A Video Series on the Mythbuster 75/20 Rig -- Video #1

I am happy to report great progress on the Mythbuster project.  I have the receiver working on both 75/80 and 20 meters.  And it in fact inverts  the 75 meter LSB signals, turning them into 5.2 MHz USB signals for passage through my 5.2 MHz USB filter/BFO combo.  No switching or shifting of the BFO is needed. 

I am following Farhan's BITX20 advice -- I have paused in the construction and am enjoying the receiver that I have built.  I'll build the transmit circuitry later. 

Inspired by Frank Jones (you really should be reading the FMLA articles) I have this rig prototyped "Al Fresco" on a pine board that I found discarded on a neighbors front stoop.  

There is no RF amplifier in this rig.   Following the advice of multiple receiver gurus, I ran the BP filters right into the ADE-1 diode ring mixer.   I have the TIA amps set at about 24 dbm.  There is a lot of audio gain from the LM386 and the audio pre-amp.  This seems to be enough, even on 20.  I hear the band noise when I connect the antenna on both 75 and 20.  

Here is the first video in the series.   I'm posting them first on Patreon, then, a few days later, here and on the YouTube channel. 

The Woz on Homebrewing and The Right to Repair

There is a lot of wisdom and history in this Cameo video by Steve Wozniak.  

Thanks to Chuck KE5SPY for alerting us to this.  

Here a good BBC article that summarizes the Right to Repair issue and Woz's involvement.

https://www.bbc.com/news/technology-57763037

The Woz has The Knack.  

A Great Line from the FMLA Articles

The narrator was in CW contact on 6 meters with a guy who turns out to be... Frank Jones. 

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 I threw the switch on my AEA keyer and sent the station description while I deciphered my notes. When the keyer signed, Frank said: QSL THE COMMERCIAL GEAR - EVER THINK OF TAKING UP AMATEUR RADIO? QRQ?  

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More to follow.  

The complete FMLA collection can be found here: 

http://soldersmoke.blogspot.com/2021/07/summer-reading-for-homebrewers-frank.html

Romanian Mighty Mite and Ciprian's Knack Story

Another wonderful video from Ciprian in Romania. 

Any suggestions on his Mighty Mite power output problem? 

Here is Ciprian's YouTube channel. His intro video presents his Knack Story.  

https://www.youtube.com/channel/UCgaWKPt1P-4D6YI-Opd15_Q

I really hope Ciprian can get a license very soon.  His homebrew projects alone should qualify him. Ciprian has The Knack. It would be great if the IBEW (especially the European branch) could help Ciprian get some more parts and test gear. 

M0NTV's Latest Breadbox Rig -- The Radio Gods Have Spoken (TRGHS)!

Tony G4WIF sent me this video from Nick M0NTV.  It presents Nick's latest Bread Bin project -- "The Optimizer." 

-- I really like the Bread Box enclosures.  And leaving the b and the d on the box is just brilliant.  These letters now stand for BiDirectional!  They even appear symmetrical.  TRGHS!

-- The switch for a tuning tone is a great idea.  I still have to plug my Maplin AF sig gen into the mic jack to do this.  FB. 

-- I too have the connector on the back for keying the outboard linear amplifier.  (Shhh! Don't tell G-QRP!) 

-- As for the bidirectional TIA amps.  I'm really glad that someone else is using these circuits.  Wes's article came out in 2009 and concluded with a call for someone to build a complete rig with these circuits.  I wonder how many rigs like this have been made.  It is a great circuit.   One thing I would suggest for Nick:  Wes's article points out that you CAN have higher gain in one direction than you have in the other.  Just use resistor values in the chart provided in the 2009 article.  You could have an amp with 15 db in the transmit direction and 24 db in the receive direction.  BTW:  I have been getting a lot of help from Alan W2AEW and Farhan VU2ESE on how to use the NanoVNA to confirm the input and output impedances on solid state amplifiers. 

-- For many years I had the same map of the Moon in my shack.  I hope that map makes it to the new house Nick. 

-- Finally, I was really surprised to hear EI0CL calling CQ during Nick's demo of the receiver.  That is Michael Higgins out in Galway.   Michael was one of my regular contacts when I was out in the Azores.  He is a truly amazing guy.  He is mentioned frequently in my "SolderSmoke -- Global Adventures in Wireless Electronics" book.  TRGHS. 

Summer Reading for Homebrewers: Frank Jones and the FMLA by Michael Hopkins AB5L (SK)

 

Frank Jones W6AJF (SK)

I read these stories when they were first coming out and I really liked them.  Here are all the FMLA episodes.  Don't try to read them all in one sitting.  Spread them out.  Savor them.  Think about the message that Frank was sending us.  

All of the FMLA episodes:  https://tomfhome.files.wordpress.com/2019/12/frank_and_the_fmla.pdf

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Related articles, books and links: 

Frank's obit: https://www.pressdemocrat.com/article/news/frank-jones/

Frank's book "5 Meter Telephony": https://w5jgv.com/downloads/5-Meter%20Radiotelephony%20by%20Frank%20Jones.pdf 

Frank's 1937 Antenna Handbook: http://rfcec.com/RFCEC/Section-3%20-%20Fundamentals%20of%20RF%20Communication-Electronics/23%20-%20RADIO%20ENGINEERING%20DATA/1937%20-%20Jones%20Antenna%20Handbook%20(By%20Frank%20C.%20Jones).pdf

About the author, Michael Hopkins AB5L: https://www.rantechnology.com/index.cfm?key=view_resource&TransKey=615604E8-9DAA-40A3-9E48-4160806D893D&CategoryID=8E884CE4-9CED-4957-872B-5EBDB058D540&Small=1

Michael Hopkins AB5L (SK) 

Thanks to Dave Wilcox K8WPE for reminding us of all this, and for sending us the link to the FMLA archive. 

Viva el FMLA!   Viva el CBLA!  Vivan! 

The World's Largest Heathkit Collection (Video)

And this was apparently AFTER they relocated and organized things a bit. 

I have my eye on those QF-1s.  Someone stop me before it's too late.

I also spotted a Globe VFO Deluxe.  

10 Pole Crystal Filter Passband as Seen in Antuino and NanoVNA

I continue to work on the "Mythbuster" rig,  but I am taking it slow, trying to learn something from each stage.  I'm especially trying to master the used of the great test gear that has arrived in my shack in recent years:  The Antuino, the NanoVNA, and the TinySA.  

Above you can see the passband of the 10 pole crystal filter as measured across the 50 ohm terminations on the filter.  I use simple FT37-43 transformers to match the filter impedance down to 50 ohms.  I used the Antuino first -- it scanned the passband and held the image on its screen.  I then disconnected the Antuino and connected the NanoVNA.  So in this shot you can see the passband on both devices.  

You will notice that the Antuino says there is a 20db insertion loss.  That's only because in the Antuino 20db is really 0 db loss.  I think the NanoVNA gives a more accurate insertion loss reading -- about 3-5 db.  The cool thing is how similar the shapes of the passband are.  

Jack NG2E's Pebble Crusher

 Check out NG2E's Pebble Crusher homebrew transmitter.  Doug DeMaw would be enormously pleased.   

Jack will no-doubt have this 250 mW rig on the some peak along the Shenandoah Valley, handing out QSOs to SOTA fans.   

Jack's blog page has a really nice video on this project: 

https://jackhaefner.blogspot.com/2021/06/pebble-crusher-40m-xmtr.html

SolderSmoke Podcast #231 -- Travel, SST, Mythbusting, Filters, TIAS, NanoVNAs, DC RX in SPRAT, Drake A Line, Spillsbury, STICKERS! Mailbag

SolderSmoke # 231 is available: 

http://soldersmoke.com/soldersmoke231.mp3

Annual Field Day Special Edition

Travelogue:   To the Dominican Republic! 

New dog -- Meet Guapo (see below). 

A great Father's Day for Pete and Bill.  I got a TinySA. 

Pete got some cool chick magnet glasses (see below).  

Watch out Newbury Park! 

Bill's Activity

SST Transceiver. Took it to Dominican Republic.

Made only one contact, but QRP-QRP. 

Not a lot of CW activity, and not a lot around 14.060. 

A lot more FT8 visible on the NA5B WebSDR.

That might be better for this kind of operation.  

I might try SST CW out today from the backyard. Field Day!

Fired up my 20 meter DSB NE602 rigs.  Made two contacts.  

Still trying to fully understand the NE602 Gilbert Cell.  Lots of mystery in there. 

Building "The MythBuster."  75/20 with sideband inversion.  

10 pole 5.2 MHz filter.  Used Dishal and AADE. 

Used NanoVNA to see the passband. 

G3UUR for crystal parameters.

Cohn Constant K topology. 

Also used NanoVNA to check input and output impedance on the TIA amps I will use around the filter. 

Pete's activity: 

Article on DC receiver in SPRAT. FB response. 50 receivers under construction.   

Work on Drake A Line.  

Jim Spillsbury. 

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The N5JHH IBEW SolderSmoke stickers (see above and below).  How we will use them. 

Mailbag:

N2SVD

K8ITY

Tom (Junkbox receiver)

N0ZIB (Curse you, SolderSmoke!) 

DL6ID

N2NLY

VK2EMU

ZS1KE

AF7O

NG2E

VU2ESE

OK1RP

N5JHH

Radio Netherlands -- Bonaire Relay Station

Thanks to Rogier KJ6ETL, PA1ZZ for sharing this video with us (that's Rogier on the Vespa). 

I wonder what they did with the towers and the transmitters?  

 

Jean Shepherd on CW, and Strange Propagation -- QRP!

From 1965.  Great CW stories from Shep.  QRP!  Shep running 2 watts on 20 CW, working DX. 

He discusses shortwave listening,  and predicted that CW shortwave listening would become more popular (sorry about that Shep). 

It was real hoot to hear the 1965 public service ad from NYC Mayor John Lindsey. 

The Kazoo CW was a bit hard to copy OM.