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RF Exposure Question

T

tjm_pro

Hello -

Over the holiday weekend I was talking to a friend of mine, a Ham radio operator who is considering temporarily locating his club's 2 meter repeater at his residence for a couple of months while a major construction project on the roof of building where the repeater is normally located is completed. To his benefit, his house is located atop one of the highest points in the area.

He asked me I knew if the RF exposure would be harmful to his family (and now pregnant wife). The transmit antenna will be located on his tower about 15 feet above his bedroom. I think he said the repeater had a TPO of 50 watts. As I am more of an IT/Audio guy I could not give him a clear answer to his question.. Any thoughts / suggestions from the group would be appreciated.

Thanks and 73's
 
all kind of debate on rf danger levels, but i would just use good common sense and say NO to that idea, especially since his wife is pregnant and exposure to that rf sure can't be good for her..and i think her doctor would strongly agree..
 
tjm_pro said:
Hello -

Over the holiday weekend I was talking to a friend of mine, a Ham radio operator....

He asked me I knew if the RF exposure would be harmful to his family (and now pregnant wife). The transmit antenna will be located on his tower about 15 feet above his bedroom. I think he said the repeater had a TPO of 50 watts.
Click to expand...

Presumably your friend is a licensed ham.

If that's correct, he answered minimum one question on his license test, possibly several, and may even have had to calculate RF exposure.

And he's asking you, an audio guy?

I'll admit to being a licensed ham and not having the information at my fingertips but know one can find specifics on the FCC website and would certainly go look it up if thinking about that distance...particularly since repeaters generally see lots more traffic than a totally private system does. TIME of exposure is a critical element of risk....
 
tjm_pro said:
Hello -

Over the holiday weekend I was talking to a friend of mine, a Ham radio operator who is considering temporarily locating his club's 2 meter repeater at his residence for a couple of months while a major construction project on the roof of building where the repeater is normally located is completed. To his benefit, his house is located atop one of the highest points in the area.

He asked me I knew if the RF exposure would be harmful to his family (and now pregnant wife). The transmit antenna will be located on his tower about 15 feet above his bedroom. I think he said the repeater had a TPO of 50 watts. As I am more of an IT/Audio guy I could not give him a clear answer to his question.. Any thoughts / suggestions from the group would be appreciated.

Thanks and 73's
Click to expand...

Here is a piece of the chart (the complete chart is at http://www.ycars.org/presentations/RF Exposure Evaluation for Amateur Radio Operators.ppt at the bottom starting at slide 39 of the PPT).

It appears that if the gain of the antenna is >6 , it would fall into the acceptable level as far the
chart recommends, but I wouldn't do it. It's below 1 GHz, so the radiation is non-ionizing but
still, I'm kinda shocked someone would even consider it especially someone who supposedly
is an amateur operator.

(Developed by Fred Maia, W5YI Group, working in cooperation with the ARRL.)

Estimated distances in meters from transmitting antennas necessary to meet FCC power density limits for

Maximum Permissible Exposure (MPE) for either occupational/ controlled exposures (“Con”) or general

population/uncontrolled exposures (“Unc”) using typical antenna gains for the amateur service and

assuming 100% duty cycle and maximum surface reflection. Chart represents worst case scenario.

Freq Antenna

(VHF/UHF) Gain Peak Envelope Power (watts)

(MHz/Band) (dBi) 50 watts 100 watts 500 watts 1000 watts

Con. Unc. Con. Unc Con. Unc. Con. Unc.


144 (2m) 0 1.0 2.3 1.4 3.2 3.2 7.1 4.5 10.1

144 (2m) 3 1.4 3.2 2.0 4.5 4.5 10.1 6.4 14.3

144 (2m) 6 2.0 4.5 2.8 6.4 6.4 14.2 9.0 20.1

144 (2m) 9 2.8 6.4 4.0 9.0 9.0 20.1 12.7 28.4

144 (2m) 12 4.0 9.0 5.7 12.7 12.7 28.4 18.0 40.2

144 (2m) 15 5.7 12.7 8.0 18.0 18.0 40.2 25.4 56.8

144 (2m) 20 10.1 22.6 14.3 32.0 32.0 71.4 45.1 101.0
 
oldiesstation said:
......especially since his wife is pregnant and exposure to that rf sure can't be good for her..and i think her doctor would strongly agree..
Click to expand...

It could be worse.

Were it a CB antenna RF exposure would have a devastating effect:

Baby's first words would be: "Hey, Good Buddy......"
 
radiosaur said:
Ah, I've been working around RF for 30 years, No problems here.

The voices say there's absolutley no harm in it....
Click to expand...

Hearing voices is one of the signs of RF overexposure ;D
 
Lots of discussion about the possible danger of radio waves for humans. As far as I've heard and read, no illness has ever been related to radio waves. There are thousands of families living happily and healthy right next to a broadcast tower...
 
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