Syllabus 2019 tutors SDR presentation

On 17 March, a Syllabus 2019 presentation on Software Defined Radio for tutors took place at Jury’s Inn, East Midlands Airport.

Over 50 tutors, representing clubs from all over the country, attended the meeting and saw presentations by Alan Betts, G0HIQ and Mike Bruce, M0ITI on the essential learning and tutorial slides for Software Defined Radio. This was one of the initiatives promised by the Syllabus Implementation Working Group in January this year.

As the morning progressed, any concern amongst the delegates was replaced by relief with the realisation that the new material was not going to be a game changer. This is particularly at Foundation and Intermediate levels, although those who had not taught at Full licence level found the material at that level rather more challenging.

The session began with a presentation by Mike of material prepared by Alan Messenger, G0TLK for the 2017 RSGB Convention, which covered the theory of Digital Signal Processing (DSP). The presentation included animated demonstrations of the effects of sampling below the required Nyquist rates, as well as an explanation of Fast Fourier Transform and how all the elements are brought together in a complete DSP system.

After the break, Alan Betts presented a set of model slides that could be presented to students at each of the three levels. He started with Foundation level which showed the very straightforward level of information that will need to be recalled by students. For SDR at Foundation level there is no maths to be applied, only a simple recollection of the principles of digital sampling, the conceptual design of SDR at Foundation level and the advantages that Digital Signal Processing can achieve.

Alan went on to Intermediate level where the time and frequency domains were clearly explained. Although these are not new to the syllabus, their application in DSP is. This led to an explanation of sampling error and how this is filtered. There was then a more in-depth explanation of Fourier analysis and how different frequencies, and modes in the frequency domain, are represented in the time domain.

Finally, Alan went through the slides for the Full level syllabus. These dealt with some of the more in-depth issues with sampling, under-sampling and aliasing, and the small amount of maths required to understand alias frequencies. The presentation continued with a re-visit of phasor diagrams and their application in understanding each type of modulation and how these are applied in SDR architecture. Alan’s presentation concluded with a closer look at the FM modulation index and finally an introduction to switched mode power supplies.

During, and after, the presentations there was a very informed debate with useful contributions from delegates which will be used to refine the presentation slides. These will be available for download from the RSGB website by the end of March.

In concluding the presentation, Mike assured delegates that the question bank on the new syllabus topics would initially contain questions at the most intuitive level of each topic at each level. It is recognised that the tutor community will have to take on understanding of new material at a level sufficient to teach it. It may be several months after the start of the new syllabus becomes live before individuals are fully comfortable with the subject matter.

‘The purpose of training is not to set barriers to becoming a radio amateur’, said Mike, ‘it is to enable radio amateurs to enjoy the hobby legally, safely and to enable them to explore all the possibilities and opportunities that amateur radio offers’. Closing the event, Mike thanked the delegates for attending and requested that any additional observations or comments be sent to him at m0iti@rsgb.org.uk

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