Multiple STB advice

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samnorr

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#40568 31-Aug-2009 15:41

I have a scenario I need some help with:

I currently have a single Sky dish on the roof, which is connected straight to a DVB-S tuner card in my PC (to view Freeview).

I now want to purchase an STB to get Freeview on a TV in another room (at the same time as on the PC), but only have the single cable coming out from the dish.

What's the best way to go in this case? I read somewhere that simply using a splitter will weaken the signal and cause the two tuners to interfare with each other, so do I have to purchase a new dish or swap the LNB on the current one (for a multiple output version)?

The Sky dish was left on the house from the previous tenants, who used it to watch Sky TV. So do Sky actually own the dish, meaning I won't be allowed to modify it?

I would really appreciate some advice. :)

Jaxson

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#251977 31-Aug-2009 15:58

Assuming your gear is in ok condition already you'll be fine splitting the signal into two.
A basic splitter will do this.
Alternatively, you could run the existing cable to the set top box and use a loop out from this off to the next point.
If you get a splitter you'll need some new f plugs to hook it up.

Remember that something needs to power the lnb. Look for one that has 'all ports power pass' configuration, as this allows each device to independantly power the lnb on the satellite dish. That way you don't have to have one device permanently on to use the other device. (hope that makes sense).

There's a lot of debate about who owns what with the sky dish. In practise you're probably fine to go ahead and do what you like to it. Others here will chip in with their opionons too. It's a grey area, that's all there is to it. You don't actually need to modify anything with it to achieve what you're after if you use a loop out, or put your splitter on the end of the cable that's already there.

Remember that your standard lnb can only do horizontal or vertical at any one time. If you tune in SBS which is vertical, you can't watch anything in horizontal (freeview) at the same time, and vice versa.

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Dingbatt

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#251978 31-Aug-2009 16:00

I run 2 sky decoders, one satellite STB and an HTPC with a satellite tuner card all off one dish (1 cable). Have not had any tuning interference apart from being unable to tune SBS because it is the opposite polarity from freeview/sky.
You can use a diode steered splitter to ensure the lnb is powered regardless of which tuner is switched on.

“We’ve arranged a society based on science and technology, in which nobody understands anything about science technology. Carl Sagan 1996

samnorr

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#251999 31-Aug-2009 17:07

What's SBS?

samnorr

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#252130 1-Sep-2009 09:52

bump

Dingbatt

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#252132 1-Sep-2009 09:56

samnorr: What's SBS?

See thread in this forum.

“We’ve arranged a society based on science and technology, in which nobody understands anything about science technology. Carl Sagan 1996

samnorr

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#252417 1-Sep-2009 22:00

I went into Dick Smith today to look at STBs, and asked about splitters. The guy there told me that they didn't have dual power-pass splitters (just single pass) and suggested that I look in another shop down the road (Jaycar Electronics)

The man in Jaycar showed me that they did indeed have dual power-pass splitters, but warned that having two connected devices providing power at once could fry the LNB. He said that in order to avoid this you have to go into the menu of the STB and disable LNB Power, a setting which was hard to access on some models. He reckoned that in my case it would be safer to just use a single power-pass splitter (which Jaycar didn't sell, meaning going back to Dick Smith), as the STB would probably power the dish in stand-by mode anyway.

I haven't bought anything yet, as I would like some more clarification from you guys first. Was the Jaycar man correct about the dual power-pass splitters damaging LNBs? Will the STB still power the LNB (and allow the PC to receive a signal) in stand-by mode? And what is a "diode steered splitter" that Dingbatt mentioned (is it different from a dual power-pass)?

Also, is the DSE-7500 STB a good buy (or are there any others to choose from)? It's on special in Dick Smith at the moment ($169), and seemed to be the only satellite STB model they had. Or are they perhaps cheaper somewhere else?

I hope that's not too many questions.

cyril7

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#252543 2-Sep-2009 12:54

Hi, you only require a dual power pass splitter if you intend to have one of the STBs not connected to the power pass port. In most folks homes the STB in the lounge runs 24/7, if thats the case then just get a single pass splitter and connect the lounge STB/s to that port and this will mean that as long as the lounge STBs are on then the LNB will get power and the STB on the other leg will still get signal.

If you want to have it so you can turn off or remove the STB on the path that passes power and still get the other STB to work then get a diode steer splitter, this will prevent the power from one STB going back up the other STB. A power pass without diode steer is a very uncommon splitter indeed, I would doubt jaycar would have one (not that I have checked) but its more likely its diode steer even if it does not state it. A dual pass (non diode steer) will not damage the LNB but might get the DC feeder in one of the STB tuners a bit warm, but still not likely.

Personally I dont like the DSE 7500, it works ok but nothing flash, you would be better with a non certified box like the one linked below, that site also has two way splitters that pass power to both ports (with diode steer not that it states it).

http://www.freeviewshop.co.nz/topfield-tf6000fe-digital-satellite-receiver-p-491.html

Cyril

richms

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#252585 2-Sep-2009 14:42

I can assure you that a diode steered power pass splitter will not fry your lnb. The ones without diodes are just normal splitters that they have no DC blocking on any of the ports, and are normally used on VHF/UHF insalls where you are sending DC/AC over the coax to power masthead amps or carry IR signals back to source equipment.

A non diode all port powerpass splitter will cause you problems when one piece of gear is off and the other is not, and it drags the voltage down on the LNB feed.

Richard rich.ms

samnorr

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#252589 2-Sep-2009 14:46

cyril7: Hi, you only require a dual power pass splitter if you intend to have one of the STBs not connected to the power pass port. In most folks homes the STB in the lounge runs 24/7, if thats the case then just get a single pass splitter and connect the lounge STB/s to that port and this will mean that as long as the lounge STBs are on then the LNB will get power and the STB on the other leg will still get signal.

If you want to have it so you can turn off or remove the STB on the path that passes power and still get the other STB to work then get a diode steer splitter, this will prevent the power from one STB going back up the other STB. A power pass without diode steer is a very uncommon splitter indeed, I would doubt jaycar would have one (not that I have checked) but its more likely its diode steer even if it does not state it. A dual pass (non diode steer) will not damage the LNB but might get the DC feeder in one of the STB tuners a bit warm, but still not likely.

Personally I dont like the DSE 7500, it works ok but nothing flash, you would be better with a non certified box like the one linked below, that site also has two way splitters that pass power to both ports (with diode steer not that it states it).

http://www.freeviewshop.co.nz/topfield-tf6000fe-digital-satellite-receiver-p-491.html

Cyril

Thanks for the advice.

So do you think it's best to get a diode-steered or just a single power-pass splitter? The STB would be used in a bedroom, so would it be fine to leave it on 24/7?

And you're certain the LNB wouldn't get damaged from two power streams going to it at the same time? A diode steered splitter wouldn't stop that from happening would it? Would it only protect the STBs?

richms

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#252598 2-Sep-2009 15:01

Diode steer will allow the highest voltage to power the lnb, and stop it going back to the other stb.

If you get a single port splitter, you end up with the power dropping out making the other box lose signal on channel changes between transponders I have found, also the DSE box doesnt powr when off so that means that the other leg would have to be powering it if it wants to recieve.

Richard rich.ms

cyril7

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#252601 2-Sep-2009 15:05

Hi, well as long as you are aware that you need to keep the STB thats on the power pass port on for the other box to get signal then there is not an issue, if thats going to be operationally not good for you then a power pass both port splitter is the business.

The diodes will steer the current from the supply thats got the highest voltage (within 0.6V) to the LNB, the lower volts STB will end up not providing any of the current, no biggie, no damage to anything, naturally the diode will also stop the current from back flowing toward the other STB. That said even without diode steer assuming both STBs are on the same polarity they will source a supply current with a voltage very close to each other, so any current flowing between will be small and of little issue.

Trust me these splitters are in use every day and dont cause a problem. A quick look at the jaycar site, and it seems they only have sat rated splitters with power pass on one port, the V/UHF rated splitter LT3044 will pass power on both ports but is not suited for satellite use as its limited to 900MHz top frequency.

Cyril

Jaxson

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#252613 2-Sep-2009 15:37

samnorr: Thanks for the advice.

So do you think it's best to get a diode-steered or just a single power-pass splitter? The STB would be used in a bedroom, so would it be fine to leave it on 24/7?

And you're certain the LNB wouldn't get damaged from two power streams going to it at the same time? A diode steered splitter wouldn't stop that from happening would it? Would it only protect the STBs?

Trust Cyril, you won't regret it.

My advice, get a splitter. It's a pain when you want to use the device in another room and it says no signal which then reminds you to get up and turn on the other device. A splitter gives control to whatever device you needs it at the time.

You'll need to get one as Cyril has pointed to which has all ports power pass written on the front, and one that is designed for sat use. If purchased from a reputable dealer (freeviewshop is very helpful and quick too) then it will give you the most flexibility and not harm your gear. It really is over to you now.

samnorr

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#252754 2-Sep-2009 21:28

cyril7: Hi, well as long as you are aware that you need to keep the STB thats on the power pass port on for the other box to get signal then there is not an issue, if thats going to be operationally not good for you then a power pass both port splitter is the business.

The diodes will steer the current from the supply thats got the highest voltage (within 0.6V) to the LNB, the lower volts STB will end up not providing any of the current, no biggie, no damage to anything, naturally the diode will also stop the current from back flowing toward the other STB. That said even without diode steer assuming both STBs are on the same polarity they will source a supply current with a voltage very close to each other, so any current flowing between will be small and of little issue.

Trust me these splitters are in use every day and dont cause a problem. A quick look at the jaycar site, and it seems they only have sat rated splitters with power pass on one port, the V/UHF rated splitter LT3044 will pass power on both ports but is not suited for satellite use as its limited to 900MHz top frequency.

Cyril

Thanks heaps for the explanation - I think I understand now.

Sounds like the diode steered splitter would be the best bet then. I will see what I can find on the Freeview online shop - it looks like they have a far wider range of STBs than Dick Smith do as well.