A new Radio Amateur

I’d like to take a moment to congratulate my friend Shaun on passing the Canadian Amateur Radio Basic Qualification examination last night. Shaun took the exam while Ernie (Ve3EJJ) and I were giving an introduction to the practical aspect of operating a radio station at the club station VE3JW at the Museum of Science and Technology. Shaun scored high enough to earn Honours and so he has HF privileges. So I’d once again like to say good work, and welcome to the fraternity. Shaun’s pending callsign will hopefully be: VE3XUB

CARBET exam generator

As an aid to getting Shaun his qualifications, I developed an online Basic Exam generator which I have nicknamed: Project C.A.R.B.E.T. The front-end is all PHP (web based) and should be available soon (pending further bug testing and “hardening”). Keep an eye out for this study tool. This project is in conjunction with my work on an Android application to offer the same study aid – but in an “offline” format.

I am presently working on adding the Advanced question bank to the question pool for those who wish to challenge this qualification level once they have their Basic privileges. This will take a bit of time as I am trying to add in an explanation for all answers – something that is not as feasible with the Basic question pool (due to sheer size).

 

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Exam Software – Android

Well .. looks like I couldn’t leave well enough alone .. I’ve started yet another project. I am attempting to write a Canadian Amateur Radio Basic Exam application for the Android platform.

So far, I have put every single exam question from RIC-7 into a MySQL database, which has:

  1. taken a lot more effort than I had expected
  2. produced some interesting results

Basic exam question pool distribution

After analyzing the distribution of answers in the basic exam question pool, I can offer the following data. Here is the distribution of correct answers by their answer number:

  1. 27.73%
  2. 23.87%
  3. 24.20%
  4. 24.30%
  • Section #1 : (regulations) only 20.79% of answers are “2”
  • Section #2: 29% of answers are “1” whereas only 18.35% of answers are “3”
  • Section #3: 29% of answers are “1”
  • Section #4: 36% of answers are “2” and < 15% of answers are “3”
  • Section #5: 31% of answers are “1”
  • Section #6: 30% of answers are either 1 or 2
  • Section #7 & 8: 33% of answers are “4”

Not a terribly even distribution of answers if you ask me… I always suspected there was some skew to the distribution though I had never analyzed it until now.

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Teaching & Collaboration

Its that time of year again, and the OVMRC is once again hosting its Amateur Radio Course. I’ve been asked to help provide some of the lectures once again, and it is my honour and delight to offer my assistance to Ernie (VE3EJJ). We have a fantastic turnout this year with lots of eager students who have already shown how engaged they are in their learning (fantastic!).

I gave a lecture on Current & Ohm’s Law – two fairly fundamental topics which are pivotal to other topics to be discussed later in the year. The slides are available in the Files / Downloads section as always.

In other news, Marc (ON5RR) from Belgium phoned me up a couple of weeks ago asking if I would be interested in collaborating with him on a Doppler tuning project he is working on. I imagine that Marc called me as he must have seen the FT857D CAT control library that I wrote for the Arduino platform.

I am excited to be working on this project with Marc, and I eagerly await his return from a vacation so that we can start plugging away more at the code side of the collaboration. I’ve completed the library (in terms of Clar. functions) and this was the first hurdle in the project. Next, Marc will be porting his code over to the Arudino platform as his Arduino Uno board arrived in the mail recently.

More to follow …

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ALC Project & RasPi Updates

Hi all,

Well .. I haven’t updated the blog in a while as I did not have any updates to share at the time. Since my last posting, I have placed a rather large order with DigiKey which has allowed me to forge ahead with my micro-controller & FT857D project.

ATtiny85 microcontrollers

One of the recent acquisitions I have made was to purchase a USBASP ICSP programmer which will allow me to program AVR micro-controllers without having to either DIP-swap chips on my Arduino, or (temporarily) re-purpose my Arduino as an ICSP programmer (which actually works quite nicely btw).

I picked up a handful of ATtiny85 micro-controllers which cost a mere $1.37 each. These little gems have 8kB of program space and boast 6 io pins (which can be re-purposed in software) whose functions include:

  • 3 analog ADC pins (also can be digital IO) [pins 2,3,7]
  • 2 PWM outputs [pins 5&6]
  • reset [pin 1]

My intention for the automatic control of ALC of a Yaesu FT-857D radio requires four pins which in my current prototype layout are:

  • pin 1 = (future)
  • pins 2&3 = software emulated I²C UART for control of a DAC
  • pin 4 = GND (from radio’s MIC port)
  • pins 5&6 = software emulated serial UART for the FT857D CAT control functions
  • pin 7 = “analog input 1”  = analog input from front panel (MTR jack)
  • pin 8 = Vcc (from radio’s MIC port)

Prototype ALC control circuit

I was originally planning on using an ATMega328(or similar) micro-controller which boasts a much larger compliment of (23 io) pins and program space, however, I decided to try a minimalist approach. After all of the code-space requirements, I should have a few bits left over for unforeseen additions. If I have a PCB board fabbed for my project, I imagine that I would be able to install my ALC control module inside of the radio’s chassis!

In addition to the micro-controllers I ordered, I also grabbed some op-amps, negative voltage regulators, a few DACs and a bunch of other goodies. I’m certainly set for a while now!

On a software side, the ATtiny85 provides a large number of challenges. For starters, I had a chicken-or-egg problem of having to update my USBASP programmer’s firmware which required me to repurpose my Arduino as an ICSP programmer and effectively bit-bang the new firmware onto the programmer using AVRDude. The command I issued was:

avrdude -c stk500v1 -b 19200 -P com6 -p atmega8 -U hfuse:w:0xc9:m -U lfuse:w:0xef:m -U flash:w:usbasp.atmega8.2011-05-28.hex:i -v

Along with having to re-flash the programmer, if you wish to use the Arduino development suite, you have to download the latest WinAVR files and replace the Arduino files with the updates. Part of this process requires editing of the avrdude.conf file to tweak some values. I’ve uploaded my config file to save those who are foolish enough to follow in my footsteps some grief. Simply download the conf file to:

C:Program Files (x86)arduino-1.0.1hardwaretoolsavretc

After the development suite hacks were done, I was able to load my FT857D test code and successfully control the radio with the ATtiny85. I’ve started coding the ALC threshold routine, and will test connectivity with my I²C DAC chip soon enough. For now, I’m glad to finally be started on this project.

In other news, a replacement PIC controller arrived for my TNC-X which solved my issue of not being able to trigger the PTT of the radio. The only problem I see now is all kinds of garbage text in the decoded packets coming in. I am not sure what the root cause is, so it looks like more tinkering for me!

On a slightly related note, I intend to look at the Raspberry Pi again – I’ve been busy in the Linux world doing other things, so this has been back-benched a little for now. I’ve still got to look at the resource management to see if I can get the software decoding of AX.25 (packet radio) frames working. If this works out, we could have a fantastic TNC/digipeater for in around the $60 mark with FAR, FAR, FAR more functionality than anything on the market today.

Once I get a bit more headway on my current project, I’ll be tackling the RasPi-peater project.

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