Apologies for the long post.
I have a DSE-7500 Freeview STB which has previously worked for both Freeview carriers on a Sky dish in Rothesay Bay. I have now installed it in our new house in Hellcrest (NthShore) using the previous owner's Sky dish. It has a dual LNB with single output (Sharp 2 horn type supplied by Sky LO=10750)
Sky came in without trouble. I then installed a 2 way splitter and added the DSE7500. It initially received Carrier 2 (12456 - C3,C4 etc) but not Carrier 1 (12483 -TVNZ). Sky still ok.
I am fortunate enough to have access to a portable signal analyser which measures sig strength, BER and shows the spectrum so I used it to fine tune the pointing of the dish. It was almost spot on. I was getting 80dbuv at the LNB output but now have 83.5dbuv.
However, now the DSE-7500 tunes only Carrier 1 and only intermittently to Carrier 2! Sky is still good.
After reading various posts on this forum I thought it might be a matter of 'skew' of the LNB so I tried different positions and watched the results on the analyser. There was a position where I could reliably get Carrier 2 but then I lost carrier 1 and the BER on Sky went too high.
I set up the analyser to look at 4 frequencies, 2 for SKY and 2 for F/V. All frequencies have similar signal strength but it is pretty clear that when the skew of the LNB is good for SKY and Carrier 1 the quality of Carrier 2 is poor and I guess that is why the STB will not tune to Carrier 2. Here are typical results at the output of the 2-way splitter at the end of the cable from the LNB. One o/p to the F/V box the other to the S22. The LNB is powered by the F/V box (18V measured).
Freq Sig ChBER PvBER MER
12519 71.1db 6.2-04 0.0-8 9.5
12421 71.5 4.5-04 0.0-8 9.8
12483 71.4 4.5-04 0.0-8 10.3 F/V Carrier 1
12456 72.5 1.4-03 0.0-8 8.5 F/V Carrier 2
So my questions are:
* Why is carrier 2 such bad quality when it is on the same transponder and supposed to have the same characteristics as Carrier 1?
* Is this likely to be a LNB problem?
* What other explanation.
Any advise from the forum would be greatly appreciated.