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Ofcom EMF risk assessment & UK SOTA

[I couldn’t find this topic discussed elsewhere hence the new thread]

I’ve just found out - although apparently everyone else including the RSGB has known about this issue since the Spring and consulting with members - that Ofcom is proposing to introduce license changes to require all UK operators of transmitters with 10W EIRP or more to carry out a risk assessment as to the exposure risk to the public due to the EMF (Electromagnetic Fields) produced.

My immediate reaction was, … hang on … what about all the 1000’s of scientific studies into the effects of human exposure to RF [even microwave RF] at normal levels showing no ill effects? But, if Ofcom requires it, my opinion is of no consequence.

You can download a PDF of the Ofcom doc here …

Here’s a few extracts …
if the general public are not exposed to EMF from an amateur’s radio equipment in any area that is accessible to them, then the licensee would comply with the licence condition.

an amateur radio licensee does not need to comply with our licence condition in respect of their own exposure to EMF

e.g. you may cook your own brains but not your neighbour’s.

The way I interpret this is, I’ll need a risk assessment for my VHF rig/2m colinear and another for my HF rig / long wire antenna at the home QTH [either calculated or measured] - unless I can reasonably show that my nearest neighbour is too far away.

What about the postman who comes to the front door [albeit for less than a minute]?

And what about portable SOTA locations with my various antennas and several rigs not to mention summit locations some with other walkers around. So how many risk assessments is that so far?

Will common sense prevail?

73 Andy

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One word… duty cycle.

Putting my Health and Safety hat on.

The HSE always says “you need a RA if there is “significant risk”.” How do you know when you need a RA, when the assessment says you have a significant risk!
There are many cases on record from people who have been prosecuted for not having a suitable and sufficient written RA.

It does not help our case.


Andy, if that’s an oblique reference to the non-continuous nature of most amateur transmissions, Ofcom acknowledge that argument but apparently - reading between the lines of their doc - are going to ignore it so amateurs are not off the hook.

They said they will work with the RSGB to make the process as straightforward as possible.

Plug in your values (power and frequency) into the ofcom spreadsheet and see what kind of distances you’re looking at. It might not be an issue for your usual setup(s) anyway, in which case you know you’re in the clear.

And if you plug in the numbers and it comes out as a much bigger distance than you currently have, then you probably want to rectify that anyway, for your own sake if nothing else.

Or stick to less than 10W. :wink:


I’m a novice in this area but I think you can get 10W EIRP (Effective Isotropic Radiated Power) or more for less than 10W RF transmitter output if your antenna has gain, e.g. you have a directional antenna like a Yagi.

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A quick google search brought up a calculator that would figure it all out for you if you just plug in the gain etc, which I think would give you the number needed for ofcom’s calculator.

You can always play around with the numbers a bit and see how much you are “allowed” with your current mast height/ distance to antenna at the frequencies of interest to you.

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This thread is going to turn into a Chicken Licken problem so I’m clicking the mute button at the bottom of the page on this thread.

But once you’ve run the OCFOM spreadsheet and seen there is no problem and saved the data you may want to ask… who is going to come and check you have done an assessment and that you are compliant with the conditions?

I’m fearing a tap on the shoulder from the Ofcom man in the next week or so when I’m activating Great Gable - there’s no hiding place from them.


Grow up.

Andy … cool it. It was a joke!

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That’s when you employ a “dynamic risk assessment” :stuck_out_tongue_winking_eye:

You can average over 6 minutes, hence the mention of duty cycle - also the postie is OK unless he stops for a chat :wink:
Actually looking at the numbers the requirements are not that demanding for amateurs.

But how does it work for (say) a broadcast transmitter such as Wooferton - 500KW RF out with ERP’s even higher ?


Its likely that the anti-5G swivel eyed loons have brought this likely regulation about.

Having been subjected to a full OFCOM (RA as it was then) station inspection over 20 years ago, with measurements taken on my garden boundaries and on a distant neighbours driveway I’ve been there and I (almost) got a clean bill of health - the one item the RA said was missing from my station was a peak reading wattmeter (I had three standard non peak reading ones!) - so I bought one. The station inspection, with three engineers spending around 3 hours in my station and on a neighbours driveway was instigated by a neighbour living 200m away in an adjacent street, who took a dislike to my mast and yagi aerials, which had planning permission.

At my home now, the same property, this will mean assessments / measurements in effect on the 8 antennae I use at present over 12 frequency bands from 1.8 MHZ to 144 MHZ.

For portable operation such as SOTA, then we have an unknown quantity - how close will the public get to the radiation for the typical antennas we use in terms of distance, on land that we do not have ownership? As the operator of the transmitter we will be able to calculate the EIRP based on the power and the type of antenna used and the period of time which we are transmitting. It may be best for the RSGB not to mention portable and mobile operation when they negotiate further on the issue with OFCOM in my opinion as that will open up another can of worms.

I’ll wait until the dust settles on this latest announcement (not unexpected in my case - I’ve known about this for several rmonths) and then do the maths based on the tools the regulator and RSGB agree on what we need to use. I can’t say I’m worried about it affecting my hobby myself…

73 Phil

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It doesn’t matter what evidence you bring up about exposure you have a law that addresses it. You MUST conform or risk de-licencing and more.
The rules have been crafted by lawyers with some scientific advice. This means there are plenty of situations where inconsistencies apply.

It’s a bit like speed limits. You can argue all you like but you will still be in the wrong if you don’t comply with the regulations.

This was argued about for decades in the last half of the 1900’s. It’s too late now to complain.

Just fill in the form, keep a copy in your computer and in a drawer in the shack. Review annually or when you change the station.

Yes it has implications for many SOTA operators, so do the same assessment for your SOTA station and carry a paper copy along with a copy of your licence when activating.

Don’t complain, you are a generation too late. Fill out the form. And if you don’t comply do something about it.

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Can’t get out of it that easily… the new requirement will apply to any license which authorises a transmitted power in excess of 10W eirp - ie all amateur licences (10W erp is equivalent to a shade over 17W eirp if my addled brain recalls correctly)

Back when I was living in the UK, Ofcom had had to hand a significant portion of its workload back to the BBC, such was the runaway success of its privatisation. Not sure if that’s still the case, but I wouldn’t worry about Ofcom very much.

Nonsense like that is highly contagious these days, I think you’re right.
73 Matt

Doesn’t matter who was responsible it’s law over most of the World. And in the UK if you are known to be noncompliant someone might just have a word in the appropriate authorities ear.

Not complying would contravene the SOTA Rules that mention bringing SOTA into disrepute.

When activating I try to get the antenna high enough for compliance and/or watch when people approach my antenna. Some people just have to have a feel of your wire. So far I have refrained from asking them to step back 3 paces or I’ll try their gonads. A short dissipation on SOTA is usually enough.

It’s no more onerous than complying with band frequency limits.


I hope you meant FRY their Gonads and not TRY them OM…

73 Phil


I just downloaded Ofcom’s trial calculator (Excel) and looked at their example (100W EIRP @ 450MHz) and the calculated ‘separation distance’ [how far away the public need to be from the pointy end of your Yagi] is 3m.

Thank goodness for the inverse square law. I tend to sit away from others at crowded summits anyway so this new requirement shouldn’t affect our hobby with a bit of attention.

As others have said, use the calculator and keep a print-out with your license.

As for the milkman, he can chat with me all day …