DVB-S signal loss

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wdoa

80 posts

Master Geek

#74414 29-Dec-2010 19:41

Today I am experiencing signal loss similar to rain fade. I am in West Auckland and it's a glorious day ( I know, why am I home).

I read somewhere that it is possible for this to happen due to thermal waves?? from a tin roof? is this possible, as my dish points directly across the top of my neighbours tin roof. I can't remember it happening last summer.

The signal will come back, and work for a few seconds up to a minute or 2 then pixellate or freeze and then I get the no signal message.

It is a Windows 7 Media Centre PC.

Cheers

Stuart

Damager

2125 posts

Uber Geek

#422471 29-Dec-2010 21:08

I'm getting similar loss of signal here in hamilton. Dvb-t here though. Started about 30 minutes ago. Happens across all channels.

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wdoa

80 posts

Master Geek

#422500 29-Dec-2010 21:59

Interesting that DVB-T and DVB-S would do the same, when mine does work the Satellite is a whole advert behind real time tv.

Damager

2125 posts

Uber Geek

#422502 29-Dec-2010 22:03

my issues seem to have stopped. i was getting signal loss around every 5 or 10 minutes. i wonder if our issues are related? cant imagine dvb-s and dvb-t will both experience issues unless it's from the source..

no one else has commented so must assume we are concidently having unrelated issues at the same time.

wdoa

80 posts

Master Geek

#422512 29-Dec-2010 22:25

mine are still ongoing

Jaxson

8041 posts

Uber Geek

Trusted

#422524 29-Dec-2010 22:54

A few have reported older LNB's starting to fail by drifting a little as they get hotter. DVB-S problem only obviously but could explain the initial posting problem perhaps?

wdoa

80 posts

Master Geek

#422591 30-Dec-2010 10:37

Hi Jaxson, how do I test for that. I was thinking of taking my Media PC to my mates and plugging it into his dish and see what happens, then would it be a case of getting dish alignment checked and lnb checked by someone. It is still the same this morning and its a wee bit cooler now and no sun?

wdoa

80 posts

Master Geek

#422673 30-Dec-2010 17:40

Ok. took my media center pc to mates and plugged in his sky dish and it worked fine. So i guess it is either my dish alignment or lnb failure. is there anyone in west auckland avaialable to have a look for me?? What would it cost?

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RunningMan

8953 posts

Uber Geek

#422675 30-Dec-2010 17:54

It's pretty easy to check the alignment if you can reach the dish easily - they can get moved around by the wind over time.

If you are able to move the dish a few mm left / right / up / down and see if the signal improves, then it's usually pretty easy to loosen the mounting bolts and re-align it. You could also try altering the skew (rotation) of the LNB slightly.

The other common failure is the LNB itself starts going bad with temperature fluctuations - only cure is to replace it.

wdoa

80 posts

Master Geek

#422713 30-Dec-2010 19:30

How long do you need o hold the dish in a new positions, cos I tried that, and it kinda worked, but i was only persone home and was going by the sound levels I could hear!! :-)

How much is an LNB?

RunningMan

8953 posts

Uber Geek

#422727 30-Dec-2010 19:53

You usually need to hold it for several seconds for the signal to stabilise - far easier if you can either see the TV or have 2 people.

Some STBs do have an audible signal strength meter which is quite handy from on the roof!

If you have 2 people though, and 1 can call out the signal strength, while the other is on the roof, that would be fine - just be prepared to overshoot a couple of times

LNBs, depends on what you need. Could be anywhere from $10 second hand to over $100 for dual/multi output models...

wdoa

80 posts

Master Geek

#422762 30-Dec-2010 21:10

Thanks RunningMan,

The dish is just below the 1st floor deck, about 15 feet from the TV but round a corner out of sight. We will give that a go. Do not know what an STB is. It is an old Sky dish with a dual 10750 lnb ?? does that sound right?

RunningMan

8953 posts

Uber Geek

#422783 30-Dec-2010 22:05

Sorry, STB = Set Top Box - standalone sat receiver.... Not sure what your PC has in the way of a signal meter though...

wdoa

80 posts

Master Geek

#422786 30-Dec-2010 22:17

I have just a home built pc with Windows 7 and a Hauppaugge Nova-S Plus card and Media Centre, been running fine for a year or so!

RunningMan

8953 posts

Uber Geek

#423313 2-Jan-2011 07:37

How did you go with the alignment?

Found this on TradeMe - it may be the one you are looking for of you need a new one...

illicit

553 posts

Ultimate Geek

#423621 3-Jan-2011 08:40

I'm 99.9% positive thats its the LNB - the dual throat (oval head) Sky 10750 LNB's have problems with heat (as mentioned already).

You have caused yourself more grief by moving the dish - 9/10 times; dish alignment isn't the issue - but it is now that you've moved it.

Interim fix would be to set your frequencies around 3-4 higher - ie: 12459 instead of 12456.
That would have sufficed until you have the LNB replaced (preferably by an installer - so they can realign the dish accurately with a proper meter).

I recommend a good quality LNB (such as the Strong brand), not a trademe cheapie; there is a significant difference