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My 2 dishes in Cyprus

bignick

Specialist Contributor
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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

Regular Member
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My Satellite Setup
Various
#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

Specialist Contributor
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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
 

deepbluesky

Specialist Contributor
Messages
997
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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 ?
 

Orthoclipse

Regular Member
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My Satellite Setup
Various
#5
If focal point is the same, and diameter goes up, does not F/D decrease? Or am I missing something?
 

bignick

Specialist Contributor
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336
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My Satellite Setup
Back in the UK and missing Cyprus!!!
My Location
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
 

deepbluesky

Specialist Contributor
Messages
997
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72
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

Specialist Contributor
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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

Specialist Contributor
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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
 

Orthoclipse

Regular Member
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My Satellite Setup
Various
#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

Regular Member
Messages
170
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2
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
 

deepbluesky

Specialist Contributor
Messages
997
Likes
72
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

Regular Member
Messages
170
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2
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.
 

deepbluesky

Specialist Contributor
Messages
997
Likes
72
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

Specialist Contributor
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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