hispasat and sl65 problem

[gcos]

Hi to all, hope some learned person can sort this one! I have my Silvercrest sl65/12 with an 88cm dish pointed at Hispasat 30w, and receiving many free to air stations perfectly. Looking at 'King of Sat' listings, I should be able to receive e.g.Tele Local 2 at 11616 H, 27500. When I put these details into the menu and scan acordingly, results show no channels. However, if I search with polarisation set to V, it will pick up half a dozen stations. Then when I go to view any of these stations, the screen says 'no signal' but the strength and quality meter are up at 73% for both. Also, the correct name for the channels is listed.
I am receiving various other channels in both V and H. I don't understand why the listings show the stations as H, but the receiver only picks up something if it's set at V, and then shows good quality but no picture or sound.
Anyone any thoughts on this.
Many thanks in advance for any suggestions
Gerard

[robbo71]

Hi Gerard,

Just a couple of queries/suggestions really, as I don't have a clue about your box. But,
Is your Skew on your LNB set correctly?
ARe the channels you are looking for free to air or scrambled?
Robbo

[gcos]

Hi Robbo,
Thanks for the quick reply. I am using a motorised dish, so I presume the skew won't come into it. The channels are listed as 'clear'
I just know you have the answer on the tip of your tongue.!!!!! It's driving me mad trying to figure out something that should be so simple.
Regards
Gerard

[robbo71]

Unfortunately I no longer have my 90cm dish pointed at 30W, so i can't check. But on Lyngsat the channel you wanted is on 11615H, but there is another transponder on 11617V, but these are all scrambled as part of the TV Cabo package. So that could explain why you get stuff from the vertical polarisation ( but not why the channel names are correct). I think for these two transponders you are relying on good cross polarisation rejection ( or whatever the proper technical term for it is). As far as I remember, when I had my dish at 30W I had a similar problem with transponders like that. Unfortunately I never solved it. Maybe you could try 11615H instead of 11616H, but I don't hold out much hope, but worth a try anyway.

Robbo

[gcos]

Hi Robbo,
You set me thinking in your first post about the skew. I went back into the 'antenna setup' and changed from USALS to 1.2, and used the remote control to move the dish a blip at a time, having the polarisation set to H, and watching the signal strength and quality meter. After a couple of key 'blips', I got the signal up to about 43% - enough to show me that the channel is there. Its pixellated and the sound breaks up, but this seems to prove that my dish is not absolutely aligned. I suppose I forgot that some signals are stronger than others, and once I had plenty of good signals, well, I presumed the dish must be properly aligned. The dish follows the arc over to 28e, so I never thought to look more precisely. It seems now I may have to peak it slightly up or down to increase the signal. Possibly the signal is not very strong on that frequency to Ireland.
Your cross polarisation interference theory sounds more technical than I want to even start thinking about, so I think I'll just peak the dish over the weekend and see how that goes.
Many many thanks for your interest and help, and for providing the spark that helped me at least find picture and sound.
Regards
Gerard

[robbo71]

Glad your'e getting closer to getting it sorted, the solution was not obvious from your description of the problem, but makes sense when you know the answer. I think there was an arc tuning guide on here somewhere, but I can't find the link for it at the moment.