Question about Diseqc and whats possible

machiavellianme

Hi,

I currently have a SKY+ box and am interested in adding another receiver to pick up 19e. I have seen pics on this forum that give me confidence in attaching a second LNB via bracket to the sky dish to achieve this but I have a question regarding whats possible with Diseqc.

Unfortunately, I am restricted to the two cables currently running from my sky box to the dish and canot add another. I know I could simply work with 1 cable to each LNB, with the 28 degree LNB connected to the sky box and the 19e connected to my other receiver.
I would prefer however to do something more elaborate as Sky+ might require 2 connections are various times (watching soccer while recording soaps etc) and 19e would only be for occasional use. I would rather not have to manually reconnect each cable to the desired LNB each time so was hoping I could do something like in my picture below:


I.e. can I have a Diseqc switch on both ends of one of the cables?
1 would combine the LNBs while the other end would select which receiver.
I was thinking of getting something like this for the (diseqc2) end where the receivers are connected so I could manually swap over and this for the other (diseqc1) end.

Is what I have outlined feasible? Or are there any better ways to do it?
Thanks for any help.

Peter Rhea

That should work & is better than a loopthrough from the FTA receiver, just be aware that the manual switch is simply that; a manual switch. DiSEqC is the protocol for receiver controlled (i.e. automatic) switches.

Sky boxes don't do DiSEqC, so connect 28E to port 1 of the switch.

zg3409

The first image is not working for me (work probably blocking the site)

You do not need to use a mechanical switch.

Basically you want a setup so that if the 19E box is plugged in, it will automatically take over the cable & when it is turned off, the Sky box uses the cable.

One problem you may come across is that the Sky boxes uses both input 1 and 2 from time to time for different things. You may be better to use input 1 on the Sky box. This is mainly used for live TV, while input 2 is mainly used for recording in the backround. By using input1 you would notice when it is not working. If you split input 2, recordings will fail without you noticing at the time.

Another option is to set, in the menu of the sky box "single cable mode". If you attempt to do something that needs the second cable, the box will warn you what you are doing is not possible. Then you can make sure both cables are working, then change the box out of single cable mode.

As Peter said use a two port DiSEqC switch up at the dish end. Put the Sky LNB on port LNB1, the 19E LNB on port LNB2, and the cable down to "receiver"

But at the receiver end I would recommend this:
http://www.pulsat.com/products/Digiality-Smart-Priority-Switch.html

You would put the 19E receiver on Port A. The Sky box goes on port B. You would need to unplug the 19E box and when you do so, the Sky box is automatically connected. It probably won't work if the 19E is just put into standby mode. Best to get a box that has a mains switch on the back, to save you plugging it out all the time.

You should probably connect the 19E to the TV with Scart and set it up so once the 19E box is on, it takes over the TV and the TV automatically switches to Scart.

In this way it would be less likely that someone would get confused and end up trying to record when the second lead is not connected.

If you can at all run an extra cable. This sort of setup would drive me insane. At least if you use the Sky box in single cable mode you are less likely to miss recordings.

Extinction

Why not just use a stacker-destacker for the sky+ box and use the second cable for 19E?

zg3409

You could use a stacker destacker.

http://www.satbuyer.co.uk/global-stacker-de-stacker-diseqc-enabled-p141.html

However they are very particular on the quality of the installed cable. They are also expensive. Best to put 19E on "RF O/P SAT: 949-2149MHz" as this is the side that is most likely to not work properly.

The staker and destacker needed to mounted as close together as humanly possible. You may find problems on certain channels and not on others.

Peter Rhea

A loop from the 19E receiver's IF out will do the same job as the priority switch. The switch is only for cases where the receivers are far apart (say different rooms) & it's more convenient to split the cable before it goes to either.

Stacker/destacker is complete overkill. The OP's own solution with the manual switch seemed simplest for users of the Sky box to understand, just make sure it's set to 'Sky' & no need to worry about what the other box is doing.

zg3409

Peter Rhea wrote: »

A loop from the 19E receiver's IF out will do the same job as the priority switch.

No it won't. If the Sky box is connected to the IF out of the 19E box. then there may be problems. For example if the Sky box is on (which it always is) and it decides to select a horizontal transponder it will supply 18V. If 19E box is watching a vertical transponder it will be sending 13V to LNB. Suddenly the 13E box will stop working.

So no the IF out is not the same as a priority switch. In a priority switch a physical wire moves (not so much now a days) that disconnects the Sky box, and instead connects the 19E box, which is not what an If out does.

Peter Rhea wrote: »

Stacker/destacker is complete overkill.

It depends. If the other half misses a corrie recording then the OP may end up killed!

Peter Rhea

zg3409 wrote: »

. . . For example if the Sky box is on (which it always is) and it decides to select a horizontal transponder it will supply 18V. If 19E box is watching a vertical transponder it will be sending 13V to LNB. Suddenly the 13E box will stop working.

You're right of course, the higher voltage will win out rather than the 1st in line receiver.

machiavellianme

Thanks for the help guys. I think I will have to go with the diseqc solution with the switch zg3409 suggested as the stacker option won't work beyond 30 metres. I measured it at 35. Moving it is not an option. The voltage issue is interesting and something to be aware of. I'll definitely keep that in mind. Unless the long distance 60m stackers are worth it?

zg3409

Stackers only work well when top quality cable has been used with copper screen and 100% copper core. Also no sharp bends or squashing or kinks or twists on the cable. As I said ideally over the shortest distance possible.

The main issue is losses in the cable. Less so with interference from nearby wifi (laptops etc.), mobile phones, mobile phone masts etc.

With the proper test equipment it is possible to see if it will not work. Otherwise it's probably a 50/50 thing assuming you have the correct cable installed.

machiavellianme

Not sure its worth a < 80 euro risk for a 50/50 outcome for a stacker/destacker.

zg3409

Did you check the existing coax so see if the screen was copper (orange/brown) or tin (grey)? If grey then forget it.

kooga

apologies from the outset if i get the terminology wrong.

Trying to install a stacker destacker

2 existing 60cm dishes one at 19.2 and 28.4 and 2 receivers in separate rooms.

I want to set up a SkY HD box and have its own feed. We put a Stacker on the 28.4 dish and destacker set up in the TV room however only one of the outputs from the destacker is getting a signall. so at the mo i need to move the sat cable between the sky box and my combo box. My installer is mystified and feels that the stacker split on the dish before the diseqc in the attic is causing the problem

My only alternative is to drill a hole in the wall and run a separate connection from the sky box to the sat LNB. Ment to post this earlier but was holding tough till my setanta card arrived which it has today.

Again guys i am open to clarification

Mrs. reluctant about the drilling just want to examine all avenues

Tks again

Peter Rhea

The DiSEqC switch won't pass the upper range of frequencies from the stacker.

kooga

Peter Rhea wrote: »

The DiSEqC switch won't pass the upper range of frequencies from the stacker.

Thanks Peter, could the stacker be installed after after the diseqc, that is dish, diseqc, stacker, Sat boxes?

Peter Rhea

kooga wrote: »

. . . could the stacker be installed after after the diseqc, that is dish, diseqc, stacker, Sat boxes?

Should work that way, yes.

kooga

think i have it cracked i need an SDS Line Amplifier as well which allows signals to pass through the diseqc switch. All comments greatly appreciated especially how i might configure/ lay out this arrangement.


The SDS has been designed to allow two satellite signals to be fed down one coaxial cable before being returned to its original configuration to feed two STB’s or a twin tuner satellite STB. Signals can be supplied by either a universal multi-port LNB or more typically from a multiswitch. By allowing DiSEqC commands to pass through the “Stacker” it is possible to connect the unit to a DiSEqC multiswitch for operation on a 9 wire system

line_amp.jpg

Peter Rhea

I presume you twigged that SDS = Stacker De-Stacker.

You should only need the amplifier if your cable length exceeds 30m between stacker & destacker. It's just to allow the possibility of the system working over longer cables, nothing to do with 'allowing signals to pass'.

Also, you mention a combo box: is there a terrestrial aerial connected & does it have its own cable?

kooga

hi peter tks for that no i hadn't twigged SDS.

I have a combo box and coming out of the wall to it is a terrestial and sat feed. My sat feed is 19.2 and 28.4 i have the same set up in the bedroom.

I got a sky hd box and at the moment i have to share the sat cable between the combo box and sky box. I got the sky box to get a bt sub. Between the attic and the tv outputs is one single cable within the walls.

previously when we set up the destacker downstairs only one of the outputs was getting a sat signal. we were under a bit of time pressure and the reason given was the signal when split on the stacker on the dish couldn't get through the diseqc switch in the attic. I am really trying to avoid a drill through the wall and connect externally up to the dish. (new house extension etc).

Any suggestions, i know in the attic we have diseqc etc, so could the stacker be installed after the diseqc? u had mentioned that might work

Peter Rhea

The frequency range of the DiSEqC switch is probably something like 900-2400 mHz. The Global stacker uses freqs. up to 3700 mHz, so the switch is going to cut out most of the signal from the 'converted' lnb. Even if the switch did pass the whole frequency range, you would lose the feed from the stacker whenever you view a channel from 19E.

You already have the solution i.e. put the switch before the stacker.

28E lnb ------ DiSEqC port 
                         /----- Stacker input
19E lnb ------ DiSEqC port                  /----------to destacker                          
                                                     
28E lnb2 ---------------------- Stacker input

kooga

tks peter will investigate and keep you updated.

kooga

Peter Rhea wrote: »

The frequency range of the DiSEqC switch is probably something like 900-2400 mHz. The Global stacker uses freqs. up to 3700 mHz, so the switch is going to cut out most of the signal from the 'converted' lnb. Even if the switch did pass the whole frequency range, you would lose the feed from the stacker whenever you view a channel from 19E.

You already have the solution i.e. put the switch before the stacker.

28E lnb ------ DiSEqC port 
                         /----- Stacker input
19E lnb ------ DiSEqC port                  /----------to destacker                          
 
28E lnb2 ---------------------- Stacker input

just to add where can i add my saorview aerial to the above to have it all coming down the one cable ?

Peter Rhea

One of the stacker inputs will accept terrestrial signals. You will need to combine the satellite & terrestrial signals going to this input with something like this.

kooga

I have edited diagram that was on the TV trade website which i sent to my installer who belives that we cannot get 4 feeds down a single cable and the only alternative is to run a single cable from the astra 28.2 dish indepently to the new sky hd box.



That is drill a hole in the wall rather than through the attic ( the sky box is recently acquired as i wanted a setanta sub) everyting else is in place.



Tks again Peter

Peter Rhea

kooga wrote: »

I have edited diagram that was on the TV trade website which i sent to my installer who belives that we cannot get 4 feeds down a single cable

Provided the stacker/destacker is 'DiSEqC compatible' there is no reason why such a setup won't work. (Provided the DiSEqC switch is feeding a DiSEqC compatible receiver, not the Sky box as shown in your diagram.)

It's only actually 3 feeds at any 1 time: the terrestrial signal & 1 of the sat. feeds on the 'unconverted' leg of the stacker, the other sat. feed on the frequency converted leg. The Global stacker can output in the range 15-3700 mHz.

kooga

Peter Rhea wrote: »

Provided the stacker/destacker is 'DiSEqC compatible' there is no reason why such a setup won't work.

It's only actually 3 feeds at any 1 time: the terrestrial signal & 1 of the sat. feeds on the 'unconverted' leg of the stacker, the other sat. feed on the frequency converted leg. The Global stacker can output in the range 15-3700 mHz.

Thats what i keep saying to my installer who has been excellent i have done a lot of research on this topic and with assistance from your goodself..........now the prob is he believes it won't work and a separate run to the dish is the only option. in addition i have paid for the sky box and the job done and i don't want the drilling as if i opt at a later date for a triple tuner my second sat feed will not have astra 19.2

Throwing it out to the floor anybody in cork city centre that could assist. i know the stacker is expensive the previous non disecq one was costing me €85 anyway realise the disecq enabled one is a bit more.

Any assistane would be great.

Peter Rhea

kooga wrote: »

i don't want the drilling as if i opt at a later date for a triple tuner my second sat feed will not have astra 19.2

Triple tuner? To replace the Sky box & the combi with 1 receiver?

You can always add another DiSEqC switch to include 19 east on the second feed. You will need to do this whether or not the SDS is installed.

kooga

Peter Rhea wrote: »

Triple tuner? To replace the Sky box & the combi with 1 receiver?

You can always add another DiSEqC switch to include 19 east on the second feed. You will need to do this whether or not the SDS is installed.

tks peter, appreciate the advice

Peter Rhea

As regards your attached diagram above: you should either have destacker output 1 feeding the combi satellite input or, have the DiSEqC switch on stacker input 2, with the sat./terr. combiner.