Diseqc and quad LNB switching problem

[007.4]

I've been using a 4 way diseqc switch (aa,ab,ba,bb) for many years without problems (Dreambox 7000s).

I wanted to share a dish with other system so have replaced a single LNB with a quad LNB. However, this new LNB takes over control of the diseqc switch. It will not allow switching to the other dishes.

ATM the quad LNB is simple acting as a single LNB as I have not connected to the other system at all. It is a Zinwell ZKF-BJ44.

It works fine alone and if removed then I can automatically switch between the other dishes. However, when it is connected again switching stops.

Any ideas anyone?

TIA
007.4

[BrownBoots]

In theory the 4 outputs from the quad lnb should be independent (it is a quad lnb and not a quattro ?). If there is some kind of cross-talk effect going on then it's either a wiring fault or a faulty lnb. Unless you need 4 outputs it might be worthwhile changing to a twin output lnb. Have you tried connecting the other system to one of the other outputs on the lnb ?.

[007.4]

I've now connected this quad LNB/dish to my other (second) system and automatic switching works fine between all four dishes. I'm using a diseqc 1.2 switch

However, on the first system it seems like there is some cross-talk and this LNB takes over control. I've tried two different outputs from it and re-done the F-connectors on both ends.

It is an old diseqc switch and I'm not sure what version (I've tried 1.0 , 1.1 and 1.2 in the dreambox set-up - all with the same result).

The new quad LNB is on the 19e dish and all works OK on here. However, if I switch to the 13e dish/channel eg novacinema 1 - no switching occurs. But if I zap to novacinema 3 then it switches OK. The strange thing is both these channels are the same polarity and high band. I do not understand why this should happen!

Anything else i can try?

[BrownBoots]

I think you might have faulty lnb, not necessarily the new quad one. The post got my attention because it's similar to a situation I had a year ago. I initially had a Dreambox connected to a diseqc switch with 3 single output lnbs at 1w,13e and 19e with a twin lnb feeding a S*y digibox directly and the Dreambox via the fourth port on the disecq switch. This worked perfectly until I moved the digibox to a mini-dish and lnb of its own and set up a second Dreambox with a second diseqc switch and upgraded the 3 single lnbs to quads. This setup allowed me to receive 28.2,23.5,19 and 13e on both Dreamboxes. The problem was that when Dreambox 1 was switched to 28.2 the signal level on Dreambox 2 at 19.2 dropped significantly and I lost channels. The lnb at 28.2 was original one which had only ever had one ouput controlled via the diseqc switch. The other one was permanently connected to the digibox. There was certainly some sort of cross-talk effect occurring and I cured it by changing this old lnb, co-incidentally, to a Zinwell. I don't know enough electronics to speak with authority on this but I suspect that long term direct connection to the digibox might have 'conditioned' the lnb in some way and lead to it's gradual break-down.

[007.4]

Hmmm... I think you are probably correct, that there is a fault somewhere. The problem is finding it. :(
This is complicated by the fact that on the second system all is working fine.

I guess the obvious thing to try first is the diseqc switch - although it was working OK before I changed the LNB.
Thanks for your input.

[007.4]

Just an update for anyone with a similar problem. I replaced the diseqc switch and everything was OK.
It seems that thay can develop intermittant faults after sometime.