Space Hints from the Dominican Republic in 1994

Check out the article in the link below.  I too got a QSL from RS-10! 

https://www.gadgeteer.us/SPAHINT.HTM

The 2 meter portion of the Ray-Gun appears below.  I still have the elements. 

Solar Powered Drone from South Africa

 I've been flying a DJI 4K Mini drone here in the Dominican Republic, so I am interested in the whole drone thing.  The technology involved is pretty amazing, with many of the drones featuring GPS tracking systems, onboard compasses, and inertial (gyroscopic) stabilizers.  This in addition to high resolution, stabilized cameras, look-down landing cameras, and obstacle avoidance systems.  Oh yea, if you lose sight of the 249 gram drone, you can just hit the HOME button and it will miraculously fly to its start point and land.  Wow.  

This fellow in Capetown takes things quite a bit further. I like his solar-powered drone.  He has a really cool workshop.  There is something for everyone here:  He uses 3-D printing, carbon fibers, and computer assisted design tools.  And he does a lot of good-old soldering.  I really like his portable wind meter.  I will get one for this very windy location in the Dominican Republic. 

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: 128 Completed, 121 + 7 Honorable Mentions: (As of April 5, 2026, 0833Z)

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 April 5, 2026 0833Z:

So far Total Receivers Built: 128. 121 plus 7 honorable mentions.  Total Count:  128.  Receivers built in 18 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

KC9LFP         Joe

SP9DEL          Marian

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

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

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

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

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

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

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

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

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

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

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

Thanks Rex, thanks Charlie! 

Stuart Brand

A couple days after I announce that I don't want to help Jeff Bezos make any more money, it might come as a surprise that I am linking to this article about a guy who seems to LIKE Bezos (and also Musk!).  But I do like Stuart Brand.  I have a copy of the Whole Earth Catalog, and it had a lot of good ham radio content in it: 

https://soldersmoke.blogspot.com/search?q=Whole+Earth+Catalog 

Anyway, here is the article.  I found it very interesting. 

https://www.theguardian.com/technology/2026/feb/25/tech-legend-stewart-brand-on-musk-bezos-and-his-extraordinary-life-we-dont-need-to-passively-accept-our-fate

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! 

Saw the Hubble Space Telescope Again this Morning

Skies were brightening at 0626 local.   And there were a lot of clouds.  But HST appeared right on  schedule, and I saw it between the clouds as it passed overhed.   There should be even better passes in the morning during the next two days. 

The Mahbood Radio Service Company of Hyderabad, India

Our friend Farhan sent this today.  It is really beautiful and captures very well the magic of radio.  Thanks Farhan. and thanks too to Mohammad Moinuddin of the Mahbood Radio Service. 

“Before television and smartphones, Hyderabad listened to the world through radios. And in those days, my father ensured that the city stayed tuned in.

My father, the late Shaik Mahboob, founded Mahboob Radio Service in 1933 in Dabeerpura. At a time when radio was still a luxury, he began selling and repairing sets for households across the Old City. In 1948, after Hyderabad’s accession to the Indian Union, he shifted the shop to its present location in Chatta Bazar, where it continues to stand even today.

Interestingly, he did not begin with radios. In the late 1920s, he was involved in the PVC pipes trade. But as radio technology slowly entered Indian homes, he recognised its future and transitioned into the business of radio sales and repairs. That decision shaped our family’s destiny.

Like my father, my brother and I grew up surrounded by valves, wires, and wooden cabinets. After school, we would sit beside him, carefully observing how he handled brands like Murphy, Philips, Bush, Marconi, and later Sony. Those were the golden years of radio in Hyderabad.

Among our customers were prominent families of the city. We even serviced radio sets for the palace of the last Nizam, Mir Osman Ali Khan. Payments would arrive in a sealed lifafa — a gesture that felt both formal and special. In those days, radio wasn’t just entertainment; it was how people heard news, music, cricket commentary, and the world beyond their homes.

Over time, technology changed. Transistors replaced valve sets. Then came television. Now, smartphones have taken over. Radio sets are no longer common in households. Many shops that once repaired them have shut down.

My brother, who shared this passion with me, is no more. But I continue to open the shutters of our shop every morning. People still travel from different parts of the country — some carrying radios that are older than me — hoping to restore a memory. I repair them not just as machines, but as pieces of someone’s past.

Today, in my late seventies, I sit at the same wooden table where I learned this craft as a boy. Because this is not merely a business, it is continuity. It is a responsibility.

On World Radio Day, my only wish is that people remember the warmth of gathering around a radio set. I also hope today’s radio jockeys continue to create thoughtful and meaningful programming. Because radio is not outdated — it is timeless.  As long as I am here, Mahboob Radio Service will remain tuned in.”  

– Mohammad Moinuddin, Mahboob Radio Service