Instead of Daisy Chaining UHF...

[timfooty]

I have several sat boxes which I use to send I single UHF feed to a loft box.

Is there a way to combine the UHF outputs of these receivers to a single output instead of daisy chaining together (some devices have no UHF in)?

The nearest I have come to this is the Vision V51-106 Amplifier, but that only has 3 UHF inputs (plus 1 FM and 1 DA. I need at least 5, and in the future may need up to 8 inputs, ideally with variable gain on each input.

Any suggestions?

 

[rolfw]

You may want to consider modulators with a loopthrough as their output is normally cleaner than that of domestic receivers, I think vision do one. Are you also distributing the off air local terrestrial transmissions?

 

[timfooty]

> local terrestrial transmissions

Yes, but only via my Triax loftbox. A quick description of the current setup:

Triax Loftbox
TV Aerial feeds into loftbox
Sky (4 feeds) into loftbox
UHF Return from main Sky+ installation back to loftbox as the return feed
Separately I have sevaral satellite receivers + cable boxes sending UHF output to loftbox as one of the spacec UHF inputs.

It's the latter I'm really interested in tidying. I need to add another box but that does not have UHF loopthrough, so I was wondering if there is a neater way to combine the UHF outputs from all these (5, will be more) boxes for sending back to the loftbox for distribution.

Currently I have the daisychained, but there must be something neater.

My installation is a smaller version of this:
_http://www.pubfootball.co.uk/betting-companies.php

I take it i this photo all the UHF outputs of the sat receivers are combined? What device would do that?

 

[rolfw]

To combine that many feeds, they have probably used separate modulators, as daisy chaining more than four receivers is a recipe for disaster.

Some modulators can output as much as 90db, so running large numbers of receivers into an 8 or 12 way combiner is not a problem. It will also depend on what frequencies are used by the Terrestrial channels, a large system would use an equaliser to filter out all but the desired channels, leaving the rest of the spectrum clean for the satellite receiver channels.

PS. They have possibly even used a channelised amplifier system and that is probably more than you'd want to pay out.

 

[timfooty]

Thanks for this rolfw. I'm a bit new to this part of home installations!

Exactly how would the modulators work? How does this affect the combiners?

I've been searching around to find any suitable kit, but (as I mentioned earlier), the best I have found is a 3 input amplifier. Exactly what kit would I need to buy to set this up as you have suggested?

Regards, and thanks again for your time.
timfooty

 

[timfooty]

Incidentally, do you have an example of a "channelised amplifier" - I'd be intersted to know what the cost is. I'm so keen to get this sorted now that I'm ready to consider anything!

 

[rolfw]

A channelised system uses several single frequency amplifiers, as many as there are channels, these are daisy chained, but anything which shouldn't be there is filtered out.

What are your terrestrial analogue and digital frequencies?

_http://www.aerialview.co.uk/CDI_Commercial_Installation_Photographs.htm

 

[spiney]

The easiest way to combine the outputs of several uhf modulators - sat, freeview, vcrs, etc, is simply to feed them into a multiway sat signal splitter used in reverse, in which case it behaves as a signal combiner.

Assuming all the devices already have inbuilt UHF modulators, the splitter itself should cost something like £10.

This "passive" method is preferable, and avoids feeding through several rf amplifiers in series, where the imd products cause all sorts of distortion and patterning. It also means you can switch some of the connected devices off! And, you don't need any UHF inputs.

Channel filtering is expensive, and not necessary unless you have severe problems, however you might need to search for the best usable free channels, as UHF re-moduators inside consumer devices are double sideband (for cheapness).