19 April 2018 – Oscilloscopes, by Bryan, M0BIK

Bryan began by saying he last did a similar presentation in 2002. This time he had eleven oscilloscopes lined up on tables in front of the members; all units were seen to be working.

The first slide of the presentation asked, What does it do? (it displays voltage waveforms against time), What is it useful for? (useful for observing voltage waveforms) and Do I need one?

The majority of scopes on display were ‘vintage’ and most obtained for little money in spite of their original cost which, in some cases, was considerable.  Some were made to function properly with only a dose of switch cleaner!

Bryan went on to explain the types of scopes and what the various controls could achieve. A brief look at wave forms and measurements followed. Bryan explained that the trace can tell many things about a signal, such as, the time and voltage values, the amplitude (voltage) and frequency of a signal, determine if a malfunctioning component is distorting a signal, determine how much of a signal is DC or AC, and observe any noise on the signal.

He then came to the question, Do I need one? Although the question wasn’t answered directly, it was pointed out that the units can be found at rallies and junk sales for £25 and less, and in working condition!

Members were invited to have a look and adjust the various controls of the units on display.

Bryan (Left) making adjustments.


12 April 2018 – Clive Sinclair, by Brian, G8GHR

Brian demonstrates ZX Spectrum+2

Brian’s presentation had all the usual flourish in that many working items were on display which had been developed by the subject of this evening’s presentation.

Brian explained that Sir Clive Sinclair is best known as an English entrepreneur and inventor, most commonly known for his work in consumer electronics during the late 1970s and early 1980s.

Clive started out as a writer and editor of electronic publications, but soon had ideas about producing electronic products which were smaller and less expensive than anything on the market at that time.  Although many items were before their time, they were dogged by the quality of the components and quality control during manufacture.

Brian charted Sir Clive’s progress through the years by displaying and explaining the miniature radios, small digital calculators, electronic test equipment, very small portable TV sets and eventually computers.

The C5 electric miniature car and electric bike were among Clive’s last efforts. He’s aparently now retired and appears to have finished innovating.

ZX80, ZX81 and DM2