i
Quelle/Source:

1/4 Wave Ground Plane Antenna Calculator
youtube | Andreas Spiess | #291​ External antennas and ESP32 Long-Range mode
youtube | Andreas Spiess | #368​ How to build performing antennas for LoRa, WiFi, 433MHz, Airplanes etc.(NanoVNA, MMANA-GAL)

jcoppens.com - Quadrifilar Helical Antenna
changpuak.ch - Quadrifilar Helical Antenna
-
-
dipole-calculator
-
-
-
Link to pdf file >> TheBasicsofQuadrifilarHelixAntennas.pdf