Here is a list of our current online calculators to help you with your radio needs. Please let us know if there is a calculator you think we should add to the list.
Dipole & Vertical Antenna Length Calculator
Enter a frequency to get the length for a half-wave dipole and a quarter-wave vertical (ground plane). Uses the standard 468/234 formulas (95% velocity factor for wire antennas).
Coax Cable Loss Calculator
Estimate signal loss for a given cable type, length, and frequency. Enter your transmit power to also see how many watts actually reach your antenna.
SWR Calculator
Enter the forward and reflected power readings from your wattmeter to calculate SWR, return loss, and how much power is being reflected back.
Grid Square (Maidenhead) Locator Calculator
Convert between latitude/longitude and your 6-character grid square.
Ohm’s Law / Power Calculator
Enter any 2 values and the other 2 will be calculated automatically.
dB / dBm / Watts Converter
Convert between absolute power (dBm, mW, Watts) and relative gain or loss (dB, ratio).
Battery Runtime Calculator
Enter your battery’s capacity and the average current draw to estimate runtime.
RF Exposure (MPE) Calculator
Estimate your station’s RF power density at a given distance and compare it to the FCC’s Maximum Permissible Exposure limits (47 CFR 1.1310).
Free Space Path Loss Calculator
Estimate signal loss over distance for a line-of-sight link (VHF/UHF simplex, satellite, microwave).
Line-of-Sight / Radio Horizon Calculator
Estimate the maximum theoretical VHF/UHF range between your station and another station (like a repeater), based on antenna height.
Great Circle Distance & Bearing Calculator
Find the distance and compass heading between two locations, for aiming a directional antenna.
Multi-band EFHW / Random Wire Length Finder
Pick the bands you want to work, and this finds wire lengths that avoid landing on a half-wave multiple (the hard-to-match spots) on any of them.
Feedline Velocity Factor / Electrical Length Calculator
Find the physical length of a quarter-wave, half-wave, or full-wave section of coax for a given cable and frequency (useful for matching stubs, phasing lines, and cutting feedline to an electrical half-wave multiple).
12V Wiring Voltage Drop Calculator
Check how much voltage you’ll lose over a wire run, for sizing power leads to your radio, amplifier, or accessories.
Toroid / Ferrite Winding Calculator
Find how many turns you need for a target inductance, or see what inductance a given number of turns produces.