Posted on August 5, 2017
The final part of this u.RAT “science fair project” is wiring the variable capacitor and roller inductor with a 50 ohm dummy load resistor and then attaching the Rig Experts AA-30 so we can see how tuning the components affects SWR and what the L, C and X values are.
I have been playing with different “equivalent circuits” and using a 56 ohm as a dummy load for an antenna, but the control that seems to affect the SWR the most is the variable capacitor.
Which shows the components that would be in an “L Tuner” and the other components / values for the equivalent circuit. I will re-read my theory books to figure out why the capacitor is the component that is doing all the work. The inductor almost seems to look like a short because of the resistor – I’m not sure.
Posted on August 5, 2017
I’m hearing several ZL stations very well on Top Band this morning, and they are on SSB no less.
I hear some lightning strikes that seem to be mostly in Kansas and Nebraska, but not enough to quell the ZL’s.
Its really starting to feel like the “Lowband Season” is near – we lose a full hour of daylight this month, and the first 5 days of August we have already lost 7 minutes of daylight. While I love riding my bike to and from work in the daylight, I must admit – I like my cozy shack when “Lowband Season” is in full swing. This Fall and Winter I will be in mt best shape low band wise. The Mod Bob and BT1500A and the DX Engineering DV-40-P phased array antennas are all I need. The 20M 2 element home brewed yagi might get a work out – for 3Y, yesterday a CE station came booming in, and so that path to 3Y was looking great there.
Yes, I’m still a DXer, just one at the end of my “paper chasing” phase. One day soon I will only be on the low bands.
Posted on August 3, 2017
There is a very cool blog called “geeky gadgets” and they have featured the u.RAT. I’ll follow them for sure – and I continue to be amazed at the cooperation and collaboration between “Makers”
Posted on August 3, 2017
It was 1976, I was newly minted WA2QHN (after passing my General Class Ham Radio test on vacation in Seattle at their FCC Office), and I thought I wanted to be an Electronic Engineer. It all started in Ms. Goodin’s 4th grade class when she taught a series on “The Inventors”. I wanted to be an inventor at age 9 or 10. At age 11, I built my first Heathkit, the SW-717:
My Novice station in Newton, NJ was this receiver, a Hallicrafters HT-40, a Dow Key Relay and a handful of crystals.
Anyway, my father’s good friend and Electronic Engineer, Joe Secundo, visited and plopped an IMSAI 8080 on the kitchen table and after I tried to impress him with my proclamation “I am going to be an Electronic Engineer”. He said “No you are not!” and went on to convince me to instead become a computer programmer. Two years later, I was getting straight A’s in my COBOL, Fortran and Basic classes at the County College of Morris – and after a year transferred to Lock Haven State College in PA. I graduated with a Business Computer Science degree.
My first job was at Kodak in Rochester, NY coding Octal Assembler and Machine Code on PDP-11’s using the Kodak Park OS:
I hated it. It was too abstract – my job was “process control” – to try to track waste in the manufacturing of Instant Print Film. Ironically, I’d love this job now!
I have told this story in my old blog, but after designing and building the u.RAT, things have magically come full circle. Today, designing and building something electronic is the same as designing a system and drawing a block diagram. You assemble a set of boards that have functions, wire them together, and then download code from Github and mash them up to make the set of circuits to do what you want.
My parents bought one of these for me in my 9th birthday…
I am 100% sure that I thought that in the future this would happen. I had “Systems Analysis I” and “Systems Analysis II” classes, and we basically drew block diagrams at the systems level and drew flowcharts at the program level. We even used those plastic templates and drafting paper if I remember right. That’s when I thought “what if the system was a block diagram?”.
Well, that’s exactly how I approached the u.RAT, and 40 years later, my 1970’s era thoughts and predictions just happened with my first “Maker” project.
Posted on August 1, 2017
The Adafruit Blog, Copyright Adafruit featured this blog today, August 1.
Adafruit was founded by “Lady Ada”, AC2SN, and I am finding more and more that if you want a reliable component, you will never go wrong ordering from Adafruit. Their site is amazing wealth of resources – including CAD drawings for their designed components – such as the cute little Pi-OLED that really make the u.RAT rock! Some drawings are in Eagle and Fritzing format, and they always have tutorials and information to help you make your project a success. Their forum is very helpful – and in the case of the Pi-OLED, Mike, KJ4Z helped me find Larry Banks FB library, and I shared that with the Adafruit forum – so that others using C will be able to make the Pi-OLED work.
Adafruit products are available at their site and also sold at Amazon and other outlets on the web. I have been burned by some cheap knock off Chinese clone products, and so will be a lot more likely to look for the Adafruit, Arduino or Raspberry Pi official logos. And their prices are very good too.
Posted on August 1, 2017
This hands down the best electronics book that I have ever purchased. Yes, even better than the venerable ARRL Handbook. I say this because today’s electronics is more about integrating pre-assembled boards and processing power than soldering discreet components.
I still encourage all hams to purchase the ARRL Handbook, ARRL Antenna Book and (especially) the ARRL ON4UN Lowband DX-ing Book, because they cover the things that this book doesn’t – RF from DC to daylight.
In the 90’s I did try to get back into ham radio by building several QRP Kits with discreet components – the SST, K1, KX1 and a few others, but there is no way that I would do that again – now everything I build will have a processor at its core, and the Raspberry Pi Zero W is by far and away my favorite platform, and Python and C are my favorite languages.
So, for “modern” circuit building, and even the theory part of the book, this one is my new favorite.
Posted on July 31, 2017
What started out as a personal project – to use the Elecraft KPOD to control the Palstar BT-1500A, has turned into an educational platform that I can use to write articles and give presentations at Makers Meetups and Ham Radio Club and convention gatherings. I’m giving my first urat presentation at EBARC in San Pablo in just two weeks – August 11. EBARC has a bunch of Diablo DXers, so that is “my club”. I presented at their February meeting and it was “Low Band DX Antennas”.
Here are the “facets” or educational aspects of this project, and its far more than I really thought much about when I started this project:
- The Raspberry Pi Zero W and its uses, plus “headless” operation
- Controlling Stepper motors with the Raspberry Pi, the GPIO and WiringPi – that emulates the Arduino
- Embedded devices and the Internet of Things (IOT)
- Ham Shack Remote control – wired or wireless
- Antenna tuners and when you need a balanced antenna tuner
- Arduino vs. Raspberry Pi
- C and Python as Maker languages
- USB device drivers and HID vs. HIDRAW
- OLED devices on the Raspberry Pi Zero W
- Github and Open Sourcing a project
- How antenna tuners work – and the different circuits employed
- Antenna impedance matching and solid state amplifiers and what they “need” . ..
Now – this just leaves sitting on my fat behind waiting, bitching, pissing and moaning about “bad conditions” or pining for the fjords for that next ATNO. Holy smokes – this is a hobby, not a frickin job – so lets have fun!
I am going to add in wiring for my antenna analyzer – the Rig Expert AA-30 and then I can really start also teaching antenna feed points and matching circuits. I can teach all variations of an LC network. That leads to vertical feed vs. tuned feeder feed, etc. Then we can get into radials vs. non radial based low band antennas. Its the gift that keeps on giving.
I have gotten WAY more of my money’s worth out of this project – than sitting around doing the DXCC list chasing thing. Wow – DXCC can be a very limiting experience!