The Connevans 40IFSCE Audio Frequency Induction Loop field strength meter with additional 20 point calibration is a precision measurement device. It is designed to meet the requirements of BS7594.
Two different frequency response characteristics are provided: 'NORMAL' which is a restricted response, similar to that of a hearing aid, and 'FLAT' which is a wide, flat response, similar to that of an equalized induction loop receiver for wide-band communication. Both filter characteristics meet the requirements of BS7594.
The meter is calibrated in two ranges; +3dB to -24dB and -24 to -51dB with respect to the field strength of 0.56A/m recommended by BS7594, allowing background magnetic noise levels to be measured as well as AFILS signal strength. The measured audio signal may be monitored using headphones on all range and filter combinations.
This meter has a number of important features that distinguish it from other similar meters on the market:
Includes: Loop Field Strength Meter, carrying pouch, headphones, 1 x PP3 battery & instructions.
Power: 1 x PP3 9V alkaline battery (supplied)
Battery life: >10 hours
Indicating ranges: -51dB to -24dB and -24dB to +3dB with respect to 0.56A/m
Headphone monitor: max 2 x 19mW into 32 ohms
Relevant standards: BS7594, BS6083, BS6840, BS EN 60118
During the manufacture of 40IFSCE, the calibration is set and/or checked at the following points:
the transition from 0 to +3dB
the transition from 0 to -3dB
the transition from -21 to -24dB
the transition from -24dB to -27dB on the LO range
where 0dB = 0.56A/m, as required by BS7594.
The two filter responses are tested for compliance with the relevant masks of BS7594.
This full amplitude calibration for 40IFSCE is also available. The actual magnetic field strength at which each LED on the display transitions to its neighbour is measured and a table of results incorporated into a calibration certificate. This comprises a total of 22 measurement points, measured to an absolute accuracy of 0.2dB.
The instrument is calibrated against laboratory standards whose values are traceable to UK National Standards, or other standards laboratories of similar regard.
It is recommended that the instrument is re-calibrated annually or whenever it suffers physical shock e.g. by being dropped.