About us

Tony Koral has worked in the area of High Frequency Electronics and particularly Radio Frequency Heating and Drying for over 40 years. Commencing his career with English Electric Valve Company (now E2V) in Chelmsford Essex, he has been involved with high powered RF design throughout that time.

Moving to Strayfield Limited in Reading, Berkshire in 1979, he was swiftly promoted to Chief Engineer and later became Technical Director and General Manager until leaving to form Koral Associates in February 2009.

Tony holds a Batchelor's Degree in Electrical and Electronic Engineering, and gained an MBA from Durham University Business School in 2003. He is also a Chartered Electrical Engineer registered with the UK Engineering Council and a Fellow of the UK Institution of Engineering Technology.

For many years, he has been well known for technical innovation in the RF Heating industry Worldwide and has written magazine articles and delivered many Technical Papers on High Frequency Heating and Drying to various conferences covering the food, textile and RF industries.

During his time in the Industry, Tony has developed an extremely wide Network of contacts in both Industry and Academia around the world. He also is a member of the British Standards committees involved in developing technical Emissions and Safety standards for the Electroheat Industry.




My good friend Ricky Metaxas of Cambridge University regularly runs a course entitled "Introduction to RF and Microwave Heating" at the University . This is an excellent opportunity to pick up both theoretical and practical knowledge about RF Heating and Drying. For details of the next course please see:




Other News:

HMI PANEL Refurbishment

For those users of Strayfield Equipment who have the now discontinued Mitsubishi MAC90 operator control panels where the screen has become worn or damaged, there is now an alternative to expensive replacement and/or reprogramming of the PLC and/or screen. We have been able to locate a company who can replace just the screen. We can also offer repair or refurbished PLCs, HMI Displays and other Mitsubishi components. Please contact us for further details.

A typical MAC90 screen replacement (before and after) can be seen below:



I have contributed to two chapters in a new, recently published book on RF heating entitled  "Radio-Frequency Heating in Food Processing: Principles and Applications" edited by George B. Awuah, Hosahalli S. Ramaswamy and Juming Tang.


ISBN-10: 143983704X
ISBN-13: 978-1439837047


For a short excerpt from the book  please see:



Triode Valves / Triode Tubes in some of the older RF equipment for Dielectric or Induction Heating are becoming obsolete as they are no longer manufactured by E2V.
This does not necessarily mean that the equipment must be written off and scrapped. It may be possible to perform a conversion to a current, modern device.


Tubes such as the BW1601F, BW1608F, BW1183J2s, BW1647J2F, BW1184J2S, 1.21.101 and 1.21.103 are no longer manufactured by E2V and are rapidly disappearing as old stocks run out.

Koral Associates has recently carried out  a number of tube conversions on equipment ranging in power from an 8kW Plastic Welder which previously used an E2V BR1589F tube to a 250kW Induction Heater which had used twin Toshiba 9T64A tubes in parallel.  Conversions are not difficult, but you need to know what you are doing. It is very important that the replacement tube should run under the correct operating conditions and with the correct cooling otherwise it can fail very quickly.

Please contact us for details - we may be able to save you £££££'s!



From time to time various good quality used machines become available. Koral Associates are often contacted about used equipment and we are able to put prospective vendors and purchasers in touch with each other. Please click the link to see what is currently available: used equipment

We are located at:

Maple Lodge
Goring Road

South Oxfordshire


Contact us today!

If you have any questions or wish to enquire further about our services, please contact us:


Telephone: +44 118 3280450 +44 118 3280450


Or use our contact form.

which you may find of interest:


Ampere Conference - Nottingham 2013 Extended Paper
AMPERE 2013 Extended Paper.pdf
Adobe Acrobat document [237.4 KB]
Article for European Baker
Article for European Baker.pdf
Adobe Acrobat document [413.7 KB]
Industrial Dielectric Heating Equipment and its effects on Broadcast Transmitters
Industrial Dielectric Heating Equipment [...]
Adobe Acrobat document [322.7 KB]
IMPI 2008 Paper: Radio Frequency Dielectric Heating re-emerges as an Effective Process in the Food Industry
Radio Frequency Dielectric Heating re-em[...]
Adobe Acrobat document [511.6 KB]
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