24 March 2022 – The Annual General Meeting

A total  of 14 members and one visitor turned out for our annual meeting. Apologies were received from Owen, G0PHY,                  Geoff, G4CEP, Ron, M0WPY, Geoff, G3XDE and Ian, G1JCC.

After the usual reports from club officers, there followed the election of officers and committee members. Those elected were:        Ken, G4YRF Chairman, David, G8UOD  Secretary, Owen, G0PHY  Treasurer, Don G4LOO  Equipment and Contest Officer,  Committee members elected were, John, G6RHL, Paul, G1GSN, Terry, G4OXD and Graham, G4JBD.

Steve Durham, M0DYR  was returned as Auditor.

A brisk discussion followed during ‘Any Other Business’.  Topics raised were suggestions for social events by Victor, G3JNB, A query about future Junk Sales by Brian, G8GHR and a question about future audio systems in the hall by John, G6RHL.

The meeting ended at 20:55.  Tea and biscuits (plus cake supplied by John, G6RHL)  were offered to all.

17 Mar 2022 – Part two, Optimising small antenna systems by Graham, G4JBD

As a follow up to last week’s presentation, Graham started with a short refresher of what to consider when planning an antenna. By using Sim Smith he demonstrated how to choose correct inputs and the results of those choices. He showed that power could be lost due to the wrong choice and correct matching provided the best power transfer from the rig to the aerial at the chosen frequency for that particular aerial. These results can be seen in real time using Sim Smith which would be rather laborious to calculate using a paper Smith Chart.

To further curtail losses, Graham suggested materials suitable for aerial wire and also inductor construction. He pointed out that lots of gain can be ‘found’ if you know where the losses are!

10 Mar 2022 – Optimising Small antenna systems by Graham, G4JBD

Graham began by stating that with small aerials you can’t have all the most desired features regardless of what the advertisements say. He defined what a ‘small antenna’ would be with regards to your available garden. i.e. any antenna too small to be resonant at the desired frequency, a dipole less than a half wavelength, a loop less than one wavelength in circumference, a vertical less than a quarter wavelength in height. However, a small aerial can be effective with careful design.  Graham spelled out what we should design for, such as being able to radiate as much RF as possible and to hear weak stations especially on Top Band.

A number of different matching networks were considered and Graham showed the pitfalls of some and the advantages of others.  At this point, he introduced the software programme Sim Smith which can introduce various circuit arrangement for best matching and display the results. Some looked like the most used methods of matching but the programme showed heavy losses in their use. The programme showed the advantage and disadvantage of some baluns and ATUs and where they were best placed.

More discussions followed the use of Sim Smith and how the active Smith Chart could actually make design much easier and faster.  At this point, we ran out of time but Graham said he was willing to come again next week to explain more about the matching conundrum.

3 Mar 2022 – TOKO Inductors by Paul G8IUG

Paul explains a high quality receiver

Paul began by handing out copies of an article showing how to repurpose Toko inductors to be read while he continued with his presentation. He then said there was a number on the reverse and that was every ones free raffle number. During other explanations about the equipment on display, he would call out a number and award the holder an item from the table. There were several meters, an early Icom TV tuner, a tin of biscuits (un opened) and two tins of Quality Street, also still sealed.

Paul stated he is a ‘valve man, twenty years out of date’.  He then compared some of his large sized test equipment on display and passed around the equivalent modern item which would fit in the palm of his hand. He recounted his work at Henlow, ICL and Stevenage stating that many of the sites have been closed or sold off and the highly qualified workers dispersed.

On his laptop, Paul showed Circuit Wizard, a programme which can be tried for free but a payment is required for the full working version. He explained the usefulness of being able to try a circuit before building it.  Pointing to a very clean looking radio from the 60’s he said the man at the market said he would have to pay a fortune to get it working. But Paul bought it anyway saying it would be worth the time he would spend checking it and replacing parts to make it work!

Paul and some of his eqipment