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Old 4th Mar 2021, 2:08 am   #21
JohnBHanson
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Default Re: OFCOM re: International Commission on Non-Ionizing Radiation Protection (ICNIRP)

There is a lecture by the IET on the 11th May which maybe of interest

https://events.theiet.org/events/ele...trol-measures/
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Old 4th Mar 2021, 4:23 am   #22
M0AFJ, Tim
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Default Re: Ofcom re: International Commission on Non-Ionizing Radiation Protection (ICNIRP)

Quote:
Originally Posted by Panrock View Post
Quote:
Originally Posted by Radio Wrangler View Post
Very, very few people have calibrated field measuring equipment, so almost everyone is going to rely on calculated values.
Is it possible to hire this sort of thing?

Steve
Yes, EMC Hire, Shefford, Beds. Not cheap, but proper equipment,
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Old 4th Mar 2021, 6:58 am   #23
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Default Re: OFCOM re: International Commission on Non-Ionizing Radiation Protection (ICNIRP)

Post #20 last paragraph quote:

"With HF aerials you have to consider near fields as the wavelength is much longer than the safety distances will be. So a typical problem is at the ends of wire aerials where the E field is very high - and these are often near the ground e.g in inverted V (and maybe tied to the fence? That is the kind of thing that will ask for trouble)."

My aerial has both ends about 7 ft above ground in the back corners of my property. One is boundary of 2 neighbours, the other a boundary of one neighbour and a public footpath.
Although great neighbours at the moment live there, a new neighbour who is upset by this could cause me a big problem I imagine.
I wonder how long before planning departments and solicitors use the ofcom requirements against amateurs?
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Last edited by CambridgeWorks; 4th Mar 2021 at 7:00 am. Reason: Typo
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Old 4th Mar 2021, 8:12 am   #24
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Default Re: OFCOM re: International Commission on Non-Ionizing Radiation Protection (ICNIRP)

Ofcom released a new version of their checking spreadsheet without warning. The earlier version, 0.1.1, gave sensible results. The new one only works above 10MHz and as noted gives rather strange results independent of power so clearly has bugs. The EMC committee, who were not told of this change and its reasons, nor for that matter the reduction of time for implementation, are on the case.

I am hoping the onus on us amateurs is minimal but Ofcom sadly seem to have a mind of their own and very few staff who even know what V/m is.

Dave G3YMC
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Old 4th Mar 2021, 9:17 am   #25
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Default Re: OFCOM re: International Commission on Non-Ionizing Radiation Protection (ICNIRP)

My loudest TX is 5 watts and I use a dipole with ideal gain of 2.5dB. This is under 10W ERP. May be a non issue for us QRPers although I need to clarify difference between ERP and EIRP.

100% though this is not going to be enforced because anyway.
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Old 4th Mar 2021, 9:23 am   #26
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Default Re: OFCOM re: International Commission on Non-Ionizing Radiation Protection (ICNIRP)

There are 2 antenna gain references , a dipole so your dipole is 0dBd, or an isotropic radiator which is 0dBi. The dipole has gain over isotropic of 2.15dB.

Your EIRP is then 5Watts, 7dBW + 2.15dB= 9.15dBW less than 10dBW or 10W.
You scraped in!
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Old 4th Mar 2021, 9:34 am   #27
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Default Re: OFCOM re: International Commission on Non-Ionizing Radiation Protection (ICNIRP)

Gotcha that makes sense. Thanks for the clarification. Well that saves me a headache!
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Old 4th Mar 2021, 9:51 am   #28
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Default Re: OFCOM re: International Commission on Non-Ionizing Radiation Protection (ICNIRP)

QRP rules!

With my remote (isolated) location and QRP (currently) leaning even the postman or our cats can't get in the way of any NIR.

But it's not been an issue for the last 40+ years of amateur radio..... why now?

ISTR working on many an RFA vessel and seeing 'approach warning' labels for their transmitting antennas but this amounted to both a red/white sign and a painted white line some 3-5 metres from 1kW+ vertical whips.

Is there any precedent for the current 'panic' that seems to be happening?
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Old 4th Mar 2021, 9:59 am   #29
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Default Re: OFCOM re: International Commission on Non-Ionizing Radiation Protection (ICNIRP)

Remember that the above figures get modified in two ways:

Firstly, there is that averaging function. We are talking of the average over several minutes.

Secondly, for the dipole example, a human is not big enough to intercept even a moderate fraction of all the power going into say an 80m or 40m dipole. You can immediately assume that 50% of the power is going to the other end. It's really a matter of power density. But there is evidence that the material coming from OFCOM hasn't been checked by anyone experienced in the field.

I think VHF antennae which are small-ish and can have much higher gains are the category most at risk. Modes which are key-down almost full time lose out on the averaging front as well.

David (G-QRP 3252)
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Old 4th Mar 2021, 10:02 am   #30
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Default Re: OFCOM re: International Commission on Non-Ionizing Radiation Protection (ICNIRP)

Oh, Am I just a cynic, or does it seem like the thing was an attempt to write the threshold around what typical cellphones do?

David
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Old 4th Mar 2021, 10:22 am   #31
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Default Re: OFCOM re: International Commission on Non-Ionizing Radiation Protection (ICNIRP)

I think it's typically a design by committee specification. Someone says "we ought to specify a limit here because it's our job to do that kind of thing". Cue consumption of large amounts of Pret sandwiches by consultants and out pops a magic number. This is then sent out for consultation, responses ignored, backs patted and the process repeated.

I suspect this is because there has been a lot of negative 5G stuff in the press from a particular class of lunatic.
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Old 4th Mar 2021, 10:31 am   #32
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Default Re: OFCOM re: International Commission on Non-Ionizing Radiation Protection (ICNIRP)

I know this was a couple of years ago when I did my RF awareness courses for working with RF. The main effect of HF frequencies were causes by induced fields into large structures such as cranes, towers, where the physical length of a structure could approach that of half/full wave length etc, these could then lead to electric shock, burns, stimulations or what every you wish to call it if you were were in contact with the structure, the heating effects at those frequencies were I believe lesser.

The high band frequencies 120 MHz and above were closer to the physical length of a person, so local effects to high field strengths could be felt in the softer tissues, such as joints, we have, after all a large percentage of water in our bodies so do conduct RF to some point. Again electrical fields could be picked up in smaller pieces of metal work, step ladders, hand rails, etc.

Start going into the higher frequencies to get more of a heating effect into soft tissue again, eyes, brain and organs in the body.

I will have a look for my course notes if I still have them. As to why this is coming about bureaucracy and the proliferation of 3, 4 & 5G systems is the more likely case, meant for commercial organisations to force them into considering RF fields, that then has percolated down to amateur use.

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Old 4th Mar 2021, 10:50 am   #33
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Default Re: OFCOM re: International Commission on Non-Ionizing Radiation Protection (ICNIRP)

I am sure it was 5G nutters that kicked off the debate. The problem was that previously it was not so well defined as to how dangerous RF might be. More recent research started to show that it might be more dangerous than originally believed.

Quote:
But it's not been an issue for the last 40+ years of amateur radio..... why now?
You should read the license. It was always an issue - but previously it was expressed in this rather fluffy way:

In all frequency bands, high intensities of radio frequency radiation may be
harmful and safety precautions should be taken. Advice concerning safe levels
of exposure to radio frequency radiation is provided by Public Health England.


So there was always a requirement to consider health effects. All the new rules really mean is that you must show that you bothered to do this.

Another factor is the effect of things like the EMC directive. In the EU there has been a significant improvement in the requirements for RF immunity by electronic devices.
In the old days you would probably get complaints about interference before health effects were an issue. But now, (real) CE marked devices are fairly robust, and I also know that the use of digital transmission systems means that most people have difficulty identifying interference too. All this, and a revised view of the danger leads to the upcoming changes.
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Old 4th Mar 2021, 11:16 am   #34
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Default Re: OFCOM re: International Commission on Non-Ionizing Radiation Protection (ICNIRP)

REAL CE marked devices (that fully conform) are not too numerous!
It is a shame the effort like in this current OFCOM paper was not put into EMC regulation and enforced back in the day. We all suffer the results of that now when trying to listen, especially on hf. Ofcom didn't have the staff or finance back then and I imagine maybe even less today?
I doubt this new ICNIRP will be enforced by them anyway. They don't have the staff. Surely, it will be other parties who will quote it and ask for proof that you are complying. Legal and planning as two examples.
Rob
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Old 4th Mar 2021, 11:42 am   #35
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Default Re: OFCOM re: International Commission on Non-Ionizing Radiation Protection (ICNIRP)

Quote:
I doubt this new ICNIRP will be enforced by them anyway. They don't have the staff.
I think you are missing the point. The new rules make enforcement trivial.

Keep in mind that this is not about complying with the ICNIRP rules, it is about DOCUMENTING that you did. The offence is to not have the documentation.

If any amateur station gets the OFCOM spotlight on it then the very first thing they will ask to see is your ICNIRP compliance documentation. Fail to deliver on this and it is a classic "Go to jail, do not collect £200".

As to whether it is correct - well that gets hard. Probably too hard unless there are obvious gross errors.

This is much the same situation as with CE marking. Actually checking that the Declaration of Confirmity and supporting documentation is true is not only hard, but barely worth doing because test results are not entirely repeatable so even if it turns out as a failure today it doesn't prove that it wasn't OK yesterday. That would be down to a very expensive court case.
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Old 4th Mar 2021, 11:53 am   #36
G6ONEDave
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Default Re: OFCOM re: International Commission on Non-Ionizing Radiation Protection (ICNIRP)

So what about radio rally talk in, use of point to point U.H.F. dishes at ground level, any RF transmission from a vehicle with aerials on the roof or wings, radio amateur contest days and demonstration events etc., etc.?
Dave
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Old 4th Mar 2021, 11:57 am   #37
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Default Re: OFCOM re: International Commission on Non-Ionizing Radiation Protection (ICNIRP)

Agreed to some extent. Faced with a local authority planning solicitor asking for my proof I was complying is not something I would take lightly. We all know how official bodies just love documentation! I think it will be wait and see who is the first to be challenged officially. I will be keeping my head down!
Rob
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Old 4th Mar 2021, 1:00 pm   #38
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Default Re: OFCOM re: International Commission on Non-Ionizing Radiation Protection (ICNIRP)

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Originally Posted by G6ONEDave View Post
So what about...
And is this the end of mobile operation? After all, you'll be going past people quite close to you on the pavement and if you actually have to stop, at lights say, your risk of irradiating someone to death is all the greater.

Anyone else just feel like giving up?

Like earlier posters, I feel all of this has only surfaced now because of the '5G is evil' lunatics.
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Old 4th Mar 2021, 1:48 pm   #39
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Default Re: OFCOM re: International Commission on Non-Ionizing Radiation Protection (ICNIRP)

Quote:
So what about radio rally talk in, use of point to point U.H.F. dishes at ground level, any RF transmission from a vehicle with aerials on the roof or wings, radio amateur contest days and demonstration events etc., etc.?
Yes, you have to have your safety case documented for that. But you were never going to expose members of the public to dangerous RF were you? I hope not!
For vehicle use I think you will find that keeping the power down below 50W is the way to avoid difficulty. Vehicles have the advantage of moving so the duty cycle can be low when whizzing along.

It is not just amateurs!
This applies to taxis, park rangers, etc. - anyone using powerful PMR gear.

But I think the only people who will have significant problems will be those using powerful amplifiers or very high gain or exotic aerials. The rest will hopefully be able to use the soon-to-be-published RSGB tool for doing the maths and creating the safety document. Just don't wait until they come knocking at your door!
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Old 4th Mar 2021, 3:32 pm   #40
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Default Re: OFCOM re: International Commission on Non-Ionizing Radiation Protection (ICNIRP)

It’s over thirty years since I was active on the air. Over the last couple of years I have been toying with dusting off the old stuff and operating again and have got as far as hanging up an inverted L to see what’s going on at HF.

However, with an S9+ noise level, not to mention the periods of computer and SMPS, etc., interference; periods of square wave up the mains that blot out almost everything except Droitwich (fifteen miles away); planning issues and complaints from neighbours about aerials (one has already commented on my wire yet their house sports two satellite dishes in addition to traditional TV aerials); bands that have only small amounts of activity compared to my youth; and now risk to life and limb that requires health and safety assessment and more documentation; I have only one question to ask:

Why bother?
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