LNB strength

dardruba · 02-12-2008

When using a dual output lnb does the inner or outer have a stronger signal than the other.

My setup is complicated, 85cm dish with 3 dual output lnb's. The 3 outers go to a diseqc and the 3 inners to another diseqc. One cable goes thru the wall to SkyStar2, the PC and DVB Dream (with Prog DVB as an alternative if needed). The other cable goes round the house to the backroom downstairs, to a TM 1500 and the TV.
I can't see if its the inner or outer which goes thru the wall to the PC but
the TM 1500 with the long cable run shows strength at around 75, the DVB Dream (and Prog DVB) on the short cable run shows Quality around 48 to 50 and Level around 44 to 48. Normally its upstairs live or downstairs live, but today I've run a check with them both live and got the same results.

All this is because on the Pc I constantly get 'Timeout - This PID is empty. Rescan' and doing several rescans a day is sending me bonkers.
I would have expected the lower strength to be on the longer cable run.

**Low Profile** · 02-12-2008

The quality (and signal levels) are not comparative between the two receivers. You might find that the TM is more sensitive (to weak signals). You might also find that one diseqc switch is lossier than the other, and one LNB OP might be slightly higher. I would take the TM upstairs to see how it performs, this will identify whether it's the Rx that is more sensitive or if you are losing signal to your Skystar.

**Robbo** · 02-12-2008

Originally Posted by dardruba

I would have expected the lower strength to be on the longer cable run.

Yes, a longer cable will attenuate the signal more, but all other factors must be the same to make a compative mesaurement.

dardruba · 02-12-2008

=. I would take the TM upstairs to see how it performs, this will identify whether it's the Rx that is more sensitive or if you are losing signal to your Skystar.

Great suggestion, Thank You. Funny how you dont think clearly when you are stressed.
I ran the TM1500 on the upstairs incoming cable. I got a good signal on 19E of 75 (same as downstairs) but zilch on 13E or 28E. It doesnt show an error message.
When I put it back into SkyStar2 I got the same error message in vPlug on all 3 Timeout- This PID is empty. Rescan

Perhaps I've disturbed the diseqc box. I bought the 3 lnb setup and asked the installer to install my existing LNB but I was greedy. It was too heavy for the arm which swung around in the wind.
I uncoupled the 4th LNB and sliced off the cables before they went into the diseqc. This summer I've removed the cable stubs and the Fconnectors but I didnt have the proper tape so I left the plug bare and just put the weatherproof cover back on and ziptied it.
The other 3 in and the single out are still properly sealed.
Did I do the right thing, and could this be the reason for the constant need to rescan ?

**Robbo** · 02-12-2008

The only way to find out is to gradually work your way back through the system, until you get to the LNBs, testing the signal along the way.

You can test the other LNB outputs by swapping the outputs, and see if the upstairs still works Ok, and that the downstairs doesn't any more.

dardruba · 03-12-2008

Oh Yes! Thanks Robbo
I'll save that task for a warmer day.

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LNB strength Information exchange on LNBs, Single satellite, motorised and multi-satellite systems. DiSEqC switches, positioners, motors, actuators, dish-alignment etc.

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