WWII Homebrew In Norway

 

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r/amateurradio•14 hr. ago

steeljoo

How My Grandfather Tuned Into London During WWII with a Radio He Built in Secret

General

My grandfather was a lifelong radio enthusiast and ham radio operator. In his early twenties during World War II, he lived in the remote mountain village of Hjerkinn, working at the railroad station high above the treeline when Germany invaded Norway.

He joined the resistance movement and built radios using parts from a downed Luftwaffe aircraft—mainly the radio tube, as seen in the photos I’ve attached. With it, he secretly tuned into broadcasts from London. It was a risky and courageous act, but it kept him and others informed when access to truthful news was critical.

Later, he introduced me to the world of radio. As a kid, I spent hours scanning ham bands, police channels, and even unencrypted cellphone calls. I was probably way too young to be listening to some of it, but in the pre-smartphone era, it felt innocent enough. That early exposure sparked a lifelong passion for electronics and radio—one that still defines me today.

A few weeks ago, I visited my mom and saw one of the wartime radios he built. I thought this group might appreciate it—not just as a relic, but as a story of ingenuity, resistance, and the enduring magic of radio.

Thanks to Jim VE1KM for alerting us to steeljo's story. I told Jim that that Nazi tube is reminder of just how dangerous this all was for his grandfather. 

The Computer Hardware of the Apollo Program

Watching this, it seems like a miracle that we made it to the moon.  Some of this construction is downright scary.  Sometimes soldering is not good enough -- so they weld.  Other times they don't even solder -- they wire wrap!  Even in 1965, the wiring of the memory modules was so complex that it was beyond human comprehension.  All of this brought back memories of that wonderful book "Sunburst and Luminary" by Don Eyles.  I have hopes that he will appear in the MIT video about landing on the moon.  Don worked on those programs.  

On the importance of taking a break.

Thomas K4SWL has a good post about the importance of taking a break from radio.  Following up on this, I noted that "taking a break" is often a good way of finding a solution to a difficult problem. I noted that I have confirmed this -- it has worked for me.  Pete Juliano N6QW recently announced that he is taking a break from the MHST project. That is a good idea. A solution will likely emerge. 

I noted that there is some evidence backing up our suspicion about the benefits of breaks.  I earlier shared some comments from Harry Cliff's excellent book, "How to make an Apple Pie from Scratch." 

https://soldersmoke.blogspot.com/2024/04/cloud-chamber-finale.html 

Harry also wrote about the usefullness of taking breaks.  In 1917 Ernest Rutherford was having trouble  understanding the presence of some hydrogen nuclei.  Harry writes: 

"Again, he was forced to put his work on hiatus to go on a mission to the United States in the summer of 1917, but it turned out to be one of those useful breaks when stepping away from a problem lets your mind slowly work out the problem in the background. When Rutherford got back to the lab in September he had the answer..."

There are many other examples. 

So, if you get stuck, take a break!   

Peter Parker VK3YE finds a Homebrew Double Sideband Transceiver at an Australian Hamfest

Peter's detective work on the mystery box starts at around 13 minutes into this video.  He quickly found a balanced modulator and did not find a crystal filter.  This led him to correctly suspect a double sideband transceiver.  A look at the LP filter and the VFO led him to suspect a 160 meter rig.  Nice work Peter.  That's what it is:  a 160 meter DSB transceiver. 

I had a similar experience with a direct conversion receiver, but never with a full double sideband transciever.  Nice find.  Peter should try to bring that rig back to life, and he should try to find out who built it. 

The Solid State Basics book by DeMaw and Rusgrove looks good.  I hadn't seen that one, but I will get one. 

Thanks Peter! 

Doug AA0MS's FB SolderSmoke Direct Conversion Receiver: "This project has been a hoot!"

Doug built a really beautiful receiver, but reception was marred by a bad hum.  It was quickly determined that this was caused by a noisy "wall wart" located close by.  A re-location of the power supply remedied that,  and allowed Doug to pull in some really nice signals. 

Doug writes: 

Had a lot of fun doing this over the past couple of weeks. Not my first DC receiver build--I built a Neophyte Receiver from QST years ago--but this one was the most fun. Thanks Bill, Dean, and the whole DCR challenge community--I'm learning a lot in my old age!

I'm a retired pastor who's been fiddling with radio stuff since about 1991, and though I've been inactive for long periods of time, I've always enjoyed QRP and homebrewing (and I've built a bunch of kits, too, including my main rig, an Elecraft K2). It's been a while since I had a halfway decent antenna up, but that's in the works. As a boy I was at my dad's side in his modest shack whenever he was building or operating (he was K8LZO back in the day), and one day while listening to shortwave broadcasts during the first Gulf war, I tuned around and heard some CW signals and decided it was time to learn the code and get my license. Anyway, this project has been a hoot, and I so appreciate all of you and your generosity with your experiences and experiments and successes and failures. Thanks! 73, Doug, AA0MS

Congratulations Doug and welcome to the Hall of Fame.

 

Ramakrishnan VU2JXN's FB SolderSmoke Direct Conversion Receiver: "Extremely thrilled! Hooked!"

This is a really important Hall of Fame entry for us.  This is our first completed SolderSmoke Direct Conversion Receiver from India (more will come).  

Most importantly, this receiver was built by our good friend Ramakrishnan VU2JXN (ex VU3RDD).  Ramakrishnan goes way back in SolderSmoke history.  He was the one who first suggested (in 2006!) that our podcast needed a blog to go with it.  This was the origin of the SolderSmoke Daily News.  A short time later we announced the birth of Ramakrishnan's daughter.  That same daughter now has her ham license and will build a second receiver with her dad.  

Ramakrishnan VU2JXN

The roots of this receiver are deep in India. When Dean and I first went to the local high school to talk about ham radio support, I carried with me a Direct Conversion Receiver inspired by Farhan VU2ESE.  In fact, that receiver had a picture of Farhan and quotes from him taped to the wooden base.  When Dean and I designed the receiver that we tried to build with the High School kids, we used an oscillator based on the DC receiver that Farhan was building with youngsters at Indian girl's schools.  That is the receiver design that we are using in this SolderSmoke Challenge. 

Ramakrishnan is in Bangalore now, which is where he built this receiver.  Ashish N6ASD is also there now, and is building a receiver. 

Ramakrishnan writes:  

This morning before I got ready to come to work, I got a few minutes 

to turn on the radio and catch the morning nets. Extremely thrilled to

 get this working. The PTO is very stable.

Needless to say, you folks convinced me to get back into homebrew
and you have hooked me into it with this project.

I am off to my ailing mother's place tonight. I don't have a station 

there, but I am carrying a copyof EMRFD with me (I have two!).

I want to listen with this receiver as you all always say 

and make simple modification to this receiver and improve it.

 
Again, couldn't turn off from it even though I am at work! The bug has
caught me.

Here is some more video of Ramakrishnan's receiver: 

Congratulations Ramakrishnan. Welcome to the Hall of Fame! 

Wow! DOVAD and Doppler at White Sands Missile Range

EI7GL has a really interesting blog post about a VHF system used at White Sands to accurately track early rocket tests:  https://ei7gl.blogspot.com/2025/05/369-mhz-doppler-radar-antenna-at-white.html 

He has nice picture of the antenna.  The plaque has the interesting info: 

The plaque on display reads as follows...

"36.9 Megahertz Helix Antenna Doppler Velocity and Position (DOVAP)

Reference Transmitter Antenna

Developed during World War II by the Germans as part of a V-2 guidance and control system, DOVAP traced the course of a rocket using the Doppler Effect caused by a target moving relative to a ground transmitter and receiving stations.

Unlike radar, Dovap did not allow scientists to "see" the rocket on a screen. Instead, it sent up radio waves, which were received and rebroadcast back to earth by the rocket. The returned waves combined with the original ground broadcast and produced a musical tone which varied with the rocket's speed - the faster the rocket, the higher the pitch.

DOVAP data was extremely accurate: it could place a rocket's position at 100 miles up within 50 feet. It could collect data at the extreme altitudes of 100 to 300 miles. Dovap's disadvantage was that it took 3 to 4 weeks to reduce the data.

The antenna is a helix because of its physical and electronic characteristics. A helix is simple to construct and operate, provides necessary signal gain and directivity, and can be operated in several modes or polarizations.

The DOVAP system provided trajectory data and ground guidance for most of the early rocket systems: Corporal, Sergeant, Honest John, Little John, Redstone, and Aerobee Upper Atmosphere programs.

This particular antenna was built in the mid-1960s near C Station. Like much of the early instrumentation used here, it was designed and built at White Sands Missile Range.

Erected by White Sands Missile Range Museum. (Marker Number 06.099.)"

Building "Newt" for "The Lightning Code"

This is part of our "Other Kinds of Workshops" series.  Newt was a little Arduino-R/C robot built for a movie called "The Lightning Code," which apparently has something to do with Nikola Tesla.  

Thanks to Hack-A-Day for the heads up. 

I admit it. I am not 100% homebrew. I hang my head in shame.

Walter KA4KXX and Mike WN2A and I were recently talking about the degree to which we are 100% homebrew. Both these guys come a lot closer to this goal than I do.  Here is my assessment of my gear: 

I fall far from a state of 100% homebrew grace:  

-- I use commercial power supplies.  I justify this by saying that I could use batteries, and I wouldn't build them. 

-- I use a D-104 with a Tug-8 amp in the base.  I justify this by saying that I COULD homebrew a mic, but I'd just be using a commercial electret element. 

-- My .1 kW amplifier is from a CCI kit.  I find it hard to homebrew 100 watt amplifiers that do not oscillate. Kits make this a bit easier.  

-- I use a K4KIO Hex beam.  I had a homebrew MOXON, but that got destroyed by a Northeaster.  And I have to limit trips up to the roof. Like to zero. (I ask the gutter guy to do this.) 

-- I have a DX-100 and an HQ-100 that I use to check into the Old Military Radio Net on Saturday morning.  I had a DX-100 as a kid, and John Zaruba K2ZA later gave me his dad's DX-100.  That is the one I use. I picked up the Hammarlund HQ-100 in the Dominican Republic in 1993 and have been repairing it ever since.  It is not a great receiver, but it looks good atop the DX-100 and I have a sentimental attachment. 

-- I have an HT-37 and a Drake 2-B that I have had since I was 14 years old. I have a strong sentimental attachment to this gear.  I have worked on most of this old stuff.  

The three SSB dual banders that I am running are mostly homebrew.  The Mythbuster uses a VFO out of the Yaesu FT-101. The 17/12 rig has an LM386 AF Amp. The 15/10 rig has an SBL-1. 

I will try to increase my HB percentage. 

"Unlocking the secrets of the heavens with a tool fashioned by one's own hand."

 

Click on the image for a clearer view. 

https://stellafane.org/tm/atm/

This quote is obviously about telescopes, but I think in many ways it applies to homebrew radio.   We sometimes use the term "first light"  to describe the first signals heard through a new homebrew receiver.  That term comes from astronomy, and is used to describe the first light seen through a new telescope.  I think there are strong parallels with homebrew radio.  

John KN6FVK's FB Homebrew SolderSmoke Direct Conversion Receiver -- Crickets Killed with Barkhausen-Be-Gone Spray!

I went to bed worrying about this one. John KN6FVK had been having a lot of problems.  He had repeatedly reported hearing nothing (crickets!) when he fired up the receiver. Members of the Discord group had provided a lot of coaching, but still, CRICKETS!  John had a good sense of humor.  When I pointed out that oscillations in the AF amp are caused by a feedback path that meets "the Barkhausen criteria" John said he went to Lowes and bought a spray can of Barkhausen-Be-Gone.  It seems to have worked.  Actually I think John put some additional capacitance on the DC rail of the AF amp.  In any case, he was going to wait for the evening for test out the fixed receiver.  The time difference with California meant that I went to bed with fingers crossed.  Happily the BBG spray and (more likely) the extra capacitance worked.  John sent us some really nice videos of his receiver in action.  I really like the inscriptions on his pine board.  This should become "a thing."   

John writes:

I'm very ok now.... --- sigh / smile --- THANK YOU ALL for your help and patience. As painful as this was, it was a lot of fun and I learned a lot. After I build an actual work bench, I might try this again (looks are important). But I'm definitely going to start playing with it and learning from it. On to Mods and Upgrades! Need to learn-up on this "Barkhausen" silliness too. -73

Here is John's receiver pulling in CW (WB6CGJ):

Congratulations John,  Welcome to the Hall of Fame.  

Alan Wolke W2AEW's FB Homebrew SolderSmoke Direct Conversion Receiver

It is really and honor to have Alan Wolke W2AEW build one of our receivers.  Alan is a true wizard. Armed with an amazingly popular YouTube channel, he has taught electronics and ham radio to thousands of grateful viewers worldwide.  A Field RF Application Engineer for Tektronix, Alan has a special knack for showing us how to get the most out of our test gear.  

So many times have I gone back to videos that Alan made years ago, just in an effort to refresh my memory on the insights that he shared.  For example, it was from him that we learned how the diode ring mixer really works -- what it really means to say that this mixer multiplies signals by 1 and -1.  Alan even showed us how to get our 'scopes to display the multiplication.  This was all very cool and very typical of Alan's work.  His videos have been an important reference for this direct conversion receiver effort.  

On this project, Alan dug into his junk box, only to discover to his dismay that he didn't have the AF transformer that we recommended.  I am sure that Alan could have whipped up several alternative circuits that did not require the transformer, but he wanted to build the receiver the way we recommended, so a slight delay took place while Mouser filled his order. 

Alan did build the circut modularly, stage-by-stage, using the Manhattan method, but he admits to giving in to his temptation to use a very  small board.  This may be the most compact of our 60+ DC  receivers.  In an encouraging reminder that even the great ones worry about unwanted feedback,   Alan writes:

Why am I always compelled to build as compactly as possible?  I hope feedback doesn’t bite me in the butt!

Thank you Alan!  And welcome to the Hall of Fame! 

(This picture was created by displaying NTSC video from my digital camera on Alan's old Tektronix 485 oscilloscope using a simple converter circuit that is described in a video on my YouTube page)

QR code for his YouTube site

X Y Screen

On the SolderSmoke Blog there are 41 posts tagged with "Wolke--Alan": 

https://soldersmoke.blogspot.com/search/label/wolke%20--%20Alan

Alan's QRZ page: 

https://www.qrz.com/db/W2AEW