EM Field Exposure

The Amateur Licence now requires all amateurs to check compliance with EMF exposure limits.  More information can be found on the Ofcom web page ofcom.org.uk/emf.

RSGB Guidance for Amateurs:

See also the reference material page

Current RSGB EMF Calculator: v2.0.5 22/12/2022

RSGB calculator is available as a  web app  to calculate your EIRP from practical station parameters, then calculate compliance distances for ICNIRP reference levels. This issue 2.0.5 has more prompts and guidance based on feedback from the trial issue 2. It removes the earlier minimum frequency restriction of 10 MHz, the minimum separation of the near field boundary and calculates using ICNIRP 1998 or ICNIRP2020 limits. It adds a recommendation that a minimum compliance distance of 2.4m be observed to prevent people touching the antenna.  This update does not change any of the compliance checks so the results from the the trial version are still valid and results saved from the trial version can be used as a compliance check(including for frequencies below 10MHz)

How to use the results from the App / Calculator:

This estimates the boundaries of the EMF Exclusion Zone (EZ), so you then need to ensure that no-one is present in the EZ zone while you are transmitting. If these EZ boundaries are close to accessible areas, we recommend you take one or more of the following actions:

  1. Increase antenna height and/or relocate the antenna, to move the EZ away from accessible areas.
  2. Reduce power to shrink the size of the EZ.
  3. Take practical steps to manage and/or monitor access to the E Z. Use the results to judge what would be most appropriate in your particular situation. Remember also that if no-one is actually present in the EZ, you are always free to transmit.

Earlier versions of the calculator which can still be used are archived on  EMF earlier documents page

Pre-assessed configurations:

Draft versions of pre-assessed configurations will be posted here as they are prepared. These can be used to check compliance of your configuration.

Ofcom have published information about compliance, assessment and record keeping:-

  • A simplified guide specifically for radio amateurs What you need to know as an amateur radio user  should help most amateurs demonstrate compliance by using the RSGB calculator or pre-assessed equipment configurations
  • An overall guide for all spectrum users: Guidance on EMF Compliance and Enforcement covers advice and relevant standards should you need to use advanced modelling and / or measurements to show compliance
  • Ofcom online calculator can be used above 1MHz it requires you to separately work out EIRP and enter it along with frequency, it then calculates using ICNIRP1998 limits.

EMF teamwork: RSGB/ARRL volunteers are using advanced computer modelling to better estimate RF exposure particularly close to antenna elements and/or close to ground. This will help assess compliance when a simple calculator is too conservative. RSGB is also working with Ofcom to measure some typical configurations initially below 10MHz to check that reference levels are not exceeded outside proposed exclusion zones

The data will be analysed to :

  • Identify pre-assessed ‘compliant by design’ configurations
  • Establish recommended exclusion zones (relative to the antenna) to avoid the reference levels for a given transmit power being exceeded
  • Provide practical guidance on mitigation measures such as ensuring no-one is present in a non-compliant location before transmitting

RSGB plans to extend the current guidance on good ‘RF housekeeping’ for managing EMC issues to include good practice for compliance with EMF exposure limits.

 

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