Andreas HB9BLA's Ideas on Building a Lab or Workshop

Lots of great ideas on workshop or lab design from Andreas, the guy with the Swiss accent.  Andreas is HB9BLA.  I liked all of this, especially his idea on books.   

A while back Andreas was interviewed by Eric Guth on QSO today: https://www.qsotoday.com/podcasts/hb9bla

Thank you Andreas!  

A Request for Digital Help from a Ham in Argentina

Can someone out there help OM Martin LW9DTR? 

His e-mail is on his QRZ.com page: https://www.qrz.com/db/LW9DTR

MARTIN LW9DTR has left a new comment on your post " The JF3HZB Digital VFO Dial in the DJ7OO Direct Conversion Receiver (Who is JF3HZB?) ":

Technical support
Dear Klaus Kirschelmann
My name is Martin and my call sign is LW9DTR
I am writing to you from my hometown of Buenos Aires, Argentina.
I need your tech support because I'm trying to run the assembly you posted with the AD9850 + Arduino Mini + Oled to apply it in a QRP transceiver project and I've encountered two problems.
The first problem is that I can't find the code to program the Arduino on your website.
The second issue is that the QRP transceiver design I'm using requires an inverted DDS output, ie as the frequency on the display increases, the output frequency should decrease.
I lack programming skills, so I'm coming to you knowing you can guide me on what commands I can change in the program to make this happen.
I will be very grateful to you in advance for your tremendous support.
I say goodbye with all due respect and wish that this April 18th, International Amateur Radio Day, surprises you with joy and new projects.
A big and warm hug.
With respect:
Martin Silva, LW9DTR

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

Farhan Takes us Back into the Daylight -- An Analog Rig with a Homebrew Crystal Filter and an LC VFO

 

There is so much radio goodness in this rig and in the blog post that describes it.  Farhan's blog post will keep us busy for a long time.  There is much to learn there.  But perhaps even more important is his larger view of the role of analog circuitry in ham radio.  Here are a couple of excerpts from his introduction: 

 Here is the memo : The analog never died. The world is analog all the way, until you descend into Quantum madness. The antennas are analog, Maxwell died a content, analog man. Our radios, ultimately, are analog machines and we are all analog beasts too. Amateur Radio technology has evolved into the digital domain. However,  it has only made it easier for us to do analog with computers to simulate and print our circuits.  So, it’s time to bid good bye to our Arduinos and Raspberry Pis and build an Analog Radio for ourselves. So let’s see what we can achieve in hindsight, a return to our native land and a rethink of our approaches. The radio is called Daylight Again, a nod to being back at the FDIM in 2022 after a gap of two years. It is named after the Crosby, Stills, Nash and Young’s song that had been humming all the time while put this radio together, emerging after 2 years of lockdown.  This radio that took two days to come together, no actually two years! That’s: parts of it got built and stowed away, thoughts were struck in the shower, questions popped up during early morning cycle rides and notes and circuits were scribbled in the notebook.  I must take the first of many diversion here: I hope you all maintain a notebook. Write down the date and whatever you thought or did on the bench and the result. Nothing is trivial enough to leave out. Wisdom comes to those who write notes.  I started to build this on Saturday the 14th May and I checked into the local SSB net on Monday morning, the 16th May 2022.

AND

Having clean VFO  is the most important way of increasing the dynamic range of your radio. A free running JEFT VFO that has sufficient power and a good Q components, will be unmatched by any synthesized or direct sampling radios. The math is all on the side of the free running VFO. We are talking -150 db/Hz at 10 KHz spacing, by comparison the Si5351 is -125 db/Hz, it is 300 times worse.

That is just part of the intro.  We should all study the rest of Farhan's blog post very carefully and incorporate the wisdom into our new rigs: 

Here is the blog site: 

https://www.vu2ese.com/index.php/2022/08/04/daylight-an-all-analog-radio/

Enough of the darkness.  Step into the daylight my friends. 

A Modern Mechanical Television -- Nipkow Discs and Arduinos Lead to a Mechanical Color TV (video)

I had, of course, heard about the mechanical TV systems that pre-dated the CRT-based "electronic TV" invented by Philo Farnsworth.  But I never really understood how they worked until I saw this Hack-A-Day article by Jenny List.  And wow, I see it now.  Nipkow discs.   Color TV.  Parts made in a 3D printer. Excellent. 

Here is Jenny's post:  https://hackaday.com/2022/05/27/3d-print-a-colour-tv/

Here's the IEEE Spectrum article by Markus Mierse (the brilliant fellow who built this amazing device): https://spectrum.ieee.org/mechanical-tv

Be sure to watch the video (above).  Take a look at the awesome quality of the 32 line color TV picture. And check out Marcus's amazingly beautiful construction.  (Note:  Built on a wooden base). 

Marcus Mierse's Modern Mechanical Color TV

Level UP EE Lab Builds a Superhet Receiver

I was really glad to have stumbled across Darren's YouTube channel: 

(46) Level UP EE Lab - YouTube

Heck, he has an S-38E on the shelf above his bench.  He is clearly one of us.  What is his callsign?  

This morning I watched the first and last of his 10 videos on his superhet receiver project.  Very cool.  Lots of good info in there.  And there is something for everyone:  Arduinos and Si5351s, along with a lot of standard analog circuitry.  The first episode appears above. 

The variable bandwidth filter looks very interesting. And there was a nice shout-out to Charlie Morris and one to Hans Summers. 

I really like his effort in episode 10 to measure Minimum Discernible Signal using commonly available test gear.  This helped me in my effort to get more rigorous and serious about receiver performance measurement.    

Darren has many other excellent projects on his YouTube channel.  My Hammarlund HQ-100 receiver started giving me trouble this week, and I was debating whether or not to fix the old thing.  Darren's channel provided the inspiration I needed.  It will be fixed!   

Please subscribe to Darren's channel.  And spread the word about his videos.  We definitely want him to make a lot more.  

Thanks Darren! 

Help! Can You Write the Software to Control the MAX2870 Board?

 

It is not every day that you get the chance to help a master homebrewer like Pete Juliano N6QW.  But today is just such a day.   Pete asks for some coding help: 

https://n6qw.blogspot.com/2022/03/march-18-2022-help-software-programmer.html

The Radio Gods would be pleased if you help.  The Mojo and Juju levels of all your projects would increase.   If you can help, please do so.  

My Kind of Chip: A Homebrew Discrete 555 Timer Built on Wooden Boards (video)

This is really beautiful. Radraksha Vegad (Pargrahi) from India built a discrete component version of the venerable 555 timer chip.  He built it on wooden blocks.  This leads to the kind of understanding that even Jean Shepherd would have admired.  No longer is the 555 a little mysterious black box.  No, Pargrahi shows us how it works.   

 I know we could do something similar with the NE602 or the LM386.  But probably not with an Arduino microcontroller or an Si5351.  And that says something about understanding and complexity. 

Thanks Radraksha.  And thanks to Hack-A-Day for alerting us to this: https://hackaday.com/2021/12/20/all-hail-your-new-giant-555-timer-overlord/#more-512230 

Hack-a-Day: Has DIY become Click-and-Buy?

https://hackaday.com/2021/12/11/has-diy-become-click-and-buy/

Hack-A-Day today asks about the boundaries between DIY construction and the use of purchased, completed electronic components.   This is closely related to our long-standing discussion of what really constitutes "homebrew." 

Is it really homebrew if you buy a bunch of  already-stuffed PC boards and connect them together?  

Is it really a homebrew receiver if 90% of the components are inside one chip? 

Is it really homebrew if most of the signal processing is done in your computer (that you definitely did not build)? 

The comments below the article are interesting.  There we see some of the same arguments used by ham radio operators who are more inclined toward click-and-buy. They argue that since none of us are making our own resistors and transistors, we are ALL therefore click-and-buy people, so we should just get over it and pull out the credit cards. Some commenters carry this to extremes and ask if the real homebrewers are out there mining the copper for their wires.  

The debate seems to spill over into the software area:  One person asks if it is really DIY if you are using software libraries that contain code written by someone else.  Or to be truly DIY should you write all of your own code in assembly language?    

There is one very insightful comment about hams who are inclined to disparage the homebrewing that they did in their youth.  We often hear this:  "Oh, I used to build my own gear, but now-a-days I just buy commercial transceivers -- they are so much better."  As if homebrewing was a folly of youth, something that they grew out of (and up from) as they became able to afford the latest ham radio appliances.  As if homebreweing were a regrettable thing that was done only out of necessity.   This is, I think, sad.  

I think I'm a lot closer to the traditional concept of DIY than I am to click-and-buy.  I still prefer LC oscillators to Si5351/Arduino combos.  I prefer traditional filter rigs to SDR rigs.  And I prefer to make my own crystal filters.  I don't like to use ICs unless I really understand what is going on inside them (so I can be comfortable with an NE602 or an LM386, but I'm not comfortable with a CPU chip that may have millions of transistors in it).  But I am not homebrewing my own transistors nor am I mining copper. 

What do you folks think about this? 

https://hackaday.com/2021/12/11/has-diy-become-click-and-buy/

KG7TR's Magnificent 75S-2B Receiver -- Tubes, an Si5351, an Arduino, a Bit of Collins, and a Bit of a Drake 2-B

 

Oh man, I share this with much trepidation because the last time I posted something about the work of Mike KG7TR,  Pete N6QW said he felt like putting all of his own work in the dumpster, so much better was the artistry of KG7TR.  This receiver is so cool and so well-done that we now  might have to post a guard outside the N6QW shack -- heck Mike even has an Arduino Uno and an Si5351 in there!  Don't do it Pete!

I was led to this magnificent receiver by the very humble 6U8 tube.  Scott  WA9WFA and I have been learning (mostly from Grayson KJ7UM) that the much used and sometimes loved 6U8s (three of them in our "Mates for the Mighty Midget")  might be a bit long in the tooth, old even by Thermatron standards.  I was worried when I remembered that my Drake 2-B has a 6U8 in it -- V2, the first mixer.   So I Googled for more info and was led to this amazing receiver, a 2018 creation by KG7TR.  How did we NOT see this for almost four years?

Here is more info and pictures: 

http://www.kg7tr.com/75s-2b-receiver.html

Here is Mike's write-up of the project: 

http://nebula.wsimg.com/c2281e9bdf3b54da42ca4b0b541b4ec9?AccessKeyId=D18ED10DA019A4588B7B&disposition=0&alloworigin=1

Mike KG7TR's web site:

http://www.kg7tr.com/ 

As for the 6U8s, well Grayson says the tube has been getting something of a bum rap.  And  KG7TR has two of them in this receiver, so I will obviously have to give the 6U8 another chance.  

--------------------

I didn't know that Lew McCoy had his own crystal and crystal filter company: 

http://www.kg7tr.com/the-real-mccoy.html

M0NTV's Latest FB SSB Transceiver

Wow, Nick has a really wonderful rig and has made this great video to explain it. 

Elements that I really liked: 

-- The simple mic and compression.   Very nice. 

-- Termination Insensitive Amps.  TIAs Rule! 

-- Grey Altoid-like boxes. 

-- Diplexers!  Yes! 

-- Doug DeMaw S-meter. 

-- No AGC.  

-- Pentium CPU cooling fan. 

-- References to EI9GQ (I must get his book!) 

-- Al Fresco!   Good luck with boxing it up Nick. 

Farhan's sBITX -- Combining SDR with the Traditional Superhet

Here is Farhan's amazing presentation to the virtual 2021 FDIM event.  There is a lot of tribal knowledge in this video.  Lots of old and new technology.  I was especially intrigued by Chris Trask's Kiss mixer.  Farhan's discussion of simple Arduino-based speech equalization and compression made me think that I have work to do in this area. And of course, Farhan's whole discussion of how to bring SDR into -- literally into -- the circuitry of a uBITX is really cool and very educational.   

An End to the HDR - SDR Conflict? Kevin AA7YQ Combines the Best of Both Worlds

We've had some pretty amazing contact with Kevin AA7YQ over the years.  Kevin and I originally bonded due to our common experience with parachutes  (he was smoke-jumper, I jumped while in the army).  Kevin once used a parachute to insulate a QRSS beacon.   And one day, while thinking about SolderSmoke during a drive through Montana, Kevin turned on his rig only to hear... ME!  He caught one of my infrequent CW contacts. TRGHS.  

Now we hear that OM Kevin may be poised to end the HDR-SDR civil war that has for so long been dividing our great podcast.  Can Kevin's new rig heal our wounds and allow us to enjoy the beauty of SDR waterfalls while not forsaking the joy of hardware defined rigs?   Kevin will soon launch a blog describing his effort at rig-building. See below for a preview.  Stay tuned.  

Kevin wrote: 

I am currently working on a new rig design.  It is a hybrid HDR(Hardware defined)/SDR radio that incorporates some classic superhet design along with some of the more useful features of SDR.  I have found that pure SDR is really not that enjoyable for me.  I love using GNU radio to mock up and test design concepts, but SDR basically dilutes the “magic” of radio to nothing more than software and touchscreens, stuff we use every day all day.  Its not the Ham Radio I grew up with as a kid and was fascinated by.  On the other hand, I have always fought temperature drift, large variable capacitors minimal tuning range, and associated with classic VFO and VXO designs.  In fact, in 1997, for my senior capstone design in EE at Montana State University, I designed a 20m superhet that used a DDS LO.  At the time DDS was cutting edge technology I used an AD7008JP50.  I had to beg and plead with ADI to get a couple samples for my design, since they exceeded my self-funded college student project budget. 😊  But that’s another story.  SDR has made me grow extremely fond of the waterfall display.  I love having the visual “situational awareness”  of what is going on in a moderate bandwidth outside of the spot I am tuned to. I also am a big fan of digital filtering and modification-ability that comes with boot-loadable microcontroller designs.  So this design includes most of the real highlights of SDR but does not take the fun out of designing,  building, and operating a HDR.

Anyhow, this design is a big goal of mine to complete and build in 2021.  I am not retired yet so I still have to balance, work, family, and tinkering time, but I am very excited about this project.  I have “noodled” this design to the point of what I have achieved full-on “analysis paralysis”.  That is, I keep designing and redesigning, optimizing, and figuring to the point where after months of thought, I have nothing to show for it 😊.  So my New Years goal for 2021 is to make “good enough” rather than “perfect” design decisions and move forward.  I will keep you posted on the design and possibly start a blog so I can get some peer review input from the greater RF Design/Homebrew community on my project.  I’ll keep you informed on my progress.

Adam N0ZIB's Direct Conversion Transceiver

This is obviously very cool, but looking ahead I think Adam should think about adding one more mixer, changing the bias on the TX amps, and adding a mic amp.   Boom:  A Double Sideband Transceiver.  

Pete wrote: When I was in the US Navy and a particular unit did something outstanding – the Command ship would raise the Bravo Zulu Flag  for a job well. Don’t know if you can see it there in MO but I have raised the BZ flag to you. Outstanding and congratulations.

Bill and Pete: 

Just finished a DC transceiver using Arduino nano, SI5351 (my sincerest apologies, Bill), diode ring mixer and lm386 audio amp.  The transmit portion is a two-stage class AB pre-amp (from EMRFD page 2.32), which is driving an IRF510 final (biased at 2.08 volts) from Pete’s design. Output is about 5watts into a CWAZ low pass filter, based on the design from here: https://www.arrl.org/files/file/Technology/tis/info/pdf/9902044.pdf

I’m using a manual TX/RX switch which is doing multiple things. It brings the Nano A1 LOW, offsetting the transmit frequency 600 Hz for CW, grounds the audio input to prevent deafness (learned that one the hard way), and it engages a relay that switches the antenna from the receiver to the transmit, and also turns on the transmitter stages. Keying is through the first stage of the pre-amp.  

I still have some tidying up to do, and I’m not sure the LPF works so well using two component inductors instead of all toroids, but I finished it today and made my first QSO into Ontario almost 1000 miles away.  It’s been great fun! 

73,
Adam
N0ZIB
Missouri

Global Collaboration: The uSDX -- A Multi-Mode QCX

Bill:

There is a new open source, home brew, multi band, multi mode QRP transceiver that grew out of the QRP Labs QCX. Through some serious magic it retains an efficient class E RF amplifier for sideband and digital modes. It crams impressive SDR capabilities into an Arduino. More info at https://groups.io/g/ucx/topics

The basic work appears to have been accomplished by Guido Ten Dolle PE1NNZ. It uses pulse width modulation of the PA supply voltage to transmit  modes other than CW while retaining class E efficiency and uses a direct conversion SDR receiver.

 https://github.com/threeme3/QCX-SSB .

There are several variants by different developers. I built a variant designed by Barbaros Asuroglu WB2CBA  

https://antrak.org.tr/blog/projeler/usdx-an-arduino-based-sdr-all-mode-hf-transceiver-pcb-iteration-v1-02/ that uses through hole components (mostly) and I'm pleased with it's performance. I also designed and 3D printed a case.

This has an interesting development process with contributions by many, including the usual gang of suspects: Hans Summers, Ashhar Farhan, Manuel DL2MAN, Kees K2BCQ, Allison KB1GMX and Miguel Angelo Bartie PY2OHH. I apologize to the many others whose names I didn't list.

The band switch multiband version by DL2MAN is even smaller, but with SMD components which I wasn't ready to tackle yet.

BTW - your podcast encouraged me to go in this direction. I built a BITX 40, a uBITX (sent you a pix of it in an old Heathkit Twoer case), U3S, QCX and now my first step from kits to built from plans.

73

Bob   KD8CGH

https://antrak.org.tr/blog/projeler/usdx-an-arduino-based-sdr-all-mode-hf-transceiver-pcb-iteration-v1-02/

Arduino, Si5351, GPS linked atomic clock, GPS disciplined frequency counter and more...

Wow, it has been a while since I first talked to Rick, N3FJZ.  Above you can see his QSL card.  And here is a link to a SolderSmoke blog post (with videos) that describes our Homebrew to Homebrew contact:

http://soldersmoke.blogspot.com/2015/10/hb2hb-n3fjz-n2cqr-si5351-and-bitx-tias.html

The e-mail below shows that Rick continues to melt solder, bringing into his rigs some very cool technology:  atomic clocks, GPS modules, and color displays.  That's a long way from the original PTO Direct Conversion receiver that he first heard me with.  FB Rick! 

--------------

Leif, 

I've made great progress on my Arduino Mega 2560 based rig controller I call the ZX-Front-Panel. I just finished a feature I always wanted which is a built-in *GPS disciplined frequency counter*. It uses the 1-pulse-per-second timing output from the GPS module to create a frequency counter with atomic-clock accuracy. It's on the solderless breadboard with the rest of the ZX-Front-Panel right now, and even so, it can count up to 30MHz with no trouble! and it should be able to count up to 100MHz or more if built on a ground plane with a little shielding. The best part about it is that it only required one additional chip (a 74LV8154 32-bit counter $1 from Mouser) in addition to the existing parts already on the ZX-Front-Panel; i.e. the Arduino Mega 2560 ($10), the Ublox NEO-6N GPS module ($15), the display ($25), and the Si5351 PLL RF Oscillator ($8). 

Check out my video series covering the ZX-Front-Panel development progress. The first link below will bring up the video page on my website with the latest video at the top, so you'll have to scroll down a bit to get to the earlier development stages. Check out the rest of the website too for the schematics of my Bitx / TIA inspired rig design (which I call the ZX-SSB-II) that I used an early version of to make my first HF HB2HB contact with Bill (N2CQR) back in 2014 or so (Bill and Pete, via the Soldersmoke podcast, were my inspiration to build my first SSB homebrew rig). 

YouTube videos: http://www.remmepark.com/circuit6040/ZX-SSB-II-Front-Panel/ZX-SSB-II-Front-Panel.html#video 

Homepage: http://www.remmepark.com/circuit6040/index.html

Dean AC9JQ and I have been communicating via emailing about his progress in building his own copy of the ZX-Front-Panel, and I'm very excited to learn that he might be thinking about producing a future homebrew rig featuring the ZX-Front-Panel as its controller/VFO. The best thing about the ZX_Front-Panel is that ounce you install the sketch into the Arduino Mega, you don't need to modify the Arduino sketch itself when you build your rig; i.e. the SSB crystal filter's center frequency (the I.F. frequency), the Si5351's clock output drive level, the display brightness and contrast, and the Si5351 crystal correction factor (crystal trim) are all configurable, real-time, right from the ZX-Front-Panel's user interface, and once set, can be saved to the Arduino's non-volatile EEPROM to be automatically loaded on the next power-up. Also, since it has a GPS module, it features a UTC/Local real-time clock with atomic clock accuracy too. 

Anyway that's all for now, take care Leif. 

73 Rick.

Homebrew Az-El Satellite Antennas from the Philippines and Australia

https://nightskyinfocus.com/2020/05/18/diy-satellite-tracker/

DU1AU is way ahead of where I was when I was working with Low Earth Orbit satellites.   I just aimed the antenna about 45 degrees up from the horizon,  and spun it around with a TV rotator with me --not the computer -- as the controllers of the rotator.  In essence I did the AZ manually and completely ignored the EL.  This design moves the antenna in Azimuth and Elevation, and has the computer control the movements via an Arduino.  FB. 

DU1AU points to the work of VK3FOWL and VK3YSP.   Their site has very detailed info on how to build several versions of this kind of Az-El rotator: 

https://www.sarcnet.org/rotator-mk1.html

This Az-El project represents a great opportunity to move beyond hand-held satellite antennas,  and beyond my Az-only manual approach.   It also give us a way to bring some real homebrewing into a part of ham radio that has come to be dominated by commercial equipment. There are some Arduinos and some lines of code, some motors and some metal work.  Great stuff!   

ZL2CTM Charlie Morris on "QSO Today" with Eric Guth 4Z1UG

Eric Guth 4Z1UG had a really nice interview with our friend Charlie Morris ZL2CTM.  Charlie shared with Eric a lot of wisdom about how to homebrew radio gear.  I especially liked Charlie's comments on keeping most of his rigs on the wooden prototype boards.  He said something important when he talked about the benefits of taking a break from a difficult problem, then coming back to it with a rested and refreshed mind. I noted, however,  that he said most of these frustrating problems have to do with software.  

I got got several chuckles out of Charlie's comments on the difficulty of building stable analog LC VFOs (here he seemed to be channeling our good friend Pete Juliano).  I chuckled because as I listened I was happily building the analog LC VFO for my Q-31 Quarantine receiver.  The centerpiece of this project is a variable capacitor that Pete gave me;   Pete took it out of an old  Galaxy V transceiver.   Believe me guys, no rotary encoder could possibly look as nice or have as much soul as that capacitor from Pete, with all its gears, reduction drives, and anti-backlash mechanisms.  It even smells of machine oil.  Call me a Luddite, but I will stick with the coils and capacitors.  

Listen to the interview here: 

https://www.qsotoday.com/podcasts/zl2ctm

Thanks to Charlie and Eric. 

The Low-Cost, Open Source COVID-19 Ventilator that Farhan is Helping to Build (Video)

While many of us are just trying to pass the time by building Quarantine ham radio rigs, our good friend Farhan VU2ESE has been hard at work on a really serious project:  He has been working out how to use an Arduino microcontroller as the electronic core of a simple ventilator that could save thousands of lives in the current crisis. See video above. 

Here is background info on the project (from ARRL): 

03/23/2020

Amateur radio volunteers from around the world have volunteered to assist University of Florida Professor Sam Lampotang and his engineering team in their quest to rapidly develop an open-source, low-cost patient ventilator that can be built anywhere from such commonly available components as PVC pipe and lawn-sprinkler valves. The amateur radio volunteers are developing Arduino-based control software that will set the respiratory rate and other key parameters in treating critically ill coronavirus victims.

Multiple volunteers responding to a call for help from Gordon Gibby, MD, KX4Z, included noted software developer Jack Purdum, W8TEE, and  uBITX transceiver maker Ashhar Farhan, VU2ESE. University of Florida physicians are working to address the critical legal aspects as the design moves closer to fruition.

The ventilator’s valves would precisely time compressed oxygen flow into patient breathing circuits under Arduino control, allowing exhausted patients with “stiff” lungs impacted by viral pneumonia to survive until their body can clear the infection. The software design team is also adding simple features such as an LCD display, encoders to choose parameters, and watchdog safety features. -- Thanks to Gordon Gibby, KX4Z

It is important realize that in countries around the world, many victims of COVID-19 will have no hope of getting anywhere near the kind of $50,000 ventilators found in U.S. or European hospitals.  That is one of the things that makes this low cost, open-source project so important. 

More details on the project here: 

https://github.com/afarhan/osventproto

Please pass the word on this project.  Please forward on Facebook, Re-tweet, etc. 

Antuino: Farhan's Compact RF Lab In-a-Box

I now have Farhan's latest invention, the Antuino.  Pete will have his shortly.  Very cool.  SWR meter and antenna analyzer, power meter and scalar network analyzer all in one box. I put an old-school knob on the rotary encoder -- it seemed like the right thing to do.  Soon I will be able to find out if my rigs have spurs or are somehow non-compliant.   I'm sure Farhan's "RF Lab in a box" will be an important addition to my test gear arsenal. We will be talking about this in upcoming podcast episodes. 

Mike N2HTT did a nice write up of the new device: 

https://n2htt.radio/2019/05/26/hello-antuino/

And here is the info from the htsigs.com page: 

http://www.hfsignals.com/index.php/antuino/

Thanks Farhan!