Old dig. EchostarDSB1000Ci2 ... absolutely dead?

[Llew]

nopfusch, I assume you are on a vertically polarised TP with no adjacent horizontal channel on that frequency to cause cross polarisation.

First off, twisting the LNB 180 degrees merely returns you to the original polarisation.

Here's my hypothesis which may explain why you still receive a good picture (assuming the signal is a good one, and assuming, as above, that there is no adjacent horizontal channel on that frequency. Only a theory, mind, may not explain your problem) -

Your LNB was -45 degrees ccw to start with. You rotated it +90 degrees, which would still be only 45 degrees off vertical, the same as the original position wrt 0 degrees, giving you the same signal strength.

Twisting the LNB 180 degrees ccw is the same as leaving it in your last position.

This of course only holds true if you were originally at -45 degrees (or thereabouts).

Perhaps my angular theories aren't correct, in which case someone may be able to enlighten me?

Llew

 

[nopfusch]

Before I come to my progress, let me ask a few question.

Channel Hopper, you mentioned the dielectric plate and you also called it “depolarizer” plate. Does it allow to receive with one (polarizing-) setting of the LNB, any polarized signal? I thought that devider plate is only for l.h. and r.h. rotating signals? I might be – of course – wrong.
Maybe I have to come back to your offer and send you some wine instead (I can’t send beer …).

With respect to Llew’s comment on rotating the LNB: to have the best possible adjustment I proceeded with my analog receivers always like: look for a strong signal for known polarization. Turn CW the LNB to receive a very bad signal and mark the position of the LNB. Repeat the turning of the LNB in CCW direction until one receives an equally bad signal as before. Mark the position of the LNB. In the center of the two marks is then exactly the position for the ‘other’ polarization. And 90 degrees off that, the exact position for the presently received signal.

That’s why I was – and still I’m – so puzzled. In any position of the LNB I received a vertical polarized signal. And that LNB is nothing special. Just the one you use for home purposes. I have not removed the front cover, so I don’t know if there is a divider plate in it. I think there is none.

The feedhorn on the big dish, has a divider plate. But that is a total different set-up.

Progress:

The receiver works on C-Band, any polarization because of the mech. Polarizer, “skew”; the latter also still works. Ku Band on vertical polarized signals. I have not tested the H-polarized signal yet with the smart card, as get into trouble with the rest of the family, when I remove the smart card for a day or longer. And there is no other H-polarized Ku-Band FTA channel receivable.

So I think I consider the repair as completed. If there is no H-polarized Ku Band FTA signal around – I don’t need it.

Thanks to pgh13, Channel Hopper and Llew for all of your comments and suggestions. I nearly forgot to mention ECHOSTAR: many thanks to the Service Dept., they send me the schematics and a tiny EPROM 5mm x 6mm including 8 legs, OW03 PH 0324. I can’t remember if there is such a small IC in that receiver .........
regards
nopfusch