topic Re: RF Emissions in Communications and Wireless

RF Emissions

jim wright — Wed, 19 May 2004 22:46:34 GMT

I'm using one of those higher power PCMIA cards in a laptop, and it protrudes from the slot fairly close to the keyboard so my hand is close to it.

Is this safe? Are the RF radiations from this device safe from a long term medical effect?

I don't see much on this discussed but it seems like it could be the same as having a cell phone to your ear for exceptionally long periods.

Any comments?

Re: RF Emissions

Ernest Ford — Thu, 20 May 2004 06:57:50 GMT

Jim,

You don't tells us what sort of "higher power PCMCIA card" you're asking about, but since you're asking about RF emissions, I'm going to assume it's a wireless network card.

These cards operate at 2.4GHz for 802.11b or g and 5GHz for 802.11a at power levels upto 300mW - most operate at around 30mW, but I have found some rated at 100mW, and very few at 200mW or 300mW.

2.4GHz happens to be the resonant frequency of water, and the human body happens to be maybe 60 or 70% water - so there is actually a greater risk than that of a cell phone operating at 800MHz - although the lower power and the greater distance from the side of your head do mitigate this risk.

Bottom line - as with cell phones - there is no definitive evidence one way or the other. I would certainly not attach an antenna to that card and you could also use the card utilities to reduce the radiated power when not required.

My 100mW Cisco cards let me go all the way down to 1mW.

Re: RF Emissions

jim wright — Thu, 20 May 2004 18:35:30 GMT

Yes, it's a wireless PCMIA card. It's a SMC Elite 801.b card rated at 200mw which I got because I was having trouble getting good quality links to the access point. The card did help with that, but then I got to thinking about possible health issues since the card is so close to the hands on the laptop.