About

In radio frequency (RF) engineering and radar systems, power levels span massive ranges, making linear units like Watts cumbersome. Engineers prefer the logarithmic dBm scale (decibels relative to one milliwatt) to express signal strength, gain, and loss. However, converting high-power transmission values - such as those from microwave transmitters or broadcast towers - requires bridging the gap between Megawatts (MW) and dBm.

This tool performs the logarithmic transformation necessary to map high-energy inputs onto the dBm scale. Understanding this conversion is vital when calculating link budgets or ensuring that high-power amplifiers do not saturate sensitive receivers. Unlike linear converters, this tool accounts for the orders of magnitude shift, where a seemingly small change in MW results in a specific additive change in dBm.

Formulas

The conversion from linear power (P) to logarithmic power involves referencing the value to 1 milliwatt (0.001 W).

P_dBm = 10 × log₁₀(P_MW × 10⁹)

Alternatively, knowing that 1 MW equals 90 dBm, the formula can be simplified for mental checks:

P_dBm = 90 + 10 × log₁₀(P_MW)

Reference Data

Source Example	Power (MW)	Power (W)	Power (dBm)
Small Test Signal	1 × 10^-9	0.001	0
Mobile Phone (Max)	2 × 10^-6	2.0	33
Community Radio	0.0001	100	50
Microwave Link	0.001	1,000	60
FM Broadcast Tower	0.01	10,000	70
TV Transmitter	0.1	100,000	80
Standard Radar	1.0	1,000,000	90
Naval Radar	5.0	5,000,000	97
Pulse Magnetron	10.0	10,000,000	100
HAARP Array	3.6	3,600,000	95.56

Frequently Asked Questions

dBm stands for decibel-milliwatts. It is a unit of level used to indicate that a power ratio is expressed in decibels (dB) with reference to one milliwatt (mW).

1 MW is 1,000,000,000 milliwatts (10^9 mW). The log base 10 of 10^9 is 9. Multiplying by 10 (per the decibel definition) gives 90. Therefore, 1 MW = +90 dBm.

Yes. If the power is less than 1 milliwatt, the dBm value is negative. However, since this tool takes inputs in Megawatts, users will typically see large positive values unless they enter extremely small decimals (e.g., 0.000000000001 MW).

Signal processing often involves gains and losses that span huge ranges (e.g., a signal might lose 99.99% of its power). Using logs allows engineers to simply add or subtract dB values (e.g., +10dB gain) rather than performing complex multiplications with many zeros.