Just Sharing This Depolariser

[Trust]

Trying some time ago to build the best C-Ku lnb combo , I noticed that a DE plate disturb the linear C and Ku signals . So I decided to make a 3 lnb changer , C-Lin - C-Circ and Ku .
For C-Circ the "bottle" depolariser with stubs was the most effective to my set-up .
However its performance change by the frequency , some signals improved by pulling the "bottle" a little bit out of the wavepipe .
Since the only at my location receiveble (120 cm dish) C-Lin signals dissapeared ( 10º E) there was no need for that lnb anymore . A Ka lnb could fill that place .
But to keep the possabillity receiving C-Lin in the future I (hopefully) develloped a way to receive both , C-cic and C-lin in one lnb by rotating the "bottle" in such position it dont interfear the Hor en Vert lin signals .
Also improvement of the Circ signals at different frequencys by turning it a little bit instead of pulling it out .
So I made a prototype but to test it I have put a set-up at a other location since more east as 46º I cannot receive by trees .
For the moment I use a small E-motor to a even small gear box , no feedback or end switches .
Finaly I intend to use a servomotor as used by RC cars and boats .
The gear ring around the wave pipe is made of a 63 mm PVC pipe adapter .
It was a hell of a job to make those 39 teeth to it .

 

[Trust]

Here in live

 

[Vipersan]

Excellent job buddy ..
I went down a similar route trying to rotate a Pride Plate ...but only manually within the waveguide.
Never followed it up simply because I couldn't find a position where the plate had no effect on fringe linear signals.
Looks like you might be on to something using the Doctors Teeth.. instead of a plate.
;)
rgds
VS

 

[Channel Hopper]

The original mechanical polariser used on the IRTE (NEC branded) dishes had something similar for Ku band. It was a long time ago though (late 80's).

 

[Trust]

The original mechanical polariser used on the IRTE (NEC branded) dishes had something similar for Ku band. It was a long time ago though (late 80's).

Intresting , never seen it , do you have a picture or type nr ?

 

[Channel Hopper]

Highly unlikely. I can remember a C120 flange at both ends, one connected to an NEC LNB, square in shape (with N connector). The depolarising stuff was a 'concertina' shaped vane that was aligned and fixed at one end nearest the LNB, with the important gubbins on a cog that could rotate through 120 degrees nearest the feed. When rotated the metal segments of the concertina would twist down the throat of the polariser, aligning the required polarity of signal to the detection equipment in the LNB.

 

[Channel Hopper]

This might have been it, but it has a WR 75 flange at the sharp end. The fact that it is linear, rather than the 90 degree version from Chaparral is promising though

 

[Channel Hopper]

Ah, maybe not

http://www.dxsatcs.com/content/mech...etic-polarizer-irte-and-their-advantages-and-