Multi sat on a sky dish

[bob999]

Hi. I'm new on this forum. I have my dish pointing at 28. On the right I put an extra lnb. I got astra 19.2 east. Happy with these 2 satellites. Also put an extra lnb. No luck with this one. Please can anyone help how to get another satellite. I don't want to replace it with a bigger dish.

 

[ozumo]

The LNB should be below the rail, not above. You will struggle to get much past 19.2°E with the dish centred on 28.2°E. With 19.2°E in the centre you may be able to get 28.2°E & 13°E on either side.

Your skew for 28.2°E looks to be off as well. The cables should be exiting the LNB between 6 & 7 o'clock when looking from the front.

 

[bob999]

The LNB should be below the rail, not above. You will struggle to get much past 19.2°E with the dish centred on 28.2°E. With 19.2°E in the centre you may be able to get 28.2°E & 13°E on either side.

Your skew for 28.2°E looks to be off as well. The cables should be exiting the LNB between 6 & 7 o'clock when looking from the front.

Hi. Thank you. I don't want to move the dish to put astra 19.2 in the middle. Scared to lose everything

 

[bob999]

I try this. Any idea what satellite I can get on the left(I will keep astra 28 in the middle)

 

[ozumo]

Try some of the transponders on william-1's strongest transponder list on the satellites between 28.2°E & 42°E:

Just Sharing This - Strongest transponders

The Strongest transponders for January 4th 2021 All active Ku band satellites from 50° east to 45° west This list was compiled by William-1 $ = encrypted TM5402HD M3 +100cm Dish+Inverto Black Ultra Lnb-Signal Quality in dB Turksat 4B @ 50° east 11196 V 2222 TürkSat Tanitim==14.7 AzerSpace-1 @...

www.satellites.co.uk

PS your skew for 28.2°E is still a way off what I would expect.

 

[a33]

If possible, I would put the "rail" UNDER the necks of the LNBs.
When it is above the LNB necks, you have the risk that part of the signal is blocked, by the rail.
[ I've never seen the sky dish measured, to calculate the exact "clearance" of the dish (the distance of the bottom of the dish, above the vertex of the parabola); assuming the dish is a perfect paraboloid.
Nobody took my offer for such a calculation.]

Furthermore, did you experiment with the rail tilt, while trying to get 13E?
With 28E central, for Dartford, that would be somewhere between -15 to -20 degrees, to also get 13E. (The given tilt angle is measured from horizontal, looking along the viewing direction of the central LNB.)

When you mount LNBs left and right symmetrical to the rail, the rail tilt would be about -20.5 degrees.

Greetz,
A33

 

[ozumo]

[Nobody took my offer for such a calculation.]

I can assist, though I only have the larger 'zone 2' dish, it's also an older version.

 

[a33]

That would be interesting!

The original offer was here (when I had just a multi-step algorithm for it, and not the later developed, more simple direct equation): Measuring and calculating zone-1 and zone-2 dish

The straight forward offset angle equation to use, I described later in a topic (and in an article, including the derivation of the equation), here: Just Sharing This - Calculation of the focal length of an offset satellite dish antenna, Revisited
From the offset angle and the depth measurement, all other parabolic specs can be calculated (including the topstring and bottomstring lengths, where the feedhorn of the LNB should be).

When you give the four needed measures, I'll put them in my calculator!

Greetz,
A33

 

[william-1]

4 satellite positions is possible with a 60cm Zone 2 dish,
28E 19.2E 13E & 4.8E
I think 42E will require a 90cm dish for multi Lnb's


Not my set up.

 

[william-1]

This was my Multi-LNB set up 28E 19.2E 13E & 4.8E on a 88cm Raven Mesh Dish.

 

[LeBelge]

I try this. Any idea what satellite I can get on the left(I will keep astra 28 in the middle)

LNB 45°E - 39°E - 33°E - 28°E



And it works fine here.

Signal


There are 10 FTA channels

 

[Fisty McB]

The Sky dish in the image attached by the OP looks like a Zone 1 model. If that's the case, you might be able to get an offset LNB for Astra 1 at 19E and that's realistically about it, especially if the main focus of the dish is retained at 28E - the spacing between 19E & 13E will be too small with most LNBs and even then, the LNB offset for the 13E LNB (15 degrees) will likely give poor results particularly on some transponders, even if there's no LNB for 19E present. Likely to be the same using an offset LNB for Turksat (42E) on the same dish - a few transponders might come in but they'll be little rain fade protection.

If the OP is concerned by the aesthetics of a satellite dish "standing out" compared to a Sky minidish, it would be worthwhile considering getting a Zone 2 dish installed instead, which is much friendlier for multi-lnb setups in my experience. A common setup with this is to have the main focus at 19E with offsets at 28E and 13E - the 19E and 13E LNBs will almost certainly be touching together and it's best to get some of the more "narrow" 40mm universal LNBs** when doing this. 28E, even on the Astra 2G European beam will throw in plenty of signal strength to compensate for the dish offset, and 19E is similarly powerful - 13E is usually the (slightly) weaker of the three but if done properly should get all transponders in most parts of England. Those three satellite positions together should give you a lot of what is broadcast above the European skies and a good place to start at before potentially going bigger (e.g. further multi-lnb setups or a motorised system).

Beyond a Sky Zone 2 dish, any multi-lnb setup really needs to start at 80cm or bigger to help compensate for the loss of signal receiving a satellite at an offset-from-focus position even among the more powerful birds in the Clarke Belt. My own rule-of-thumb/experience is that at such a regular offset dish size, up to +/- 10 degrees from the focus position will usually be "okay" for an offset for a reasonably powered satellite - beyond 10 degrees, the offset losses start to rise more quickly the further you move away from the focus position. For example, where I live (County Tyrone) I presently have an 80cm dish focused on 13E - this has four Ku Band LNBs aimed at 23.5E, 19E, 13E and 9E (though the 9E LNB is a bit of a struggle as it's tight against the 13E LNB and likely isn't in an optimal offset position) - 5E is also a possible option, but I'd either need a very slim LNB or leave out 9E altogether.

** I would have previously recommended Inverto Eco LNBs (the ones with the green cap) for this but I'm not sure Inverto make these any more.

 

[Adam792]

The Sky dish in the image attached by the OP looks like a Zone 1 model. If that's the case, you might be able to get an offset LNB for Astra 1 at 19E and that's realistically about it, especially if the main focus of the dish is retained at 28E - the spacing between 19E & 13E will be too small with most LNBs and even then, the LNB offset for the 13E LNB (15 degrees) will likely give poor results particularly on some transponders, even if there's no LNB for 19E present. Likely to be the same using an offset LNB for Turksat (42E) on the same dish - a few transponders might come in but they'll be little rain fade protection.

If the OP is concerned by the aesthetics of a satellite dish "standing out" compared to a Sky minidish, it would be worthwhile considering getting a Zone 2 dish installed instead, which is much friendlier for multi-lnb setups in my experience. A common setup with this is to have the main focus at 19E with offsets at 28E and 13E - the 19E and 13E LNBs will almost certainly be touching together and it's best to get some of the more "narrow" 40mm universal LNBs** when doing this. 28E, even on the Astra 2G European beam will throw in plenty of signal strength to compensate for the dish offset, and 19E is similarly powerful - 13E is usually the (slightly) weaker of the three but if done properly should get all transponders in most parts of England. Those three satellite positions together should give you a lot of what is broadcast above the European skies and a good place to start at before potentially going bigger (e.g. further multi-lnb setups or a motorised system).

Beyond a Sky Zone 2 dish, any multi-lnb setup really needs to start at 80cm or bigger to help compensate for the loss of signal receiving a satellite at an offset-from-focus position even among the more powerful birds in the Clarke Belt. My own rule-of-thumb/experience is that at such a regular offset dish size, up to +/- 10 degrees from the focus position will usually be "okay" for an offset for a reasonably powered satellite - beyond 10 degrees, the offset losses start to rise more quickly the further you move away from the focus position. For example, where I live (County Tyrone) I presently have an 80cm dish focused on 13E - this has four Ku Band LNBs aimed at 23.5E, 19E, 13E and 9E (though the 9E LNB is a bit of a struggle as it's tight against the 13E LNB and likely isn't in an optimal offset position) - 5E is also a possible option, but I'd either need a very slim LNB or leave out 9E altogether.

** I would have previously recommended Inverto Eco LNBs (the ones with the green cap) for this but I'm not sure Inverto make these any more.

I use the set-up you've described - a Zone 2 dish with 3 Inverto Eco LNBs, aligned on 19.2°E with 13°E and 28.2°E offset, it's been working perfectly for me for the last 12 months now.

The 13°E and 19.2°E LNBs are very close, and the 28.2°E LNB is realistically about as close as you can get on the other side without using a very thin LNB or modifiying the 40mm LNB bracket - the screw gets in the way. I'd initially wanted 7°E - 13°E - 19.2°E (satellite only secondary for UK stuff here, we mainly use DTT).

 

[ozumo]

I forgot about the mk4 screw, on a mk2 dish the LNB collar is a similar diameter to a 'normal' 40mm feed horn. Currently I have a mk2 Zone 2 pointed at 28.2°E with a standard 40mm LNB, 19.2° offset with an Inverto Eco, and between them I zip-tie in a 23mm Inverto Multiconnect LNB for 23.5°E. I've tried to add 13°E but couldn't lock anything, though it maybe partially blocked by foliage.

@a33 give me a couple of days and I'll dismantle a Zone 2 so it can be measured

 

[Adam792]

I forgot about the mk4 screw, on a mk2 dish the LNB collar is a similar diameter to a 'normal' 40mm feed horn. Currently I have a mk2 Zone 2 pointed at 28.2°E with a standard 40mm LNB, 19.2° offset with an Inverto Eco, and between them I zip-tie in a 23mm Inverto Multiconnect LNB for 23.5°E. I've tried to add 13°E but couldn't lock anything, though it maybe partially blocked by foliage.

@a33 give me a couple of days and I'll dismantle a Zone 2 so it can be measured

Yeah that's it, even with it being one of the cheap 40mm adapter ones rather than the Sky LNB-sized ones that come with the dish, the screw still sticks out a fair way.

 

[ozumo]

Interesting the gap between 19.2°E & 28.2°E on your dish is closer than mine, even without the screw I don't think a slim LNB would fit in there? My LNB rail is curved so maybe that makes a difference

 

[Adam792]

Interesting the gap between 19.2°E & 28.2°E on your dish is closer than mine, even without the screw I don't think a slim LNB would fit in there? My LNB rail is curved so maybe that makes a difference

Yeah the cap of the 28.2°E LNB is all but touching the screw.

Interesting about the curved rail, I imagine that gives a slightly better signal than a straight one like the one I have in terms of making the LNB point more accurately at the reflection point!

 

[ozumo]

Interesting about the curved rail, I imagine that gives a slightly better signal than a straight one like the one I have in terms of making the LNB point more accurately at the reflection point!

A washer or two under one of the legs of the LNB holder should add a bit of angle, or the rail could be bent. Will have to try 19.2°E in the middle and compare signal sometime.

 

[Fisty McB]

A washer or two under one of the legs of the LNB holder should add a bit of angle, or the rail could be bent. Will have to try 19.2°E in the middle and compare signal sometime.

I've used several of those rails in the past & present for multi-lnb setups. The rail, whilst generally stiff, can be bent with a bit of force where it might help. Alternatively, I've often found that for the more easterly satellites away from the focus come in a little better if the LNB is tilted backwards a little bit i.e. the face of the LNB looks slightly more upwards towards the dish, and the best way I've dealt with this is to use a small bit of a thin cable tie (e.g. 3mm) placed between the LNB holder and the rail below the screws - this tilts the bracket up slightly as you screw it to the rail to give a better signal. Also, if you have two LNBs touching each other where the outer of the two LNBs gets a better signal if you force it to look more towards the centre of the dish, but the bracket can't hold the LNB in that position, use an object to bridge the gap between the body of the two LNBs in question that'll stay put - I just use a small stone jammed into place.