This is the second part of my article “A Homemade AZ/EL Antenna Rotator for Ham Radio Satellite Communication“. In the previous part, I introduced the project from its hardware perspective and mechanical structure. Today, we will center on its software concept, setup for use, and its known problems. Software Flows Upon power-on, the setup() function … Read more
When doing the field radio operation, the battery is always one of the things I care about most. For a small QRP station, the power problem is usually not very difficult. The current is low, and a modest battery could last for a long time. But I do not always run QRP. Sometimes I want … Read more
Introduction I got my first ham radio license in 2000, but it was 24 years later before I made my first satellite QSO with a U7V4 cross yagi mounted on my homemade AZ/EL antenna rotator. For years, I had known how much fun satellite operation could bring to a ham radio operator, but I never … Read more
Ham Radio Tools SWR & Return Loss Calculator Convert between SWR, return loss, reflection coefficient, reflected power ratio, and mismatch loss. Add forward power when you want reflected watts and net power at the measurement point. SWR and reflected power diagram A transmitter sends forward power through a feedline to an antenna, with a smaller … Read more
Ham Radio Tools Antenna Length Calculator Estimate starting lengths for common ham radio antennas from frequency. Calculate half-wave dipoles, quarter-wave verticals, full-wave loops, end-fed half-wave wires, 5/8-wave verticals, and custom wavelength fractions in feet and meters. Wire antenna length diagram A simple ham radio antenna diagram showing a center-fed dipole, a vertical antenna, and radio … Read more
Ham Radio Tools Coax Electrical Length Calculator Calculate the physical length of coax needed for a target electrical length. Enter frequency, coax velocity factor, and phase length to find quarter-wave, half-wave, full-wave, or custom cable sections for ham radio feedlines, stubs, and phasing lines. Coax cable with wavelength marks A coax cable path with quarter-wave, … Read more
Ham Radio Tools Coax Loss Calculator Estimate how much transmit power is lost in a coaxial feedline before it reaches the antenna. Enter the operating frequency, coax type, cable length, and transmitter power to calculate line loss, antenna-end power, efficiency, and heat lost in the cable. Transmitter, coax feedline, and antenna A station diagram showing … Read more