September’s Meeting

Aerials, Transmission Lines (Coax), Transmission Line Transformers and Transformers.

Thursday 21st September at the Premier Suite, Cheltenham Football Club.  7.30 for 8pm

The stimulus for this talk was my lack of understanding of how to determine the voltage at the end of an aerial, needed for the new regulations, and the operation of the 49:1 baluns so often used to feed wire aerials. The answer, it turns out, to these and other problems is to be found in determining and analysing the equivalent circuit of the aerial, transmission line, transmission line transformer and  transformer.

In the talk we will look at the early contributions to radio of Faraday, Maxwell and a little known maverick Heavyside, and see how a telegraphy operator sorted out a load by identifying the correct equivalent circuit for a transmission line. We will then look at the equivalent circuits of the afore mentioned RF components and see how wonderful computers are at doing sums to give us an insight in to the operation of these RF components. Don’t worry I will keep the maths to a minimum and give you a warning before showing any equation! While there will be a few equations in the talk, it is my intention to provide a clear practical view of how these devices work rather than produce a maths induced coma in the audience.

At the end of the talk I hope we will all be able to go away having a better understanding of how aerials, transmission lines and transformers work.

Mike G4GHL