On Saturday G3PVU, G1LQB, G0RQQ and M0TEF started work on getting the 6M HB9CV beam up and running unfortunately they didn’t get finished before having to go home.
Peter 2E0FGA, Les G1LQB, Alistair M0TEF and Keith G0RQQ took part in Mills on the air from Ellis Mill in Lincoln on Sunday 13th May. Shock came with a station coming in on 2m FM from near Wolverhampton during setup although GB5EM was not set up correctly to work them at that time. Despite a noise level between S5-9 a few contacts were made; even Les had a contact on HF. Contact was also made with Tim M0ZRR a former member of the club and now living in Shepshed.
Keith G0RQQ reenacting “the thinker” by Rodin
Unfortunately Mills on the Air coincides with the Lincoln Grand Prix making it difficult for others to get there as the traffic management kept everybody out of the race area.
Photos M0TEF & 2E0FGA
This part of the project is to help you understand how we are going to control the motors of the rotator and we are deviating from the 2rpm motor to a higher rpm to be able to quickly move from one location to another at a higher speed then slow down to be able to follow the path of the satellite.
In the previous post I gave links to the parts needed and for this part of the project, we will be using the H Bridge, 2 motors, and the Arduino Nano.
I have found a good video which explains the principle of driving the motors, but before watching it I thought it better to explain a bit about writing code for the Arduino. The code is known as a “Sketch” and contains all the information for the Arduino IDE to compile it and load it into the Nano so that it can run the program.
A variable is a number that can be changed by the sketch and is usually given a “label” that identifies it in the sketch, say for example we define “Int variable1 = 5”, “Int variable2 = 2” (Int tells the compiler the type of variable it is and in this case an integer) and later as the sketch is running we want to perform a mathematical calculation and change “variable1” to another value “variable1 = variable1 + variable2;” (the “;” defines the end of the line) the microcontroller will process this and “variable1” will now = 7 (5+2). Another way to increase the value of the variable is “variable1 ++1” which will increase the variable by +1 and tends to be used in loops. See here for more information about the syntax for arithmetic calculations and more information of the programming syntax can be found here.
(For those who want more information, when the sketch is compiled, the compiler changes the label “variable1” to a fixed memory address which contains the value of the variable so calculations result in the microcontroller changing the value of the fixed memory address.)
The next post will be on the magnetometer and how we use it to control the motors of the rotator.
I had been asked to do a talk on the Arduino for a long time but never did get round to it, but I was influenced by Adrian M0NWK’s excellent talk and decided the best thing to do was to do a series of posts on a project that Ian M0RPD asked me to help him with and at the same time give people an understanding of the power of the Arduino system in microcontrollers and its benefits to our hobby of Amateur Radio.
This should be a good start to your journey into the Arduino, the project that we will be working on can be found here, but remember that I am not following the Arduino side of this project but modifying it in true Amateur Radio style.
At the moment rather than having pretty pictures to look at you will find a lot of links in this article as I prefer to use other people’s work to explain what I am doing rather than repeat it myself. (I am getting lazy in my old age)
For anyone the doesn’t understand microcontrollers they are like a computer with only one job to do, so they are programmed to undertake tasks whether it be a single task or a multi-task they are very good at what they do, like your washing machine which is controlled by a microcontroller.
The rotator project interfaces with the HRD satellite program on your computer and uses ready available modules that can be purchased cheaply on the internet and the system will run on a 12V making it ideal for portable use. Using a regulator like the LM7805 to drop the voltage down to 5V for the Arduino system is not very efficient so I am using a buck converter which has an efficiency of about 80% thus saving battery power. How the Buck Converter works
Instead of expensive stepper motors or servo motors, this system uses 2 cheap Chinese 12VDC Reversible High Torque Turbo Worm Geared Reduction Motor these have a power rating of 60mA
Interfacing the motor with the Arduino is easy and we are using a dual H Bridge module, the bridge is rated at 2A so plenty of power to drive the motors. You can find out how the H Bridge works here.
To reduce the size of the project I am using the Arduino Nano which is a smaller format of the UNO but has the same capabilities. Because we wanted this system to be remote you will need to buy 2 Arduino Nanos for this project.
The heart of this project is the GY-273 HMC5883L 3V-5V Triple Axis Compass Magnetometer Sensor Module which will give us the compass direction and inclination of the aerial which is fed back to the Arduino so we know the exact position of the aerial and is fitted to the aerial. More information on the chip.
Finally is the remote control radio module NRF24L01+ 2.4GHz Wireless RF Transceiver and you will notice that there is also a back plate which you plug the module into. The 3.3V supply on the Arduino will not drive this module sufficiently and you had to add capacitors on the module across the input voltage for the module to work properly but with the back plate, this is not needed as it has its own 3.3V regulator on the back plate. Because this module has different variants with external aerials and higher power, I will cover the transceiver in a separate post.
Don’t be put off with computer programming and having to know the C++ language as the code will be provided later. If you are thinking of doing other things with the Arduino, other people could have done something similar to what you want and willing to share their code. On the internet, there are thousands of people using the Arduino system. Make Google your friend for finding the information you seek.
To start with you need to download the Arduino IDE (Integrated Development System) to be able to program your Arduino board. (There is a number of different boards that run the Arduino System) and this link should give you a good idea of how it works.
On a final note to this part of the Arduino project, eBay is a good source of Chinese clones and they are as good as the real ones and I have not had any problem with them in the past, my Scottish genes tend to point me to the cheapest source.
You may contact me using the form below.
Tonight Jason G7KPM gave a 10 minute talk on his home brew J-Pole dual band antenna; the design was taken from the ARRL Manual. The J-Pole is an effective, low cost antenna made from bits available from Birketts and the local DIY store. This antenna will go well with the new Baofeng dual band radios recently ordered by the club and is a possible project for future candidates on the Intermediate Course.
Other topics in the ’10 minute talk’ category were Potholes – Les G1LQB and Wine and Whisky – everyone.
The first named invigilator was in trepidation mode for her first ‘on-line’ examination; would everything be as straight forward as the paper based exams? Yes. There was a slight hiccup at the beginning; she had forgotten where the PIN number was to be found and she had left her paperwork at home but Peter (2E0FGA) the second invigilator was more organised and had his copy with him so this was soon sorted and the exam began only to be followed shortly afterwards by the Model Railway people delivering equipment to their room; the wind was so strong the adjoining door kept blowing open. Luckily they were only there about five minutes.
This interruption didn’t put our candidates off; Clive M6BGR and Stephen M6TSJ successfully completed their Intermediate Course by passing the examination.
Peter and Les (G1LQB) just before the exam.
Clive and Stephen just prior to starting their exam
and Stephen and Clive after passing it. Stephen, Clive, Les and Peter.
Update 03/03/18 @ 07:45: With more snow overnight, icy conditions and more snow expected in the East Kirkby area Steve M5ZZZ and myself Adrian M0NWK will not be travelling to East Kirkby today.
Please watch this space for updates.
For Attn of LSWC members
The next meeting at Lincolnshire Aviation Heritage Centre, East Kirkby to operate special event station GB2CWP is planned for Saturday 3rd March. Meet in the NAAFI at 10:00. Other dates can be found here.
Important note: Members will need to present their East Kirkby LSWC photo ID card to gain access to the Aviation Centre. If you don’t have one you will be required to pay the entrance fee . If you are an LSWC member and would like a pass, please see here for details of how to apply for one.
With temperatures in Lincoln expected to be minus three tonight, why not put the heating on join us on our Thursday net?
Open to both LSWC members and non-members we meet on air at 20:00 every Thursday. We use Lincoln repeater GB3LM the first Thursday of each month and have simplex nets on the other Thursdays.
Need help using repeaters? Please ask a member of LSWC and they will be more than happy to help you!
For more information about the Lincoln repeaters please click here. More information coming soon.