At the July Committee Meeting it was suggested by our training instructor Malcolm Harman G3NZP that we should run a "show and tell" evening at which all recent Intermediate students bring along their radio related project and spend 10 minutes or so explaining reasons for choice and how it works. The committee agreed that this was a good idea and it was left that Malcolm should liaise with the members concerned.
Part of the RFC /RSBG Intermediate Exam involves a whole series of practical assessments of which the Radio Related Project is just one. Nevertheless it's the most interesting because it's down to the student to agree with the Instructor a sufficiently challenging construction task to be assessed as part of the course work.
This would accomplish two things. Most importantly it would offer an opportunity for others to get to know our new members better and personally welcome them into the club. Secondly it will provide a very interesting evening of mini-talks.
We had at least three Intermediates confirmed and two possibles, dependent on work commitments, each kindly agreeing to make a short presentation on a project they have built.
On the evening we had three new members, Ian Coulson, David Davies and Barry Denyer-Green. Two other members who had hoped to be available and to give presentations, Biton Walstra and Graham Parsons, had work commitments and sent their apologies. Hopefully they will have other opportunities in the coming weeks.
The Valient 3 - Ian, David and Barry
Ian bravely started the ball rolling with a small FM receiver/tuner kit that he had built. This covers 1.5 to 100 MHz and after a few initial problems and “a prod with a sharp stick” burst into life. Ian explained that amongst the difficulties that he experienced were that the kit was now obsolete and the amount of backup from the supplier was pretty limited. However he has spent more than half a century using a soldering iron and the practical aspect held no real fears for him.
Next up was David Davies. He described a low-ish cost alternative to the Kinetics SBS-1 radar receivers that currently retails for around £400. David works at Redhill Aerodrome and there was a need for three such receivers in order to receive the ADB-S (Automatic Dependent Surveillance Broadcast) signals from approaching light aircraft and to triangulate their bearings. He found a kit designed and marketed by a German amateur which sold for some 50 Euros and decided to give this a try. The result was a very neat and cost-effective little unit, which plugs into the USB port of his MacBook. Operating on the appropriate 1090MHz channel frequency, and running the appropriate software which includes PlanePlotter, (a program for Windows that provides a radar-like display of aircraft derived from ADS-B position reports), and with a makeshift antenna David was able to give a live demonstration of the receiver with the screen rapidly filling up with aircraft ID signals. Fascinating.
David's radar receiver
David with the read out from his radar receiver
Barry, last but by no means least, had two projects for us. Starting with his PP3 - powered solid-state regenerative receiver this was a very neat 3-band radio covering 80, 40 and 20 metres, and will have brought back happy memories to many of us who similarly cut their teeth on these simple but effective designs. Barry spends quite a lot of his working life staying in hotels and this little receiver with a length of wire strung out of a window keeps him in touch with the world.
Barry's receiver and signal generator
Barry’s second piece of home brew was an RF signal generator with switched bands and housed in a small Eddystone-type aluminium enclosure. Very useful for aligning and fault-finding on other receiver projects.
Barry with his signal generator
This is only a very brief write up of the various projects and in no way does justice to the amount of work that these brave chaps put into building and de-bugging their projects.
Thank you, Ian, David and Barry for your excellent presentations, which made for a most enjoyable evening.
John G3VLH
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