Wireless Signal Strength

dBm (decibel-milliwatts) is an abbreviation for the power ratio in decibels (dB) of the measured power referenced to one milliwatt (1 mW = 1/1,000 of a Watt). It is used in radio, microwave and fiber-optic communication networks as a convenient measure of absolute power because of its capability to express both very large and very small values in a short form. The following data is based on that published in the Cornet ED-85X Manual; the meter’s antenna is centered at 2,450 MHz and can meter RF Microwave Radiation from 700 MHz to 6,000 MHz.

Note: see Case No. 18-1051, Mozilla v FCC to learn that, as of 2017, the FCC, by choice, classified broadband information services as Title 1 (unregulated), which means that there is no preemption of local authority for any Wireless services other than for telecommunications service which is Title II (regulated) wireless and wireline phone calls.

Importantly, functionally equivalent services are defined as “personal wireless services that directly compete against one another” in the 1996-TCA Conference Report. Personal wireless services are defined as “commercial mobile services, unlicensed wireless services, and common carrier wireless exchange access services” in the 1996-TCA. Finally, mobile services is defined as “a radio communication service carried on between mobile stations or receivers and land stations, and by mobile stations communicating among themselves” in the 1996-TCA. None of these definitions include wireless or wireline broadband.

Signal Strength (dBm) Power Density (µW/m²) Compare vs. 5-Bars Land of . . .
30 dBm 580,000,000 µW/m²  

Land of

(No 1996-TCA Preemption of
Local Authority)

25 dBm 180,000,000 µW/m² 100,000,000,000x higher  
20 dBm 58,000,000 µW/m²    
15 dBm 18,000,000 µW/m² 10,000,000,000x higher  
10 dBm 5,800,000 µW/m²    
5 dBm 1,800,000 µW/m² 1,000,000,000x higher  
0 dBm 580,000 µW/m²    
-5 dBm 180,000 µW/m² 100,000,000x higher  
-10 dBm 58,000 µW/m²    
-15 dBm 18,000 µW/m² 10,000,000x higher  
-20 dBm 5,800 µW/m²    
-25 dBm 1,800 µW/m² 1,000,000x higher  
-30 dBm 580 µW/m²    
-35 dBm 180 µW/m² 100,000x higher  
-40 dBm 58 µW/m²    
-45 dBm 18 µW/m² 10,000x higher  
-50 dBm 5.8 µW/m²    
-55 dBm 1.8 µW/m² 1,000x higher  
-60 dBm 0.58 µW/m²    
-65 dBm 0.18 µW/m² 100x higher  
-70 dBm 0.058 µW/m²    
-75 dBm 0.018 µW/m² 10x higher  
-80 dBm 0.0058 µW/m²    
-85 dBm 0.0018 µW/m² 5 Bars on a cell phone

Land of

(1996-TCA Premption)

-90 dBm 0.00058 µW/m²    
-95 dBm 0.00018 µW/m² 1/10th lower  
-100 dBm 0.000058 µW/m²    
-105 dBm 0.000018 µW/m² 1/100th lower  
-110 dBm 0.0000058 µW/m²    
-115 dBm 0.0000018 µW/m² 1/1,000th lower  
-120 dBm 0.00000058 µW/m²    
-125 dBm 0.00000018 µW/m² 1/10,000th lower  

Conclusion: 0.002 µW/m² (-85 dBm) is all the RF microwave radiation that is needed for strong cellular service in a residential neighborhood. A locality can set a maximum power output limit from all frequencies/antennas from a WTF in the public rights-of-way at 0.1 Watt of Effective Radiated Power (ERP) because that provides -85 dBm signal strength at a ½-mile down the street, with five bars on a cell phone and everyone can make a call.

  • 0.002 µW/m² is 5 billion (5,000,000,000) times lower than the scientifically-unsound, FCC RF microwave radiation maximum public exposure guideline of 10,000,000 µW/m².
  • 0.002 µW/m² is still 2 billion (2,000,000,000) times higher than the PicoWatt (0.000000000001 Watt) electrical rates of power that human cell membranes use in regulating many key biological functions.

The simple math, above, clearly explains why so-called “small” Wireless Telecommunications Facilities (sWTFs) are hazardous and should not be allowed in public rights-of-way in residential zones.