Labgear HDU681 DA query

[AceB]

I've got a Labgear HDU681, pretty much fully loaded, one of the Sky+ feeds goes via LNB2 in and combines with everything else on the downlink. There's a return feed on the uplink and I've also got a camera, FM and UHF antenna connected. Sky+ works fine, the signal via LNB2 on the DA is good and the LED is illuminated as you'd expect but the question is, what does the Sat/CCTV+UHF switch actually do?

The unit comes with a cable loop presumably to loop downlink and uplink and provide a path for camera, uhf and fm if there's no return feed? I've tried switching said switch but using a local monitor plugged into an output I can see no difference to any of the signals. The 'manual' it has to be said is shockingly bad, nothing more than a connection sheet with no detail or description. I'll include a link here to show what I mean http://www.beststuff.co.uk/images/hdu681_diagram.jpg There's a comment about what to do but it doesn't actually explain why. LNB1 in and out is literally that btw, merely a straight through connection on the PCB.

[Rick]

I've fitted a few of those and the manual is shockingly bad. The switch in SAT mode sends the UHF and CCTV paths to the downlink instead of the room outputs, it also turns on the remote eye power. With the unit in UHF mode there is no need for either the downlink or uplink.

[AceB]

Ah, cheers Rick. It's not a bad product and seems quite immune to strong signal overloading as I'm very close to a 2kW relay but rely on a similar output repeater from 10 miles away for DTT, it's just the literature that lets it down. I do wonder how many people have bought it thinking that it distributes sat IF along with everything else because the poor documentation could be interpreted as such. If mine wasn't in such a pig awkward spot I'd have played around patching cables but I was hoping for a reply before I had to resort to that

[Rick]

They certianly do the job, but the litrature is crap. I suspect you may be correct as the literature is misleading.

[mark64]

Sorry to resurrect an old thread, but having a problem with my HDU681s, all the signals appear to be working correctly, the problem is with the multiplex signal, there is no UHF signal on the tv oulet of the PSW351T , all the other rooms supplied direct from the loftbox have a good UHF signal. Anyone have any ideas
The setup has Sky+ and the switch is in the sat position
thanks

Mark

[Rick]

Is the TV socket with no UHF on the downlink ? When running with a sky box, the TV aerial needs to run through that.

[mark64]

Hi Rick

yes it's the socket on the downlink thats not working. I have tried connecting the UHF through the sky box with no success. The other concern is that I understood the HDU681 supplied the power to the the remote eyes, they do light up, but don't control the sky box until I turn the RF2 power on in the sky box setup. I'm thinking there may be a problem with the HDU it self.

regards

Mark

[Rick]

It's possible you do have a problem then as it should power the sky eye's. The downlink does not carry UHF. That is introduced to the system via the uplink from the RF2 of the sky box. If a replacment unit dosen't solve that problem it really is a case of looking at the signal levels at each point, to find out what's causing the problem. You might try a booster on the uplink as it leaves the sky box rf2.

[mark64]

Thanks for the reply Rick, I am now a little confused (easy done), on the HDU there is an input for UHF, this appears to feed all the room outlets (they are recieving Digital & Analogue), do I have to have a sepparate UHF down to the Sky Box. I (wrongly it seems) assumed that the UHF into the HDU went through the downlink, the face plate has a TV oulet from the muliplex side of the face plate. There is a blanking type connector on the CCTV input, could this be causing any problems?

thanks

Mark

[Rick]

given it's manual confusion is easy done.

In none sat mode the unit takes UHF via the UHF socket, but in sat mode it's supposed to come in via the Uplink and the UHF leg is effectively redundant. (or atleast that's how it's supposed to work).

The terminator on the CCTV input is normal and should be there