SolderSmoke Daily News -- Ham Radio Blog

Saturday, July 3, 2021

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.

Thursday, July 1, 2021

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.

Wednesday, June 30, 2021

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.