RF Field Toolkit
Calculate coax loss, Fresnel clearance and RF voltage from dBm.
RF Field Toolkit
How to use the RF Field Toolkit
Choose the RF calculation, enter the requested values and review the live result.
How it works
The RF field toolkit brings together quick supporting calculations for cable loss, first-Fresnel-zone clearance and the voltage associated with a dBm power level at 50 or 75 ohms.
Example: A 25 m cable specified at 12 dB loss per 100 m is estimated to lose 3 dB. At 0 dBm into 50 ohms, the voltage is approximately 0.224 V RMS.
What to keep in mind
Cable loss varies with frequency, temperature, connectors and installation. Fresnel clearance is calculated at the path midpoint for equal path sections. Voltage results assume a resistive matched load and sine-wave RMS convention.
Frequently asked questions
Where do I find cable loss per 100 metres?
Use the manufacturer’s datasheet at the operating frequency.
Why use 60% Fresnel clearance?
It is a common planning target that reduces obstruction loss, though real link design may require more detailed analysis.
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