A Wonderful Homebrew Direct Conversion Receiver (and other HB projects) from Italy

This morning I asked YouTube to show me recently posted videos of "ham radio homebrew."  The results were disappointingly meager... except for the content of this site, which were downright inspirational.

Don't let the Italian language bother you.  You can see what he has been doing just by watching the videos, the shorts,  and the posts. 

There is a lot of Manhattan-style construction here.  There is even a Tuna Tin 2 (made in a mushroom can!).  Above all, there is a lot of FB homebrewing in this site.  Va bene!  

Here is the YouTube site:  https://www.youtube.com/@SelectaCs   

Please view and subscribe.  He could use the visits and we definitely want to encourage construction like this.  

Also, who is he?  Who is "Selecta Cs"?  (Listening to his CQ in one of the videos, I think it is Samuele, IU2QBW.)

UPDATE:  It is Samuele IU2QBW.  He writes: Good evening, dear William!! It's a great pleasure to meet you, and I'm so happy to hear this email! Thank you so much! I'm flattered to have been featured on such an important blog as SolderSmoke! I'd be delighted to collaborate with you and all other DIYers!  Thank you so much again for the compliments and encouragement! It means a lot to me! A big 73 from IU2QBW Samuele

 

A FIRST! K1OA Contact with N2CQR -- All Homebrew with SolderSmoke Direct Conversion Receivers on Both Ends

At around 0630 EDT on June 7, 2025 I heard K1OA calling CQ on 7030 kHz CW. This was exactly where I had a crystal.  I called him, but he didn't hear me.  I sent him an e-mail.  We tried again -- he heard me calling him and I heard him responding by calling me, but I don't think we succeeded in exchanging signal reports. It was close, but no cigar.  

I had to walk the dog. Scott and I agreed to meet on 7030 kHz at 0730 EDT.  Arggh.  There was a QSO there.  I thought we might have to try to change frequency, but this would have been tough because both of us were crystal controlled on transmit.   Fortunately, the contact on 7030 kHz wrapped up.   Scott called me, I responded, and we were able to exchange signal reports.  I was so excited that I almost forgot to hit the record button on my phone.   But I caught the last minute or so.  See above.  

This was really something.  This really goes to prove what Dean and I have been saying all along:  this receiver is not a toy!  It can be used for real ham radio contacts.  And now we have had these receivers on both ends of a contact.  For transmit, Scott was using a KA4KXX transmitter with about 3 watts output.  I was on my Tuna Tin 2 at about half a watt output.   

Thanks Scott! And thank you Walter!  

A Tale of "Ten Minute Transmitters" and "Tuna Tin Twos": N2CQR Goes Back to CW QRP!

Inspired by K1OA and KA4KXX, I put the SolderSmoke DC receiver to work on the CW portion of 40 meters. At first I used a very (perhaps overly) simple "Ten Minute" transmitter. On June 4, 2025 I worked N2WJW in New Jersey. But the transmitter drifted as it got hot. So I switched to the more robust Tuna Tin 2 (TWO transistors!) and worked W2XS in NY and N9FGC in Indiana on June 5. With both transmitters I was "rock bound" -- crystal controlled. Power out was always less than 200 milliwatts. Antenna was a low to the ground dipole. The receiver was powered by our beloved 9V battery. The transmitter had a second 9V battery. Some observations: First, even if you CAN hear other signals, the different tones allow your brain to seperate them out (this has long been known to CW operators, but might not be readily apparent to newcomers). So even if the DC receiver is broad in frequency response and even though it IS also receiving the other side of zero beat, you can make CW contacts (unless, of course, another station is on a frequency that produces exactly the same tone as the one you are trying to work), even at very low power . Second, you don't always really have to be right on the other station's frequency. Here's why: If he is looking he can see you in his waterfall! So that SDR waterfall is now a friend to crystal-controlled HDR operators. Who would have thought? Above is a picture of the my station with the Ten Minute transmitter. See the notes I wrote on the QSO with N2WJW.

Ten Minute Transmitter (the gray thing is a CW key)

Direct Conversion Receiver

Tuna Tin 2 that replaced the Ten Minute Transmitter

Note battery and crystal

Listen to Rex. W1REX. Lots of Tribal Wisdom in this Ham Radio Workbench Interview

 

https://workbench.libsyn.com/hrwb-193-building-projects-with-rex-harper-w1rex

This week's Ham Radio Workbench podcast features an interview with Homebrew Hero Rex Harper, W1REX of QRPMe fame. (The bulk of Rex's portion starts at about 1:26:30.)

I really liked this talk with Rex.  His enthusiasm for homebrewing is really inspiring -- it is very reassuring to know that there are others like us. Rex clearly has The Knack.  

I got a kick out of Rex's story about the outhouse at Dayton.  FB OM.  

Here is the video of the mojo transfer ceremony in which shared some of the Tuna Tin 2's mojo with my BITX 17.  Thanks again Rex!  

And thanks to George and the gang out at Ham Radio Workbench. 

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. 

Hammarlund and Homebrew Heroine: Janis AB2RA, HQ-100 Filter Cap Question

 

I was searching for Hammarlund HQ-100 wisdom when Google pointed me to the Electric Radio articles of Janis AB2RA.  They were in  ER #380 and #381 (February and March 2021).  Lots of good stuff  in there.  

This morning I happened upon a 2014 SolderSmoke blog post (as you do) about my Tuna Tin 2. Turns out that Janis was my first contact with this rig.  And she too was running a homebrew rig. TRGHS. 

https://soldersmoke.blogspot.com/2014/03/i-too-built-tuna-tin-2.html

I continue to work on my HQ-100.  The AC hum is getting worse so I have ordered a replacement capacitor can from Hayseed Hamfest.   But I was a bit confused about which cap to order.  Hayseed has two caps listed for the HQ-100 -- one (it seems) for the early model of this receiver and one for later models.  Is that right?  Did Hammarlund update the power supply to add filter capacitors?  Take a look: 

https://hayseedhamfest.com/collections/hammarlund

Dean KK4DAS is getting ready to work on his dad's HQ-170A.  He too will find lots of wisdom and tribal knowledge on Janis's wonderful web site.  

Her main page: http://www.wireless-girl.com/  (with a vast amount of technical info available through the links on the upper left side of this page) 

About Janis: http://www.wireless-girl.com/AboutMe.html

Thanks Janis!  

The Original Wireless Girl

http://www.wireless-girl.com/OrigWirelessGirl.html

The SolderSmoke Team Talks to the River City Amateur Radio Communication Society (Video)

Pete and I had a great time speaking to this really nice California ham radio club (video of the event appears above).  Special thanks to club president Dr. Carol Milano, MD.  Wow, what an impressive person and ham radio operator she is:  https://www.qsl.net/kp4md/#New%20York

This club is doing a group build of a version of the famed Tuna Tin Two.    I mentioned that I had held the original TTT in my hands, and that Rex Harper had conducted a "Mojo Transfer Ceremony" that imparted TTT Mojo to my BITX17 transceiver (which was also discussed).  I promised to share the video of that momentous event.  Here it is: https://youtu.be/9RZRaFUtTcc

Thanks to Carol and the members of the RCARCS.  This was a lot of fun.  

The Original Tuna Tin 2 (and the Mojo Transfer Ceremony with W1REX)

From the Amateur QRP Radio group on Facebook:‎

Brian Murrey‎to

 Amateur QRP Radio

The Original Tuna Tin II built by Doug DeMaw W1FB (SK)...Ed Hare W1RFI of the ARRL Lab, brought this to FDIM in 2001 and allowed us to borrow it for a night. It was so cool. The little guy was found at a hamfest somewhere on the east coast, and brought back to the ARRL. Bruce Muscolino W6TOY (SK) recieved it from the ARRL and he replaced missing parts and got the thing working again. It's in the museum at the ARRL HQ today. I think we made like 16 contacts using that for the transmitter, and a homebrew receiver from Diz W8DIZ that was part of the MultiPig Rig. Antenna was a dipole we had strung up out the window of the Ramada Inn (FDIM Central).
-----------------------------------
Here is my only encounter with the original Tuna Tin 2 -- In 2014 Rex W1REX conducted this solemn ceremony in which some of the TTT mojo was transferred to my homebrew BITX 17. 

Fish Soup 10 QRP Transceiver in Action on 40

I took this quick video during a QSO on July 20, 2019 with Ed K3VA in Philadelphia on 40 meters.  Note: Plenty of of audio from the Herring Aid 5 -- no additional amplification in the speaker. 

Making Fish Soup from Herring and Tuna (How to Build a Fish Soup 10 Transceiver)

Just in case some other fanatic someday thinks about trying to turn a Herring Aid 5 and a Tuna Tin 2 into a Fish Soup 10. This will also serve as a note to myself on how I did this.  Above are my suggestions on how to get the VFO signal into the transmitter and the receiver.  Both RX and TX can easily be returned to their original condition. 

A Frequency Readout for the Fish Soup 10 (with cool BLUE numerals)

Note the cool BLUE numerals.  They represent 7040, 7050, 7060, 7070.  The little black "pointer" is from a power cord wall fastener.  My tuning cap has a nice reduction drive -- the pointer follows the movement of the capacitor blades.  The VFO is very stable. 

Simplicity is a virtue.  CW is, I think, outmoded and kind of absurd (one letter at a time?  really?), but it does allow for extreme simplicity.  Using a rig with just 10 transistors, putting out half a watt of RF,  I am regularly communicating with people.  This is what I like about CW.   

I've had about 12 solid contacts with this rig since putting it on the air earlier this month.  The VFO was a huge improvement over being crystal controlled. Crystal control was OK back when receivers were broad and hams tuned around for replies, but those days are gone.  Getting the transmit offset set correctly was another huge improvement. 

Video of Fish Soup 10 QSO (from N3MLB)

So cool.  During our QSO on 40 Meter CW today, N3MLB recorded it and put it on YouTube.  This is what my 500 milliwatt Fish Soup 10 rig sounds like in Pennsylvania. Thanks a lot Chris. 



From Chris's QRZ.com page: 

The "Fish Soup 10" Homebrew QRP CW Transceiver

The box with the two grey knobs on the left is the Herring Aid 5, the receiver that took me 38 years to complete. The box on the right is a VFO I originally built for my first BITX40Module -- it started out around 4 Mhz but I pulled turns off the coil until it was in the 40M CW band.  The Altoids in near center has the buffers -- a 40673 MOSFET and a 2n3904 BJT. The box in the back holds the Tuna Tin 2.  There the oscillator has been reconfigured as an amp.  A relay switches the output from the buffers between the receiver and the transmitter.  That big switch in the center switches the antenna and the 12 V for T/R.  The circular black thing is piezo buzzer used for CW sidetone -- I have it glued to the board upside down to keep the volume down. 

The whole thing is mounted on a kitchen cutting board.  A breadboard! 

The most difficult part of all this was getting the needed 800 Hz drop in TX freq on transmit.  You need to do this with a rig like this or else you won't be in the other fellow's passband.  I did a lot of cut and try -- in the end I put a 5 pf cap across the coupling cap from VFO to buffer.  This 5 pf cap switches in on transmit via a small relay.   It works.  I just spoke to N8AFT out in Columbus, Ohio and I was in his passband.  

So five transistors in the receiver, two in the transmitter and three in the VFO/Buffer. So it is the  Fish Soup 10.  

It puts out about half a watt.  On CW.   I am feeling virtuous and vaguely superior. I've made several more contacts.  It all works very well and is a lot of fun. 

The Fish Soup 7 QRP Rig -- On the Air on 40 Meters (video)

I don't know why, but this weekend I got the urge to get on the air with a very low power homebrew QRP rig.   I reached for my Tuna Tin 2 -- Herring Aid 5 combo.  I call it the Fish Soup 7 (seven transistors in total). 

I first tried to turn this rig into a transceiver by taking the VFO signal from the receiver (it is direct conversion) and using it to excite the Tuna Tin 2, but it just didn't work out.  The oscillator in the Herring Air 5 is very bare bones -- no buffering and an LC circuit that is mostly L (10 uH).  It became very difficult to get a stable amount of CW offset.  So I went back to crystal control for the transmitter.  I did replace the 5K tuning pot in the RX with a 10k 10 turn pot (thanks to W8NSA).  Tuning is now very smooth.  I used my old UK freq counter to monitor my receive freq. (Thanks to Tony Fishpool G4WIF-- back in 2009 he sent me the CMOS chip that brought this counter back to life.) 

I was putting out about 750 milliwatts.  

I had a very quick contest-like contact with K2D -- one of the "13 Colony" stations.  Then a longer chat with Hank K1PUG (see video above).  

I had lost my 7050 crystal, but this morning it re-appeared.  TRGHS. 

As you can see in the video I am using the beautiful VU3XVR  key that Farhan brought me from India. 

This was fun.   I may try to put a VFO of some sort into the TT2, just to get more agility.  But I want to keep things simple.  

Look for me on 7050.  

Straight Key QRP Homebrew Adventures -- TRGHS

Last Saturday I put the Tuna Tin Two Top together with my Herring Aid Five 38 (year) Special and the Indian key that Farhan gave me.   I discovered that some of my 40 meter CW FT243 crystals had disappeared into the entropy of the shack.  But I was able to find one for 7050 kHz. That was a bit of good luck because it turns out that 7050 is the frequency of a congenial group of operators known as the Straight Key Century Club.  I felt right at home.  I have been inducted.  My SKCC number is 17272.  Very QRP, don't you think?   It is almost a Vanity SKCC.  Clearly, TRGHS.

I have been having excellent luck with this 7 transistor rig.  I have had one contact each day since I put it on the air, all of them in response to my CQ calls.  I've worked:

K1PUG Hank in Connecticut (twice)
W8HOG  Jerry in Ohio
WA4GQG Kevin in North Carolina
WA2AAW Frank in New York
KM4FO Dwight in Kentucky

This morning I added a little piezo buzzer for sidetone.  I am thinking of adding a VFO to the Tuna Tin.

A Fishy Rig: Herring Aid Five, Tuna Tin Two, VU2XVR Key

Haunted by a fear of rapid expulsion from the QRP Hall of Fame, I decided that I should immediately do something to establish some form of QRP street cred.  Looking around the shack, I realized that all of the ingredients were there:  My Herring Aid Five Direct Conversion receiver (completed after only 38 years), my Tuna Tin Two transmitter, the VU2XVR key that Farhan gave me, one 7050 kc  FT243 crystal.   I put it all on a piece of scrap plywood. A couple of nice connectors from W8NSA supported the DPDT T/R switch and the coax connector. I keep the receiver LO running all the time.

Now, let's be clear: running 250 milliwatts, rock bound with a Direct Conversion receiver that tunes both sides of zero beat is not for the faint of heart.  The log book does not fill up rapidly. But hey, I made one contact the following morning.  K1PUG said I was 559 in Connecticut.      

YS1RS's Salvadoran Tuna Tin and Drake 2B

Roberto YS1RS recently acquired a Drake 2-B and has some minor tech troubles.   I am sure Alan Wolke will come up with the proper diagnosis. (The receiver works fine on the standard bands, but not on the accessory bands.  He can hear the crystal oscillator working fine on the crystal frequencies, but the radio is for some reason deaf on all the accessory bands.)  

Above you can see Roberto's Salvadoran Tuna Tin. 

 Roberto Describes it: "Homebrew: The Tuna Tin 2 QRPp Transmitter (TT2) with 300 mW output power, 14.060 MHz (20 meters band), Crystal controlled, 13 Volts, CW-Only. As its name implies, its main chassis is a Tuna Tin Can.  In our case, it is a delicious and exotic Salvadorian made tuna in chunks, topped with Jalapeño Chile. "

Check out Roberto's QRZ.com page:

http://www.qrz.com/db/ys1rs

Roberto has an amazing collection of gear, much of it thermatron, some of it homebrew.  And he has only been on the air five years.  He is a true member of the International Brotherhood of Electronic Wizards.  His work takes him to some of the most difficult places in the world.  FB Roberto! 

Colin's Tuna Tin Mighty Mite (Video)

You will remember Colin as the builder of that beautiful BITX20 that he first used from his backyard and later used with great success from a hilltop in Northern England.  In this video we see Colin demonstrating his Michigan Mighty Mite.  Lots of soul in that little machine!   Colin notes that this rig worked well from the start.   The Radio Gods were obviously pleased by his use of a tuna tin as the chassis.  I think they also liked the MePads from W1REX and the Tek 465 'scope.   And of course the T-shirt was obviously a key element in Colin's success.  

Here is that beautiful BITX, now equipped with an internal speaker:



Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Doug DeMaw's Rigs Found, Donated to ARRL for Exhibit

http://www.arrl.org/news/museum-donates-doug-demaw-w1fb-homebrew-equipment

This is really good news (Thanks to Pete Eaton for the alert.)

I wonder if the Barebones "Barbados" Superhet was in this batch.

We KNOW where that Tuna Tin 2 is....  

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20

Kirk's Herring Aid, Tuna Tin, and Regen Adventures

 

Hello Bill!

 

Just a quick hello from MN to tell you how much I have been enjoying your podcast. Although I have "plugged" your stuff in multiple magazine columns over the years, I'm a bit late getting into the listening game. My current contract job has me doing a lot of driving, however, so I now have several years' worth of soldersmoke to enjoy.

 

Several of the most recent episodes have made it clear that we have covered some common ground in our amateur radio careers.

I was licensed in 1977 at age 15 -- a year after I built my Tuna Tin 2 :) The transmitter was a smashing success. I used it with my Tempo One transceiver, or at the electronics repair shop at a local National Guard base (where my mom worked as a civilian administrator). I would ride my bike to Camp Ripley (only 8 miles or so), and the guys in the signal shop would let me use the shop's Collins KWM-2 HF transceiver (and attached dipole). Other than my efforts, I don't think the KWM-2 got much use...

 

I, too, tried to get the Herring Aid 5 to work, with no luck at all. Listening to your podcast was like being in a time machine of sorts :) I wonder if I got the "sense" of the oscillator secondary messed up? I never did get that thing to make even a sound. I don't have it any longer. The same goes for the TT2. They got "lost" when I stored a bunch of stuff at my dad's place in-between moves, as did a home-brew 4-400A amplifier and a 6146B amplifier for my Ten-Tec Argonaut. Darn!

 

Don't forget about the matching VFO -- the Chopped Beef Slider (CB Slider), which was built into a chopped beef can, of course! I didn't build one, but as I recall it was a diode-tuned 40-meter VFO for the TT2.

 

Your "regen rage" and its subsequent easing was also amusing. I have had a love-hate relationship with those buggers, too, although mine was mostly love. You referenced Dave Newkirk's (now W9VES) 40-meter QST regen article in a podcast. I was fortunate enough to be a QST editor at the time Dave was in his "second residence." That guy forgot more about receivers than I will ever know, and he helped me tremendously in official and unofficial capacities.

I have attached a photo (above) of a multiband regen that Dave helped me build (he designed and dispensed wisdom while I built the radio). He took a schematic from a 1930s ARRL Handbook and tweaked it a bit, helping me add a VR tube, "more modern" tubes and a few other goodies. Just to be difficult, I sampled the tank circuit with a tiny-value capacitor and a high-gain MMIC amplifier so I could drive a frequency counter, which displayed the receive frequency as long as the tank was oscillating. It was fun, but it was difficult to isolate the digital noise from the counter, so I only really turned on the counter as necessary, or to calibrate a dial, etc. The chassis used to be an Eico audio signal generator... In the photo the Jackson Brothers dial and bezel/tuning scale isn't completely installed. After sitting in a box for 25 years, the regen still works but probably needs new tubes, as it's rather deaf :) Blasphemy aside, I'm moving on to solid-state regens...

 

I, too, just got a Rigol DSO. Wow, the "one-button" measurement is almost too easy.
 

I'm prepping my book, Stealth Amateur Radio, for release on the Kindle (and maybe other e-book formats), but it's available now from my website, www.stealthamateur.com.
 

Keep up the good work, Bill.

I'll be listening. :)

73,

--Kirk Kleinschmidt, NT0Z
  Rochester, MN

Editor, 1990 ARRL Handbook
Technical Editor, Ham Radio for Dummies
QST Assistant Managing Editor, 1988-1994
Ham Radio Columnist since 1989 for:
   Popular Communications
   Monitoring Times and now,
   The Spectrum Monitor (www.thespectrummonitor.com)

My book, "Stealth Amateur Radio," is now available from
www.stealthamateur.com and on the Amazon Kindle (soon)

Our book: "SolderSmoke -- Global Adventures in Wireless Electronics" http://soldersmoke.com/book.htm Our coffee mugs, T-Shirts, bumper stickers: http://www.cafepress.com/SolderSmoke Our Book Store: http://astore.amazon.com/contracross-20