This is one type helical antenna where the main radiation mode are normal to the boom. The helix will be << lambda in diameter, many more turns than an axial for the same gain and spacing << lambda as well. ie: the helix will be physically smal compared to lambda. which has a narrower main beam but larger side lobes.
As usual all results: AS IS, no responsibility assumed.
Dimensions are wire centre to centre.
For a standard custom design both S and D will be used.
Here we also design an optimum antenna using the established criteria. This means that the optimum pitch will be determined (ie: S ignored)giving rise to the length L. Max-Min boundaries will be given the wire diameter d and the the ground plane sizes.
We also include the dimensions of a suitable quarter wave line to match the antenna to the typical 50 Ohm line.