My 2 dishes in Cyprus

bignick

bignick

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My Satellite Setup
Back in the UK and missing Cyprus!!!
My Location
Aylesbury
#1
3.1m Famaval for 28.2 (astras 2A, 2B & 2D Horizontals) & 28.5

1.5m is presently on 19.2e, 13e, & 7e and into a DM500s

Hope you like

Nick

PS yes I know the Famaval needs a wash down, I keep asking the wife to do it.
 

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Orthoclipse

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#2
Roughly what difference is there in performance with the bare dish vs dish + petals?

Do you need to change the F/D setting on the feedhorn when you add the petals?
 
bignick

bignick

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My Satellite Setup
Back in the UK and missing Cyprus!!!
My Location
Aylesbury
#3
Orthoclipse said:
Roughly what difference is there in performance with the bare dish vs dish + petals?

Do you need to change the F/D setting on the feedhorn when you add the petals?
Here in Cyprus the petals are for BBC/ITV reception purposes, they add about 2db. You can get everything except Astra 2D without them fitted. F/D does not change (0.41), focal distance remains 93cm. Beamwidth goes from 0.7 to 0.5 degrees so tuning is more of an art!

Nick
 
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deepbluesky

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My Satellite Setup
Octagon Quad Optima OQSLO @ Laminas OFC-1100 @ Powertech DG-380 @ Vu+ Solo²(OpenATV) / Technotrend S2-1600
Sony KDL32W656A / TBS 6220 (DVB-C)
Terratec T-Stick+ (DAB+)
My Location
Stuttgart (48.79N/9.19E)
#4
Nice setup you've got there bignick.

Isn't a 1.5m offset too small to have all frequencies of Astra 1G/H/KR without any breakups ?
 
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Orthoclipse

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#5
If focal point is the same, and diameter goes up, does not F/D decrease? Or am I missing something?
 
bignick

bignick

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My Satellite Setup
Back in the UK and missing Cyprus!!!
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Aylesbury
#6
deepbluesky said:
Nice setup you've got there bignick.

Isn't a 1.5m offset too small to have all frequencies of Astra 1G/H/KR without any breakups ?
I think a few have a problem, though I haven't noticed them as they are none of the ones I'm interested in.

cheers

Nick
 
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deepbluesky

Specialist Contributor
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My Satellite Setup
Octagon Quad Optima OQSLO @ Laminas OFC-1100 @ Powertech DG-380 @ Vu+ Solo²(OpenATV) / Technotrend S2-1600
Sony KDL32W656A / TBS 6220 (DVB-C)
Terratec T-Stick+ (DAB+)
My Location
Stuttgart (48.79N/9.19E)
#7
I see. I was asking since even in Rodos or Eastern Kriti 1.80m are recommended.

Thanks for your interest.
 
bignick

bignick

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My Satellite Setup
Back in the UK and missing Cyprus!!!
My Location
Aylesbury
#8
Orthoclipse said:
If focal point is the same, and diameter goes up, does not F/D decrease? Or am I missing something?

F/d does not change with the diameter of the dish. It is a ratio of sorts between the depth and diameter of the dish. Please check out http://www.satellite-calculations.com/Satellite/reflector.htm to see.

Think of drawing a circle with a set of compasses - the pin end would stay the focal piont no how long you draw the line - of course that only works for less than a half circle in satellite terms :)

Cheers

Nick
 
bignick

bignick

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My Satellite Setup
Back in the UK and missing Cyprus!!!
My Location
Aylesbury
#9
deepbluesky said:
I see. I was asking since even in Rodos or Eastern Kriti 1.80m are recommended.

Thanks for your interest.
In a way this is bigger than 1.5m as this is an offset and measured across the width (the shortest length) as it should be - though rarely is by local installers here!! It is closer to 1.8m in hieght!

Nick
 
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Orthoclipse

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#10
@bignick - I have looked through some old books I have on satellite reception and I can only see f/D ratio being focal length divided by diameter.

If you add the panels to the dish, and the focal length stays the same, the f/D ratio must decrease.

Famaval list the focal length as 93cm. So for 230cm, f/D is 93/230 = .404 and for 310, f/D = 93/310 = 0.3.

This is the same figure quoted on the famaval website:
h**p://www.famaval.pt/en/tiki-index.php?page=antenas_310

The other way to think about it - if the focal length stays the same but the diameter increases, you need a wider illumination angle to cover all the surface of this dish. The illumination angle increases as f/D decreases.
 

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patmos

patmos

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My Satellite Setup
STRONG SRT-4910+,SunRay4HDse,TBS5922, 2.4M P.F Apstar7(76.5 DEGE), 120cm dish PAS 10 Ku( 68.5 DEGE),3.0M Mesh Motorised dish on arc (AM44 (11DEGW) to AM33(96.5 DEGE),150 cm dish W3C(16 DeG E)+ side LNB Ew2A(10 DEGE),90cm W4/W7 (36 DEGE)
My Location
Mauritius
#11
Bignick Please can you give the height of the post(pedestal) for this antenna. i will get a 3.6m dish to point to PAS10 /63deg elevation. it will be fix. I am trying to use a short a pedestal(on roof top) as possible and at the same time being able to access the lnb when in it's lowest position. thanks
 
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deepbluesky

Specialist Contributor
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My Satellite Setup
Octagon Quad Optima OQSLO @ Laminas OFC-1100 @ Powertech DG-380 @ Vu+ Solo²(OpenATV) / Technotrend S2-1600
Sony KDL32W656A / TBS 6220 (DVB-C)
Terratec T-Stick+ (DAB+)
My Location
Stuttgart (48.79N/9.19E)
#12
patmos said:
Bignick Please can you give the height of the post(pedestal) for this antenna. i will get a 3.6m dish to point to PAS10 /63deg elevation. it will be fix. I am trying to use a short a pedestal(on roof top) as possible and at the same time being able to access the lnb when in it's lowest position. thanks
Sorry but why are you going to use such a big dish for 68.5E ? As far as i know 1.80m is sufficient for IS10 (PAS10) C-Band in Cyprus.
By the way, the elevation is roughly 35°.
 
patmos

patmos

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My Satellite Setup
STRONG SRT-4910+,SunRay4HDse,TBS5922, 2.4M P.F Apstar7(76.5 DEGE), 120cm dish PAS 10 Ku( 68.5 DEGE),3.0M Mesh Motorised dish on arc (AM44 (11DEGW) to AM33(96.5 DEGE),150 cm dish W3C(16 DeG E)+ side LNB Ew2A(10 DEGE),90cm W4/W7 (36 DEGE)
My Location
Mauritius
#13
deepbluesky said:
Sorry but why are you going to use such a big dish for 68.5E ? As far as i know 1.80m is sufficient for IS10 (PAS10) C-Band in Cyprus.
By the way, the elevation is roughly 35°.
No sir I am in Mauritius . this is a fringe area for PAS 10 KU. Situation is almost similar to Cyprus case for Astra. I now use a 1.2 m offset but with occasional break. i cannot get a 1.8m offset here. my friend got a 3.4m( i think) in an auction and would give it to me. I will go to fetch the dish this week. This dish has a 7dB gain over my 1.2m. I am now refurbishing a 12 foot mesh for PAS 10 C and other hunting.
 
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deepbluesky

Specialist Contributor
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My Satellite Setup
Octagon Quad Optima OQSLO @ Laminas OFC-1100 @ Powertech DG-380 @ Vu+ Solo²(OpenATV) / Technotrend S2-1600
Sony KDL32W656A / TBS 6220 (DVB-C)
Terratec T-Stick+ (DAB+)
My Location
Stuttgart (48.79N/9.19E)
#14
Oh, i thought you would gonna receive from Cyprus.
 
bignick

bignick

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My Satellite Setup
Back in the UK and missing Cyprus!!!
My Location
Aylesbury
#15
Orthoclipse said:
@bignick - I have looked through some old books I have on satellite reception and I can only see f/D ratio being focal length divided by diameter.

If you add the panels to the dish, and the focal length stays the same, the f/D ratio must decrease.

Famaval list the focal length as 93cm. So for 230cm, f/D is 93/230 = .404 and for 310, f/D = 93/310 = 0.3.

This is the same figure quoted on the famaval website:
h**p://www.famaval.pt/en/tiki-index.php?page=antenas_310

The other way to think about it - if the focal length stays the same but the diameter increases, you need a wider illumination angle to cover all the surface of this dish. The illumination angle increases as f/D decreases.
I stand corrected, it appears f/D does change. My understanding of the relationship between focal distance & differing dish diameters was flawed :-ohmy. Still, doesn't change the fact that the Focal distance remains constant, though I will start to take a closer look at the scalar ring settings.

You live & learn.

Cheers

Nick
 
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