Many of you more experienced folks may already know this, but for the ''newbies'', you can use an online calculator at Online Calculator: http://n5xu.ece.utexas.edu/rfsafety/
This calculates the RF Power Density for your station and has an option to also calculate Ground Reflection Effects to get a ''worst case'' scenario.
To calculate RF Power Density for your station, these are 4 data inputs needed:
From your equipment manuals get:
1) Average power at antenna in watts
2) Antenna gain in dBi
3) Freq of operation in MHz
Measurement you need to take for your site:
4) Distance to area of interest in feet from center of antenna
Actually, you probably need to make a number of measurements to get item #4.
1) height to antenna center
2) distances from the antenna to your property boundaries (nearest point of contact to the uncontrolled space) and to various rooms in your home (the controlled spaces)
Use the Pythagorean theorem to calculate the distances needed. For those who forgot how to do this, use this link to another online calculator http://www.analyzemath.com/Geometry_calculators/pythagorean.html
Keep a log of your calculations and station equipment. Any changes may require you to recalculate the RF safety for your station in order to be in compliance with good and safe practices.
To learn more about RF Saftey, visit http://www.arrl.org/news/rfsafety/ as well as the the FCC?’s Office of Engineering and Technology issued Amateur Radio Supplement B to OET Bulletin 65 (http://www.fcc.gov/oet/info/documents/bulletins/#65).
Have a safe and happy station for 2008 and beyond.
Calculation for ground reflection effects (optional)
By KI6GIG
This calculates the RF Power Density for your station and has an option to also calculate Ground Reflection Effects to get a ''worst case'' scenario.
To calculate RF Power Density for your station, these are 4 data inputs needed:
From your equipment manuals get:
1) Average power at antenna in watts
2) Antenna gain in dBi
3) Freq of operation in MHz
Measurement you need to take for your site:
4) Distance to area of interest in feet from center of antenna
Actually, you probably need to make a number of measurements to get item #4.
1) height to antenna center
2) distances from the antenna to your property boundaries (nearest point of contact to the uncontrolled space) and to various rooms in your home (the controlled spaces)
Use the Pythagorean theorem to calculate the distances needed. For those who forgot how to do this, use this link to another online calculator http://www.analyzemath.com/Geometry_calculators/pythagorean.html
Keep a log of your calculations and station equipment. Any changes may require you to recalculate the RF safety for your station in order to be in compliance with good and safe practices.
To learn more about RF Saftey, visit http://www.arrl.org/news/rfsafety/ as well as the the FCC?’s Office of Engineering and Technology issued Amateur Radio Supplement B to OET Bulletin 65 (http://www.fcc.gov/oet/info/documents/bulletins/#65).
Have a safe and happy station for 2008 and beyond.
Calculation for ground reflection effects (optional)
By KI6GIG
