A Funny Thing Happened on the Way to the U.RAT . . .

OK, so that’s a bit dramatic – but I’ll be busy first wrapping up the final “packaging” of the u.RAT Demonstration Board, and then writing articles and presentations. I will submit the article to QST with the main theme one that I will repeat at EBARC and Pacificon – which is that the “Maker – Ham” connection is a real force to be reckoned with, and if you are bored waiting for that next DX-pedition, or Public Service Event, maybe its time to get the toolbox out.

The best thing is that the motivation for this project was my own “Mod Bob” remote antenna tuner, but along the way, I have learned so much and had more fun in ham radio than I can ever remember. The richness of the project and all of the areas that it cuts across:

  1. Antennas
  2. Antenna impedance matching and solid state “full gallon” amplifiers
  3. Giving new life to old manual / analog antenna tuners using Stepper Motors
  4. The “maker – ham” connection from a social point of view
  5. Low Band DX-ing in conjunction with the Mod Bob
  6. How a balanced antenna tuner works and when to use one
  7. Arduino vs. Raspberry Pi – when to use one or the other – Raspberry Pi Zero W especially
  8. Deep dive into the Raspberry Pi, Steppers and Stepper drivers
  9. The C and Python languages on the Raspberry Pi and perhaps Open Sourcing a project
  10. The Raspberry Pi GPIO, emulating Arduino on the Pi and the USB and OLED C libraries

There is no doubt more, but these are 10 very solid aspects or facets to this project. In fact, as I mentioned before, I am much more interested in sharing and possibly Open Sourcing the u.RAT than adding the u.RAT to my remote antenna tuner. Its like this project tok off and has a life of its own – but its opened up far more interesting avenues than what I had originally intended. This is the mark of dreaming, discovery and a fun journey. I feel like I went on a DX-pedition but never left my house or yard. A journey of the mind indeed!

It reminds me of the title of an R.E.M. album, “Life’s Rich Pageant” . . . .

Presenting at Pacificon 2017

I’ll be presenting at the Pacificon 2017 Antenna Forum on Friday and then again on Saturday. Friday’s presentation will be “Low Band DX Antennas” and will feature the Mod Bob and touch on the BT1500A with uRAT, and then on Saturday it will be all about the U.RAT from more of a ham – maker perspective.

I’m quite excited about Pacificon this year, especially since I have expanded my horizons beyond just DXCC List Chasing, the Maker aspect really has me amped up.

In September I will be presenting the URAT at the East Bay Amateur Radio Club meeting – and several “Diablo DX-ers” are regulars there – so it will be especially fun. That will be a good “dress rehearsal for Pacificon. I already gave the Low Band DX Antenna presentation at EBARC last February and it went over very well.

U.RAT Roller Inductor Stop Warning

A micro switch turns on when you are tuning at the end of the roller inductor. Very easy to implement, and it did not require any code changes – just old school wire tie, two part epoxy and a LED.

I will put the Raspberry Pi W and voltage control on this polycarbonite project case.

OK – now I really am done with all of the hardware and software parts of this project. Now I just have to package it all up and write the article and create a slide deck with embedded videos for my presentation(s).

U.RAT Demo Board

The u.RAT with stepper motors bolted in and coupled to the variable capacitor and roller inductor

The two drivers and Raspberry Pi Zero W will be placed in between the capacitor and inductor. I have an Astron switching supply and a 12v to 5 volt step down component to supply the stepper motors and the Raspberry Pi Zero W.

The NEMA-23 steppers only draw .5 amp at peak load (tuning fast), and its lower than when I used a regular Raspberry Pi 3 b. I don’t know why, but I like it. I am pretty sure a set of NEMA-17 steppers and lighter duty drivers would do – what I have is way overkill, but I like that, actually.

The shaft couplers are really superb and are actually flexible aluminum, beautifully machined. Because they allow for a slight angle, the “purchase” seems better than straight through and with stainless steel couplers.

I expect that the wood does absorb some vibration that all steppers give off. So the problem of the set screws loosening is solved.

I have a pair of these and will probably mount them at each end of the roller inductor. They are perfect and I did find an easy to mount place. All they would do is turn on a red led that tells you that you are at the end of the roller inductor. They have exactly the right “play” before they switch on.

U.RAT is Ready for Open Sourcing!

The u.RAT is now ready for Open Sourcing, but I need to talk to the fine people at Elecraft about this, since the project is driven by the KPOD and is “KPOD Centric”. I guess someone could replace the KPOD with their own rotary encoder and switch instead of the KPOD, but I very specifically wanted to drive the project from the KPOD.

The best part about this project is that I went from dream to a finished “product” (or is it just a “hack”?) by playing, learning and collaborating with others. Its amazing how powerful the Open Source Community, the Maker Community and the Amateur Radio Communities are. I believe Hams and Makers are one in the same – just a different genre. All three of these are very much intertwined.

I haven’t had this much fun in years as far as Ham Radio is concerned.

I will next put the Raspberry Pi Zero W in a cool see through Plexiglas case that I have, and then wire it up permanently. This will be my “show and tell” rig for presentations. I have another Raspberry Pi Zero W for the Mod Bob and the BT1500A, but at this point I’m going to spend my time writing an article and putting together a presentation for clubs and Pacificon.

U.RAT OLED Display Works!

I now have both the KPOD and and the Adafruit Pi OLED working on the Raspberry Pi Zero W.

As soon as it arrived, I soldered the header on to the Pi Zero W. I then used the Make script to build the OLED_96 library, then did the Build of WiringPi, then compiled the hacked Elecraft URAT code to use both libraries.

Huge shout out to Larry Bank who made this display possible! And thanks to Mike, KJ4Z, who found Larry’s GitHub library!

The KY6R LAB text you see above is in the urat.c code, and it initializes the OLED with that little “splash screen” text. I’ll need to look into how to write both text and an integer using the OLED_96 library next.

Earlier today, I built a plywood display platform which I will use to give presentations and demos.

The center section will have a nice Raspberry Pi Zero W in a fancy case. The KPOD will be out front so people can play with it.

It’s a bit orange because I was on our very nice back deck where we have orange canvas “sails” as an awning.

With my waning interest in DXCC, this ham maker stuff sure is rekindling my love of the hobby.

So much so, I can’t believe my ham life just revolved around the very silly and arbitrary DXCC list for 16 years.

Well, doing both is even better ….

Adding the u.RAT Adafruit Pi-OLED

The urat.c program with printf statements ready to be replaced by OLED print commands . . 

My good friend Mike, KJ4Z found a C Library for the Adafruit Pi-OLED, something my Google searches just didn’t find. Thanks Mike! Here is the link, and I shared it with Adafruit and their Support Forum – since no one there had found this wonderful C Library:


So, today I will solder the header on one of the two Raspberry Pi Zero W’s and plug the cute little Adafruit Pi-OLED in:

I still cant get over this cool little Linux computer and display. All for under $30

Adafruit really rocks. They design products that really open up the Maker world, and have all plans in the form of CAD and Fritzing schematics, spec sheets, code and lessons. No wonder they have gotten the press and accolades that they have.

The OLED_96 library example program – all I need to do now is replace my printf statements with the oledWriteString commands

The project happened due to a combination of Elecraft being so supportive with their code, a guy in Hawaii who had the best wiring diagram for the steppers and my drivers, a guy in Devon in the UK with a great library to make the steppers move, and this library to display the C and L positions of the KPOD rotary encoder on the OLED.

I prefer Python for business and BI (Business Intelligence) apps at work, but I do like C for this lower level hardware work. Arduino supports C – but its a special form of C because of its development environment, and the Raspberry Pi with C compiled on Linux using gcc is more of what I am used to as far as C goes. You have a choice of languages on the Pi – on Arduino you do not. Arduino C is about the easiest form of C that I have ever tried – C# is easy, but I had found C++ to be quite difficult back in the 80’s – when I worked for Oracle.

If the KPOD itself didn’t dictate that I use C, I would have probably used Python, but we shall see – I’m surprised how much I still like C.

OK – I hope later today (or at least this weekend) I can post a video showing the roller inductor and variable capacitor mounted properly on a plywood board and the Raspberry Pi Zero W with Adafruit Pi-OLED displaying the L and C values in a way nicer than this:

The “final frontier” will be to possibly add a shaft encoder to the roller inductor shaft which turns on a LED when I get to one end or the other – so I won’t bang the roller at its stops:

There are many, and F6HQZ has on based on WiringPi:


This will be the point where I have to decide what would go in an Open Source project and what won’t. Since any tuner components would really need the OLED, I think that’s worth including, but since someone could use a switched inductor tuner – like the Johnson Viking KW Matchbox, then they would need a relay switching schema and not a shaft encoder in their project.

Even the OLED might be dictating too much, but I think the Raspberry Pi Zero W plus OLED along with the KPOD is an unbeatable combination. I have suggested to Elecraft that they consider a new and more super charged KPOD that has a little OLED display right on board – then the game steps up quite a bit as far as having a Universal Maker controller using the KPOD.

But hey – since I am sharing my work back with Elecraft, who knows – if they see a way to market to hams and makers, maybe I will have come up with my first product design “hack”.

Are we having fun yet?