Farhan VU2ESE FDIM Interview (#6) by Bob Crane W8SX: VHF Rig, sBITX, and Good News on Raspberry Pi 4

It was great that Bob was able to catch up with Farhan and talk to him about his VHF rig and about the sBITX. 

    

Farhan said that the VHF rig (the BITX23) was presented at the homebrew show-and-tell as a project.  The idea was to encourage others to get into VHF homebrewing.  Farhan points out that many of us are reluctant to go into VHF building, thinking that we need special or exotic test gear. No true says Farhan.   He is trying, with this rig, to bust this myth.  FB.

    

On the sBITX, Farhan points out that he too -- coming as he does from the homebrew tradition -- finds some of the modern rigs quite intimidating.  So he designed the sBITX to be less intimidating.  It is, he says, a tinkerable rig that could be homebrewed. It is all open source.  

    

Farhan points out that the rig is built around the Raspberry Pi 4, a device that has recently been hard to obtain.  This has driven up the price of the sBITX a bit.   But good news:  Farhan says that the word on the street is that the Raspberry Pi 4 will be available in quantity starting at the end of June.  

Here us Bob's interview with Farhan: 

http://soldersmoke.com/VU2ESE23.mp3

BITX23 VHF Rig

And here is a video of Farhan describing the BITX23: 

https://soldersmoke.blogspot.com/2023/05/farhan-describes-his-new-2-meter

Thanks Fathan!  Thanks Bob! 

Rick Campbell KK7B at FDIM: Interview #5 by Bob Crane W8SX

/KH6

Having recently been involved in an effort to teach students about radio electronics, I found Rick's comments especially interesting.  

At FDIM,  he and his daughter were presenting a hidden transmitter hunt using rigs and Yagis at 432 MHz.  This was in part the result of his students having wanted to do something new with ham radio.  It was very impressive that the students had done this all with gear that they had built themselves.  Rick also made sure that they all learned how to solder.   

Rick ended the interview with a nice shout-out to SolderSmoke. 

Here is the interview: 

http://soldersmoke.com/KK7B23.mp3

And here is a paper Rick did on VHF.  It is a bit old, but it is good.  

 http://www.pnwvhfs.org/conference/2009/Introduction-to-VHF-Experiments.pdf

 Thanks Rick!  Thanks Bob! 

Eric Schwartz WA6HHQ of Elecraft -- FDIM Interview #4 by Bob Crane W8SX (audio)

 

It was really cool that our correspondent at FDIM caught up with Eric Schwartz WA6HHQ of Elecraft.  Some highlights from the interview: 

-- Eric met Wayne Burdick through the NORCAL 40 (Wayne had designed it, and Eric was writing articles about it).  That was a very influential rig -- it was the basis for a book and a CALTECH course by David Rutledge. 

-- Elecraft has a strong QRP element in its DNA. 

-- The K2 is "Heathkit style" and offers the builder the opportunity to understand the rig at the component level. 

-- Eric says that using something you built yourself is worth at least 10db. 

Here is Bob's interview with Eric:  

http://soldersmoke.com/WA6HHQ23.mp3

Thanks Eric and thanks Bob.  

Jerry KI4IO (Wizard of Warrenton) Describes His ALL ANALOG Phasing Transceiver -- Bob Crane FDIM interview #3 (audio)

Wow, this one really resonated with me.  Jerry had me won over when, early in the interview, he described his decision to dispense with the Si5351/Arduino combo:  "I said the hell with this digital stuff!"  I hear you Jerry.  I feel your pain OM.  

Jerry then goes on to describe a rig with bits of circuitry from some legendary sources:  The Ugly Weekender transmitter.  SSDRA and EMRFD.  W7ZOI's 1968 Direct Conversion receiver.  

Jerry discusses the "presence" of the direct conversion receiver.  And he decries the pernicious effects of AGC.  (Indeed, real hams MANUALLY control the gain.) 

The Wizard of Warrenton then shares some important tribal wisdom:  After building that new piece of gear, leave it on the bench for a couple of weeks.  Beware of "radio infatuation" (what a great term -- we will have to include this in the lexicon).    Jerry points out that while at first, the new rig will seem just perfect, with time time the need for improvements and modifications will become apparent. 

Jerry also has connections to India and Nepal (where he helped Father Moran).  See: https://www.qrz.com/db/KI4IO

Here is W8SX's interview with Jerry: 

http://soldersmoke.com/KI4IO23.mp3

Thanks Jerry!  Thanks Bob! 

Greg Latta AA8V on Making Aluminum Chassis -- FDIM Interview by Bob Crane W8SX #2 (audio)

Our correspondent Bob Crane W8SX caught up with prolific builder Greg Latta AA8V.  Greg gave an FDIM talk on how to make aluminum chassis without having a machine shop.  I guess I am now going to have to buy a belt sander from Amazon.   

I was really glad that Greg mentioned his real passion: retro building.  FB Greg.  I have talked to Greg several times on the ham bands -- it is always an inspirational experience.  

Here is Bob's interview with Greg: 

http://soldersmoke.com/AA8V23.mp3 

Here is Greg's pdf file on his aluminum chassis construction technique.

https://www.frostburg.edu/personal/latta/ee/chassis/aluminumchassisconstructionnomovies.pdf 

And here is Greg's amazing web site: 

https://www.frostburg.edu/personal/latta/index.html

Thanks Greg!  Thanks Bob! 

Hans Summers G0UPL and his new QMX: The Bob Crane W8SX FDIM Interviews Part 1 (audio)

http://qrp-labs.com/qmx.html

We are very pleased and grateful to present this year's series of Four Days in May interviews by our FDIM correspondent Bob Crane W8SX.   Once again Bob did an outstanding job interviewing the FDIM participants. 

In this interview, the amazing Hans Summers talks about his latest QRP Labs kit, the QMX.  It is a combination of the QCX Mini and the QDX.  

Hans explains the M:  QMX. The M is for Marriage. Magnificent. Merger. Marvelous, many things like that. It’s what you get when you marry the mechanical and conceptual design of QCX-mini, with the SDR, multi-band digital implementation of QDX. Simply: QDX + QCX-mini = QMX. 

It has a very clever switching power supply that automatically adjust to prevent spurs and harmonics from the power supply from appearing in the band of interest. 

I was especially interested in his plans to implement an SSB option in future software updates.  Hans will use the same very complicated SSB generation scheme used in the trueSDX rig, but hopes to achieve higher performance and  improved signal quality due to the much more robust hardware of the QMX. 

Here is the interview: 

http://soldersmoke.com/G0UPL23.mp3

Here is the QRP Labs site about the QMX:  http://qrp-labs.com/qmx.html

Here is the QRP Labs web site: http://qrp-labs.com/

And here is a really wonderful and very current article by Hans on the evolution of QRP Labs and its rigs from 2010 right on up through 2023 and the QMX.  It is really interesting: 

http://qrp-labs.com/images/qmx/docs/fdim2023.pdf

Thanks to Bob Crane W8SX, Hans Summers G0UPL, and all of the FDIM organizers. 

Hans G0UPL-- Homebrew Hero

Coffee with Farhan VU2ESE (video)

Early morning in the N2CQR shack, May 16, 2023

-- Propagation

-- Web sites (RBN, PSK Reporter, others)

-- CW

-- Homebrew rigs

-- VFOs

PSSST! MostlyDIYRF Will Sell a Kit of Pete's Rig!

 

From the wizard of Newbury Park! The Pssst Transceiver Kit

Sometimes you just want to put something together and have it work, you know? No futzing with isolation pads, superglue, and blank copper-clad, no dead-bug make-shifts, no ugly, ugly, ugly component acrobatics. Sometimes, a nice and orderly printed-circuit board that's just like uptown, along with sorted and clearly-labeled components and step-by-step instructions, can provide respite from the terrors and risks of scratch-built homebrewing. Just once in a while, mind you. Here's a dandy kit that can get you on 15, 17, or 20 meters pretty quickly, is fairly simple to put together (only eight transistors), and is small enough to take on a trip. At the same time, its modular architecture makes it also an experimenter's platform. It's not a single PCB and a mess of components. Each circuit block is its-own module which you can swap out for a different one you scratch build later on.

Why would you want to do that? Suppose, for instance, you want a narrower passband for the SSB filter (maybe even narrow enough for CW use). Likewise, you might want a wider or narrower front-end bandpass filter, or a different frequency response for the mic amp. Or, how about an active or triple-balanced diode-ring mixer for the product detector, or maybe higher gain in the RF amplifier on receive? Because the circuit modules in the Pssst just plug into a motherboard, you can unplug one and put another one in. Of course, you can do this to change bands as well. All you need to do is to swap out the front-end band-pass filter and you can put the rig on 15 or 17 or 20 meters (along with changing a jumper on the digital VFO/BFO board). The Pssst was designed and originally built by Pete Juliano, N6QW (Pete's Simple Single-Sideband Transceiver). Rather than use bidirectional circuits for many of the blocks, he relies on inexpensive relays to "steer" the modules from receive to transmit modes. Each active module uses a single transistor for gain (except for the final amp which uses three), and in that way the Pssst is a minimal design that, because of its modular architecture, can be made as complex and as elaborate as the experimenter wishes. The Pssst is designed for a nominal output of 5 Watts on 20M when fed with 12VDC. By feeding the final amp with a higher voltage and providing some active cooling (from a three-dollar "pancake" fan), output can be increased to beyond 15 Watts. In addition to complete and detailed kit instructions, the Pssst design has an existing Groups.io "reflector" forum for the exchange of ideas and questions. The kit will be available in two basic versions: with or without enclosure panels and hardware. Available on the 150th birthday of Lee DeForest, the inventor of the Triode (August 26th)

This was in the latest newsletter from MostlyDIYRF.  

Thanks to Pete Eaton for alerting us. 

FB Todd!  

https://mostlydiyrf.com/

Farhan Speaks to Students about Satellites and Direct Conversion Homebrew Receivers (audio)

In our talks at the local high school we have frequently mentioned Ashhar Farhan, his Cubesat experience, and his use of a direct conversion receivers teach electronics to students in Hyderabad, India.  So we were really please to have the opportunity to bring Farhan himself in to speak to the students we have been working with.  

Here is the audio of Farhan's talk: 

http://soldersmoke.com/FarhanTJ.mp3

The acoustics in the room are not great, so you may have to listen carefully, but it is worth it.  Farhan dispenses a lot of tribal knowledge and wisdom about satellites and about the value of homebrewing simple radio equipment. 

Farhan and Bill Fire up the sBITX and (at the other end of the tech spectrum) a Direct Conversion Receiver (video)

At the high tech end: the sBITX.  At the low tech end: The high-school direct conversion receiver. 

Check out the frequency readout on the DC receiver!  

Farhan Describes his New 2 Meter SSB Transceiver (Video)

On May 16, 2023 Farhan gave us a look at his new BITX23 2 Meter Transceiver. Two days later he made a presentation on this rig at the Four Days in May event. Highlights: -- Use (and non-use) of the Cascade tool -- Cascade and the original BITXs -- ADE-1 -- SI570 -- Raspberry Pico -- Diplexer -- Different Grounds to get rid of digital noise -- Gimmick Capacitors (and gimmicks made from coax) -- Ugly SMD Capacitor Soldering -- Tombstoning! -- Melting RG-174 Coax -- No need to learn Arduino programming -- Dilbert! -- Bill and Pete -- Techie Tatts! Thanks Farhan!

Two days later, Farhan presenting the rig at FDIM

Two Videos from Farhan's Visit (more to follow)