This calculator estimates the **received signal power** (in dBm) by accounting for all gains and losses along the signal path. This is known as an RF link budget — a fundamental part of wireless system planning.

It considers:

• Transmit power (converted from watts to dBm)
• Antenna gains at both ends (dBi)
• Feedline and system losses at both ends (dB)
• Free-space path loss based on frequency and distance

The received signal is computed with: \[ P_{rx} = P_{tx} + G_{tx} + G_{rx} - L_{tx} - L_{rx} - L_{fs} \] Where:

• \( P_{tx} \) = Transmit power (dBm)
• \( G_{tx}, G_{rx} \) = Antenna gains
• \( L_{tx}, L_{rx} \) = Cable losses
• \( L_{fs} \) = Free space loss, calculated as:
  \[ L_{fs} = 20 \log_{10}(d) + 20 \log_{10}(f) + 32.44 \]

A received signal level of around -100 dBm is typical for usable weak-signal VHF, while digital systems may require -85 dBm or better. Compare your result to your receiver sensitivity or noise floor to assess performance.