Advice Needed Fibre vs Coax for IRS for one building?

[tfc]

All the information that I have seen concerning Fibre IRS is using fibre for long distances to the dish, or for multi building application.

Is there any point in using a fibre solution over a coax solution for one building with 32 flats with one dish? How would the switching be done to allow residents independent choice of channels?

Also how would (or could) the system work if two dishes were required?

Thanks

 

[Terryl]

Take a look at the Pro line of EMP switches.


Here is an example, it's only 26 outputs but they have bigger ones.

http://www.emp-centauri.cz/index.php?lang=en&page=prodview&id_kateg=1&id_pkateg=12&id=236

 

[rolfw]

There are big advantages to using Fibre on larger apartment blocks and it depends on the number of outlets required in the apartments as to how cost effective it is. I installed a fibre to apartment system last year, two blocks of five, linked by underground car park, using a quad IRS unit in each apartment and a fibre splitter with two quad units in the penthouse, so no copper cables and earthing required from head end to apartment. Obviously can be used also to terminate in a riser using a quattro GTU and expander, then radiate via copper cable to apartments. Global Invacom make a fibre unit wich will handle two dish inputs and 32 fibre passive optical networks, but the two sat version is a more expensive option and not suitable for fibre to apartment installations for cost reaons.

Global Invacom

 

[tfc]

Take a look at the Pro line of EMP switches.


Here is an example, it's only 26 outputs but they have bigger ones.

http://www.emp-centauri.cz/index.php?lang=en&page=prodview&id_kateg=1&id_pkateg=12&id=236

Thank you for your reply. I understand that such devices are available, but they are using coax connections. Where would fibre be used? Presumably in the backbone between the dish and the multiswitch, and that would have to be positioned reasonably centrally. But in a single building with a longest run of say 60 metres, the backbone would be about 5 metres. What am I missing?

 

[tfc]

There are big advantages to using Fibre on larger apartment blocks and it depends on the number of outlets required in the apartments as to how cost effective it is. I installed a fibre to apartment system last year, two blocks of five, linked by underground car park, using a quad IRS unit in each apartment and a fibre splitter with two quad units in the penthouse, so no copper cables and earthing required from head end to apartment. Obviously can be used also to terminate in a riser using a quattro GTU and expander, then radiate via copper cable to apartments. Global Invacom make a fibre unit wich will handle two dish inputs and 32 fibre passive optical networks, but the two sat version is a more expensive option and not suitable for fibre to apartment installations for cost reaons.

Global Invacom

Thank you for your reply. That was useful. I can see that the GTU cost is the thing that can kill it, particularly if 2 dishes are required.

 

[PaulR]

I would guess you would need something like this to combime the two satellites optically for distribution. I've no direct experience (unlike Rolf) but probably this would be needed as well (instead of?).

The idea is to distribute optically as much as possible. But it's expensive and really the cost is only justifiable on large and/or long distance distributions.

 

[tfc]

I would guess you would need something like this to combime the two satellites optically for distribution. I've no direct experience (unlike Rolf) but probably this would be needed as well (instead of?).

The idea is to distribute optically as much as possible. But it's expensive and really the cost is only justifiable on large and/or long distance distributions.

Thanks, yes I can see where it becomes expensive now. I agree, it only seems to be cost effective on large or long distance distributions.

 

[PaulR]

I recently bought a 9 in 8 out EMP Centauri multiswitch following a link from a post by Manicscrewdriver here.

In fact it sounds like you need one of these. Plenty of outputs there, enough for a double feed to almost every apartment. Or you could use two or three of these and position them to best effect on different floors. You would also need a launch amplifier and splitters (possibly just splitters if you're lucky) to feed these multiswitches and a lot more cabling between floors but the cabling from the multiswitches to the apartments could then be less. You would have look at the layout of the apartment block to make your decision.

 

[PaulR]

One thing I forgot to mention is that they are open to "best offer", especially if you're buying multiple items.

 

[rolfw]

Thank you for your reply. That was useful. I can see that the GTU cost is the thing that can kill it, particularly if 2 dishes are required.

How many feeds do you require to each apartment, 32 apartments is considered as a large system (how many apartments per floor), particularly if you require more than two satellite feeds to each unit.

 

[A nonymous]

I would say it all depends on how far away the furthest point would be from the headend and how far the dish and aerial are from the headend before deciding on wether to go down the fibre route or stick with the cheaper copper cable.

I haven't aas much experience with fibre as Rolf so i would go with what Rolf advises on that one.

Normally the building owner will usually go for the cheapest cost providing the system will actually work.

Nano

 

[Terryl]

Thank you for your reply. I understand that such devices are available, but they are using coax connections. Where would fibre be used? Presumably in the backbone between the dish and the multiswitch, and that would have to be positioned reasonably centrally. But in a single building with a longest run of say 60 metres, the backbone would be about 5 metres. What am I missing?

With those short runs good high quality coax can be used, fiber would only be used if the run from the dish was over lets say 100 meters or more, under 100 meters then RG-11 coax can be used to get the signals down from the LNB to what ever switch will be used.

Right now fiber for satellite systems is a bit expensive, and doing it yourself requires some skill.

 

[A nonymous]

And a fibre splicer and fibre meter

 

[rolfw]

And a fibre splicer and fibre meter

Don't need a splicer, just use pre-terminated cable, not expensive and easy to use. I've never used a fibre meter, just used a quad MTU to convert to IF.

 

[tfc]

How many feeds do you require to each apartment, 32 apartments is considered as a large system (how many apartments per floor), particularly if you require more than two satellite feeds to each unit.

We want for each apartment the ability to be able to receive DTT, DAB, FM, Freeview, FreeSat+, Sky, Sky+ at a multiplexed faceplate e.g. Triax 304264. All the apartments are in the same building, a straightforward block. There are no external connection requirements.

There are 8 floors, 4 apartments each floor. The dish(es), and DTT and DAB antenna will be on the roof.

I would have expected that a solution would involve basically a 9 channel 4 way splitter to 4 off 9X16 Multiswitches, then 2 coax cables to each apartment. To try and be flexible we would like the system to be able to handle 2 dishes if required in the future, hence the 9X16 multiswitches.

I should point out that because of the existing 'TV position' within the building design, the cabling is almost certainly to be external, so the multiswitches will be positioned in a plant room on the roof near the dish(es)/antenna.) This precludes the possibility of having multiswitches in an internal common area distributed on alternate floors, because of the extra cost and disruption of cabling within each apartment (from one end to the opposite corner of the apartment).

There has been a suggestion that we should consider fibre solution. From what I have gleaned it seems that fibre is used in the backbone between ODU units at the head end, and GTU units, and then into multiswitches which are coax to the faceplate. In our example the fibre would be about 5 metres long at the very most. To me this system approach would seem to offer no advantage over a conventional multiswitch solution.

I think that there is the possibility to split the ODU signal X2 then X4, then 8X4 and feed the resultant 32 fibres to a GTU (e.g. Invacom F102029 or F102030) , one to each apartment . That would be distributing optically as much as possible. (I am assuming these GTUs have the ability to accept commands from a receiver to select the relevant satellite feed, polarisation and High/Low settings needed.) This seems nice and futuristic, but in the real world, the cost of 32 off GTU units alone would seem to be much greater than the equivalent multiswitches, and if we add in the additional dish flexibility, the cost of each GTU is almost double again. In fact I think the overall cost might be even greater than a 3 or 4 dish multiswitch distribution system.

I feel that there must be something really missing in my understanding, so please don't be afraid to point out where I have gone wrong. Thank you for assisting.

 

[rolfw]

OK, forget fibre, not conviced it'd work for you. would be inclined to use cascaded multiswitches though.

 

[tfc]

OK, forget fibre, not conviced it'd work for you. would be inclined to use cascaded multiswitches though.

Thanks for your input and advice.