Europa -- "Attempt No Landing There."

As we get ready to send two probes to the Galilean moons of Jupiter, this sci fi movie made its way into my feed.   It is pretty good, and the ending will appeal to all true radio amateurs. 

https://www.syfy.com/syfy-wire/searching-for-life-on-europa-the-science-behind-europa-report

https://www.esa.int/Science_Exploration/Space_Science/Juice

More Info on the Cuban Jaguey Solid State DSB Transceiver

ZL2BMI Transceiver Layout (not full size here!) 

Continuing our search for information the Cuban "Jaguey" DSB rig, Trevor Woods pointed me to Dick Pascoe's QRP column in the (below) July 1998 issue of Ham Radio Today.  I think the first SPRAT article about Eric Sears' ZL2BMI DSB rig was in SPRAT 83 in the summer of 1995.  This fits well with the sequence described below by Arnie Coro CO2KK. 

I am still looking for a schematic and pictures of the Jaguey rig: If you can help in this, please let me know.  

Speaker Made from Potato Chip Bag: Tim Hunkin's Solenoid and Electromagnet Video

The potato chip ("crisp") speaker is very cool (I have it cued up here), but the rest of Tim Hunkin's video is also wonderful and worth watching.  (Note:  Posh bags work better as speakers.) 

Thinking of our use of signal relays, I kept wanting Tim to tell viewers to put a diode and a capacitor across the relay terminals to prevent back EMF from frying circuits.  But I guess this is not much of a problem with the arcade games that Tim builds.  

As always, Tim's scrounging and use of discarded parts is really admirable.   

I noticed in the credits that he is dedicating these videos to the memory of his colleague Rex. 

Thanks to Chuck WB9KZY for bringing this video to our attention.  And thanks Tim. 

The IRF510: The Car Turn-Signal Blinkers Used As RF Amplifiers

 

I have many of these MOSFETS in my rigs.  Yesterday I came across Paul Harden NA5N's excellent Handiman's Guide series.  It had this really wonderful paragraph about the history of this part.  I-R is the International Rectifier company.  

https://hyse.org/pdf/www.aoc.nrao.edu/~pharden/hobby/_ClassDEF1.pdf

https://hyse.org/pdf/www.aoc.nrao.edu/~pharden/hobby/Hobby.shtml

Helge LA6NCA Builds a Double Sideband Thermatron Transmitter

Helge is an amazing homebrewer. Check out the shack.  Note the R-390 and the Tek 'scope.  Watch how Helge designs his rig.  Watch him check the 3-D printed coil and the variable caps for resonance.  Most of all, watch his happiness when the new transmitter works.  I just wish he would have showed us some OM complaining that he was on the "wrong" sideband. FB Helge!  Thanks. 

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

Hi Bill,

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

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

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

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

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

73!
-Jim W2UO

My response: 

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

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

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

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

Please keep us posted on your progress. 

Again, congratulations!   73  Bill N2CQR

Technology and Methods from Wes Hayward W7ZOI

Great stuff.  Lots of wonderful articles filled with wisdom to ponder. 

 http://w7zoi.net/oldtech/ponder.html

Thanks to Tony G4WIF for spotting this gem and alerting us.  And thanks to Wes for all of this.  

Nice Ham Radio Documentary from Montana

Thanks to Thomas K4SWL for alerting us to this.  The 25 minute film is well-done, using modern film techniques and editing. It is a bit appliance oriented (but so is ham radio, unfortunately).  The EME stuff is interesting.  And I think the film captures the friendly, fun spirit of ham radio.  

SolderSmoke Podcast #245: Cuban DSB, DC Receiver?, Can you spot the AI? (Prize), Winterfest Loot, Gina's Podcast, 6BA6 buy, MAILBAG

 

DC RX Example by KK4DAS

SolderSmoke Podcast #245 is available for download: 

Audio Podcast:  http://soldersmoke.com/soldersmoke245.mp3  

Video:  (68) SolderSmoke #245: Cuban DSB, DC Receiver?, AI, Winterfest Loot, Gina's Podcast, 6BA6 buy, MAILBAG - YouTube

Travelogue: Cuba DSB and AM. Jose CO6EC and the Islander. We need more info, especially on the solid state Jaguey rig.

Bill’s bench:

Will the High School DC receivers get finished? Future uncertain. But the project was technically interesting. Great working with Dean KK4DAS. Battling AM breakthrough from Radio Marti. We joked that Dean has been listening to Radio Marti so much that even though he doesn’t speak Spanish, he has noticed an increased urge to liberate Havana.

Audio amps: Harder than we thought. Lots of variation in Hfe of 2n3904s. Oscillations.
Not using feedback amps nor LM386s, nor push-pull. Simplicity is a design goal.

Fixing the tuning (bandspread) problem on the VFO was fun.

Antennas? A quarter wave with ground or counterpoise works well. We tried it. (59) An Antenna for the TJ 40 Direct Conversion Receiver - YouTube
----
Back to work on the uBITX. I chickened out on replacing the predriver with a BFR-106, but then – Just in time Todd K7TFC and his Mostly DIYRF came out with BFR106 boards! TRGHS. I will do the mods on two uBITX transceivers. I even bought a solder-sucking iron for the second job.

Winterfest Hamfest. Big success. Thanks VWS. HERRING AID FIVE! Simpson 260! QF-1, Another Radio Shack DMM, Eamon Skelton’s Homebrew Cookbook, Knobs, SWR meter.
----

SHAMELESS COMMERCE: 

-- Todd’s Mostly DIY RF and the BFR106 boards, and much more: https://mostlydiyrf.com/

-- Become a Patreon sponsor of SolderSmoke: https://www.patreon.com/join/4785634/checkout?ru=undefined

----

Pete's Bench: 

Technical Note: Skype problems. Pete's Skype kept dropping out. Bad in the last podcast (#244). Three minute gap. I was ready to scrap the whole podcast when Dean KK4DAS offered to help. And he is obviously well qualified: https://potomacofficersclub.com/speakers/dean-souleles/ Dean went to work with AI. And he was able to fill the audio and the video gaps. Can you spot the three minutes of AI? Send me an e-mail with the time segment of the AI/Deep Fake portion of SolderSmoke 244. The first one with the correct answer will win a prize. 

SolderSmoke #244:

https://soldersmoke.blogspot.com/2023/03/soldersmoke-podcast-244-pete-is-back-tr.html 

Thanks Dean!

----Interview on his Pete's daughter’s podcast. https://soldersmoke.blogspot.com/2023/03/listen-to-pete-juliano-on-his-daughter.html

-- 6BA6 e-bay buy. Will we see an all 6BA6 rig from Pete?

-- The NCX-5 on e-bay

PETE’S NEW BLOG: https://hamradiogenius.blogspot.com/

Mailbag:

-- A New SPRAT arrived in the mail. PH2LB’s Gluestick on the cover.
-- Will KI4POV – Awesome homebrew – on the blog.
-- Sands, VK9WX listening to SolderSmoke on Willis Island! Wow. 
-- Andreas DL1AJG in Germany continues with the Electronics for Biologists DC RX build.
-- Dean KK4DAS and his homebrew 10 meter DSB rig.
-- Jim W2UO built a Michigan Mighty Mite and made a contact.
-- Dave K8WPE and the E in IBEW. We need new stickers.
-- Bob KC4LB – Surface Mount is SMALL.
-- Bruce KK0S on the Herring Aid 5 Board.
-- Chuck WB9KZY on Nuclear Monopole Resonance very cool video – on the blog.
-- Alan WA9IRS wants a CW editor for his phone. Really.
-- Vic WA4THR also working on uBITX power out improvement.
-- Tobias weighs in on Kludge. As in Fudge.
-- Tony G4WIF notes that when he changes his oil he often removes sludge, not slooge.
-- Consultations with Lexicographer Steve KB3SII.
-- Walt AJ6T says CW operating declined after FCC ruling in 1970s about callsigns.
-- Ramakrishnan VU3RDD now VU2JXN has joined the VWS. An old friend of SolderSmoke. Urged us to launch a blog back in 2008. We announced his daughter’s birth - - now Ram is getting ready to build a DC receiver with her.

An Antenna for the High-School Direct Conversion Receiver (and Next Steps in the Project)

We have reached the point where we have to decide on an antenna for the high-school direct conversion receiver.  It needs to be simple and easy.  It needs to be something that students can easily install from a bedroom window in an apartment or a town house.  

We thought about an End Fed Half Wave, but 66 feet of wire seemed to be too much, and the EFHW would require both coax and the construction of a transformer.  That seemed like too much. 

So here is what happens with just 33 feet of wire (1/4 wave on 40 meters), with another 33 feet as a counterpoise.  I found that the counterpoise worked just as well spread out on the bedroom floor as it did hanging out the window along the outside of the building.  As you can see in the video, the counterpoise is really necessary with this kind of antenna.  It makes a big difference. 

We know that the students could have dispensed with the counterpoise by connecting the copper clad boards to a cold water pipe, but that might be difficult for them.  So we went with the counterpoise. 

After the antenna demonstration I ramble on a bit about the high-school construction project, and where the students could go from here. 

The Awesome Homebrew of Will KI4POV

 

Will's homebrew station is really something.  The rig (it truly qualifies for this term of praise) is amazing all by itself  (see below), but a look at Will's QRZ page reveals other ingenious inventions and techniques:  There is the clock made from panel meters.  And the method he uses for making aluminum project boxes.  He even made an N0WVA regen receiver.  That's the one I used in my ET-2.   Fantastic.  

Will really needs to share his homebrew skills with others.   I hope he is soon in a local high school teaching students how to build things.  Thanks Will!  

Bill and Pete,

Just wanted to send a note to update you on the latest projects here. The last time I emailed, I mentioned wanting to build a superhet, which you (rightfully) discouraged, pushing for a DC receiver.

Well, I finished the superhet at the end of last year. I had most of the receiver working long before then, but got bogged down in an AGC system. The final receiver is a 5 band si5351a controlled single conversion superhet loosely based on Todd, VE7BPO's design with several modifications. I used a 9 Mhz IF instead of 4, I used a digitally controlled LO and BFO, and as mentioned, I added an AGC system, which ended up being the most challenging (and most interesting) part. The final AGC system I ended up with used the detector and amplifier side of Wes Hayward's "full hang" AGC from SSDRA, but I didn't have the IC IF amplifiers with variable gain, so instead, it fed a PIN diode attenuator circuit to control the IF gain. The final result worked great, but I nearly pulled my hair out getting it to work. I originally intended to build the receiver for 40 and 20 meters, but it ended up covering 80, 40, 30, 20, and 15 since I used the filter relay board from QRP Labs which had 5 slots.

After I got the receiver running, I decided I needed a matching transmitter, so I  built up a simple CW transmitter to match. It uses an si5351a VFO driving a 74HC04 hex inverter as the buffer amplifier. The trick here is that by driving all the inverter gates in parallel, the output impedance is ~14 ohms broadband, suitable for driving a BJT PA without any need for matching transformers. The PA is 3 2N2222s in parallel with heat syncs putting out about 2 watts from 80 - 15.

The part I'm most proud of is that I have the arduino for the receiver connected to the arduino for the transmitter through a serial line. The receiver sends it's current frequency to the transmitter so that the transmitter can track the receiver's frequency as you tune (like a transceiver). I'll attach a few pictures of my homebrew station below. The transmitter is on the left, receiver is on the right. The box on top of the transmitter is my homebrew keyer. Next up on my build list is a solid state T/R switch.

Bill, I've enjoyed following the updates on the school DC receiver build. My local club is wanting to do some youth outreach, and I'd love to get them involved in building. I'm the only builder in the club though, so I don't know if I personally have the manpower to make it happen. Also, thanks for the recent info and pictures of Cuban homebrew rigs. I grew up listening to Arnie Corro, so I love seeing their resourcefulness and ingenuity. Makes me want to take apart some old electronics.

Pete, I'm enjoying following the 10M SSB project. With the uptick in propagation, I've been bitten by the 10M bug, and I'm thinking a 10M rig may have to be on my project list for this year.

73,

Will - KI4POV

KI4POV's Clock

KI4POV's N0WVA Regen

Update on the High-School Direct Conversion Receiver Project: Board #4 Completed

One of the receivers. (l to r) AF, PTO, Mixer, BP filter

The students continue to make great progress on their direct conversion receivers.  Yesterday they were enthusiastically sitting down to workbenches, building Manhattan-style circuits, working directly from schematic diagrams.  It was really impressive.  They are building receivers. 

This week we had two sessions of about two hours each. We introduced the final board:  the audio amplifier.  Many of the students began work on this amplifier; others were catching up with work on boards presented earlier. 

The AF amp is their most challenging board:  It used 14 Manhattan pads and about 26 components.  We warned the students that amplifiers often aspire to be oscillators.  We told them to pay attention to layout, and to keep their leads short.  

One of my builds, and a Manhattan board pattern

At first, the students just built the first stage on the AF amp board. They tested this, then moved on to build the other two stages.   

By the end of Friday, two groups had completed the build of the AF amplifier board.  

We think there are about 13 receivers in production.  Some are near completion, others will need more work.  

On Thursday of next week those teams that have completed all four boards will put the circuits together and will test the entire system.  They will then add all needed front and back panels and socketry. 

We really want the students to complete as many of these receivers as possible.  Exam season and the end of the school year is approaching, so we have to get this done.  We will remind students that they don't want to that person who ALMOST finished a project!  We will urge them to GET IT DONE!   They can tweak it and mod it later.  This kind of tweaking and modification is part of the homebrew experience. 

We have been presenting awards to the students who are first to complete each stage:  The winners of the PTO board competition got a copy of SolderSmoke:  Global Adventures in Wireless Electronics.   Those who won the mixer competition got a W1REX Hamfest Buddy transmitter.  Thanks Rex!  And this week we presented an award to the students who were the first to complete their bandpass filter.  You've heard of the Tony, the Emmy and the Grammy?  Well, we presented "The Torry"  (from Toroidal).  The trophy was made from a toroidal winding tool made in Alaska by KL7FLR.  I explained to the students who had made it.  Thanks Paul! 

"The Torry"