# Helix TX antenna - is this good to go?

• Hello All,
Need another help again. I have made the following antenna following DC8PAT's design. Instead of copper plate I have used double side CCB.

The tuning vane/capacitor almost had to bend opposite side to get 2400Mhz tuned. Is this a problem for the signal polarization?

Thanks,
Fazlay/ S21RC

• Hello,

the polarization depends on the sense of rotation of the helix. So all ok. Looking at your pictures , you did it right and the match is good, so you should be good to go.

73, Martin

Edited once, last by dm4im ().

• Thomas, egal von welcher Richtung man aus drauf schaut, die Linksdrehung bleibt immer gleich. Wie bei einer Gewindestange, egal von welcher Richtung man drauf schaut, das Rechts oder Linksgewinde bleibt immer gleich.

Robert - DD4YR - JN57QS

• Sorry for the photo - here is the full one.
And Thanks all for confirming that it is ok. Today spent 8 hours to make a small cavity filter for 2400Mhz as my BPF is still in transit and do not know when it will arrive - BUT failed.

• I started building a helix for transmit to qo100. But I have doubts! The dish measures 0.90 meters and calculating the yield at 60% results that the gain at 2.4 GHz is 24.86 dB. Then I calculated the gain of the 8 turns = 10 dB. The total gain is therefore 24.86 + 10 = 34.86 dB ? I am also uncertain about the position of the helix, because the focus of the parabola is in only one point and the length of the coils is 229 millimeters. In which correct position should I install the helix ? That is, the focus of the dish must coincide with the connector ? Thanks for answers. Claudio IK3XKQ

## Images

• The total gain is therefore 24.86 + 10 = 34.86 dB ?

no, the gain of the dish and the helix can not be added. The gain over all is 24.8 dB.

The starting point of the windings should be in the focus of the antenna.

73 de Robert

Robert - DD4YR - JN57QS