with other homebrew gear... Trying to find a working transceiver.

AI assisted repair of Bitx40 PA in my Mythbuster 

VWS club station update, tendency of Flex and other SDR makers to not release even basic technical information.

MAILBAG: 

Ian VK3MO  Huge antennas, big signal, friendship with WA3O https://soldersmoke.blogspot.com/2025/11/vk3mo-and-wa3o-brotherhood-of-ham-radio.html

Bob KD4EBM  2 meter propagation info

Todd K7TFC  -- Mostly DIY RF

Mike K6STR  Worked Pete on 40, building for CW and SSB on 2 meters

Grayson KJ7UM    German Avionics,  MMM Origin.  Old Steampunk Homebrew rig: https://soldersmoke.blogspot.com/2025/12/a-very-interesting-old-steam-punk.html   

Phil  W1PJE   Forrest Mims III     Mims's sad denial on climate change. 

Ciprian  YO2DXE         Heard the SAQ Alternator  see: https://soldersmoke.blogspot.com/2025/12/alexanderson-alternator-on-172-khz.html

Tom NS6T:  Very useful azimuth map with grey lines: https://ns6t.net/AzShadowMap/experimental.html

Walter KA4KXX -- 20 meter Direct Conversion Receiver.  FB Walter! 

WN2A Mike   Dos Equis man is BACK! https://soldersmoke.blogspot.com/2026/01/hes-back-dos-equis-man-most-interesting.html

KB4HG Rhett:  On USB on the Old Military Radio Net with a PRC-74.  Want one! 

SolderSmoke Homebrew Direct Conversion Receiver Hall of Fame Update: 108 Completed + 7 Honorable Mentions: Total Receivers Built: 115 (As of February 20, 2026, 1503Z)

Please let us know if you spot any errors, or if we have inadvertently missed anyone.  Don't worry about being late to the game -- the challenge continues.  All of the info is still available. 

As of February 20, 2026 1503Z:

So far 108 completed receivers, and 7 honorable mentions.  Total Count:  115.  Receivers built in 17 countries.   

NE3U (KY4EOD)  Matt 

KQ4AOP       First ham signals ever heard! 

N9TD             Derek

AC3NG          Ryan

VK3TPM       Peter Marks  

W4KAC         Ken 

W4KAC         Ken built a second one! 

N2EPE           Erik

VA3NCA        Wayde    

KI5SRY         Mark -- Gears on PTO screw

 

KA1MUQ       Frying pan receiver

AA1N              Adam

ZL1AUN         Aaron -- Using SSB transmitter -- New Zealand

W8UC             Never before homebrewed. 

VK4PG           Phil -- Nice case, "really pleased"

G7LQX           Working well, video of CW and SSB.  -- England

KE2AMP        John     Spring on PTO screw -- great

N9SZ              Steve  nice receiver

KD9NHZ        Piotr  Nice one

KE8ICE          Calvin, Very cool receiver. 

 

WV3V              Jayson!  Got it done!

GM5JDG         Martin.   -- Scotland 

KF8BOG          Jim:  A long struggle, but success.  

Chris Wales    Fantastic video.  -- Wales

YD9BAX         Wayan! Homebrew transformer!  Indonesia

N0NQD         Jeff 

WN3F              Roy -- Made new stickers! 

AB5XQ            Bill  

KB7ZUT          Andy  

AA1OF            Jer

VictorKees        Holland

KC9OJV           John -- Manhattan-style convert

WZ5M              1, 2 or maybe even 3 receivers!

K1KJW             Jim in Vermont

KC5DI              Dallas -- friend of WZ5M

Gary                 Australian -- Wooden PTO form

LU2VJM          Juan in Argentina  -- Argentina

K1OA               Scott "Most fun in 50 years"

KC9DLM         Ben -- Had EFHW problems

PH2LB             Lex  Yellow, Glue Stick -- Netherlands

AI6WR             David

G6GEV            Dave (It was a blast!) 

KC1ONM        Wayne  MakerLabs NH

KB1OIQ          Andy    MakerLabs NH

KA1PQK         Jay       MakerLabs NH

W1TKO           Mike    MakerLabs NH

K5KHK            Karl

SM0TPW         Mikael  -- Sweden

KI7LKB           Brian (coat hanger tube)

M6CRD            Chris

W2DAB           Dave in NYC

W4JYK            Wes of VWS

KA4CDN          Mike of VWS

M7EFO             Adrian 

VK5RC             Rob

KD8KHP          Dave

VK1CHW         Chris

KA0PHJ           Brian

W0IT                Louis

W1PJE             Phil

W2AEW           Alan

KN6FVK          John (Barkhausen-Be-Gone Spray) 

VU2JXN           Ramakrishnan -- India

AA0MS            Doug 

9V1/KM7ABZ   Paul  --  Singapore

VK2BLQ          Stephen -- Australia

N3FJZ              Rick

Daniel               VE5DLD  -- Canada

Student 1          Student of VE5DLD

Student 2          Student of VE5DLD

Student 3         Student of VE5DLD

K7WXW          Bill 

NK3H               Mitch

KN4ZXG         Ted

WA1MAC        Paul

N4AVC             Chuck 

K3IY                 Kevin

N6ASD             Ashish in Bangalore

W1DSP             Rick

WD4CFN         Steve

KM5Z             Mike

KF5DAN         Dan

Fritz                 Fritz

N9OK              Joe

WA5DSS         Bill 

K0GDB           Grant

G0JNR            Shane Glow-in-Dark Coil Form

KK7BCO        Tobias

K2BVR            Bob

Robert              Sutton

K5YFO           Dave (Texas) 

KD4PBJ          Chris

KN4GAH        Chris -- EE perspective

F1GMA           Philippe  -- France

W2TEF            Todd

EI9ITB            Karl  -- Ireland

VU2TUM         Puneit Singh

AA7EE             Dave Richards

KI5VIR            Jay

CT7AXD       Graham -- Promoted from Honorable Mention!

G3MOT           Josh

KW4H             Steve

NJ7V                Charlie (RedSummit)

N2ETZ            Denny

AB9LM           James

W9XT              Gary

G0PJT             Alex

Ohio                Tyler

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

Honorable Mentions: 

*AA7U            Steve No PTO

*VK7IAN        Ian -- No Manhattan boards -- Tasmania

*KC1FSZ        Bruce's build on a PC board

* DL1AJG      Andreas -- Germany

* Matthew      Student of DL1AJG

* Arash           Student of DL1AJG 

*KA4KXX     Walter -- FB 20 Meter version

Walter KA4KXX's Innovative 20-meter SolderSmoke Direct-Conversion Honorable-Mention Receiver

 

It is a thing of beauty.  We were really pleased to see our old friend Walter KA4KXX take on the SolderSmoke challenge, and we weren't a bit surprised to see him do so using some real twists in the design.  You see, Walter is a very experienced homebrewer.   He has built many, many rigs over the years.  Just check out his QRZ page and you will see what I mean: 

 https://www.qrz.com/db/KA4KXX

Walter supported our original high school effort by offering the students a $500 prize for any student who used our receiver (and a similar transmitter) to check in to the 40 meter Sunrise Net.  Sadly, there were no takers.  But we really appreciated the attempt. 

We have listed Walter's receiver in the Honorable Mention category, only because his build is so innovative:  20 meters instead of 40.  An IC in the audio amplifier.  There were differences, but even a quick look at the above picture above shows that Walter's receiver is very much a SolderSmoke Direct Conversion Receiver.  

Here are some additional photos from Walter. 

Congratulations Walter.  Welcome to the Hall of Fame!  

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

From Walter's QRZ page

"Homebrew you say? But did you DESIGN it yourself?"

Raymond A. Heising  (1922)

That is a question we get fairly regularly when we tell the other fellow that our rig is homebrew.  I often get the feeling that the question stems from a certain insecurity -- the guy who asks it may feel a bit insecure because the "rig" he is running is completely commercial and his only role in its production was to flash a credit card number.  

But lately I have been reading through Jim Williams' wonderful book "Analog Circuit Design -- Art, Science, and Personalities" and I can see that there may be something to this question. 

It was the chapter by Barrie Gilbert that made me think more about this. Barrie is the legendary designer for whom the Gilbert Cell is named.  This circuit is at the heart of the NE602 chip that many of us used to build our first "Neophyte" receivers and other homebrew rigs.  Barrie's chapter is entitled "Where do Little Circuits Come From."  Uh oh. 

Barrie grew up in the post-war United Kingdom.  He father had been killed in a German bombing raid. As a kid, he built crystal radios and, with his brother, "shortwave sets" on softwood bases.  He used a TRF receiver that employed Manhattan-style construction.  Barrie, it seemed, was one of us.  

But then, he suddenly seemed more advanced.   He wrote:  

"Later, I began to build some receivers of my own but stubbornly refused to use circuits published in the top magazines of the day, Practical Wireless and Wireless World.  Whether they worked as well or not they had to be "originals" otherwise, where was the satisfaction?  I learned by my mistakes but grew to trust what I acquiered in this way:  it was 100% mine, not a replication or mere validation of someone else's inventiveness."  

Wow, that is certainly hardcore.  I will note,  however,  that in getting back to the the question about whether I have "designed" the rig myself, I have NEVER had the questioner come back to say that HIS rig was homebrewed from HIS OWN original design.  Never.  Not once. 

And I will note that building a rig from the schematic is an enormous challenge.  It is not easy.  It is not the mere replication of someone else's inventiveness.  Anyone who thinks it is easy should try to homebrew a simple direct conversion receiver.  They will discover that it is NOT easy. 

I guess this comes down to what we mean by "homebrew."  I prefer to stick to the old ham radio meaning of the term:  It is homebrew if it was built at home, even if it is built from a schematic done by someone else. When Jean Shepherd built his Heising Modulator, was he working off a schematic from a ham radio magazine?  He almost certainly was.  But he gathered the parts, laid out the chassis, and put the circuit together.  Most importantly, when trouble cropped up, he was able to step in and make the needed corrections.  Was his modulator "homebrew?" Of course it was.  Did he design it himself?   No, his name was not Heising! 

More than 100 people built our SolderSmoke Direct Conversion Receiver.  We resisted pressure to turn this project into a kit.  The folks who built it worked off schematics that we had prepared.  They gathered the parts and built their own circuit boards, Manhattan style. They struggled to get the whole thing to work, to make sure the VFO was on the right frequency and at the right level, that the AF amplifier was not oscillating.  Were these receivers "homebrew?"  Of course they were. 

Jim Williams warned that Analog Circuit Design was "A wierd book."  He strongly discouraged collaboration between the authors, and noted that this would probably result in "a somewhat discordant book."  We see that discord in the hardcore position taken by Barrie Gilbert.  Many of the other designers seem to take a more flexible, less austere position.  Some even seem to downplay the role of mathematics.  

I think Barrie had a right to be proud of his fundamentalism.  But not all of us are capable of that.   Writing in Jim Williams' book,  Samuel Wilensky sums it up nicely: 

"I classify analog designers into one of two categories.  There are those who do truly original work, and these I consider the artists of our profession.  These individuals, as in most fields, are very rare.  Then there are the rest of us, who are indeed creative,  but do it by building on the present base of knowledge."   

Dave Richards AA7EE Builds and Documents the SolderSmoke Direct Conversion Receiver

As always with Dave's builds, " 'tis a thing of beauty."  His photographs and documentation make it even better.   Please go directly to Dave's site and enjoy his look at the SolderSmoke HOMEBREW Direct Conversion Receiver:  

https://aa7ee.wordpress.com/2025/12/04/the-soldersmoke-direct-conversion-receiver/

Thanks Dave! 

Jim Williams -- Analog Man -- Book Review: "Analog Circuit Design -- Art, Science, and Personalities"

 

Jim Williams at his bench.  Note the mess. 

The Bob Pease book that KD4EBM gave me led me to the Jim Willams book entitled Analog Circuit Design -- Art, Science, and Personalities.  I'm only about a quarter of the way through it, but I can already tell that it is great.  Get this book.   Make room on your shelf.   

Jim was the editor, and it is a collection of contibutions made by a many different analog luminaries.  Curiously, none of the bios show that there are any hams among them (but the articles of many of them seem to hint at ham radio backgrounds).  MIT shows up a lot in the bios.  Jim notes in the very first line of the preface that "This is a weird book."   He talks about how it came together -- he met with the contributors and each of them pledged NOT to consult with the others about what they would write.  Jim notes that the result is "a somewhat discordant book," that "Hopefully would lend courage to someone seeking to do analog work." " The single greatest asset a designer has is self knowledge."  "Take what you like, cook it any way you want to, and leave the rest."  Indeed. 

I found that Jim's own contributions were among those that I liked the most. He writes about "analoggery" and "digital fakery"  but then acknowledges that this is a "good natured" controversy.  He notes that "no true home is complete without a lab" (a shack?) and that "no lab is complete without an HP series 200 oscillator."  His bio reveals that he lived in California with his family and "14 Tektronix oscilloscopes."   In a chapter entitled "Should Ohm's Law be Repealed?" Jim describes the very early influence of a neighbor, Dr. Stearn,  who owned a Tek 535.  It allowed them to see into circuits:  "You knew the excitement Leeuwenhoek felt when he looked in his microscope."  But that was not always enough:  Jim tells how Stearn once successfully troubleshot one of Jim circuits simply by running moistened fingers over circuit while watching the scope. 

Tom Hornak also really struck a chord with me. He writes of things that happened in the year "10 BT" (Before Transistors).  He talks about how he and a childhood friend had trouble understanding the differences between voltage and current.  "We found someone who knew the right answer, but he did not help us too much. Instead of using a simple analog such as a phasor diagram, he started to talk sine and cosine. We accused him of not knowing the answer either, and covering up his ignorance my muttering mumbo-jumbo."  Tom explaines:  "I know that trying to 'understand electricity' early in life had a lasting benefit to me. I got used to 'seeing electricity' in analogs and I am still seeing it that way. I believe every electronic circuit designer could benefit from thinking in analogs, and it is never too late to start. This belief made me write this chapter."  

Barrie Gilbert -- the man credited with inventing the Gilbert Cell (the heart of the NE602) -- has a chapter in the book.  He writes of circuits "laid out Manhattan-style" and "built on softwood bases." He hombrewed a very early TV receiver. He tested AF amplifiers "by placing a finger on the grid of the first tube."  (We recommended something similar with the SolderSmoke Direct Conversion Receiver, but some builders seemed not to believe that this would work!)    

It is undoubtedly a tragedy that we lost both Jim Willams and Bob Pease in June 2011. Jim died of a stroke at age 63; Bob died of a possible heart attack or stroke while driving home from Jim's memorial service. But here we are in 2025 still talking about their work and their books. In a certain sense they live on through their writing.  This is a lesson and an inspiration for those of us who sometimes get a bit down by the vagaries of AI and the algorithms:  We never know when -- perhaps long after we are gone -- someone might come across something we have written and find inspiration there.  

Three cheers for Jim and Bob.   

https://soldersmoke.blogspot.com/2025/10/troubleshooting-analog-circuits-by-bob.html

https://www.jameco.com/Jameco/workshop/inthenews/pease.html?srsltid=AfmBOoqCC_QLhohtE3--OhGRLuQ0kQDyAq0rDsRhkdQDeIeZmGZs7nvN

https://www.edn.com/analog-engineering-legend-bob-pease-killed-in-car-crash/

Jay KI5VIR's FB Homebrew SolderSmoke Direct Conversion Receiver

Jay KI5VIR is a new ham, but you would never know this by looking at his build of the direct conversion receiver: It looks like something built by someone with a lot more time the amateur ranks. (See above.) 

Jay writes: 

I have completed the direct conversion reciever and I can't thank Bill, Dean and those that commented and asked questions on discord enough. This was my first build and I can't believe how much I learned. I have a long ways to go,  but this was just what I needed to get started in homebrewing.  1- (BIGGEST CHALLENGE)  was probably the diode ring mixer and learning to use my scope and setting it up to test the circuit. (this was also the most rewarding stage) 2-(WHAT DID YOU LEARN AND WHAT WAS YOUR BIGGEST CHALLENGE?) I got a basic understanding of how to read a circuit and what different components do in the circuit.(I still want to revisit each stage and make sure I get a little more) 3-(WHAT WOULD YOU LIKE TO HOMEBREW NEXT?) I want to first dissasemble each board and rebuild while it is fresh in my mind and make sure I get a little better understanding. After that, I want to either build a transmitter to go with this reciever, or build a complete transciever. Not sure whether to build ssb or cw, but I definately want to build something I can make at least a few contacts with. 

 Congratulations Jay, and welcome to the Hall of Fame! 

Dave AA7EE's Beautiful (Typically Beautiful) SolderSmoke Direct Conversion Receiver

Dave Richards AA7EE is justifiably famous in homebrew circles for the beautiful photographs of his rigs, and for the superb documentation of his builds.  You will see what I mean when you visit his blog: 

https://aa7ee.wordpress.com/   

We were very pleased when Dave told us he would build the direct conversion receiver that we have been discussing on Discord. 

Dave writes: 

Phew! Well this was a bit of a journey, and a slightly humbling experience. I looked at the schematic and thought, "Hey, I can build this. Shouldn't be too hard!" But the homebrew Gods judged that it was time to remind me of my place in the big scheme of things, by imbuing my receiver with in-band breakthrough from SSB, CW, and digi stations. Strong in-band stations within about 50KHz were breaking through and being heard in the same way that you'd hear SSB, CW, and digi signals on an AM receiver without a BFO. Their pitch wasn't changing as I tuned, because they had no pitch. Bill suggested that RF was getting into places it wasn't supposed to be, and being envelope detected by the AF amp. As it turned out, he was right. If anyone's interested, I can post a video of the issue I was experiencing. In the meantime though, I'll keep this post brief. I have quite a lot of pictures from various stages of the build, but posting them all here might be a bit TMI. I wanted to make this receiver reasonably compact and build all the stages on one board. My near-pathological tendency to try and build things fairly small could have contributed to the breakthrough problem that I experienced. I won't go into all the details of the troubleshooting process here, unless people are really interested, though I'll detail them in a post on my blog, as I think that sharing this stuff can be helpful to other builders - just as I have benefited greatly from others sharing with me. I made a few small changes from the original schematic, to cure the issues I was experiencing. Will detail them in another comment underneath, as the free version of Discord puts a character limit on posts.

I made the following small changes, to cure a couple of issues this little receiver was experiencing - 1) The AF amp was motorboating at anything above about medium volume, so I swapped out the 47µF capacitor in the +ve supply line to the AF amp (C10) for a 470µF part. This killed the motorboating dead in it's tracks. 2) To solve the in-band breakthrough issue, I did two things - a) At the suggestion of Peter VK3TPM, I placed a 1K resistor in the +ve supply line to the first AF amp stage, Q5, between C15 and R8. In conjunction with C15, this forms a lowpass filter with a 3dB cutoff point at about 3Hz. With a 12V supply, ~3.5V is dropped across this resistor and at 9V, the voltage drop is ~2.3V. If this voltage drop is too much for you, you can try a lower value of resistor and perhaps increasing the value of C15. This voltage drop does decrease the gain of the stage a little. In my case, it was welcome, as the amp was tipping over into feedback at full volume. Adding the resistor eliminated this, so I can now run the AF gain pot at full tilt. b) I added a 0.22µF capacitor from the wiper of the AF gain pot to ground, as an RF bypass. Physical placement of this cap was close to Q5. It also shapes the audio a little, cutting out some of the high-frequency hiss. You can experiment with different values here. I was initially going to use a 0.1µF part, but 0.22µF provided better protection. Greater values cut out too many of the higher frequencies for my liking. For a relatively simple receiver like this, I like the wide open sound.

I removed the spring from the tuning shaft. Tuning is smoother now, and free from backlash.

Dave 

AA7EE 

Here is a video of Dave's receiver inhaling CW during the CW Sweepstakes contest:

Here is one of Dave's iconic photos of the receiver:   

Thanks Dave!  Congratulations and welcome to the Hall of Fame!  

SolderSmoke Podcast 262: Hybrid Wireless, 100 Watt Amplifier, Antipode VK6, Tropo DR to PR?, Mixers, MAILBAG

SolderSmoke Podcast #262 is available: 

Audio only: http://soldersmoke.com/soldersmoke262.mp3

Video:  https://www.youtube.com/watch?v=QSUyE4IaHFw&t=61s 

Intro: 

-- We are over 100 on the Direct Conversion Receiver Builds.  We talked about the receiver project at the GQRP convention.  Video on the blog.

-- G4 Geomagnetic storm November 11-12.  Messed up my computer.  Blackout in the DR?  

Pete: 

-- USMC Birthday. Having served alongside them they have my deepest respect. Veterans Day. 

-- Think about supporting those without a job this Thanksgiving. Cash to various organizations is best.

 -- 50 Hz off frequency -- What does that mean if you tune by ear and not by mouse/waterfall?

--  The Hybrid Wireless is on the air. A unique build and not often seen.

Dean:  

-- Progress on the HOMEBREW MOSFET amplifier.  Claude helped. 

Dean's 100 watt amplifier

SHAMELESS COMMERCE DIVISION:  Mostly DIY RF.   Become a SolderSmoke Patron.  Buy stuff from Amazon through the link on this blog (in the right side column). 

Bill:  

Bill's antipode from Virginia

-- VK early in the morning.  Also E51MWA and FW5K.  All homebrew SSB. My antipodes. VK6ACF Charley 11,629 miles.  Might be my most distant station worked. 

-- Preping for VHF in HI7.  Can I kerchunk Boricua repeaters with Tropo?  See: https://soldersmoke.blogspot.com/2025/09/puerto-rico-dominican-republic-tropo-on.html

-- Bill's mixer obsession. Grayson's HSD Chapter 12. The importance of knowing "the paticular go of it." EMRFD Chapter 5. 

-- The new look for the SolderSmoke blog. 

MAILBAG:  

-- Todd VE7BPO -- Doing well. 

-- Grayson KJ7UM on the loss of Jim Tonne W4ENE.  Gone, but through his writting, continuing to contribute.See: https://web.archive.org/web/20220429224036/http://tonnesoftware.com/appnotes/demodulator/EnvelopeDemodulators.pdf

-- Camden is a 23 year-old blind ham who is looking for some homebrew help. He lives in Pleasant City, Ohio, about an hour east of Columbus.  Can you help him? camden@bopp.net

-- Dale Parfitt into the QRP Hall of Fame!  The Radio Gods Approve! 

-- Paul VK3HN -- Bricolage, Cacharreo, Artilugio, and Jugaad.  SA612 going obsolete. 

-- Mike WN2A Mixers and all that. Tropo.  "Greetings from the National Radio Noisy Zone!" (NJ) 

-- Peter Marks VK3TPM -- SolderSmoke template help -- Digital HF Voice

-- Walter KA4KXX -- A great book by L.B. Cebik

-- Bob KD4EBM  -- The Bob Pease Analog Troubleshooting book. Pease quote: "My favorite programming language is solder," 

-- Cor PA3COR  Difference between mixers and adders

-- Mike WA3O  I still have his HW-7.  Amazing water-cooled amplifier.   VK3MO.  

-- Samuele IU2QBW     An Italian Homebrewer  https://soldersmoke.blogspot.com/2025/10/a-wonderful-homebrew-direct-conversion.html

-- Pil Joo VA3GPJ  Experimenting with TIA amps. 

-- Farhan VU2ESE -- USB and LSB LC filters -- Applicable for crystal filters too? 

-- Rogier PA1ZZ Thanks for the great videos! 

-- Captain Mike  KX4WC   Aeronautical Mobile --Santiago, Chile to Panama!  With Mike WA3O and Ian VK3MO:  https://soldersmoke.blogspot.com/2025/11/vk3mo-and-wa3o-brotherhood-of-ham-radio.html 

-- Dave AA7EE  A completely AI SolderSmoke? "Open the pod bay doors Hal." 

-- Pat W3RGA heard my 1 watt HI7 beacon.  Thanks Pat. 

-- Patrick Voets -- A Belgian living in the Netherlands -- supports our defiant NIMCEL position! 

-- Brian "Moses" Hall K8TIY, Father of Robert of "Crank it in Robert" fame.  Check out the video.  Young Robert appears around the 45 minute point:  https://youtu.be/Xqs2Ihucr6I?t=2730

-- Will Harris KI4POV -- an esteemed homebrewer -- asks about using 75 ohm coax. I say yes, Pete tells him how to do it right.