Today, construction, calibration helix antenna for contact up Link 2.4 GHz with the geostationary Amateur Radio satellite Es'hail 2 / QO-100 .
This link can assist:
http://homepage.tudelft.nl/v0e47/demos/codes/AHelix/helix.html
Well pleased, my Helix antenna homemade have a Forward reflection = -42 dBm
Return loss = -42 dBm
VSWR = 1.016 /1
Reflection coefficient = 0.008
Unless an error on my part, I calculate the helix like this:
Dish : diameter (mm): 730 x 800
focal distance (mm): 530
F/D Ratio: 0.64
f/D x10 = turns. Offset f/D 0.6. = 6 turns
So OK for service.. Soon ready for contacts.Preparation / setting up, up converter DX patrol 432Mhz / 2.4 GHz / PA 4 w / OCXO 10 Mhz / Circulator / bandpass filter.
Down Link 10 Ghz good reception with dish ofset 70 cm / Modified LNB PLL twin Octagon Green HQ / SDR RSP2 / Software SDR Play 3.09.
UPDATE: REDUCED AT 3 TURNS, WORKS FINE.
Boxed finished (UP converter 432 Mhz / 2.4 Ghz + Amplifier 4 w) installed near the dish.Next step, Due to the drift of the LNB despite it is with a PLL, (the frequency is not enough stable), I must build a 25 Mhz TCX0 controlled by my10 Mhz GPS.
READY....
In the emergency, I installed temporarily this protection .. Now it's safe.
