[bars] RF Exposure Calculator

[apizer at comcast.net]

That is 1st generation cell phone tech but we were all subjected to it.  This is your brain.  This is your brain on 800 MHz (or 900, or 1.9G. or 2.4G . . . )

 

From: bars <bars-bounces at w1hh.org> On Behalf Of Jim Idelson
Sent: Friday, August 6, 2021 8:11 PM
To: BARS Reflector <bars at w1hh.org>
Subject: Re: [bars] RF Exposure Calculator

 

How does it work out at .5 watt on 800mhz at 1 inch?

73 Jim K1IR

 

On Fri, Aug 6, 2021, 1:18 AM Bruce Anderson <w1lus at hotmail.com <mailto:w1lus at hotmail.com> > wrote:

We are all required to calculate the RF exposure to people from our transmissions.

The results should show that our antennas are located far enough from people so no one gets over exposed. 

Or inversely where to locate our antennas to prevent over exposing people to our transmissions.

The ARRL has provided a simple calculator for hams to determine this minimum safe distance.

 

http://arrl.org/rf-exposure-calculator


 <http://arrl.org/rf-exposure-calculator> RF Exposure Calculator

The FCC has adopted guidelines and procedures for evaluating environmental effects of RF emissions. The new guidelines incorporate two tiers of exposure limits based on whether exposure occurs in an occupational or "controlled" situation or whether the general population is exposed or exposure is in an "uncontrolled" situation.

arrl.org <http://arrl.org> 

 

Below in a sample calculation I did for my FT 8 transmissions on 20 Meters running 100 watts to a half wave dipole.

 

The results show two feet away for myself and family is safe and 4.5 feet away is safe for Neighbors.

Of course, since the antenna is over 15 feet high there is no issue with this antenna and power on 20 Meters. 

 

RF Exposure Calculator 

Parameters

Power at Antenna: 100 (watts)

Mode duty cycle: AFSK SSB (duty cycle=100%)  (FT 8)

Transmit duty cycle: (time transmitting)

You transmit for 1 minutes then receive for 1 minutes (and repeat).

Antenna Gain (dBi): 2.15 (1/2 wave Dipole)

Operating Frequency (MHz): 14.074

Include Effects of Ground Reflections

 

Results for a controlled environment:

Maximum Allowed Power Density (mw/cm2): 4.5437

Minimum Safe Distance (feet): 1.9897

Minimum Safe Distance (meters): 0.6065

 

For an uncontrolled environment:

Maximum Allowed Power Density (mw/cm2): 0.9087

Minimum Safe Distance (feet): 4.4490

Minimum Safe Distance (meters): 1.3561

 

Bruce

W1LUS

 

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