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domwild
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Joined: 16/12/2005
Location: Australia
Posts: 873

Posted: 12:17am 11 Apr 2016

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Hi,

Some of you are living in the bush and know a bit about sat reception. Access Antennas sells both an 80 cm (82x76) squashed dish and an 85cm dish for $50. I asked for an 85cm dish and was given this "squashed" 80 cm one. When I queried this I was told they are both the same as far as "ability" is concerned.

Is it correct to say that both dishes have the same "signal catching ability", as I used to have a Strong 85cm one before, which rusted after eight years at the mounts?

By the way, one company in WA, which shall remain nameless, sells the Strong LNB without that all-important grommet. One suspects installers of that company just help themselves to the grommets in the boxes set aside for clients. In fact, that grommet gets special mention in sat fora (forums)as it needs at least a bit of silicon or, even better, a special type of insulating tape to keep the moisture out. So selling this LNB without a grommet is asking for trouble. How is the customer supposed to be attaching the FME end of the coax to the LNB then? Have contacted the ES sales office of Strong and reported that firm, obviously without getting an answer back.

So much to learn, 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

domwild
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Joined: 16/12/2005
Location: Australia
Posts: 873

Posted: 08:39pm 13 Apr 2016

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Turns out that company does not sell any 85cm (round) dishes anyway, despite what it says on their web page. Did get my money back and found another shop in the meantime, which sells both 80 cm and 90 cm ones.

Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up.

Winston Churchill

Pete Locke
Senior Member

Joined: 26/06/2013
Location: New Zealand
Posts: 181

Posted: 09:35pm 13 Apr 2016

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Having been in that game for a year or two (a year or two back now installing Sky systems) I can tell you that bigger is better, and an off-set dish (they are oval in shape) are the ones to go for. Other odd shapes being round or square are to be stayed away from. They look cool, but that's it. The oval off-set dish is the most efficient way of collecting satellite signals. Round (known as prime focus) dishes have to be 30% larger, because the LNB sits right in the stream of signal, which is the focal point for the signal. Easy enough to picture. Try looking at a reflection in a mirror of something right behind you (prime focus dish). Your face is in the way. Now tilt the mirror and look at the reflection from an angle (off-set dish). Suddenly a clear view. Exactly how dishes work. If the weather is good most of the time and you are in the guts of the footprint from the satellite, small dishes are fine. But if you are on the fringe of the signal then up size. Biggest issue with so called 'Poor reception, rain fade, low signal etc' popping up on the TV screen is that the dish isn't pointing bang-on in the right direction (it's a 2" window the LNB has to aim through) and that the LNB isn't angled right for polarisation. Easy to sort if you have a field strength meter designed for the job

.
Cheers
Pete'
New Zealand.
Edit: Also, keep the lichen and moss off the thing if it grows.Edited by Pete Locke 2016-04-15

domwild
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Joined: 16/12/2005
Location: Australia
Posts: 873

Posted: 11:28pm 13 Apr 2016

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Thanks Pete for that. Yes, one dealer praised the performance of the offset dish and warned me there is a 17 (?) degree subtraction in the elevation. We seem to be at the end of the footprint of the Optus C1 sat in North Walpole as nothing is North of us for 100 km.

The Strong 85cm dish had rusted at the mountings after eight years and that must have messed up the azimuth/elevation.

Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up.

Winston Churchill

Georgen
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Joined: 13/09/2011
Location: Australia
Posts: 462

Posted: 11:39am 18 Apr 2016

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Looks that every place that metal has contact with another or the same material is spot where rust starts its destruction.

UV resistant plastic is probably best material to go in-between metal parts of outdoors arrangements.

I used ordinary PVC tape between clamp and pole on my dish arrangement (could not think of anything better at the time), but year or two is not long enough to tell if it is good enough protection.

George

domwild
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Joined: 16/12/2005
Location: Australia
Posts: 873

Posted: 12:58pm 16 May 2016

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Thanks for replies. Have purchased an offset 80cm one and am happy with it. An 85cm Strong prime focus one would have cost $100, while this 80cm offset one cost me $50.

Sprayed an extra coat of paint on the mountings for protection.

Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up.

Winston Churchill

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