Motorised dishes: what about LNB skew?

Artist 2004

Anatolia correspondent
Messages
252
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0
My Satellite Setup
GoldMaster 7400 CIM 2MB with Kaon board 12.03.a5. Technomate 1000, Technomate 5200 USB.
Two 80cm offset dishes.
My Location
West coast, Turkey
#1
When I point my dish at Turksat I have to skew the LNB to the left to get good reception. For Hotbird I have to skew it to the right. If I motorise the dish, I can't change the skew of the LNB when I change satellites, so does it mean reception is compromised?
 

Lancelot

Specialist Contributor
Messages
3,638
Likes
8
My Satellite Setup
SS1.
125cm Gibbi with Channelmaster feedhorn and Inverto C120 twin.
36v H to H 62E - 61.5W
My Location
South central
#2
No - that's the point of motors, they tilt the dish correctly and apply the right amount of skew (when set up properly) as they go :)

L.
 

Artist 2004

Anatolia correspondent
Messages
252
Likes
0
My Satellite Setup
GoldMaster 7400 CIM 2MB with Kaon board 12.03.a5. Technomate 1000, Technomate 5200 USB.
Two 80cm offset dishes.
My Location
West coast, Turkey
#3
Clever sods these motors. Cheers!
 

Skip Channel

Regular Member
Messages
317
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0
My Satellite Setup
28e, 19e, 13e, 30w
My Location
England
#4
So, for a fixed dish, is it better to tilt the dish (leaving the LNB unskewed) or have the dish plumb and skew the LNB?
 
J

Jeff_19341

Guest
#5
In fact it would be best to tilt the dish and that way the LNB would go with it. But it is much easier to just tilt the LNB. That is if you are useing an offset oval (with the major axis vertical) dish. But I expect that you would only gain a few tenths of a dB. The extra gain would show up more the further away from your due south that you went.
 

Skip Channel

Regular Member
Messages
317
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0
My Satellite Setup
28e, 19e, 13e, 30w
My Location
England
#6
I have a weird dish that I'm experimenting with (it's the Lidl camping dish). It is slightly oval but instead of being wider than tall (like a minidish) it is taller than wide. I've currently got it on Hispa through a window (I know, not ideal - I've already got one fixed dish outside and I live in an apartment block).

So far tilting the dish seems to produce noticeably better results (albeit fiarly minor) but this could also be down to how accurately I have to align the dish (to prevent the window frames from being too much of a problem).

BTW sorry to Artist 2004, I'm not trying to hijack your thread - honest.
 
J

Jeff_19341

Guest
#7
Hi Skip Channel
Most offset dishes are oval in the vertical plane, taking into account the offset the signal from the satellite see's a circle.
Raven dishes are oval in the horizontal plane I understand so that they can better receive from more than one satellite.
Mini-dishes are oval in the horizontal plane to cut down reception interference from adjacent satellites.
That is my understanding of the situation, I am ready to be corrected if I am wrong in my assumptions:D .
 

rolfw

Believe it when I see it Admin.
Staff member
Messages
37,678
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My Satellite Setup
Technomate 5402 HD M2 Ci, DM7000s, Transparent 80cm Dish, Moteck SG2100 DiseqC motor, lots of legacy gear. Meters: Satlook Digital NIT, Promax HD Ranger+ spectrum analyser.
My Location
Berkshire
#8
You have it Spot on Jumbuck, the minidish in particular was designed for a narrow/selective beam to avoid adjacent satellite interference.
 

Skip Channel

Regular Member
Messages
317
Likes
0
My Satellite Setup
28e, 19e, 13e, 30w
My Location
England
#10
Unlike a minidish the Lidl Porty dish is taller than it is wide. So I guess that's one of the reasons it is better with Hispa reception than Hotbird (if we leave out transponder strength, beams etc for a moment.)
 
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