Friday, October 17, 2014

Alasdair Philipps on measuring and using cordless phone


The posting below, “as it is”, is meaningless.

At what distance were the measurements taken?  
(a)    Even with specialist meters, which the HF38B is not, they should be in the far field which at 1900 MHz is about 15 cm (or more properly about 30 cm / 1 foot) away and for 2450 MHz is 12.5 cm or, better, 25 cm away.  If the readings were taken closer than this to the base unit or handset using a normal meter then they are fairly meaningless as regards the actual values displayed. In the near field you have to separately and instantaneously take 3-axis readings of both the electric and magnetic field vectors and do ridiculous maths in order to estimate the overall level. That is why SAR is used (however misleading that can be!). 

I suspect that the units were measured much closer than 2 metres away!
Also, the reading value units from the HF38B meter are not in uW;  they are in uW/m^2 
Also, DECT phone base units pulse 1% duty cycle when on standby and 4% when making a call. 
Were the values quoted meant to be peak or average? – a 100-fold or 25-fold difference

Also the Gigaset phones need to be set to Eco-DECT-PLUS mode (not just Eco-DECT mode) to switch off fully between calls.

Also, we need to see the effect (at a given distance – at least 2 metres using the HF38B) of the phone base in normal mode and in ECO-DECT mode to see if the reduction is active and actually working.

Well meaning people lacking detailed technological training and understanding about how to measure EMFs and RF/microwave energy can cause a lot of dis-information. It is not like taking a ruler to a piece of wood and simply noting the length next to the edges.

Finally, ES people should not use any wireless/mobile/DECT/Eco-DECT-PLUS phone. They should only use a wired phone.
All RF/microwave phones are all FAR too active for ES people. They always will be.

Best wishes


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