VERY well done, thanks - now in return, would Ofcom like to require all businesses and households to trace, test and log the interference and electrical pollution from their plasma tellies, dodgy solar panel inverters, wall-warts and other RFI emitting devices?

Useful tool and thanks for this John. I will be performing these calculations, however I consider they will be both bureaucratic and "under duress", all the time that Joe Public is allowed to use 5G iPhones on full duty cycle next to their ears.

If this were to make sense, we'd need to fill this out for every band and mode we use, with/without linear, for log-winded, chat QSOs vs. DX hunting short bursts, contests over 48 hours, for every rig we own. Or, somebody somewhere could come to the decision that the whole exercise doesn't make sense whichever way you look at it. This is further proof to me that we live in a literally insane world, but of course I'll comply with it because I'm a law-abiding citizen. This is as idiotic as the signs on the back of vans saying they are limited to 70 mph: Every vehicle in the UK is limited to 70 mph!

Having read the information and done my assessment, I've now virtually shut down any activity, until I can get more thorough guidance. Living in a semi-detached townhouse in a dense estate, with a compact garden, I had discretely and carefully sited a 2m Yagi and small G5RV antenna high in the loft-space to avoid antagonising the neighbours. From what I see in the portrayal of the RSGB calculations, (which seem to assume a garden mast is used), I can only now transmit a feeble signal (at best), even though the antenna is inaccessible and seemingly appropriately distant from the general public, (inc my family). To ensure that this compliance is taken on board by Hams, and that the hobby continues to be viable, greater clarity, advice and examples need to be available. If they already are, it needs to be publicised better. Or, what have I missed that would help solve the issue?

If the nearest part of the antenna is closest to a person inside the building the antenna is mounted what then? Does this count? That`s the sort of obvious question I need answering. A lot of ops have colinears VHF beams etc mounted below the ridgeline. I must admit this whole process has made me question if can I be arsed anymore. Due to this, I have not operated or bought any new equipment done any construction for months its sucked out all the joy I had for the hobby.

Thanks John, very helpful and easy to follow. Just completed my assessmenst using this as a guide and did not take very long at all. Saved all as pdf in a folder on my desktop just in case.

Download this and ran it using Apache Open office. Easy to input your parameters It works just fine. Many thanks to all at the RSGB for their fine efforts! 73 Alan G0KMC

Hi John. Thanks for this but I have some genuine concerns. Please define the point of measurement on the antenna. Is it (a) any part of it. (b) the feed point. (c) the centre of mass. Also, if it is a ground-plane antenna does the compliance distance start at the tips of the radials or the feed point? So 3.4m (for example) from the pole or from the periphery of the radial field? Also, people are not always on the ground. Neighbours live/work in upper floors. You are advocating an exercise in creative accounting. None of us (if conscientious) wish to potentially harm ourselves (although it seems that this is deemed OK), our family or the public. However, the multifactorial and non-scientific approach being advocated is disingenuous . I am simply going to write "I rarely transmit, and if I do, it is for very few seconds". That (albeit totally unscientific) seems to tick the "compliance" box. Job done. Why have a regulation that is, by definition, unenforceable due to the transient nature of our hobby radio usage? I have a system "capable" of 1500W continuous RTTY - I won't ever do that because I like to comply with my licence conditions. I still will achieve this aspiration if I write my statement as I suggest. This is the equivalent of an exercise forcing you to state "I have a Ferrari, but I will never drive over 70 mph". Continuous commercial non-ionising radiation at high power is a totally different proposal and this is the aim of the legislation from a H&S angle.

I have a 3 storey new build in a village setting with an EFHW running from a 3rd floor bedroom window, I've recalculated all my figures using SSB and my maximum power ranges from 17w on 10m up to a huge 33w on 20m. If the house is empty I can run 100w except on 20m where I can't guarantee anyone will not be outside the house. Its about time the RSGB showed some real world situations, I can't really run more than 10w on FM into a 1.3m collinear. Time to sell up and hand my licence back

So, if I don't comply, do I just sell up now and hand my licence back??

I nearly went out portable today but according to this I would have to assess the location and aerial positions first before operating and fill in the e.m.f. calculator to see if I am compliant and then return another day. Would I have to print it out and carry it to produce it to prove to anyone who asks if I am compliant? All I can say is that my FT817 because it's only 5 Watts I guess it's compliant. G4GHB.

so I take it that when this calculator comes into force ground-mounted verticals, loop antennas, and alike will be useless as they fall outside the safety margin. especially in a small garden. I also think that Ofcom will make an example of someone out there to show a point that they can and will do something, ie a fine.

Could do with the addition of more antenna types, a fair number of amateurs use ground fed wires, as in the inverted L antennas.

What I can’t understand is why the Calculator is a mish-mash of ERP, EIRP, dBW, dB, dBi and dBd, when all that is required is for all calculations to be made using straight-forward ERP Watts, dB and dBd. If it is necessary for EIRP Watts to be known, then all that is required is for the final ERP Watts calculation to be multiplied by 1.64 to give the required EIRP Watts. Wham bam thank you ma'am (the K.I.S.S. principle).

Very useful run through thanks

Seems straight forward for antennas up a mast ! What about say an inverted L wire which starts 12” off the ground and goes up and then across ?? What are the rules where this is in your own private back yard ??

Very useful video and I just made my first assessment. Apart from compliance, it's a great education tool. 73s DE M0IUR

Handy video. Thanks

Yes it is simple to use but ground fed antennas and small plots in built up areas are a problem.

I'm afraid (in my humble opinion) this spells the death of the hobby for many urban operators especially at 400 watts full UK legal power with a directional beam antenna.

It looks like I have to pack up using any radio at my QTH, ah well I had a good run,

Thanks John for the explanation. I am pleased that I only use 50w on CW and FT8/FT4 to my DX COMMANDER CLASSIC Ground mounted vertical. I am taking this has a 1/4 wave verticals. This means I am compliant without taking any more action. If I increased my power 75w which I don't I would be in the boundary of our neighbours garden. Would be interested if you agree. Steve G4YTK. Ps I do have worries for the continuation of our great hobby.

Thanks John , very useful tool , is the antenna choices going to be updated pls , for example add Ultrabeam , End fed , slope , etc ? Thanks again. I have read all the comments and I do have worries for the continuation of our great hobby.

Is this calculator anywhere near finalised yet. What about people with small plots and ground level fed antennas. The 3.4m then becomes a distance from the base as I see it. That includes my 2 neighbours property, so I am no longer able to operate legally.

for some antenna, I have a GAP Titan DX or example, it's really difficult to use this form.

One of my biggest concerns with the 'calculator' is that is uses pre-prepared data about Rigs, Feeders & most dangerously antennas. In the wrong hands i.e. a planning dept at the local council offices, or some zealous wannabe in a government dept, it 'could' be used against us, as evidence, forcing licence holders to only use 'prescribed equipment and/or antennas'! Don't say it could never happen, because its already been tried here in the UK, when Citizens Band Radio was first legalised. All operators were only supposed to use a stipulated antenna (according to the licence back then), the guidance that came with it, on where it was supposed to be mounted was farcical and the resulting TVI etc caused howls of dissent. The legislation and advice was quietly dropped- but my point is, if they've done it before then some Muppet will try it again and WE don't need to be handing them the ammunition to do it. Once this 'genie' is out of the box, you will NEVER get it back in - RSGB you have a duty to all operators when it comes to this, not just current members. Lin M0TCF.

I am confused by a fundamental issue. If EIRP power is being used, i.e. a point radiation source, why are these separation distances referenced to the nearest part of the aerial. At least for aerials with a primary radiating element less than or equal to a 1/2 wave extent, the feed point is the notional isotropic source of radiation, and distances should be referenced from that point? Clearly near field conditions mean that interactions with the whole aerial need to be considered, but outside of the reactive near field the assumptions of an isotropic source should be used consistently. Does the Ofcom calculator underlying this calculator specify that any part of the aerial, i.e. the nearest part, must be used for *all* separation distance measurements between aerial and the public?.

Hi John, Just wondered are they going to update the antenna choices? as There is no Ultrabeam 8 Band Beam, 2 El. 6-40m

As a newly licensed operator 2e0 i want a full refund from ofcom for all the money ive spent on my radio equipment. None of this shi t was mentioned while taking my money for the the 2 exams ive sat. Now they've dreamt up some rules which makes me 'non compliant' in there view. I now give up! Wheres my money ofcom/Rsgb??

Can someone tell me if ladder line comes under the regulations. In theory it does not radiate, The doublet it feeds complies but the open wire exits a wall that public could touch it . How does this fall within the EMC regulations ?

Thanks John, an excellent informative video which will help a great many people. A couple of things "other losses", if like me you have cable joins with 259's ,connections to SWR bridge, ATU, Baluns, Antenna switches etc. Also units with associated insertion losses say at -0.2dB each would surely have to be collectively added into this box? Some antennas are not yet included into the selection so you obviously use the custom setting. Again if like me you use an inverted L antenna with four traps. Investigation reveals that each trap would have a loss of around -0.8dB. So am I right in saying the the collective losses of the antenna is -3.2dBi so that would need to be input into the box? I suppose that the directivity factor would not really be known but as a rule of thumb maybe -3dBi because of the horizontal section. The vertical section comes down to around 3ft and the horizontal about 30 ft, Reading Ofcom's documentation they indicate that if a public area is enclosed by undergrowth (therefore not making it publicly accessible) or if the area is fenced off or has a locked gate with warning signs, it is not defined as a public area. They suggest this also to stop anyone "getting burned" by touching the antenna. I am going to do this anyway to one side of the antenna 2.5m away but the other side has a 7ft high brick wall 1.5m away. obviously no public access from a H&S point of view and with some overhanging branches should keep them well away. If you have a colinear for 2m on your roof, what about neighbours next door who MIGHT be in their loft so their head height would be closer to the antenna then someone on the ground. The antenna has gain but there would be substantial losses through their roof tiles say between -10 to -20dBi would you put that into the directivity factor box. Thanks again for an excellent video. Reading some of the posts, you said that you hadn't seen a compliant ground fed antenna in a small garden, is there an email I can send one of my assessment sheets to you so you can see how mine looks , they are all compliant . 73 de Mike G3ZCC

What’s the difference between SSB and SSB Processed?

Excellent thank you.

Thank you for this walk through very helpful. I have a vertical SX80 HF antenna (silver rod type) would I select the vertical di pole for this antenna in the drop down menu ?

Very well explained and very informative, thanks John!! Simon M0SYS

I measure the average of my processed SSB signal as 20% of peak (when I whistle). Any more sounds horrible. I will use 20% in my calculations. An 'inverted L' aerial which a lot use for HF isn't on the list. 'Long wire' is but how long is a long wire? Amateurs will have to talk for less than 3 minutes at a time to keep their 'transmit %' at 50%. We don't usually know what the 'directivity factor' is, it would make a lot of difference as we don't usually aim our signals at people's heads (unlike the mobile phone transmitters). My hf aerial is compliant at 6 watts average EIRP but still shows an exclusion zone as 3.4 metres - this is ridiculous. The Ofcom calculator won't work below 10 MHz, does this mean that they never intended to require calculations below 10 MHz?

Will the final version of the spreadsheet use ICNIRP 1998 limits, or the later 2020 limits? I appreciate OFCOM refer to 1998, but surely the more up to date data is the better reference.

They are killing the hobby off they fail to regulate and want you to measure your POWER LEVELS I'm Blind I run 9w no more!!!!

When the calculator say "COMPLIANT as less than 10w EIRP" does the Ofcom Compliance Distance of 3.4m still apply or is this 3.4m for non compliant setups.

Has the RSGB requested from Ofcom a written statement or been provided with one on a) how they intend to police this licensing requirement and b) how many additional field officers will they be engaging to the cope with the extra workload ?

Not good news for the hobby, field strength in my neighbour’s loft could be high on the rare occasion I used high power VHF SSB. I did use the previous calculator, I guess I need to do it all over again for every band.....

I cannot load this silly MS spreadsheet on my computer, i don't have MS office. ! I won't / cant comply.

Buy an old ft817 and put a towel over your 7300 if you need to. Simples.

Can anyone simply tell me what SSB processed is does it refer to processed audio as if there was audio gain there would likely be higher average output sorry if it's an bit dumb but 23 years out of the subject I'm not sure what the processing means

cant find this calculator anywhere

Argh! What about handhelds, do these regulations cover them? (I expect all such operation would fail if so, so probably not -- and as has been said what about mobile phones?) How much SSB compression are we talking about and how do we measure it? What about reductions in field strength due to building materials (eg in the house below from an antenna mounted on a chimney)? This kind of tool being applied to a hobby like amateur radio is utterly inappropriate as it can never compensate for all the variety of circumtances we operate in and so cannot generally yield even vaguely accurate results. The only way we can comply in reality, rather than just meaningless box-ticking, is to actually measure and document field strengths -- and that might be kinda difficult to arrange in a neighbour's garden ot loft space! To say nothing of having to re-do every time changes are made in the course of our 'experimentation'.

i had no email from ofcom about this new rule. what program opens the calculator. Another rsgb / ofcom balls up. what about the interference armatures get.

They don't police the bands so how are they going to enforce this nonsense. most big commercial radio stations won't pass this with pumping out Kw's but then they are making big money so ofcom will turn a blind eye.

what a load of bollox

WRONG WRONG WRONG! You can't play around with modes, figures etc to get yourself compliant - you must take the maximum power of the most powerful transmitter on the site and use 100% duty cycle e.g FT8 and work out your compliance distance from that for all antennas that are in use on the site ( and re-calculate if any antennas are changed or added) . OFCOM are not going to accept all this rubbish about judging how long you are going to be talking on SSB or FM or whatever - they are not going to trust unsupervised operators to adjust their output power and mode so that they are always compliant (even if you make up a huge chart showing all the various levels to achieve compliance) I'm really disappointed that the RSGB have come up with this - you cannot try to wriggle under the fence it's an international initiative and we, as 'mere amateurs' will get hammered if we don't approach this problem in a highly professional manner - which this is not - I suggest you take this video down until you can re-script it. Additionally, for those contemplating using test equipment currently on sale, the equipment will have to have been recently calibrated and a calibration cert will have to be appended to the compliance - calibration of anything comes expensive.

Stuff this crap! I'm giving up the hobby