Howto GTK

Software links

On-line: Javascript calculators

File Comments
Simple helical antennas This calculator permits designing (or analysing) helical antennas, and produces acceptable results for versions of 3 to more than 30 turns. It suggests a matching section, and gives all mechanical data, including -1dB and -3dB bandwidth, and -3dB beamwidth.
Quadrifilar helical antenna Design your own QFH (or QHA) antenna. Many people have reported good to excellent results. Practical precision has been checked from 100 MHz to over 2 GHz! The calculator also generates a PDF drill pattern to ease construction.
Balloon utilities * Convert pressure/altitude/temperature/density according to the 'standard atmosphere'.
* Calculate descent time and speed for a parachute, given diameter, weight and height.

(c) John Coppens ON6JC/LW3HAZ mail