Sat Newbie: First results, and LNB question

[rodscha]

Talking about dish wallahs,here is a link to a great prog (French tv)
made back in 1994 about India's TV scape.Very instructive!

 

[astra19]

Very interesting video. I'll watch it this weekend.

 

[NickPGSmith]

I am still playing with my multi-LNB setup trying to get it optimal. Of course I adjust one thing and everything else that is attached needs readjusting - it satisfies my need of constant fiddling. :-)

Now, I noticed DW English HD from Astra 1 is way down in strength, even when I point directly at it. Other channels come in at 100% (by whatever measure the TV is using) but DW is 0-10% and sometimes drops completely. I can't see why it would be such a struggle with the wide Europe beam:

Astra 1M at 19.2°E - LyngSat Maps

Do others see this too or is it some peculiarity of my setup?

 

[Mickha]

Just checked DW English HD, on 19.2E, 11778 V 29500 DVB-S2 QPSK 9/10 and getting a good signal, in the UK, it's also listed FTA on Hotbird, 13E, 11727 V 29900 DVB-S2 8PSK 3/4, though I haven't checked this transponder.

 

[ozumo]

I have no lock on 11778V with an offset LNB on a dish pointing at 28.2east, appears to be one of the more difficult transponders, the FEC is 9/10 so needs around 11db to lock.

 

[jeallen01]

I have no lock on 11778V with an offset LNB on a dish pointing at 28.2east, appears to be one of the more difficult transponders, the FEC is 9/10 so needs around 11db to lock.

My fixed dish for 19E isn't working, but that transponder shows a lot lower SS/SQ on the 1.25m Gibby than most of those for the other major channels here in W. London - so I think you are correct.

 

[NickPGSmith]

Thanks for the info/confirmation. I managed to move to "30%" TV report, and stable, by adjusting the LNB skew a little to max the signal. We'll have to see how it holds up in heavy rain. I can only see a few of the strongest signals at 13E currently, until next month when the obscuring tree is removed.

 

[Channel Hopper]

I am still playing with my multi-LNB setup trying to get it optimal. Of course I adjust one thing and everything else that is attached needs readjusting - it satisfies my need of constant fiddling. :-)

Now, I noticed DW English HD from Astra 1 is way down in strength, even when I point directly at it. Other channels come in at 100% (by whatever measure the TV is using) but DW is 0-10% and sometimes drops completely. I can't see why it would be such a struggle with the wide Europe beam:

Astra 1M at 19.2°E - LyngSat Maps

Do others see this too or is it some peculiarity of my setup?

Lower yes, but not by much. You might have an issue with cable or connectors.

 

[NickPGSmith]

I have no lock on 11778V with an offset LNB on a dish pointing at 28.2east, appears to be one of the more difficult transponders, the FEC is 9/10 so needs around 11db to lock.

Thanks for the pointer to consider the the encoding scheme and FEC, not just received power - I wasn't previously aware there were so many different variations possible with DVB-S2.

 

[NickPGSmith]

Lower yes, but not by much. You might have an issue with cable or connectors.

I found some other channels that provided stable viewing but actually had a fairly low reported quality. The trouble is I have no idea what the "%" the TV is reporting is actually measuring. I have had channels start to drop out at 50%, others drop out at 10%. And the signal "strength" is almost always 100% so is completely useless.

At the risk of opening another can of worms for myself, what are you using to get those quantitative graphs?

> There is a very fine line between "hobby" and "mental illness"

I concur :-)

 

[ozumo]

I found some other channels that provided stable viewing but actually had a fairly low reported quality. The trouble is I have no idea what the "%" the TV is reporting is actually measuring. I have had channels start to drop out at 50%, others drop out at 10%. And the signal "strength" is almost always 100% so is completely useless.

The channels that drop out at a higher signal quality percentage are most likely to be those that require a higher db for lock:

 

[NickPGSmith]

Hello everyone. I thought I would summarise my conclusions after much tweaking, prodding, fiddling and buying that one extra thing off eBay.

(5 year old Sony TV, moderate cable run, 4-port Technomate Diseqc switch, SE London)

- You can get usable signals from a 60 cm dish from several satellites. So it's easy if you just one of 19.2E, 13E, 42E etc.

- I found it best to not try and set the skew for what I though it should be: instead, optimise with a sat meter for direction with 0 skew, then pick a weaker channel and use the TV strength meter to judge how rotating the LNB changes the reported strength/quality.

- Of course I was trying to squeeze maximum option of 4 satellites. I found I could *just* do 3 on 60 cm dish; off-axis performance went down a lot, and there wasn't enough room physically to cram normal LNBs in there. I could just get this working acceptably:

Inverto Green LNB (narrower feedhorn) for 19.2E, with another in front/overlapping for 13E and another on the side for 28.2/5E. But adjustment was a nightmare. The LNB bracket bolts and screws would hit each other or block each other so you had to find the one way you could add/adjust them all.

But no way could I get the 4th LNB on. I also tried an Inverto Black which has a normal-sized feedhorn which is nice and long, so I could try 2 brackets. Also it seemed more sensitive than the Green LNB. But ultimately the feedhorn size was a problem.

So in the end I bought a new 80cm Triax dish - and it's all so much easier. Firstly it's much easier to adjust the vertical angle as it uses nuts only on one side. There is much more space to fit LNBs which no longer have to be overlapping with the Greens, and adjustment is possible after the LNBs are on. I should have done this from the start :-) (except my wife might have complained if I hadn't gone via a smaller dish first...) And the extra total signal capture means that absolutely exact positioning is not so critical. And you can route cables through the arm.

See pic for how I ended up: focusing on 26.5E, touching LNB on the right is for 28.2/5E, left green for 19.2E and then a Technomate far left for 13E.

Now I am not going to touch this setup, at least for a while. I did try and get 26E but it just seemed swamped by 28.2/5E. Would I need an even bigger dish to get a narrower beamwidth do you think?

Also:

- Do put the dish somewhere you can easily get to (consistent with line-of-sight of course) as you'll be up and down a ladder a lot
- Don't forget you left the sat signal strength meter on the cable outside and let it get soaked for several days. You will need to buy another one.

 

[ozumo]

You may get 11996H 27500 on 26E but as you've already found, most transponders get swamped by 28.2E. A 1M dish would get more.

 

[statalite]

The roof terrace looks prime for a bigger dish.