Tools you might need next
Calculate Standing Wave Ratio from forward and reflected power readings. Convert SWR to return loss and reflected power percentage.
Calculate coaxial cable RF signal loss in dB from cable type, run length, and frequency. Estimate transmit power delivered to your antenna.
Calculate half-wave dipole and quarter-wave vertical antenna element length from frequency. Includes velocity factor correction for wire type.
Convert watts to milliwatts (×1000), then take log10 and multiply by 10. 1W = 1000 mW = 30 dBm.
dBm = 10 × log10(P_mW)Reverse conversion: divide dBm by 10, raise 10 to that power, divide by 1000 for watts. 37 dBm = 5W.
P (W) = 10^((dBm − 30) / 10)dBW references 1 watt. Useful for transmitter specs. 100W = 50 dBW = 80 dBm.
dBW = 10 × log10(P_W); dBm = dBW + 30Updated: July 2026
5W = 37 dBm vs 100W = 50 dBm. Difference of 13 dB ≈ 2 S-units — significant in weak signal work but QRP contacts are routine.
Receiver rated 0.15 μV for 12 dB SINAD ≈ −123 dBm sensitivity — compare with calculated path loss for link budget.
Input 10W (40 dBm), output 100W (50 dBm) → gain = 10 dB. Verify linearity and heat dissipation at rated output.
RF power is expressed in watts (linear) or decibels relative to milliwatts/watts (logarithmic). Convert between W, mW, dBm, and dBW for link budget calculations, amplifier specifications, and receiver sensitivity comparisons.