How does misalignment affect polarity?

[Gaolei]

I just moved a superdish and managed to get stunning signals on 110 and 119, and so so (80) on 120. I can get odd channels on the 120, but not even. I guess these odd and even are determined by signal polarity. If I have enough signal for one polarity, why not the other. They come from the same point in space, just different polarity.

If alignment affects odd/even reception, what of the 3 basic alignment parameters has the biggest affect, azimuth, elevation or skew?

 

[SatinKzo]

What receiver are you using that picks up a sat at 120?

 

[Smith P.]

Guess it was 129W.
So it using not exactly POLARITY but CIRCULAR Polarization. Left and Right.
As to changing it, well you'll need to get into DishPro technology and understand, EVEN transponters map occupy IF = 1650-2150 MHz, so if your cable to 129W is bad (connectors, wet, RG-59, etc ) then it could be a reason; also if you use DP34 switch will be useful to disconnect all output cables for couple minutes to reset it.

 

[boba]

If he is using a super dish he is not picking up 129 and 110,119 unless he has modified the LNB mounting. Gaeloi needs to clarify his posting.

 

[Roadwarrior]

I'm sure he meant 121. It doesnt sound like it's misaligned to me. Maybe there arent any even channels. I don't even know what channels are on the 121 anymore. Or maybe the 121 lnb is screwed.

 

[Smith P.]

Unscrewed .

 

[Jim5506]

I don't know about superdish on 121, but on other sats, Odd transponders are lower frequencies than even, so it might be a cableing limitation, not passing the higher frequencies. Clean your connections or replace cable.

 

[Roadwarrior]

Thats pretty much it. You have it pointed right, so it's either the lnb, the switch or the cable. You could test the cable pretty easy by running wild lines from dish to switch and switch to receiver. if the dish is on a pole and the cable is buried, pull it up and check for splices or deformities (like extreme crimps or twists). Thats if you are actually missing channels that you should be getting.


I'm not sure if you can hook the 121/119 lnb straight to the receiver without the switch or not, but you could try that.

 

[Gaolei]

Yes it was a 121 sat. I found that if I just turn the rcvr off for a while and disconnect the feed cable, it fixes itself. I found this also happens when aligning the antenna. I could not find anything in the sky, until I shut down the rcvr (311) and turn it back on. Then I could get a signal. I had to do this for each LNA as I tuned the antenna. Very confusing!

I also found it is not easy to find a wiring diagram for the 121 version of the superdish. I found a pdf of the instructions, but it was for the 105 version. It makes a difference which LNA goes into the 3 switch positions and 105 and 121 are different wiring.

 

[Smith P.]

Actually you have a deal with Low Noise Block downconverter with Feedhorn ie LNBF devices.

Seems to me your 311 drifting to south - check Sat Input DC voltage. Should be around 18-19 VDC at LNBF under load.

 

[Roadwarrior]

Yes it was a 121 sat. I found that if I just turn the rcvr off for a while and disconnect the feed cable, it fixes itself. I found this also happens when aligning the antenna. I could not find anything in the sky, until I shut down the rcvr (311) and turn it back on. Then I could get a signal. I had to do this for each LNA as I tuned the antenna. Very confusing!

I also found it is not easy to find a wiring diagram for the 121 version of the superdish. I found a pdf of the instructions, but it was for the 105 version. It makes a difference which LNA goes into the 3 switch positions and 105 and 121 are different wiring.

Ahh, of course! Nice job on figuring that one out. I guess I just wasn't thinking it would be something as simple as an lnb reset and wiring order.
You didn't need us at all.