C-Band/Ka-Band Reception in the UK (Dish Project: LNBs, Dish, Alignment) - Post your results here...

[moonbase]

Morning @kippysat

One of the advantages of a mobile platform is that is can be lowered onto the castors and rolled around the garden to various locations that give line of sight to a wider range of satellites than a fixed location that may have restricted line of sight. However, if no points in your garden will give a ground level installation line of sight to 40.5W then you do need some means to raise the installation.

Rather than go for such a long pole, you could build a 1.5 metre tall hollow raised platform out of concrete blocks and mortar with footings and a flat solid top surface. The top surface It would only need to have a surface area wide enough to take a tripod ground stand or NPRM and the anchorage. The inside of the structure could be used for storage and would get you up another 1.5 metres with the dish and shorten the length of pole required. I have heavy duty tripod ground stands here that can easily cope with a 2.4m dish and they fit onto a 1.0m x 1.2m rectangle so any structure need not use up a large area of the garden.

'ere, cop for the table below, it lists the basic wind load on the dish.
Note that forces and motion (principle of moments) will add to the anchorage as the wind load might be at the top end of a 4 metre pole and the anchorage will be at ground level.
You will need greater anchorage than that shown in the table, the table simply shows the basic wind load on the dish, it does not factor in pole length and the principle of moments.





Personally, I would source the dish first and plan the install once the dish has been sourced and is on site.
A 2.0m or 2.2m dish will also be up to the task so should be considered.

 

[moonbase]

Morning Moonbase, Amdade, et al,

We did a check on dishpointer and we think we could only clear our roofline and hit 40W if we
placed the dish a few metres in the air. Thor 1 west and 5 West are easier because they are higher in the
air. Based on dishpointer, 40.5W is a lot lower in the sky and doesn't clear our roofline at ground level.
If our garden went back another 20+ metres then we would probably be ok.

I'm in the building trade and know a structural engineer who can help me with wind load calculations, but
if you guys in the know are expressing genuine concern about the dish being that high, then I'm going
to listen.

You could buy a cheap laser pointer and a digital inclinometer and use it to test clearance of your house from the back of the garden.
The theoretical elevation for 40.5W is known for your precise location, proceed as follows:

1. Setup a sloping piece of wood on a table at the back of the garden, loose bricks can be used to alter the slope and hold the wood in place.
2, Use the digital inclinometer to set the sloping wood at the elevation of 40.5W.
3. Place the laser pointer on the sloping wood and check if the beam clears your house.
4. Job done !

If you see the pointer hitting the roof tiles, it will give you and idea how much higher the lower rim of the dish needs to be in order to clear the roof ridge.

 

[kippysat]

Morning @kippysat

One of the advantages of a mobile platform is that is can be lowered onto the castors and rolled around the garden to various locations that give line of sight to a wider range of satellites than a fixed location that may have restricted line of sight. However, if no points in your garden will give a ground level installation line of sight to 40.5W then you do need some means to raise the installation.

Rather than go for such a long pole, you could build a 1.5 metre tall hollow raised platform out of concrete blocks and mortar with footings and a flat solid top surface. The top surface It would only need to have a surface area wide enough to take a tripod ground stand or NPRM and the anchorage. The inside of the structure could be used for storage and would get you up another 1.5 metres with the dish and shorten the length of pole required. I have heavy duty tripod ground stands here that can easily cope with a 2.4m dish and they fit onto a 1.0m x 1.2m rectangle so any structure need not use up a large area of the garden.

'ere, cop for the table below, it lists the basic wind load on the dish.
Note that forces and motion (principle of moments) will add to the anchorage as the wind load might be at the top end of a 4 metre pole and the anchorage will be at ground level.
You will need greater anchorage than that shown in the table, the table simply shows the basic wind load on the dish, it does not factor in pole length and the principle of moments.





Personally, I would source the dish first and plan the install once the dish has been sourced and is on site.
A 2.0m or 2.2m dish will also be up to the task so should be considered.

Thank you Moonbase for the tips and suggestions.

Erecting the type of structure you describe is totally feasible for me and my lads. I'm also glad you
said we only need to go 1.5m above ground as that is within the council threshold for a garden
structure. Council only allows you to go max 2.5m without planning permission.

We could even build it to look like a shed and have a part of it designed for genuine storage.

I'm going to do the checks you suggested with an inclinometer to see exactly what clearance is
required for the bottom of the dish to pick up a signal at 40.5w.

At the moment I think it's a fairly good guestimate that 4m will do it, but it could a lot lower
in actuality. I have to do some testing.

 

[moonbase]

Thank you Moonbase for the tips and suggestions.

Erecting the type of structure you describe is totally feasible for me and my lads. I'm also glad you
said we only need to go 1.5m above ground as that is within the council threshold for a garden
structure. Council only allows you to go max 2.5m without planning permission.

We could even build it to look like a shed and have a part of it designed for genuine storage.

I'm going to do the checks you suggested with an inclinometer to see exactly what clearance is
required for the bottom of the dish to pick up a signal at 40.5w.

At the moment I think it's a fairly good guestimate that 4m will do it, but it could a lot lower
in actuality. I have to do some testing.

@kippysat

Please note that I only suggested a concrete block structure of 1.5 metres tall as a guideline. I have no idea if it will be the best height for your circumstances.
After you have carried out a laser pointer clearance test you will have a better idea of the height required.

As you are in the building trade it should be a fairly easy task for you to erect a stable concrete block structure.
Obviously, the taller the structure the shorter the height of the pole needed for the dish.

If you know the distance from the back of your house to the dish location and the height of the roof apex ridge tiles you can calculate approximately the elevation of the ridge tiles from the planned install location. Or, if you have a laser distance measure as used in the building trade and by surveyors etc such as a Leica unit, it will do it all for you.

 

[manic01]

@kippysat what do you want from this dish that you don't already get?

 

[kippysat]

@kippysat what do you want from this dish that you don't already get?

Hi Manic,
ESPN, ESPN3, ESPN4, ESPN Extra, FOX Sports 1, 2, 3.

I think IPTV is the only other way to get these.

 

[kippysat]

@kippysat

Please note that I only suggested a concrete block structure of 1.5 metres tall as a guideline. I have no idea if it will be the best height for your circumstances.
After you have carried out a laser pointer clearance test you will have a better idea of the height required.

As you are in the building trade it should be a fairly easy task for you to erect a stable concrete block structure.
Obviously, the taller the structure the shorter the height of the pole needed for the dish.

If you know the distance from the back of your house to the dish location and the height of the roof apex ridge tiles you can calculate approximately the elevation of the ridge tiles from the planned install location. Or, if you have a laser distance measure as used in the building trade and by surveyors etc such as a Leica unit, it will do it all for you.

I understand and have taken it as such. Maybe the structure would need to be 2.0m in height. Until, I do the
line of sight checks I won't be sure.

Apologies, for stating 4m in an earlier post, I should have said I am not sure and need to check what the minimum
height requirement is. Forgive me.

 

[moonbase]

I understand and have taken it as such. Maybe the structure would need to be 2.0m in height. Until, I do the
line of sight checks I won't be sure.

Apologies, for stating 4m in an earlier post, I should have said I am not sure and need to check what the minimum
height requirement is. Forgive me.

No worries @kippysat I was concerned about the logistics and cost of an install on a 4.0m pole.
The shorter the pole the better provided it gives clearance to the lower rim of the dish.

One point to consider is that if you use an offset focus dish, the LNB boom arm dips quite low at outer parts of the arc.
Provision needs to be made to ensure the LNB boom arm does not foul anything. This issue does not arise with a prime focus dish.

 

[ArloG]

A few thoughts here. I am almost a bit embarrassed for posting a pic of my 12 footer polar mount.
I tend to not be a bragger. I just had no idea at all that some stupid regulations like a knock on the door to see if you had a tv, how many you have, if your rooftop antenna (it will never, ever be an "areial"....it's a freakin' antenna for chrissakes!) is 3cm too long. Or if you dropped it in a vessel it displaces too much water.
Really? Brits have dish size limits? I read some of the regulations. Is that for everyone including radio amateurs?
Even if you live out in the boonies?
C band reception sounds quite alien to you all 'over there'.
Phone apps that use the camera for a sky view, dishpointer.com. Saves you from purchasing digital gauges or borrowing a transit before your decision.
Another thing. C band reception is not as relaxed as ku installs. It requires quite a bit of precision. I would never recommend a pallet mount.
When zeroing in on a ku sat. Signal increases until you peak it. C band. Signal is there. And then it's not. Especially with smaller dishes.
Just moving the lnbf a hair can make all of the difference in the world.
Terms like orthomode, corotor, polarotor feeds will probably having you all "chimping-out".
So. Pull your socks up and never expect any sort of magic.
Repeatability. Movable dish mounting to hide it from nosy neighbors (notice I left out the un-needed and never required "u"....because, well...I'm a wanker!).
You would want something like a triangle of concrete pillars buried a little under the soil with locating pins for the corresponding surface dish mount to drop onto.
It ain't like going for holiday with a portable ku mount in your caravan. "Going camping in the van", we say.
Never install a dish higher up in the sky than you're willing to work off of a ladder. Remember that.
I'd like to slap the powder off of the wigs of those cape wearing lawmakers over there. The Council. Jeez.

 

[moonbase]

...
Terms like orthomode, corotor, polarotor feeds will probably having you all "chimping-out"...

@ArloG

'ere, cop for some pictures of this C-Band equipment that us Brits are "chimping-out" about. Yes, we even know how to take pictures!
I included a picture of a C-Band polariser barrel that removes the need to use a dielectric plate for circular polarity C-Band signals, just in case you aint heard of one.

1. Orthomode


2. Polarotor


3. Polariser Barrel

 

[amdade]

Just an add on comment, for quite a while the only way I could get ESPN was to put the dielectric plate in the "wrong" pair of slots in the LNBF and reverse the polarity in the RX. Since the FEC change a few months ago its back in the "correct" pair of slots and of course correct polarity setting in the RX.

Why this was the case for me I have no idea, but if you are experimenting with that TP may be worth a try.

Well C Band team, Im back to having the plate in the "wrong" pair of slots, the ESPN TP is now right on the edge. Strangely the Fox Sports TP is back (again plate reversed) with a stronger signal than ESPN. Im not sure if its my setup or something has happened to the ESPN TP. Another change of FEC ?

Im using OpenPLI does anyone know of a way to create a C-band LNB template in OpenPLI that has the polarisation reversed as default ? Im manually typing the TP's in with the opposite polarisation at the moment to match the plate position. Works fine but a bit time consuming...

 

[femi]

You can also enter both levels. One of these will work.

@moonbase
I hope you know that the AVCOMM needs to be matched to the LNB, not just the diameter!

 

[moonbase]

You can also enter both levels. One of these will work.

@moonbase
I hope you know that the AVCOMM needs to be matched to the LNB, not just the diameter!

Yes, the AV-COMM polariser I use came with an LNBF direct from AV-COMM in Australia, I assume they sent a matched LNBF?

A few colleagues I know experimented with LNBF's in an AV-COMM polariser by cutting small sections from the end of the LNBF to change the distance of the LNBF twin probes from the polariser steps.
They found that there was an optimum position for the distance between the twin probes of the LNBF and the steps in the polariser.

I have not tried this myself but the results from others looked OK.

 

[amdade]

You can also enter both levels. One of these will work.

Yes I have from time to time just selected one polarisation in the LNB setup which works if happy with one set of TPs.

Small tweak of focus has improved ESPN TP but I have lost Fox Sports 1,2 and 3 TP

Its not a big problem typing them in manually, just hoped one of you clever guys had a better idea

 

[CBAND CATCHER]

Hi. Are there any working keys for Syfy Bra HD channel in 40.5 West C Band. TP 4043 H. Thanks.

 

[bunkoknotty]

Moonbase That picture of a trimode polarotor,what is that all about?I have never seen one like that and could you explain it more because I am totally surprised at my ignorance.Thanks

 

[moonbase]

Moonbase That picture of a trimode polarotor,what is that all about?I have never seen one like that and could you explain it more because I am totally surprised at my ignorance.Thanks

It is a Chaparral S-Band, C-Band and Ku-Band polarotor.

 

[garatain]

there are more lnb chaparral