When people talk about wireless range, they usually imagine radio waves travelling in a straight line from one antenna to another. If the two antennas can “see” each other, the link should work. If a hill, building or forest blocks the view, the link should fail. This simple line-of-sight idea…
The Balun Core Loss and Ferrite Flux Density Calculator helps amateur radio operators and antenna builders estimate ferrite core stress in baluns, ununs, impedance transformers and common-mode chokes. By entering frequency, RF power, ferrite mix, core size, turns, duty cycle, SWR and transformation ratio, the calculator provides practical estimates for…
Doppler shift is one of the most important concepts in amateur radio satellite communication. Because low Earth orbit satellites move across the sky at extremely high speed, the received frequency continuously changes during a pass. The effect is especially noticeable on UHF satellite downlinks, where the signal may drift several…
This interactive antenna resonance simulator helps you understand how antenna length, frequency, velocity factor and antenna type affect resonance and estimated SWR. Select a common amateur radio band, choose a dipole, quarter-wave vertical, end-fed half-wave or full-wave loop antenna, then adjust the physical radiator length and watch the result change…
A ham radio battery runtime calculator helps estimate how long a handheld transceiver, portable QRP setup, or mobile radio can operate before the battery needs to be recharged or replaced. This is especially useful for portable field use, emergency communications, SOTA and POTA activations, public service events, and any situation…
This EFHW antenna calculator helps estimate the starting wire length for an end-fed half-wave antenna. It is designed for amateur radio operators who want a practical starting point before cutting, installing, trimming and tuning an HF wire antenna. An end-fed half-wave antenna looks simple: one long wire, a matching transformer,…