![](../copia_image/vote.jpg)
![](img/img.jpg)
QHA Quadrifilar Helix Antenna
![QHA Quadrifilar Helix Antenna](images/qha-quadrifilar-helix-antenna.jpg)
La QHA nasce come antenna per rx dei satelliti polari NOAA, METEOR
post 10 Jul 2024
Helix Antennas Links →
Helix 435mhz uhf
It's actually 9.25 turns, including the quarter-turn impedance transformation to get a 50 ohm feed
Helix antenna design and construction details
Design frequency MHz, Number of turns, Turn spacing, wavelengths
Helix antenne
We decided to put it to the test and build a PVC helix for a 'too high' frequency. Then we wanted to redetermine the center frequency. 2430 MHz is approximately 67% of 3620 MHz. So that will be the design frequency that we give to HelixCalc
34
It's actually 9.25 turns, including the quarter-turn impedance transformation to get a 50 ohm feed
Design frequency MHz, Number of turns, Turn spacing, wavelengths
We decided to put it to the test and build a PVC helix for a 'too high' frequency. Then we wanted to redetermine the center frequency. 2430 MHz is approximately 67% of 3620 MHz. So that will be the design frequency that we give to HelixCalc
![Linear-loaded-short-dipole-21mhz](/../antype/ch18/images/linear-loaded-short-dipole-21mhz.jpg)
Linear loaded short dipole 21Mhz For my amateur radio activities on the HF bands I only have a 3.6 m wide balcony available for antennas. After some study I decided to experiment with a shortened dipole for the 15 m band