Posted by kikkie2004 on Mar 08, 2011; 11:33am
URL: https://www.es-forum.com/4G-Technology-tp2597700p2650468.html


Hi

A UK friend of mine is a electronic engineer and works (amongst other things) with shielding equipment from EMF.

I mailed him this morning re the 4G and this is his reply (I'm copy-pasting the whole email, although some of it's not relevant to 4G specifically).

My email question:

Anyhow, if something has lower frequency, such as 4G vs 3G, will that mean the wave lengths will be longer?  So will it be easier to shield with aluminium mosquito net?

His reply:

Ok yes you are correct lower frequency means longer wavelength.

 

Longer wavelengths (lower frequencies) are easier to shield in terms of a faraday cage and yes you are correct lower frequencies have more penetrating ability through non metallic material such as rocks and buildings.  Theory can explain this.

 

Something also related to radio waves getting through whatever is in their way is the power they have at their source.   I think you will be shocked that TV can be 100's of kW's (enough to power many many many houses with all the lights on as well as heaters and cookers etc.) while the mobile phone cell sites are only like 1 kW.  The big difference is that the TV masts are long way away on the tops of lovely back to nature type Hills like very easily 30 to 60km away.  As we know the strength of radio waves decreases very rapidly with distance and there are equations that determine the field strength at various distances.

 

Was at an EMC risk assessment workshop a few weeks ago and the expert in this field says that the effect of a 1kW phone mast at 1m distance is the same as that of a mobile phone next to your head.  My comment was there is no way I would feel happy 1m from such a mast (a 1kW microwave oven) with everyone agreeing with me and the expert saying lets move on.  Well in this instance there was no close proximity to the mast so I was not bothered.   This is the problem that experts in the field so no problem with EMF as long as it does not affect equipment which is designed to be very immune to such fields.  The only thing that is a problem is the heart pacemaker as I do not think they can shield the wire connections so they are susceptible and even EMC experts are willing to accept that many otherwise considered safe areas are not safe for those with pace makers.

 
--- In [hidden email], "Marc Martin" <marc@...> wrote: