NA -- RF Experts

Discussion in 'Technical Corner' started by JGoodish, Jan 20, 2017.

  1. denverpilot

    denverpilot Taxi to Parking

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    LOL. No lappies here... not that I use much anyway... #savethegiblets!
     
  2. slacktide

    slacktide Pre-takeoff checklist

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    Dan
    I use a wireless mouse all day, every day. Should I be concerned about cancer in my clicking finger? It lasts for two years on a pair of AA batteries, so it cannot possibly be transmitting with much power.
     
  3. JGoodish

    JGoodish Cleared for Takeoff

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    I do understand the concept of field strength, but also attenuation. It appears that the data is inconclusive with respect to cellular phones. Certainly, I haven't seen any conclusive data one way or the other regarding the long-term effects of direct exposure, so an elevated risk must be assumed. If you can point me to credible data to the contrary, I'd be happy to review it.


    JKG
     
  4. JGoodish

    JGoodish Cleared for Takeoff

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    Don't get me wrong, I don't like the ear dongles either. You might not like the iPhone 7, but I suspect that other manufacturers are going to follow suit.

    I have BT hands free in the car, but it doesn't help me when I'm not in the car, and when I am in the car, there is sufficient background noise to make it undesirable for calls with customers.

    Fortunately, I'm not talking on the phone all that much, and don't listen to music via headphones for hours on end. Even with the iPhone 7, I still use wired headphones. Just seems like ports are disappearing and wireless everything is all the rage.


    JKG
     
  5. flyingron

    flyingron Touchdown! Greaser! PoA Supporter

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    Especially since the data collected that indicates that there might be a connection is obsolete. It was done back with the straight 850mW FM rather than the lower power spread spectrum encodings used in today's digital phones. But you are right, even back in the old days, the data was not conclusive.
     
  6. Ghery

    Ghery Final Approach

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    There was the issue with people looking down the open ends of waveguides getting cataracts. The two most sensitive parts of your anatomy to damage due to heating are the cornea of your eye and the family jewels. The cornea turns opaque for much the same reason the white of an eggs turns while when you cook it. As a result we have the limits for field strength to protect people from excessive exposure. No argument about the need, but where you draw the line on the graph is a topic for discussion.

    What I find amazing is the amount of power (and the cost of the equipment) you need in a lab to generate these fields when they are generated so simply by inexpensive devices in the field. It could be that the lab needs that field in a uniform area much larger than the low cost device generates in a localized area. BTW, those fields are orders of magnitude greater than the fields generated by a PC. The FCC limits in the US, and the CISPR limits (CISPR 22 or CISPR 32) used in the rest of the world are designed to protect radio communications services, and these are far more easily disrupted, hence the much lower limits. Any questions about these limits, let me know. I've only been dealing with them for over 30 years.

    Ghery S. Pettit
    Chair, CISPR SC I (the subcommittee that owns CISPR 22 and CISPR 32)
     
  7. gismo

    gismo Touchdown! Greaser!

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    The only possible effects from non-ionizing radiation are heating and induced electrical currents and for both of those it's the power level combined with the ability for your tissue to absorb energy at the transmitted frequency. And given the very low transmitter output level of any BT earpiece I think it's safe to say you're probably getting way more "radiation exposure" from the com radios in your airplane or even just walking around a major city with multiple cell towers every few blocks. Some things are worth worrying about but this isn't one of them. In fact I'll bet just worrying about this is more harmful to your long term heath than using a BT earpiece every day.