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Old October 12th 05, 10:14 PM
CD
 
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Default FM antenna ambient temperature

Hi all, I'm curious.

If you have an FM transmitter setup to transmit 150W and you put a
thermometer about 15ft away with the FM antenna directly pointed at it,
will the thermometer reading change?

If so, is there some sort of introduction that deals with temperature
change based on antenna radiation?


Thanks!

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Old October 12th 05, 10:30 PM
Cecil Moore
 
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CD wrote:
If you have an FM transmitter setup to transmit 150W and you put a
thermometer about 15ft away with the FM antenna directly pointed at it,
will the thermometer reading change?


If the thermometer has a 1/2WL column of mercury,
it certainly will. :-)
--
73, Cecil http://www.qsl.net/w5dxp
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Old October 13th 05, 12:20 AM
Fred W4JLE
 
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But once it heats, it will no longer be a half wave. What then?

"Cecil Moore" wrote in message
.. .
CD wrote:
If you have an FM transmitter setup to transmit 150W and you put a
thermometer about 15ft away with the FM antenna directly pointed at it,
will the thermometer reading change?


If the thermometer has a 1/2WL column of mercury,
it certainly will. :-)
--
73, Cecil http://www.qsl.net/w5dxp



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Old October 13th 05, 12:45 AM
Allodoxaphobia
 
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On Wed, 12 Oct 2005 18:20:26 -0400, Fred W4JLE wrote:
"Cecil Moore" wrote:
CD wrote:
If you have an FM transmitter setup to transmit 150W and you put a
thermometer about 15ft away with the FM antenna directly pointed at it,
will the thermometer reading change?


If the thermometer has a 1/2WL column of mercury,
it certainly will. :-)


But once it heats, it will no longer be a half wave. What then?


Thermal Modulation.
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Old October 13th 05, 02:55 AM
Amos Keag
 
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A serious reply ... YES!

From Physics, temperature rise occurs when an object absorbs energy.
Now the construction of your thermometer will determine how much of a
temperature rise.

Glass bulb Mercury is one problem; glass bulb alcohol is a different
problem; coiled spring of dissimilar metals is another problem; etc.

The temperature will rise in all of them. The question is: "How much?" I
doubt it would be observed in ordinary household thermometers.

Now, put it in a microwave oven .......

CD wrote:
Hi all, I'm curious.

If you have an FM transmitter setup to transmit 150W and you put a
thermometer about 15ft away with the FM antenna directly pointed at it,
will the thermometer reading change?

If so, is there some sort of introduction that deals with temperature
change based on antenna radiation?


Thanks!


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