Brian Howie GM4DIJ talked about and demonstrated Antenna Modelling Software at the LRS meeting on 11th March 2015. Brian has always been particularly interested in VHF / UHF radio and has designed and built most of his antennas, including a number which have been used at VHF NFD with the LRS.
Brian writes: "The design and building of antennas at one time required vast testing ranges with expensive equipment. Analysing and optimising antennas once took many hours of painstaking measurements, hand calculation (if you understood the maths) and modifications with no real guarantee of success.
The advent of powerful home computers and cheap or even free software means that all this is in the past and radio amateurs can now confidently design and build their own antennas as well as the professionals do.
Modern software allows you to determine the pattern, feed point impedance and even the SWR of your antenna system before committing to cutting metal or hoisting wires, avoiding expensive or time consuming mistakes".
Brian's first self-designed antenna was a 2-element quad for 2 metres.
Brian gave live demonstrations of the capability of the MMANA modelling software with these antennas,
all of which he designed and built himself. Unfortunately it is not possible to show them here.
The 11-element 70MHz and 9-element 50MHz antennas are those used at LRS VHF NFD events.
Brian gave further demonstrations with 4NEC2 modelling software.