TV reception problem

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Rickles

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#116175 20-Apr-2013 17:46

I have for some time been using a DVB-S card in my computer connected to a satellite dish and using ProgDVB for recordings etc. I can watch TV live or a recording on the PC monitor, or stream a recording through a media player to my large TV in the lounge (plasma, ethernet cabled).

99% of the time it is perfectly fine, but occasionally the picture will be extremely pixelated, usually in blocks of straight lines, and sometimes a squeaking sound as the sound breaks up.

The latest experinece was after recording the last Doctor Who ... all fine until halfway through the episode and then lots of picture and sound breakup.

Since the problem also manifests itself on the computer monitor, I can eliminate the network cabling, media player, and TV.

So, could be the DVB-S card, although a heap of other recordings when using it are perfectly fine, or the cable/dish. The dish is an ex Sky one, installed 5 years ago and used for Sky for 2 years before I commandered the cable.

My daughter said that Sky would often break up in this fashion, particulalrly with rain or storms elsewhere over the country.

Any thoughts on possible solutions would be welcome .... new DVB-S card? New dish/cable (both look fairly robust and clean? I've heard that the LNB's often breakdown ... worth looking at? Or is it just a foible of reception via satellite?

Cheers,

R.

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#802844 20-Apr-2013 17:54

If it's breaking up with Sky as well, then it will be some combination of dish / LNB / cable.

The first thing to check is dish and LNB alignment. The dish can move with time / wind / earthquake etc. If you have a signal strength meter or similar in your software, you can use that to adjust the dish left right / up down and the skew (rotation) of the LNB. Don't move more than a couple of mm at a time, and see if that improves things.

While you're at it, check for loose cables, rusted plugs etc.

If the signal drops at the same time every day, it could be temperature related - almost certainly the LNB on the dish is and the end of it's life.

See how that goes, and get back to us with results.

Rickles

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#802852 20-Apr-2013 18:24

Hi, thanks for replying.

First, we haven't used Sky for some 3 years now, so cannot comment on its reception .. this is all Freeview now.

I did check the dish a while ago, but will do so again .... last time it was pretty solidly in place and the cables seemed sound with no corrosion showing, and the LNB skew is still at 8 o'clock, but another check won't hurt of course.

The problem appears random, viz. no particlular time of day, weather or season. Also happens across all channels, which from the software readings seem to be at around 90% strength and 60% quality .. all are nice and clear right now and it's raining in Wellington! (very rare .. ha ha ha).

The LNB is of the oval type, so presumably the best for reception ... if I recall it is a Mitsubishi or similar well-known manufacturer (a bit dark and wet to get on roof right now).

Will do a roof check as soon as weather permits.

grant_k

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#802861 20-Apr-2013 18:33

Rickles: The LNB is of the oval type, so presumably the best for reception ... if I recall it is a Mitsubishi or similar well-known manufacturer (a bit dark and wet to get on roof right now).

If it's an oval type made by SHARP then that's the problem. This particular model of dual-throat LNB was used in the tens of thousands by Sky all around the country. In recent years, many of them have failed. I had to replace mine early last year, and have heard countless other stories of these LNBs failing.

Since the demise of Aussie FTA on Optus D1 and the other satellites located where the second throat is pointing, there isn't much reason to have a dual-throat any more, so I replaced mine with a single throat from Freeview Shop. I never encounter the "rain fade" message any more, even during the heaviest downpours. The single throat I ordered has the lowest noise figure readily available, which gives better performance during adverse weather.

Rickles

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#802868 20-Apr-2013 18:46

Grant ... yeah, could be Sharp. Thanks for your opinion regarding those dual-throat beasties ... could be source of problem, it's just so random.

Will look at a replacement anyway ... can't hurt.

R.

Rickles

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#802869 20-Apr-2013 18:53

PS Freeview Shop shows 7 KU models .... but which is best?

I'm situated in Wellington (Thorndon).

R.

RunningMan

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#802873 20-Apr-2013 18:57

Generally speaking, when the Sharp LNBs fail, they become sensitive to temperature as they die. Based on your symptoms, it's more likely to be a loose connector or dish slightly out of alignment (only takes a few mm), but don't rule out the possibility of a faulty LNB.

I'd try realignment and checking connectors before buying a new LNB. If you can grab a laptop, and watch the signal meter while you move the dish and LNB skew it should be fairly easy to get it spot on.

RunningMan

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#802875 20-Apr-2013 19:01

Rickles: PS Freeview Shop shows 7 KU models .... but which is best?

I'm situated in Wellington (Thorndon).

R.

This one's not bad - 0.2 dB noise

http://www.freeviewshop.co.nz/02db-noise-figure-11300-band-p-627.html

Or here:

http://www.jayx.co.nz/Ku%20LNB%27s.html

Quic Broadband

Move to New Zealand's best fibre broadband service (affiliate link). Free setup code: R587125ERQ6VE. Note that to use Quic Broadband you must be comfortable with configuring your own router.

grant_k

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#802877 20-Apr-2013 19:03

This is the one I chose because it has 0.2dB noise figure:

http://www.freeviewshop.co.nz/02db-noise-figure-11300-band-p-627.html

Most of the others are 0.6dB.

I also needed to use a mounting bracket:

http://www.freeviewshop.co.nz/zenus-standard-40mm-neck-conversion-p-610.html

However, I noticed that JayX have them at a cheaper price -- not sure if they're so robust though.

Rickles

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#802879 20-Apr-2013 19:04

Yup, planning to check dish/LNB stability and connections first.

Re using a laptop to check signal strength ... is there an app for that?

R.

Rickles

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#802880 20-Apr-2013 19:10

Grant .... love your weather banner, and display when clicked !

R.

grant_k

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#802882 20-Apr-2013 19:13

Rickles: Grant .... love your weather banner, and display when clicked !

R.

Thanks Rickles! I use Weather Display from a Kiwi guy based near Auckland:

http://www.weather-display.com/files.php

It is the most powerful weather software out there, but does have some flaws e.g. in my case, I am running 125% text size in Windows which messes up the text size on the banner a little, causing some of the fields to be cropped slightly. My chances of getting this fixed are not great, so I live with it. There are a few shortcomings like this with Weather Display, but overall, its flexibility is unrivalled, particularly if you have a Davis weather station as I do. Considering the small cost of the software, it's a bargain IMO.

Rickles

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#815792 11-May-2013 15:34

Quick question .... the current LNB is one of those dual-throat beasties.

Instructions for a new LNB say to set the skew so that the cable entry point is at 8 o'clock, but I notice that the current one is at about 7 o'clock.

Was that the normal skew setting for that model, or perhaps its moved?

R.

grant_k

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#815828 11-May-2013 16:35

Rickles: Quick question .... the current LNB is one of those dual-throat beasties.

Instructions for a new LNB say to set the skew so that the cable entry point is at 8 o'clock, but I notice that the current one is at about 7 o'clock.

Was that the normal skew setting for that model, or perhaps its moved?

R.

8 o'clock is roughly where my new LNB is pointing and IIRC it was pretty much the same for the old one. TBH, it's not too critical for D1 Horiz. reception (Freeview and Sky channels), but when I was also watching the Vert. channels carrying SBS Aus, it was much more important to get it right, because those signals were weaker.

Rickles

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#815861 11-May-2013 18:12

Thanks Grant .... I'm still getting random breakup of recordings. What's so odd is that for the last 3 weeks it's only been bad for Dr Who.

Time to call Mulder and Scully? .

Will order a new LNB this weekend .... presumably just a couple of screws holding it to the dish arm?

R.

grant_k

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#815865 11-May-2013 18:35

Rickles: Thanks Grant .... I'm still getting random breakup of recordings. What's so odd is that for the last 3 weeks it's only been bad for Dr Who.

That was my experience too. Some channels were unaffected at first, but gradually they all died.

Rickles:Will order a new LNB this weekend .... presumably just a couple of screws holding it to the dish arm?

Don't forget to order the mounting bracket I mentioned above, or else you'll have nothing to hold the LNB to the arm. The throat diameter is different to what you have at present.

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