Dorking & District Radio Society

Practical Evening: Making Antenna Traps - 26th June

Tom Ellinor G4DFA

Through the years Tom has worked with a range of wire antennas, some with trapped sections and some without. The incorporation of antenna traps into a simple wire antenna provides the opportunity to access additional radio bands using the same antenna. This is particularly useful where there is insufficient space to install separate wire antennas and, in some cases, can result in being able to install an antenna in a space in which it might otherwise not have fitted.

Many articles have been published on trap construction, both in radio magazines and on the internet. Tom's talk will focus on one common technique which uses coaxial cable to make the resonator. The aim is to remind old hands of the use of traps and potentially introduce new ideas to the younger operators who might not have considered this approach to HF antennas.

Tom has been interested in electronics since being given a "Philips Electronics Engineer Kit" at around 15 years old. He had already been an avid radio listener for some years, listening to the 1960s offshore broadcast radio stations. He then discovered the 160m AM band and found a local ham to visit. In 1971, while still in the sixth form at school, he studied the RAE at Carshalton College and passed the written exam.

Tom was first licensed in December 1972 as G8GYX when the Class B Licence was 2m and above only and most were still using crystal based AM rigs. He subsequently took the Morse Test and became G4DFA in May 1974. Upon leaving school, he worked for a small subcontractor assembling naval and marine distress equipment to Admiralty wiring standards. After a few years he applied to the BBC's Equipment Department as a junior technician. He was successful and his first role was testing all sorts of studio and transmitter station equipment; at this time most of the kit used by the BBC was still designed and built in-house.

Having spent some time on 80m and 160m, his interested waned and for some years he was mostly inactive. When he came back to the hobby all had changed; 2m FM was popular and a wide range of Japanese kit had arrived. His interest grew in VHF / UHF again and this is still a big part of his activity today. Tom also enjoys constructing and repairing older kit.


This is a change to our published programme - Philip Gray is unfortunately unable to be with us on this occasion. We look forward to welcoming him at a future date.