Cascading Switches and Multiswitches

[canofan]

I mean this thread as an introduction for constructive discussions on the matter of DISEqC switching and as a platform that tries to solve problems arising from such applications.

This description applies to a single user point of view because DISEqC 1.1 applies only to a single receiver.

Once you decide to go the multi LNB way, you are bound to use DISEqC switches. There are 2 types of those:
committed switch DISEqC 1.0 and
uncommitted switch DISEqC 1.1

1- The DISEqC 1.0 supports a maximum of 4 LNBs. This exists in a passive weatherproof version (gets its power from the receiver), and
an active version multiswitch (gets its power from a mains outlet and usually not weatherproof) used for quattro LNBs, which are then powered directly from the multiswitch, and where no switching within the LNB is required, this last version allows the use of multiple receiver tuning each to a different satellite/transponder.
PS a multiswitch could be used also with single Band non switching LNBs like Norsat CAL AMP and SMW

2- The DISEqC 1.1 supports more than 4 LNBs, but its main advantage is its possibility to cascade with 1.0 DISEqC switches of the two types described above. They exist in the present day as:
2 input when cascaded with DISEqC 1.0 switches max 8 LNBs,
4 input when cascaded with DISEqC 1.0 switches max 16 LNBs,
8 input when cascaded with DISEqC 1.0 switchesmax 32 LNBs and
10 input when cascaded with DISEqC 1.0 switches max 40 LNBs.
This applies whether switching or "quattro lnbs with multiswitch" are used, and of course, using the outputs from both types simultaneously is possible.

Passive DISEqC 1.0 and 1.1 switches when used for switching LNBs do carry power from the 14v/18v/22khz from the receiver to the LNBs.
Multiswitches use the 14v/18v/22khz from e.g receiver A, not to power the LNB, but as a signal for the multiswitch to select the correct polarity for receiver A. This imposes less strain on the switches and receiver.
If all LNBs are quattro (reknown to be virtually fail proof) no strain at all is imposed on the receiver or the cascaded switches, as they do not have to carry current but only voltage signal. This shows the advantage of using such equipment for reliability, stability and durability in the long run, especially when it is undesirable to access LNBs.

 

[Turok]

Hello Canofan!
nice to see you again here,after long time!

the latest diseqec specification told,that is posible to use 64 Satellites/
singel Input,how do you realeized that?

not every receiver,supports,connecting more then 4 lnbs!,over one swtich
openbox is here a very good choice,it supports 8 satelites,over simple one uncomited switch!
Topfield receivers for example,does not do it,would mean,first priority that is work,or not is also the compatibly of the stb itself!

 

[canofan]

Hello Canofan!
nice to see you again here,after long time!

the latest diseqec specification told,that is posible to use 64 Satellites/
singel Input,how do you realeized that?

not every receiver,supports,connecting more then 4 lnbs!,over one swtich
openbox is here a very good choice,it supports 8 satelites,over simple one uncomited switch!
Topfield receivers for example,does not do it,would mean,first priority that is work,or not is also the compatibly of the stb itself!

Hi Turok how is your equipment doing.
I decided to take the Kathrein cas 018, but waiting to find the transportation. One friend of mine has a mobilehome.

Imagine cascading 8 8X non-committed switches on a 8X non-committed switch. That makes 8X8= 64.
Besides, there is the possibility to use the 10X NCs in cascade with the 10X NC That makes 100.
And of course Turok The receiver should support the protocol. Most DISEqC 1.2, though, support also 1.1.

 

[Robbo]

Imagine cascading 8 8X non-committed switches on a 8X non-committed switch. That makes 8X8= 64.
Besides, there is the possibility to use the 10X NCs in cascade with the 10X NC That makes 100.
And of course Turok The receiver should support the protocol. Most DISEqC 1.2, though, support also 1.1.

So what you're saying is that non-committed non-committed DiSEqC 1.1 switches can be cascaded with other non-committed DiSEqC 1.1 switches.?

Have you tried this in practice?. How would you control the 2nd bank of switches?

DiSEqC 1.1 cascaded with DiSEqC 1.0, I have not got a problem with, as in my receiver (anyway) there are two switching options:-

DiSEqC 1.0 (1 to 4)
&
DiSEqC 1.1 (1 to 16)

but there is no option for a 2nd bank of Diseqc 1.1.

(All hypothetical of cours, as no-one is ever going to want 64 positions anyway, LOL)

 

[canofan]

Hi Robbo,

You just treat the first level NC as if it were a 1.0 DISEqC.
On my Dreambox I put the DISEqC parameter on 1.0 and select the port, but instead of using AA, AB, BA OR BB, I go further down the ladder and choose one of the numbers 1 to 16.
The actual limit, if one has the NC16 switch ( I do not know if one exists), should in theory be 16X16= 256 LNBs.

 

[Robbo]

Oh, I see, so on the more advanced receivers such as a Linux box, you are able to effectively use DiSEqc 1.1 twice.

Still, even with a standard receiver you can have 4 (Diseqc1) x 16(diseqc1.1)=64, if the hardware actually existed. But, as you say, 10 way Diseqc1.1 switches are available, so 40 can certainly be done.Where they are all going to point though, nobody knows.

 

[Turok]

Yes all okay here canofan,if you need some more info about katkrein antenna please drop a mail,otherwise,we going offtopic here.)

must a uncomited switch,not always compatible,with every diseqec standart,what i try to say was,it must not automaticly "say".that work,the comited switch protokoll on every stb,with diseqec 1.2 protokoll,some manufactors,implemantad there protocoll i think better,or the confersion of the protokoll in detail!
otherwise i could not explan,why only a little number of currencly stb support this uncomited swtich protokoll 100%,other stb,that would mean on the first view,that the have the same protokoll,hase some menu missing ,that are nesersary for the full relasation off the full protokoll suport!
wirth dreambox 800,i have also extended menus,under gimini where i can set up every detail,in the switch process i want!

and,then we have also the fact,that some swtiches,of difrent brands,works,with one stb,better then with others!

a importent fact ,is the lenth of the cable,and the most failure source,is when you using difrent lnbs,of difrent brands,and every lnb modell has a difrent charching rate,in a test,with 8 antennas,at the same time,i have many problems,with older lnbs that take up to 250 ma instead of 150 ma,it was taking a long time,after i find out what the problem whould be,testing this configuration,not every stb support it,some shows me 4 times,the same signal on 4 inputs,the signal from input one!

,but,on my 30 meter way of cable from every antenna,to the switch,there was stb that works good,and the other does not do it

the problem was an old inverto big twin lnb,that takes much power from the stb,on some modells,it helps,to setup the lnb power 0,5 db more,to let work all diseqc swiches correctly,but this lnb allone to derrange,the complete diseqec configuration!

then i found out,when,i put the old inverto lnb,to diseqec input 1 instead of others,the compatibity of difrent lnbs was much higher,with the lnbs,and the diseqec system runs more stable!

if i replace the lnbs,to all newer modells,that take low power 130 ma for e.g.it works good of course.but normaly every antenna ,has difrent brands of lnbs,and first you think the diseqec switch is fault,but in most senarios it is,the lnb/diseqec swtich/compatibly,to the stb i find out!

sorry my technical english is not the best,but i hope you understand it,what i trying to say!

 

[canofan]

When I have a problem on hand I force a solution because of the urgency to make a system work. Sometimes I change a piece of equipment and leave to a later time the search for the reason.
If you absolutely need to use the DISEqC 1.1 protocol, you know and I know that equipment exists, which use this perfectly.
My worry remains that, even with such good equipment, some problems may remain and no manufacturer's engineer is able to find solutions.
You have mentioned the possibility that excessive power drain by an LNB may fault the functioning of DISEqC 1.1. This seems logical.
You also mentioned long cables; they may impede the flow of current. This also seems logical.
We have to look into these possibilities.
In the meantime I decided to use the best cabling and by swapping LNBs (trial and error) I have arrived at a stable performance.
I admit that I do not know why, but I am determined to find out why.

 

[canofan]

When I cascaded DISEqC 1.x switches, I often found that the transponders contents of one satellite end up in the list of the transponder that has the same number, polarity and signal rate of another satellite.
This does not happen when using switches with the DISEqC 2.x specification.
I cannot explain why yet, but it is worthwhile letting you know.