Polarity Issue

JFOK

SatelliteGuys Pro
Original poster
Aug 12, 2012
1,096
827
Cape Cod - MA.
Hi all,

I spent the better part of yesterday skewing my lnbf trying to get the best possible signal, after repairing one of my dish arms that rusted away at the end.
I patched the very end of the arm, making sure the arm was the same length as the other 2. I had removed the lnbf to prevent any possible damage prior to my restoration work.
I then skewed it as I’ve always done, making sure the dish was at peak and the lnbf was at zero.
This time though, fine tuning it with my Sathero 300hd meter I was only able to get vertical polarity, which came in strong. No steady horizontal no matter how I tried adjusting the lnbf. The horizontal signal was dancing all over the place with no lock. I tried several other satellites and again no horizontal. Vertical signals were attained on all other satellites.
My question…is my lnbf going bad ?
I bought it from Titanium when he first introduced the 5g lnbf several years ago.
Thanks in advance for any responses.

John
 
Hi all,

I spent the better part of yesterday skewing my lnbf trying to get the best possible signal, after repairing one of my dish arms that rusted away at the end.
I patched the very end of the arm, making sure the arm was the same length as the other 2. I had removed the lnbf to prevent any possible damage prior to my restoration work.
I then skewed it as I’ve always done, making sure the dish was at peak and the lnbf was at zero.
This time though, fine tuning it with my Sathero 300hd meter I was only able to get vertical polarity, which came in strong. No steady horizontal no matter how I tried adjusting the lnbf. The horizontal signal was dancing all over the place with no lock. I tried several other satellites and again no horizontal. Vertical signals were attained on all other satellites.
My question…is my lnbf going bad ?
I bought it from Titanium when he first introduced the 5g lnbf several years ago.
Thanks in advance for any responses.

John
Maybe your Sathero meter isn't putting out the +18~ volts needed to select Horizontal? Check that with a meter, or check the settings to make sure it's not somehow FIXED to only +13 volts for Vertical.

Did you look in the end of the LNBF to make sure a wasp didn't build a nest in there?

Also, sats adjacent to each other tend to alternate Vertical to Horizontal. So, IF you could only get Vertical and not Horizontal on one sat, shouldn't that mean that you'd get only Horizontal on the next sat and not Vertical?
 
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Maybe your Sathero meter isn't putting out the +18~ volts needed to select Horizontal? Check that with a meter, or check the settings to make sure it's not somehow FIXED to only +13 volts for Vertical.

Did you look in the end of the LNBF to make sure a wasp didn't build a nest in there?

Also, sats adjacent to each other tend to alternate Vertical to Horizontal. So, IF you could only get Vertical and not Horizontal on one sat, shouldn't that mean that you'd get only Horizontal on the next sat and not Vertical?

primestar31,

Thanks for getting back to me.
I’ve been tearing out what little hair I have left trying to figure this issue out.
Never happened to me before.
Checked out the menu for my sathero meter at your suggestion and I don’t see where I could check the voltage.
How would I go about checking it with a meter ?
I did find that I get HSN on 103w which is horizontal and the signal is decent.
The lnbf still has its little blue cover, so no insects.
I’m at a loss to understand this issue.
Really appreciate your input.

John
 
Physically rotating it (without any other action) will null the one polarity and increase the gain on the other.
 
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telstar1,

Thanks for replying.
I understand your statement and initially tried rotating the lnbf to extremes to favor either all horizontal or all vertical.
While on 105W for example, I got a decent vertical signal on one of the Mexican transponders. Back in the house at my receiver it was 13dB, although in the past I received it stronger, around 17dB.
The only horizontal I received on my meter was a flickering 9 db, it wouldn’t lock.
Wondering if either my meter is the issue or my lnbf has flown the coop.
Thanks again for responding.

John

I should add that I had made marks on the lnbf and scaler, so it should have been an easy set up.
 
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Checked out the menu for my sathero meter at your suggestion and I don’t see where I could check the voltage.
How would I go about checking it with a meter ?
If you have a digital meter, set it to at least 20 volts DC. When the meter is set for Vertical channels, it should put out around +13 VDC. +18 VDC for Horizontal. Barrel of the coax connector should be negative, and stinger should be plus.
 
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Maybe?
I take it your scalar is still in the exact position. Ans trill parallel with the dish face.
You put the dish at zenith and checked that the skew was correct and set at 0. Check.
Returned the dish to where it was. And things went downhill.
Can you verify that even though the dish is where it should be. That the lnb throat is pointing exactly at the center of the dish. I still use my trusty telescoped paint can lids and a wooden dowel rod in holes drilled through the center dimples.
If not, fix it. Then steer the dish until you get the strongest signal you can. And see what you get now.
All theoretical checks....

A voltage check of the lnb power can be checked with a multimeter and a coax jumper from your meter to it.
Slice the coax open carefully so you get a window to the center conductor. But make sure that that the shield isn't totally severed. Just a little window and all the braid cleared so you don't short out anything while checking.
Meter probe + on the center conductor, - probe on the shield or F connector body.

I don't have a meter. A cheat would be to turn the lnbf 90 degrees (where's that little degree circle thingy keyboard combo?)
Then fix the voltage at 13 or 18 V. That will swap the H & V lnbf probe in the electronics of it.
 
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If you have a digital meter, set it to at least 20 volts DC. When the meter is set for Vertical channels, it should put out around +13 VDC. +18 VDC for Horizontal. Barrel of the coax connector should be negative, and stinger should be plus.
primestar31,

I don’t have a digital meter.
Do you believe it could be the satellite meter and not the lnbf ? I could re set my satellite meter to factory and start from there.
Very odd situation.

John
 
Correct me if I'm wrong, but on an electrically-switched LNBF, either by 13/18v or 22k tone, if it's delivering, say, the H xpdrs, then externally rotating 90 degrees without signaling an internal polarity change should null the H and deliver the V xpdrs. Then from there you just have to verify electronic switching between the 2.
 
primestar31,

I don’t have a digital meter.
Do you believe it could be the satellite meter and not the lnbf ? I could re set my satellite meter to factory and start from there.
Very odd situation.

John
At this point, all you can do is eliminate the variables. Maybe it's the sat meter, maybe it's the lnbf. IF it's the sat meter, and you don't have a digital meter to check the voltage, just put the dish at top dead center, set the lnbf as it should be, and hook the satellite receiver to it. Then see if it works with both polarities. If NOT, it's likely the lnbf bad in some way.

Or, run off to Harbor Freight and pick up one of their cheap meters. They used to give them away with a coupon. I still have one that's like 15 years old, still using the battery it came with, and still works just fine.

This one works great as a "throw in the drawer for when I need it" meter, and as a bonus, it's cheap: https://www.harborfreight.com/7-function-digital-multimeter-59434.html
 
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Correct me if I'm wrong, but on an electrically-switched LNBF, either by 13/18v or 22k tone, if it's delivering, say, the H xpdrs, then externally rotating 90 degrees without signaling an internal polarity change should null the H and deliver the V xpdrs. Then from there you just have to verify electronic switching between the 2.
telstar_1,

The problem is I’m not getting any horizontal feeds except for the one I mentioned earlier on 103W.
As I stated earlier, the horizontal feeds I’m picking up on 105W for example, with my satmeter do not lock they just flicker.
This is true of all satellites.
I’ve spun that lnbf around so many times I think I’m wearing a groove in it.😉
I’m not giving up…yet.
Thanks for responding.
John
 
At this point, all you can do is eliminate the variables. Maybe it's the sat meter, maybe it's the lnbf. IF it's the sat meter, and you don't have a digital meter to check the voltage, just put the dish at top dead center, set the lnbf as it should be, and hook the satellite receiver to it. Then see if it works with both polarities. If NOT, it's likely the lnbf bad in some way.

Or, run off to Harbor Freight and pick up one of their cheap meters. They used to give them away with a coupon. I still have one that's like 15 years old, still using the battery it came with, and still works just fine.

This one works great as a "throw in the drawer for when I need it" meter, and as a bonus, it's cheap: https://www.harborfreight.com/7-function-digital-multimeter-59434.html
primestar31,

I going to first reset my sat meter back to factory stats, even tho I haven’t touched any settings since I got it. If that doesn’t work I’ll put back my older, non 5g “fighter” lnbf. Finally if that doesn’t work, I’ll go down to Harbor Freight and pick up that cheap meter you mentioned.
All my yard and car work is taking a back seat to this pain in the ass dilemma.
Thanks again for responding.

John
 
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Maybe?
I take it your scalar is still in the exact position. Ans trill parallel with the dish face.
You put the dish at zenith and checked that the skew was correct and set at 0. Check.
Returned the dish to where it was. And things went downhill.
Can you verify that even though the dish is where it should be. That the lnb throat is pointing exactly at the center of the dish. I still use my trusty telescoped paint can lids and a wooden dowel rod in holes drilled through the center dimples.
If not, fix it. Then steer the dish until you get the strongest signal you can. And see what you get now.
All theoretical checks....

A voltage check of the lnb power can be checked with a multimeter and a coax jumper from your meter to it.
Slice the coax open carefully so you get a window to the center conductor. But make sure that that the shield isn't totally severed. Just a little window and all the braid cleared so you don't short out anything while checking.
Meter probe + on the center conductor, - probe on the shield or F connector body.

I don't have a meter. A cheat would be to turn the lnbf 90 degrees (where's that little degree circle thingy keyboard combo?)
Then fix the voltage at 13 or 18 V. That will swap the H & V lnbf probe in the electronics of it.
arlo,

All settings check out as they should with the dish and its accessories.
This ones got me stumped.
I’m going to replace the lnbf with an older one after resetting my sat meter.
Its good I’m patient, but only so much.
Thanks for your informative response.

John
 
Not sure if it’s totally proper, but I found one of my receivers wasn’t putting out the correct 13/18v. What I did was patch in a plain old splitter and short piece of coax, and tested the voltage. That made sure I was also capturing the voltage drop from the LNB.
 
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Hi all,

Last night I was thinking…why don’t I try seeing how my meter receives horizontal polarity with my kU sidecar.
Why I didn’t think of that before, I don’t know. Must be a combination of the heat and my aging brain.
I’ll try this theory and report back as soon the rain stops and I’ve had my second cup of morning coffee.
Thanks again to all those who responded, it’s MUCH appreciated.

John
 
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Hi all,

Last night I was thinking…why don’t I try seeing how my meter receives horizontal polarity with my kU sidecar.
Why I didn’t think of that before, I don’t know. Must be a combination of the heat and my aging brain.
I’ll try this theory and report back as soon the rain stops and I’ve had my second cup of morning coffee.
Thanks again to all those who responded, it’s MUCH appreciated.

John
that's a great idea, that should confirm whether the meter is working fine

now, am I understanding correctly that on C-Band you receive V, than if you rotate the LNBF 90 degrees and scan, you still don't receive the H transponders (with the receiver or meter still set to V of course)?
 
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that's a great idea, that should confirm whether the meter is working fine

now, am I understanding correctly that on C-Band you receive V, than if you rotate the LNBF 90 degrees and scan, you still don't receive the H transponders (with the receiver or meter still set to V of course)?
Brct203,

You are correct.
Vertical is there and horizontal isn’t when rotating the lnbf 90 degrees. I’m using the sat meter at the dish. Will be interesting to see what the result is when checking polarities with my kU lnb.
Thanks for checking in.

John
 
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Hi all,

Well I ran a text of my satellite meter on kU and it performed as it should…H and V received. I rescanned several kU satellites and all is well. So I’m thinking my C Band lnbf is the issue. I will check behind the little blue cap on the front, even though it appears sealed well, to check for intruders. If nothing is found, I will install my older lnbf and see how it goes.

John
 
Hi all,

Just an update on my polarity issue.
There is no change. I exchanged my newer lnbf with the older one, still no horizontal. I checked for insects under the blue cap in the newer lnbf, none.
I reset my Sathero 300 meter to factory settings, no difference.
Its odd that I can receive HSN on 103W which is horizontal, but cannot receive any horizontal on 105W for example, with the exception of Cepropie a horizontal feed which comes in very pixilated and unwatchable.
I noticed the horizontal channels I can’t receive are all s2.
Any ideas???
I’m stumped here.
The only thing I haven’t done is to try turning my dish to see if its moved at all, but a quick check shows all the marks line up.
Thanks again for any responses.
John
 
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Hi all,

Just an update on my polarity issue.
There is no change. I exchanged my newer lnbf with the older one, still no horizontal. I checked for insects under the blue cap in the newer lnbf, none.
I reset my Sathero 300 meter to factory settings, no difference.
Its odd that I can receive HSN on 103W which is horizontal, but cannot receive any horizontal on 105W for example, with the exception of Cepropie a horizontal feed which comes in very pixilated and unwatchable.
I noticed the horizontal channels I can’t receive are all s2.
Any ideas???
I’m stumped here.
The only thing I haven’t done is to try turning my dish to see if its moved at all, but a quick check shows all the marks line up.
Thanks again for any responses.
John
Have you tried with your actual receiver as of yet, or ONLY with your meter? Also, when using the meter, are you using a NEW piece of coax, ONLY between the meter and lnbf? No switches or anything else?

Titanium Brian, any ideas here? This makes NO SENSE at all. The only thing that seems to be common to all his testing, is the fact he's only done it with his Sathero meter.
 
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