Directive 89/336/EEC
The Mclennan EMC facility was commissioned to enable our products to be tested ensuring compliance with the current EMC directives in a cost effective manner. With a proven service history this service has now been extended to our customers at very competitive rates to enable them to certify their equipment on the basis of full test results, or perform multiple pre-compliance tests at very competitive rates.

Fully screened test chamber using the latest mode-stir principles -
The heart of the Mclennan EMC facility is a fully screened chamber measuring 8m x 4m x 3.4m high internally. The characterised chamber performance is greatly enhanced by the use of a rotating vane system which has been pioneered in leading Research Establishments both here in the U.K. and in Naval Military Establishments in the U.S.A. The arrangement, referred to as "Mode Stir" optimises chamber performance and greatly increases the useable working area compared with earlier chamber technology.

Cost effective EMC Testing -
Current charges for the complete EMC facility is £500 per day (part day pro rata), to book space or for further information about the Mclennan EMC facility, call our sales team on +44 (0)8707 700700, Fax: +44 (0)8707 700699, Email :- , or fill in the form on the "Enquiries" page. We are located alongside the A331 10 minutes from the M3.

• Test parameters -
  
• Radiated emissions testing from 30MHz to 1GHz
• Immunity testing up to 10V/m from 30MHz to 1GHz
• Electrostatic discharge testing from 0.5Kv to 8Kv
• Conducted interference testing from 9KHz to 30MHz
• Voltage dip and transients
• Suitable for testing products up to 2m x 2m x 1m to 250Kg mass
• Fully filtered single and three phase supplies available
• Experienced diagnostic and technical support staff available

Directive 93/68/EEC
How to ensure equipment compliance -
A popular misconception with equipment manufacturers is that by specifying "CE" marked components throughout their equipment they can automatically ensure that the total system will also comply, this is not true. When it comes to EMC remember that CE + CE is not CE for the total machine and since it is not always appropriate to CE mark some components anyway, such a policy is not practical. The equipment manufacturer bears the responsibility to ensure that the products they produce comply with the EMC legislation. There are a number of ways this can be done but they are usually quite expensive. The Mclennan test facility has been developed to provide an economic way of testing equipment to ensure compliance, enabling customers to certificate their equipment using state of the art "Mode Stir" technology.
Download a CE Logo here (26Kb PDF) or here (206Kb DWG).

What is "Mode Stirring" -
"Modes" or resonant frequencies are created when the distances between two reflective surfaces is a multiple of half the wavelength of the wave between them. By having revolving reflective paddles in the test chamber the distance between surfaces is continually changing, therefore the resonant frequency is varied across the required range. This reverberation chamber technique offers several advantages over anechoic chambers of "open area" test sites.

• The ability to generate high intensity radiated fields over large volumes using modest amounts of RF power
• The elimination of polarisation and angle if incidence dependence, hence the physical rotation requirements of equipment under test
• Potential use of the test facility for both radiated susceptibility and emissions testing with minor instrumentation changes
• The significant reduction of test times with consequent cost reduction

Who is using "Mode Stirring" in the UK -
British Aerospace Filton, DERA Farnborough, DRA Fraser, Westland Aerospace and Mclennan Servo Supplies.

The above companies are among those who have already discovered the benefits of Mode Stirring and who have developed similar facilities on varying scales. A common feature in these installations is the use of Mclennan drive technology to accurately control the paddle rotation, achieved by either of the following techniques -

• Mode Stirring - Continuous rotation of the paddles, stepping the frequency for each rotation of the paddles
• Mode Tuning  - The paddles are indexed between each test run

Current test capabilities -
Emissions -
conducted and radiated emissions to BS EN5081-1
Susceptibility -
Electrostatic discharge to IEC1000-4-2 (BS EN60801-2)
Righted emissions to IEC1000-4-3 (BS EN6667-3)
Fast transients to IEC1000-4-4
Voltage dip to IEC1000-4-11

Calibrated test house measuring equipment -
In order to ensure the validity of results, the Mclennan EMC laboratory is equipped with Rhode and Schwarz measuring equipment, sited in our development lab with fibre optic links to the monitoring equipment within the test chamber. The exhaustive testing that has been carried out on our own equipment shows that emissions can occur in unexpected ways, furthermore, conducted and radiated emissions are interactive and the suppression of one can exacerbate the other or result in excursions at other differing frequencies. It may therefore not always be appropriate to use a full day's testing, but in many cases it will be more useful to book smaller time slots, so that the chamber may be re-visited once corrective action has been taken. Consequently we will be pleased to arrange for a test programme that best suits our customers needs in this respect so as to ensure optimum usage of the facility with consequent savings in cost.

Cost effective EMC Testing -
Current charges for the complete EMC facility is £500 per day (part day pro rata), to book space or for further information about the Mclennan EMC facility, call our sales team on +44 (0)8707 700700, Fax: +44 (0)8707 700699, Email :- , or fill in the form on the "Enquires" page. We are located at Ash Vale UK.  GU12 5PQ, alongside the A331, 10 minutes from the M3.