BATC Forum

As was reported in June Ofcom carried out a consultation on EMF and announced their intention that users of equipment running 10watts or more would need to prove compliance.

viewtopic.php?f=91&t=6693

Hopefully you all responded to the consultation (only 255 amateurs out 22,000 did)?? Unfortunately it seems not enough of us did because Ofcom have just released details of the proposed new spectrum license conditions and it is not good news.

In summary - For every re-configuration of portable or fixed station equipment / aerials you must keep records of the tests you have done to prove that you are compliant with ICNIRP guidelines.

See the Ofcom webpage for more details: https://www.ofcom.org.uk/consultations- ... ure-to-emf

Noel - G8GTZ

This may be useful to calculate if your system is compliant !

http://hintlink.com/power_density_uk.htm

doesn't look good for my QO100 setup !!!

73 John G7JTT

This may also be of use for dishes and working out height of the main beam at a given distance ?

http://www.calctool.org/CALC/math/trigonometry/height

John

I guess most are transmitting somewhere between 10kw and 100kW EIRP for DATV on QO100. That's quite a bit but in my case the actual power density falls below 10w per square metre by the time it reaches the dish reflector... I have 5w at the feed. The Spreadsheet says it's safe 15m away on top of my Apple tree. That's because it doesn't know about near and far fields , nor incidentally does it know about the age and strength of the tree.

The feed has 10dB (ish) gain. 5W into the feed reached 10w/sqm at 1m, the focal length is 1.5m. If you stood with your back against the dish you are safe. By the magic of spreadsheets the dish generates power such that the field strength under 10W/sqm is right out to 15m... or in other words, the calculations don't really work like that. You need to do a more detailed calculation.

Mike

http://www.mike-willis.com/Equations/RFequations.html

This is what Ian White GM3SEK, a very well respected amateur when it comes to technical matters, posted on the RSGB technical reflector:

Let's kill this rumour before it gets any further.

Field strength assessments do seem likely - but NOT MEASUREMENTS.

Ofcom is producing a simple assessment tool that will green-light the large majority of amateur use-cases. Their spreadsheet tool needs more work, but it's a very positive step.

If the simple Ofcom test throws up a query, that only means a more detailed assessment is needed. RSGB is working with ARRL on field strength modelling to cover a very wide range of amateur situations. Still NO MEASUREMENTS REQUIRED.

That leaves only a tiny minority of amateur situations that might require more detailed assessment still... and there's cover for those also.
73 from Ian GM3SEK

(Responding only for myself at this point,
not for any national radio society.)

It reminds me of a self-assessment medical questionnaire I once had to fill in. With me not being medically qualified I queried the validity of my response. I was told that if I'd done it, a 'box could be ticked' and that was the end of the matter. Whilst high power isn't to be trifled with and care should always be taken, just who and when/how is any of this likely to be checked up on in our amateur environment. Bit like the 4 watt CB limit, fine on paper but effectively unenforceable.
Or wearing a mask, exiting pub by 10pm etc etc.....just tick the box and carry on......
Gareth

There is an update on the RSGB website on the latest situation - https://rsgb.org/main/technical/emc/emf-exposure/

Ofcom have decided to include a specific condition in Wireless Telegraphy Act licences requiring licensees to comply with the ICNIRP general public limits on EMF exposure. This condition will apply to amateur licences and a draft of the proposed regulations has been released as part of Ofcom’s second consultation document.

Be under no illusion - THIS WILL AFFECT all UK amateurs including YOU

The RSGB says: "As we produce further guidance, please be prepared for your Club/Group to respond to Ofcom before their Nov-16 deadline"

So please be ready to reposond to Ofcom - it is shameful that only 255 UK amateurs responded last time - this will be your last chance.

Murray G6JYB said

There is now a fuller draft RSGB response online which may inspire you to reply to Ofcom, but please do not copy it - please use your own original views/words

All at: http://rsgb.org.uk/emf

If possible (it's not straight forward!) please try to submit your own response to the consultation:

You need to download the word template from here: https://www.ofcom.org.uk/__data/assets/ ... e-form.odt

DO NOT copy word for word the RSGB reponse as Ofcom discounts me-too responses.

When complete you need to email the form to EMFImplementation@ofcom.org.uk

So please make a start now as your response needs to be submitted by next Monday