EME/EMR/EMF Compliant or just confused?

TopicEME/EMR/EMF Compliant or just confused?
SubtopicCalculating/Measuring EME
Equipment RequiredComputer + Internet and a tape measure
CostsNil unless relocating your Antenna’s or building enclosures
Document last reviewed and updated (reviewed each year)13th Jan 2024 (updated with new legislation details)

First of all, I am not a lawyer, nor do I have legal background, but I have spent some time going down rabbit holes reading legislation.

  • Anything stated here, should not be taken as “fact”, but as a basis for to make your own determinations and decisions.
  • This document went through a very heavy rewrite in Nov 2023, providing a little more structure with input from readers on what they wanted to know.

You have probably arrived on this page because you were searching for clarification on your requirements which are part of your Licence Conditions Determination (LCD)

We now have the new legislation which has been updated to include the new class licence conditions. Very simply, if you fit the “low risk stations” category, which is determined from the paragraphs below

F2023L0164812 – December 2023 – 31 March 2034

Now for a large majority of Amateur operators, we will fit nicely into the low risk station category, particularly as most commercial transmitters are 100W, and many of us have a fenced boundary with a gate or you can implement such arrangements.

What if I don’t comply with the “Low Risk Station” criteria

This is where the fun begins and what I originally wrote this article about.

Very simply, the moment you use anything more than 100W, you no longer fit in the “low risk station” category, unless the base of your lowest antenna is above 10m. For many Amateur Operators in Australia, without additional costly development applications ($2000 upwards), 10m is the maximum height of the entire antenna and this can be lower in some states and territories.

The EME requirements which are a formal part of the Radio Licence Conditions are “half baked” and quite simply a “dogs breakfast”.

  • ACMA’s Website offers no further clarification (unlike the ARRL site and RSGB sites which provide very clear documents that use common sense)
  • ACMA’s calculator is woefully inadequate in terms of variables and explanations and results differ widely with the U.S. & Great Britain versions. (Whilst ARPANSA is the Australian Government’s primary authority on Radation Protection, it is still based on international guidelines established by the International Commission for Non-Ionizing Radiation Protection (ICNIRP), so why do the results differ so much as I expect Britain and the U.S. will be based on similar standards??

What Started this trip down the rabbit hole?

After a recent licence upgrade, transceiver updates, as well as a few new antenna’s installed, I thought it was an appropriate time to revisit the electromagnetic energy requirements which are part of the regulations that apply to amateur radio operators.

Wow, what a mistake that was!!

The first thing you need to do is stop getting EME (Earth-Moon-Earth) and EME (Electro-Magnetic Energy) terms confused.Well, it wasn’t me that was getting the terms confused. You search on Google and it the majority of articles being returned are Earth-Moon-Earth articles (a subject that has been using the EME acronym a lot longer). You need to filter out moon and moonbounce on the end of the search terms to minimise the “noise” in your searches. Earth-Moon-Earth (EME) transmissions have been around since the late 1940’s and the term was coined as such. Why they needed to confuse things with using the same acronym, no one knows. To give you an idea, the following terms pertain to Amateur Radio

EME – Radiofrequency (RF) electromagnetic energy
EMR – Electromagnetic Radiation
EMF – Electromagnetic field

It seems that someone got over excited with the acronym dictionary. It just makes it harder doing research as EME is already an acronym in the Amateur world, so trying to get the document that you want means wading through all the Earth Moon Earth (EME) documents as well.

The Battle of the EMR / EME / EMF Calculators

ACMA – https://www.acma.gov.au/sites/default/files/2021-11/Simple%20RF%20exclusion%20distance%20calculator%20for%20antenna%20%28ARPANSA%202021%29.xlsx

WIA – https://www.wia.org.au/newsevents/news/2012/20120921-1/index.php

RSGB – https://rsgb.services/public/software/emccalculator/

ARRL – https://www.arrl.org/rf-exposure-calculator

I have located the EMR Calculator provided by ACMA, and to their credit, they refer to it as a “simple calculator” and needless to say, it is simple. Three “broad” variables to be entered, and it will supposedly spit out the minimum distance (or exclusion area from the Antenna in metres). It’s the calculator that I would assume meet or exceed these standards…

The issues I immediately came across were the following

  • IT NOW Only allows entry between 30Mhz and 300Ghz – so absolutely useless for Amateurs to understand their EMR requirements
  • No clear indication of what the power measurement relates to…is it average power?
  • It’s so simple it assumes the transmitter runs at 100 per cent power, and does not take into consideration, feedline losses, duty cycles etc
  • It is simple, and missing information, the confidence level it provides that you meet the legislative requirements of the Electromagnetic radiation requirements that pertains to the conditions under which the licence was issued, is just not there.
  • With some of the outputs from this calculator, and the minimum distance required to comply, I might as well sell all my amateur radio gear and take up shortwave listening. I am on a reasonable block (e.g. >500 square metres) but I don’t have the distances the calculator puts out.
  • If I use the RSGB or ARRL calculator, the difference is quite stark, especially as it takes into consideration many other factors and does a good job of explaining in hints. With their calculations, I can continue with Amateur Radio. I have to assume that these rules that we must comply with are international? So why do they vary so much.
  • If I just go ahead and assume, this is not something I can take into a legal argument, let alone a courtroom.
  • Now what’s worse, I want to delve further and work out what rules the ACMA calculator are based on and to provide that confidence, I find the document I need to reference is an Australian Standards document which I either a) have to pay a reasonable sum to obtain a copy or b) go to the ACMA’s office to review a copy in their office. I have never come across Legislation that has it’s workings in a commercial/technical document that I need to pay for (possibly only to look at for a couple of lines).

To show an Apples vs Apples comparison, on each of the calculators, I entered the same combination which was a 100W transmitter on 1/4 Wave vertical, with 10m x RG58 feedline. This was then entered into each of the calculators.

Here is an example of the ACMA Calculator….as I said very simple

The old ACMA Calculator – which allowed 14Mhz to be entered

The updated one – which will not work for HF Frequencies

I will admit, some of my concerns and questions have arisen after I looked at ARRL’s (U.S.) and OFCOM’s (Great Britain) calculators as they made sense, they explained the figures you were entering. The ARRL’s is a lot simpler than the RSGB, but at least both appeared to have enough information to base an answer on.

ARRL’s calculator

As you can see, at least the ability to add some important factors, and a result that varies greatly from the ACMA Calculator

RSGB’s Calculator

And finally RSGB’s calculator. As you can see, this shows a different figure again, but nothing like the figure thrown out by the ACMA Calculator. And to be fair, I may have skimmed over a few options, or it has taken into consideration more factors which have made the difference

JUST A NOTE ON RSGB Calculator : As you can see in the comments of this article (at the end), Phill Evans had raised something I missed in the Ofcom spreadsheet. Under the Annex in the Ofcom spreadsheet it does indeed make reference to not being suitable for calculations in the reactive near field (which will result in a much larger exclusion area). I do notice that the RSGB calculator provides for selecting and Antenna type. Whether this takes this into account, I don’t know, but I suspect this is used just for working out the gain over a 0 dBi Isotropic Antenna. The Ofcom spreadsheet (which contains the Annex) can be found here https://static.ofcom.org.uk/static/emf/index.html#/

VK3UM’s Calculator recommended by the WIA

As you can see, this gives the closest to the RSGB Calculator, so it at least provides some confidence, but again, would it stand up legally.

The RSGB and the ARRL give answers that appear reasonable, with the RSGB matching VK3UM’s figures closely, where as the ACMA calculator gives out an answer that is 3 times the distance.

I appreciate that each country has its own agency, however my understanding is that they are using international standards (unless Australians are more susceptible to radiation than the US or GB)

With the result from the ACMA Calculator, it gets worse as you go up in power, e.g. 400W and should it ever be granted, 1KW, it is highly likely that many will not comply, not without having large back yards allowing for. large distances between the fence and the Antenna. Especially in the modern world, having a clear 14m behind the house, and 14m from side to side is not that common if you are running 400w.

Finally, the WIA points you to a calculator created by VK3UM (SK) which is a nice calculator and from my reading, a person who really knew his stuff, but whether the calculations I take from it will stand up in a legal argument, especially as I cannot confirm what “Standards” it was based on, and even his own disclaimer states that his tool is only as accurate as the methods prescribed in the respective standards. Likewise as VK3UM is now a silent key, will the calculator be kept up to date with the standards.

The ACMA’s calculator even it admits its shortfalls, which includes not taking into account the antenna pattern, and other environmental factors and assumes that you are running at 100% power 100% of the time, with a one sided conversation. Yep, that sounds like a typical Amateur (very much tongue in cheek if you haven’t worked out that comment). It appears that they are working on absolute worst case, but that could make the difference between being able to take part in the hobby, or tossing it all in, especially if you need to downsize as you no longer have the excessive clearances that the ACMA calculator requires.

As the ACMA has made it part of the LCD to comply with these ARPANSA requirements, ACMA need to provide a real tool to make it easy for the Amateur operator to comply, especially when they don’t fit into the Criteria Level 1? Even if the ACMA approached the RSGB for their application (possibly with a small cost), make the changes for Australia, and make it available on their Website. It the RSGB and ARRL have really looked after their Amateur Operators, making it easy to comply. This becomes even more important if the ACMA changes the rules as per the next section. If I have a tool I can trust from an Australian regulator, only too happy to perform all the checks and documentation.

The move (push) to an Class licence

Personally I don’t have any concerns with moving to a class licence (and your view may differ, which is appreciated, and mine could change), but as part of this move to a class licence the ACMA has updated and clarified EME requirements for Amateurs to be consistent with other class licences. I am not saying that this is a bad idea as everyone has to play their part in the environment, safety, personal health, and the health of others, so no aversion there, however where it requires reasonable additional costs (just to obtain the standards), a large amount of time to work out whether I am compliant or not (my end of year tax returns take less time and I have much more confidence in them), and legally (as we are dealing with Legislation) I don’t know where I stand.

Whilst it is now clear that most 100w stations will be compliant as “low risk stations”, the issue remains for higher power stations, especially if the ACMA does not provide the following

  • An approved and recognised calculator or method of calculation to determine the exclusion zone for EME and one that works for <30 Mhz
  • A calculator that implements duty cycle / mode / antenna type / coax loss etc so that the figure is realistic.
  • Background text on the methodology of how it is calculated

Otherwise lets throw 30Mhz @ 400W into their calculator, it states 14m exclusion distance. Remember this is from the antenna. How many back yards have say 28m between fences, how many suburban blocks have 784 Square Metres (especially nowadays)

Otherwise the licensee must measure or calculate the RF fields produced by the transmitter in accordance with one of:

  • if AS/NZS 2772.2 applies in relation to the transmitter – AS/NZS 2772.2;
  • if C95.3 applies in relation to the transmitter – C95.3;
  • if IEC 62232 applies in relation to the transmitter – IEC 62232;
  • if IEC 62577 applies in relation to the transmitter – IEC 62577.

and the licensee (running more than 100w) must

  • Keep a record of measurements or calculations made under this subsection (see paragraph 15(1)(e)).
  • Need deep pockets to obtain the Standards quoted above (at least the ones that pertain to your transmitter).
  • If there is no decent calculator available, you are going to need to obtain or borrow the equipment to measure your RF Fields.
  • And this applies everytime you make a change to your transmitter, transmitter specifications, antenna specifications, feedline specifications

As an example, the following is a printout that came out of the RSGB Calculator, and it allows you to create reports for each of your configurations, allows you to save electronic copies and save to PDF. This meets the Level 2 requirements which are to measure or calculate RF Fields. Well worth a look to show you how it should be done, with hints on each entry, and they accept its output as having completed a review. An example of the RSGB output is as follows, downloaded and printed and done within 2-3 minutes. It shows running FT8 at 100W, but realistically, most run it at much lower power levels than that.

Clarifying Documents

One thing that ARRL and RSGB have done well to support their Amateurs is by providing (on their respective websites, documents providing further clarification), and they have done it well.

In fact in the couple of months whilst writing this article, RSGB have created a further document which is very readable

http://rsgb.org/main/files/2022/10/RSGB-EMF-Guidance-EMF-2-v2-.pdf

And the ARRL just does it well with their clear explanation

http://arrl.org/fcc-rf-exposure-regulations-the-station-evaluation

Including this little gem (which explains how their calculations come about)

http://arrl.org/files/file/Technology/RFsafetyCommittee/OET65B.pdf

Someone needs to own this, whether it is ACMA or the WIA and produce a document that makes it much clearer than what it is now. I am not stupid, I don’t have an OCD, I read technical documents all day, I regularly read business contracts, and I read local emergency legislation (and not having a good understanding will leave me in hot water). Now if I am having troubles reading, translating, and making sure I am compliant, I would say that 50% of the hams out there are in a similar boat.

Summary

These standards are being updated as a condition of holding an Amateur licence as we move to a Class Licence. Furthermore these apply to visiting operators as well. Many will not bother if they do not have a clear/quick way to confirm their compliance.

If you believe this is just “a storm in a tea cup”, just take a look at this blog https://rsgb.org/main/blog/publications/the-last-word/2021/05/19/the-last-word-emf/. I actually only found it whilst writing this summary paragraph and final review, but it clearly shows many of the same concerns with EMF conditions (and I suspect it led to the RSGB clarification document mentioned previously). Here is another forum I found recently – https://groups.google.com/g/radarc/c/ImCV4jHcT2s – Forum of confused Amateurs in the UK.

These standards have been in place for many years now, (FCC first introduced regulations in 1996) but Australia’s legislation and methdology still looks like a dog’s breakfast. It’s almost as though this “implementation” became too hard.

I enjoy the amateur radio hobby, I enjoy the privileges and want to remain compliant, but I am concerned that this is still half baked

So finally to close of this article, the recommendations are as such

What we need is:

  • Confirm what is an accepted and approved method of exclusion area calculation
  • A reasonable quality calculator that is recommended (and/or supplied) by ACMA or the WIA
    A good example is the one on the RSGB site….https://rsgb.services/public/software/emccalculator/
  • Supporting documentation on the process and what is “realistically” expected, particularly as the calculators are only as accurate as the data that goes in, and without direction, it will be a case of Garbage in, Garbage out.
    Again a good example is the following…..http://rsgb.org/main/files/2022/10/RSGB-EMF-Guidance-EMF-2-v2-.pdf
    This document even explains how to apply to mobile/handheld radios which ACMA do not address at all.

It’s not asking that much, but it will allow VK Amateur operators to meet their legislative requirements, without undue costs and stress, and could make the difference in Amateur operators embracing the process and taking a real interest in it. Amateur operators are already to a large part, self policing, provided they have the rules in black and white and there are not undue costs in meeting those rules.

Thankfully, as per the updated legislation, as I run now more than 100W and my antennas are not accessible to the public, I am compliant, but I may wish to, some day, use more than 100W, so it would be really nice to see the WIA or ACMA produce similar explaination documents and calculators.

2 thoughts on “EME/EMR/EMF Compliant or just confused?

  1. The rsgb calculator has restrictions it can not be used with antennas longer than one half wavelength
    also it can not be used to calculate field strength in the reactive near field , which may extend 30 or 40 mts from the antenna depending on antenna length and operating frequency

    so if you use a G5RVon say 10mts you fail on both counts and need to measure both electrical and magnetic fields…………good luck with that.

    if you look in the anex sheet in the exel spread sheet all the info is there

    1. Phill,

      That’s why I allow comments as everyone has an input and everyone can learn. Your comments are important as I felt the RSGB calc was quite good, but you have raised some items that I need to investigate further. I will look at the Anex sheet you mention (and might update the article to point this out)…

      Regards
      Admin

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