Re: Radio Waves and Physics


From: Richard Powell (
Date: Sat Sep 06 1997 - 21:11:31 EDT

Sounds almost like the way we used to estimate radiation exposure from a
"point" source......
Anyone out there still close enough to the Navy Nuclear Power School to
remember that one?


At 08:50 AM 9/6/97 -0600, wrote:
>> "I just love all this Physics stuff. :-) Dweebs gather to the right
>> please."
>> Chuck- I am on your right!! I love the Physics stuff too. Fortunate
>> enough to make a living at it. Professional dweeb, but I know how a lot
>> of the world works.
>James (and Dweebs!),
>I've got a physics question that I don't even know enough about to
>formulate correctly!
>Several years ago I read, well tried to read the Feynman lectures on
>physics. One area that caught my interest and has tormented me since is
>that of sound and the changes it goes thru as frequency changes.
>The Setup:
>Sound travel thru air falls off at the inverse square of the distance.
>However at about 120K (not sure the exact freq) the behaviour of these
>'sound' waves change. They no longer depend on air as a transport, in
>fact they become RF, and follow the known decay rates of RF.
>As I remember, despite the explanations given in the lectures, this
>transformation area (some frequency) seems to be a of a mystery. It
>happens, there are formulas that show it happened, but are there any
>plain english explanations that really tell what is happing as the
>frequency of audio enters this range, and at slightly higher frequencies
>is RF rather than audio?
>I guess this is QRP related (HI) as radio waves leave our antenna we
>need to know how and where they are going!
>Thanks to all who respond. I probably won't understand but I'll collect
>and keep the answers.
>| Greg Newberry |
>| WB7DUO QRP-L #760 |
>| NorCal #1899 CQC #465 AR-QRP #65 |
Richard Powell WB6JBM TENTEN - 13044

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