Orthomode Setup

[Chewie]

Hello Gents
I have a dual chaparral feedhorn with 2 Norsat 8515 on it, I am having issues with it, when I scan a Satellite the vertical TP'S get duplicated, and the second set of Tp's are label horizontal.
On other sat's it picks up some the horizontal TP'S but not all of them or totally none.
I am looking for some ideas how to set them up, so it can only pick up the correct TP'S verical and horizontal and no duplicates.
Please let me know.
Thanks in advance.
Chewie

 

[KE4EST]

Have you checked your skew?

 

[Bongu]

How are you set up to scan? How are they connected? On some receivers it is possible to set up a blind scan on H or V transponders only. On my receiver I have a H satellite name and a V satellite name and they are connected to different ports on my switch.

I posted this somewhere else:

I have an ortho with Norsat 8115s on my C-band dish that is feeding my 922 and the digitrans and I am adding the signal to 2 FTA receivers. The other diseqc ports are going to my motorized Ku dish on my Invacom QPH-031. From the QPH-031, the Linear outputs connect to port 3 on the switches and the Circular outputs connect to port 4 on the switches. This isnt a really complicated setup, but it is far from basic.

Ortho H
splitter-------- power pass-----------------------------dsr922 LNB power on
L________________________________________Digitrans LNB power off Antenna 1
L________________________________________Diseqc switch 1 port 1---fta receiver 1 LNB power off
L________________________________________Diseqc switch 2 port 1---fta receiver 2 LNB power off

Ortho V
splitter-------- power pass-----------------------------dsr922 LNB power on
L________________________________________Digitrans LNB power off Antenna 2
L________________________________________Diseqc switch 1 port 2---fta receiver 1 LNB power off
L________________________________________Diseqc switch 2 port 2---fta receiver 2 LNB power off

 

[Chewie]

Hello ke4est
I don't know how the skew should be setup with orthos, I look all over the web and did not find any instructions.
I have the Lnb's going to a 4/8 WNC multiswitch and connected to 2 receivers.
Thanks for your reply.
Regards
Chewie

 

[Chewie]

Hello Bongu
Thanks for your replay, I have the Lnb's going to a 4/8 WNC multiswitch the output connected to 2 receivers nothing in between, I think is a skew problem, if you have any ideas please let me know.
Thanks in advance.
Chewie

 

[cracklincrotch]

Hello ke4est
I don't know how the skew should be setup with orthos, I look all over the web and did not find any instructions.
I have the Lnb's going to a 4/8 WNC multiswitch and connected to 2 receivers.
Thanks for your reply.
Regards
Chewie

With your dish aimed due south, one LNB should appear to be standing on it's side and the other LNB lying flat. The one that appears to be on it's side is your horizontal LNB and the other is the vertical LNB.

If you need to adjust your feedhorn, lock a known signal (vertical or horizontal) and adjust it for maximum Q when turning the feed in the scalar.

 

[stogie5150]

If you need to adjust your feedhorn, lock a known signal (vertical or horizontal) and adjust it for maximum Q when turning the feed in the scalar.

THIS.

That's the way I install ALL of my feeds period, not just my orthos. if you make damned sure its dialed in on that one transponder and the polarity reads right and you get the highest Q possible, you will be good. Extra points awarded if you pick a DVB-S2 or other harder to get Transponder to tweak to.

 

[brentb636]

Hello Bongu
Thanks for your replay, I have the Lnb's going to a 4/8 WNC multiswitch the output connected to 2 receivers nothing in between, I think is a skew problem, if you have any ideas please let me know.
Thanks in advance.
Chewie

Have you modified the WNC multiswitch to provide only 18vdc to the lnb's ? If not, possibly you are starving the lnb's of power. Definitely adjust skew by post 6 & 7 .
Pendragon's mod is here. http://www.satelliteguys.us/fta-shack/174802-naughty-mods-ii-4x8-switch-all.html .

 

[Magic Static]

This may sound real stupid, but those symptoms describe what happens when you accidently switch the cables to the LNBs on an ortho. Check one more time to be absolutley sure?

 

[Pixl]

This may sound real stupid, but those symptoms describe what happens when you accidently switch the cables to the LNBs on an ortho. Check one more time to be absolutley sure?

If this was the case, V and H would be reversed, not duplicated.

My method for skew on a ortho is point the dish straight South at it's apex in the arc. Look down the throat of the feed at the driven element (pin antenna) in the far back and adjust for straight up/down, and lock in place. No need to skew anymore, it is set correctly. Connect V cable to this lnb, and H cable to the side lnb. Done.

 

[Lone Cloud]

As others have suggested, duplicate channels on scan usually indicate your skew is off. I can only tell you how I do mine.

When the dish is at true south/zenith, the line from the very bottom of the dish to the very top should be the same line that your vertical probe inside your lnb lines up with, meaning the vertical probe wire or rod will be parallel to the line from the very bottom to the very top of the dish. . On my BV scalar, I have that marked, so I line up vertical and horizontal to the marks I made.

Of course the BV scalar is a rigidly constructed deal. It doesn't twist, making my skew marks always good. If yours is more twisty, skew may go off, so I would get that scalar centered and secure, and then make your marks for skew.

 

[Chewie]

Hello Gents
I thank you all for your suggestions, I tried every one of them and I believe is setup up correctly but still have the problem, the WNG switch I am using has the modification on it.
I haven't try just a standard c-band LNB yet, I switch the receiver to my KU dish with no switches in between and I don't see the problem which let's me to believe for some reason my new Receiver and the WNG switch don't get along or maybe is not set up correctly in the receiver I will be checking my users guide.
I wonder if I should try a different switch without the mod, open for some recommendations on brand of switch.
here are some pictures of my setup.
Thanks in advance.
Chewie.

 

[Magic Static]

The ortho feed two LNBs and the switch together act as a new voltage switching LNBF would to the receiver. You should have no switch indicated in your receiver setup. So you are just setting this up for the first time? This is not trouble shooting an existing setup that was working?

 

[Magic Static]

A C only ortho is confusing. It was my impression the center LNB was horizontal and the offset one is Vertical skewed at 6 or 12 o'clock. But they will work switched around. Here is a casino's dishes nearby. they have two BUDs witrh orthos. Take your pick.
One is one way and the other opposite. I gues what ever trips your trigger LOL

 

[cracklincrotch]

THIS.

That's the way I install ALL of my feeds period, not just my orthos. if you make damned sure its dialed in on that one transponder and the polarity reads right and you get the highest Q possible, you will be good. Extra points awarded if you pick a DVB-S2 or other harder to get Transponder to tweak to.

For the record: you're supposed to use a spectrum analyzer and adjust the feed until you null out the opposite polarity as much as possible. But for many of us backyard types that just want working TV and aren't looking to squeeze every last ounce of dB out of a system, that's the method to use.

How did that old ABC detergent commercial go? "I can't see the difference. Can you see the difference?"

 

[stogie5150]

spectrum analyzer

I can't even SPELL that how am I going to USE it? LOL

 

[Chewie]

Hello All
I thank you all for your recomendations,
Magic - I had the orthos setup up already and i was trying to trouble shoot the issue with my new receiver, I tought maybe is not setup correctly, I follow everybody recomendations and was off by a hair.
I do not have a spectrum analyzer, never used one or know how to use it.
I took the orthos off and install my C2 LNB and the problem is gone.
I have a feeling it has something to do with the mod on the switch, I will take it off and see how things work out.
Thanks again to everyone.
Regards.
Chewie

 

[brentb636]

I can't even SPELL that how am I going to USE it? LOL

You can't even spell SEEGAR right, but you seem to able to use it ! LOL

 

[Bongu]

I have a feeling that what was going on with this setup was that the receiver was doing a blind scan for H and V on each of the LNBs. This is how the channels would be duplicated. My Skybox F3 only scans this way from what I have found. On an ortho setup that behaves like this I have a satellite position for the H LNB and another for the V LNB and I just delete the channels for each one that indicate they are V in polarity as they have reduced voltage. I dont have my MicroHD yet so I hope there is a better way to do this with that receiver. I will probably work on changing my switch/splitter setup before fall sets in.

 

[brentb636]

Hello Gents
I thank you all for your suggestions, I tried every one of them and I believe is setup up correctly but still have the problem, the WNG switch I am using has the modification on it.
I haven't try just a standard c-band LNB yet, I switch the receiver to my KU dish with no switches in between and I don't see the problem which let's me to believe for some reason my new Receiver and the WNG switch don't get along or maybe is not set up correctly in the receiver I will be checking my users guide.
I wonder if I should try a different switch without the mod, open for some recommendations on brand of switch.
here are some pictures of my setup.
Thanks in advance.
Chewie.

I see only one lnb ! My orthomode feed has an lnb for each polarity . I can't see how you can get two both polarities with your single lnb setup.