QO-100 Irradiator DC8PAT Ice Cone Feed
Patrik DC8PAT designed the irradiator for the satellite QO-100 can be made using 3D printing. It is currently in version 2.1, which you can purchase through https://nolle.engineering/qo100-products/ . However, he released the older version for non-commercial use for free at https://www.thingiverse.com/thing:3899461 , which allows other radio amateurs to make this irradiator themselves.
QO-100 irradiator using 3D printing
The DC8PAT design combines a satellite LNB for downlink in the band 10 GHz with a 3.5-turn helix radiator for in-band uplink 2,4 GHz satellite QO-100. All parts should be printed on PET/PETG, because it is resistant to UV radiation. This was provided by the seller https://www.jaspravim.sk/profil/kush3dp very professionally and quickly. I have used this 3D printing service of hamradio products several times to my full satisfaction.
I had to supplement reflector. Patrick on https://nolle.engineering/ice-cone-feed/ also includes technical drawings. I printed the template for the reflector on paper to scale 1:1. In the original, however, the reflector is made of thick aluminum 4 millimeter, which I did not have available. I therefore used kuprextite, which is much easier to work with.
The next part is helix spiral. It is also possible to print a template on a 3D printer, into which the wire is wound. I used it, but it is not necessary, the helix can be wound on a pipe of a suitable diameter and stretched to the required length.
The Helix irradiator has an impedance transformation adjusting members from sheet metal in the shape of a triangle with dimensions 17 x 71 millimeters. The shape and location is in the description and drawings on the mentioned page.
First, we mount the reflector and N-connector in the holder. Next comes the holder for the helix coil and the LNB. Finally, we screw the helix itself into the holder and solder the adjusting member.
Tuning and setting up the DC8PAT Ice Cone Feed irradiator
This part cannot do without measuring technology. VNAs are already relatively available among radio amateurs, which work on 2,4 GHz. The adjustment is made by changing the distance of the end of the adjustment circuit from the reflector and also by slightly shaping the helix of the helix. The location of the irradiator in the focus of the parabola and the action of the irradiator cover must also be taken into account. Indicative measurements of the irradiator on 2,4 GHz:
Unfortunately, the measurement was made without calibration, so it just shows the tuning. However, each constructor will still have to make his own measurements. The final securing is with a melt gun.
Practical results with the DC8PAT irradiator
I have the irradiator in a relatively large offset parabola with a diameter 105 centimeters. Practical tests confirm, that both reception and transmission with power 2 watty z transvertora SG-Labs it produces an excellently readable SSB signal. Patrik states, that the helical helix shadows the LNB and thus creates an attenuation of approx. 2 dB. However, with such a large offset parabola, the reception is excellent and the shadowing is unnoticeable. Many stations also use smaller dishes. You too will try to get to the QO-100 with 3D printing?
