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domwild Guru Joined: 16/12/2005 Location: AustraliaPosts: 873
Posted: 11:19pm 02 Nov 2010
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Friends,
As some of you live remote and have found the TV reception with normal antennae (antennas) unsatisfactory, you may have gone over to sat tv like myself. I purchased a complete kit for $450, which consists of an 85 cm dish, LNB, 20 m of RG6 quad-shielded cable, etc. A contractor charges $1,000 in our area and I thought I can do it myself but now I am in more strife than flash gordon fighting the moonlanders!
"No or weak signal" I get on my Strong SRT 4653X sat receiver (Optus C1 sat).
Possible reasons:
1. A tall blue gum is 50 m away; does it need a perfect clear line of sight to the sat?
2. The electrical building wire is attached to the horizontal components of the metal truss and I measure a potential on my AC and DC scale against earth, when I attach the meter with the antenna mast (pipe). I have insulated the dish but still have the same problem. Do I have to properly earth the antenna mast?
3. How critical is the elevation? The net tells me the elevation for a place about 10 km away as 32.2 degrees. As I am closer to the sat do I have to up the elevation to 32.4 or more or less?
4. The skew is given as 40 deg. The LNB has a scale, which goes on both sides of zero to 20 only and not to 40. I was told by the chap flogging me the kit that in WA one does not bother to adjust the skew. Is he correct?
5. Looking at the LNB I find it does not sit at the focal point of the dish. Is this a common situation or has he given me the wrong arm?
6. The LNB itself can be mounted 30 mm or so closer or further from the dish; how critical would that be?
So many questions, so little time!
Thanks.
Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up.
Winston Churchill
VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539
Posted: 02:16am 03 Nov 2010
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Hi Dom
The thing you will need is a signal strength meter, it goes into the coax to measure the signal.
The receiver needs to be mounted into the focal point of the dish, very important. The tree shouldn't make to much difference if all other things are right, as mine is surrounded by trees and still works. The exact aiming is the important thing and you can only do that with a signal strength meter. The distance to the dish can be fine tuned after you get the aiming right.
House wiring and stray potentials don't make much difference unless the coax ia faulty, so check the coax for continuity in inner and outer conductors.
The field strength meter is available on ebay for around $20.
Hope that's a help
BobFoolin Around
domwild Guru Joined: 16/12/2005 Location: AustraliaPosts: 873
Posted: 09:55am 03 Nov 2010
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Bob,
Thanks for that. A signal strength meter came with the kit. It gives a small rise when it hits the right azimuth.
A lot of LNBs I looked at seem to be below the focal point. The LNB skew or polarisation of 40 deg. seems to be a problem, the scale on mine stops at +/- 20.
I will have a chat to the dealer. I may need to contact Optus as I seem to be outside the licensed area by just a few kms, I wonder if they activated my card. People outside the area have to have it surveyed by a licensed antenna installer ($$$) and it will take six weeks to get connection approved.
Cheers,
Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up.
Winston Churchill
VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539
Posted: 11:12am 03 Nov 2010
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Hi Dom
All that trouble to watch visual garbage, best of luck with it.
All the best
BovFoolin Around
domwild Guru Joined: 16/12/2005 Location: AustraliaPosts: 873
Posted: 10:25pm 03 Nov 2010
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Bov,
Films on ABC/SBS aren't too bad, besides, if you watch SBS you learn lots of languages or at least the important swear words you can try on the waiters in foreign lands!Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up.
Winston Churchill
Barry T Coles Senior Member Joined: 30/07/2009 Location: AustraliaPosts: 109
Posted: 11:17pm 03 Nov 2010
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Hi Bob
If Optus has activated you card, one problem could be the LNB, when I had my sat up the LNB that I had needed to be set in the circular clamp with the coax cable set at 4 Oclock not six like most, sound crazy I know but thats the way it worked.
Cheers
BarryI need to learn from the mistakes of others.
I dont have the time to make them all myself.
RossW Guru Joined: 25/02/2006 Location: AustraliaPosts: 495
Posted: 11:19pm 03 Nov 2010
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Ahh, but is the focus where you think it is?
Most satellite dishes nowdays (certainly of the smaller sized ones like you have anyway) are offset feed. This means the dish is more vertical, the feed is well down from where you would typically expect it to be for a "prime focus" dish, but it's still the correct focus point. Just makes aiming them a little trickier IMO.
domwild Guru Joined: 16/12/2005 Location: AustraliaPosts: 873
Posted: 11:35pm 06 Nov 2010
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Thanks for answers. The LNB appears to be the problem. It also can be shifted forwards and backwards inside its circular holder.
The 40 deg. skew or polarisation of the LNB; any knowledge of if it is critical or not? As I said before, the scale is +/- 20 but the tables tell me I am to achieve 40. Now is that clockwise or anticlockwise? Or is it just a case of shifting and watching the signal strength?
The signal should be there regardless if I am in the licensed area or not, it might just be scrambled if Optus has not authorised it yet. Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up.
Winston Churchill
VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539
Posted: 12:08am 07 Nov 2010
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Hi Dom
The best I found is to move things around and watch the signal strength. The signal will be there regardless so tune to the strongest signal, the authorization is part of the card that works with the decoder to let your device decode the signal, thats a separate issue, but there must be good signal first so the decoder can work. Chicken before egg I think.
All the best
BobFoolin Around
Barry T Coles Senior Member Joined: 30/07/2009 Location: AustraliaPosts: 109
Posted: 11:48pm 07 Nov 2010
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Hi Dom
have a look at this link it may help.
http://www.satsig.net/polangle.htm
Cheers
BarryI need to learn from the mistakes of others.
I dont have the time to make them all myself.
Robb Senior Member Joined: 01/08/2007 Location: AustraliaPosts: 221
Posted: 10:31pm 08 Nov 2010
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Around here Optus C1 is dead easy to line up because its the strongest signal up there bar none. You should be able to tune the home shopping channel and foxtel help channel with no card in your receiver at all.
Make sure you have the right LNB details programmed into your receiver or the frequencys will be all up the spout.
When adjusting the LNB tilt I tune in a channel, turn up the volume and get on the roof. Turn the LNB one way till it drops out, mark that, turn it the other way till it drops out and mark that then set it half way between the two.
domwild Guru Joined: 16/12/2005 Location: AustraliaPosts: 873
Posted: 10:31pm 08 Nov 2010
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Barry and others,
Thanks. I will set the skew or polarisation as stated on the web page. The dealer said not to worry about skew, he does not seem to know his business.
Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up.
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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