Problem switching satellites on quad monoblock

[KidOtaku]

Hello all,

I am having an issue when switching satellites on this quad monoblock LNB: _http://www.inverto.tv/products/product.php?section=1&id=101&cat=3


I have two tuners in my setup: 1x Azbox HD and 1x TBS 8920-based HTPC. These two tuners are connected to two of the four ports on the monoblock. The other two ports are not connected to anything (in fact I ordered a twin monoblock but received a quad).

Both tuners use DiSEqC 1.0 to switch the LNBs. The default LNB (LNB1 - PosA/A) sees Astra 23.5, and the other one (LNB2 - PosA/ sees Astra 19.2.

When I operate any of the tuners independently (i.e. with the other one switched off), I have no issue, the tuner switches correctly between satellites. However, when I operate both tuners at the same time, simultaneous viewing is only possible when both receivers tune the same satellite, with the device tuning 23.5 having precedence when it's not the case.

As an example, let's imagine that both the Azbox and the PC are tuned on some channel on 19.2. If, say, the Azbox switches to a channel on 23.5, the Azbox displays the new channel correctly but the PC loses the image (i.e. displays a 'no signal' message). If the Azbox switches back to 19.2, the image comes back on the PC.

If both the Azbox and the PC are on 23.5, and, say, the Azbox switches to a channel on 19.2, then the Azbox will display the 'No signal' message. If the PC is then switched to 19.2 as well, then the AZbox will get the signal and display the channel.

The way I understand the issue is that as soon as any one of the receivers tunes 23.5, the other receiver is forced to tune 23.5 as well, and the tuner fails as it tries to tune a nonexistent channel on 23.5 with the same parameters as the channel it was on on 19.2. This can be seen when scanning channels - when one of the receivers is on 23.5, the other receiver will only find 23.5 channels even though clearly asked to scan 19.2.


Could it be an issue with my DiSEqC configuration? I was under the impression that each port on the LNB should be completely independent from the others, but does it in fact require the tuners to be configured in a special way? Does it have anything to do with the position of the cables on the monoblock, since I'm not using all the ports (even though I tried several combinations without success)? Otherwise, could it be due to a faulty LNB?


Thanks a lot for your help!

 

[Robbo]

All ports should be independent, so you should be able to view either satellite on either tuner at any time.

Maybe check your connections.

Other than that, it seems like your LNB may be faulty.

Incidentally, the data sheet says 19.2E is on port A and 23.5E is on B.....


BTW, from their website:-


Inverto UK Product support
Tel. +44 1223 969210 (for UK customers only)

 

[KidOtaku]

Thanks Robbo for your reply!

All ports should be independent, so you should be able to view either satellite on either tuner at any time.

Maybe check your connections.

Other than that, it seems like your LNB may be faulty.

That's what I thought. I actually switched the cables around the monblock ports several times, I'm pretty sure the connections are fine. And anyway it works fine when the receivers are used individually.

Incidentally, the data sheet says 19.2E is on port A and 23.5E is on B.....

Yeah, that's weird; is it possible to have the LNBs reversed through a wrong positioning of the dish? I am drawing little pictures of rays hitting dishes but I can't say that's very convincing ;)

BTW, from their website:-

Inverto UK Product support
Tel. +44 1223 969210 (for UK customers only)

I'm not in the UK so I don't know how much I can expect from this, I might try however their general company phone in Luxembourg.


Thanks for the help! :-righton

 

[Lazarus]

It is virtually always the opposite of what you first think ie the Western-most LNB head will get the Eastern-most Satellite.

Many, many punters get this back to front!

So, looking from the front, Astra 3 should be the head on the left (Port and Astra 1 the head on the right (Port A).

Ensure the LNB is fitted correctly and that your DiSEqC switching is set accordingly.

 

[KidOtaku]

It is virtually always the opposite of what you first think ie the Western-most LNB head will get the Eastern-most Satellite.

Many, many punters get this back to front!

So, looking from the front, Astra 3 should be the head on the left (Port and Astra 1 the head on the right (Port A).

Ensure the LNB is fitted correctly and that your DiSEqC switching is set accordingly.

Yes, but for some reason this specific LNB has the IDs reversed. I checked with my old single monoblock, and indeed, the heads are identified as you describe. Anyway I tried scanning 19.2 when on position A/A and it didn't work.

So actually I called Inverto in Luxembourg. They were very helpful, I was connected directly to someone on the engineering team, who confirmed that the behaviour is not correct, and also confirmed that having the LNB heads inverted was surprising. We concluded that I probably have a defective monoblock.

I'll send the monoblock back after the week-end, and will keep you posted guys about whether or not that solved my issue!

Thanks a lot for the support!

 

[KidOtaku]

A quick update for you guys.

I had the quad monoblock replaced with a twin monoblock, and am having similar (if not exactly the same) issues, so the monoblock was not faulty after all.

In fact, I found that the description I gave in my first post is not really accurate; the moment when switching is not possible varies, and try as I might, I was not able to identify a pattern that would fail all the time. Sometimes it's 19.2 which has the lead (i.e. switching to 19.2 forces the other tuner on 19.2), sometimes I can switch freely between sats provided I'm switching to unencrypted channels. But sometimes not.

Anyway, one thing that seems reliable at this point is that when I switch to a sat and get the 'tuner failed' error, then switch back to the orignal sat, and back again to the new sat, then the tuner correctly tunes the channel. So it's a minor annoyance to have to go back and forth between sats, but well, I am not willing to invest much more time in solving this issue.

Thanks a lot for your help!