Combining VHF/UHF (DTT in the future) and Satellite on the same cable

[slang]

Hiya.

I'm at a loss to find the answer. I want to put in freeview (Satellite), distribute that around the house using the already installed quality cable, but I also want to continue to distribute UHF/VHF (and in future, DTT) over the same cables.

I undestand that this will get complicated as the LNB expects/needs voltage from the STB, and the UHF/VHF get's power from a masthead AMP.

If we can engineer a path so that the STB can send it's voltage to the LNB, and can engineer another path so that the masthead amp get's it's voltage (and only it's voltage), can the two signals co-exist on the same internal wiring (if it's good enough quality)???

I'd expect that i'd need a multiplexer that takes both incoming signals (VHF/UHF and DBV-S) which would pass the power to the LNB, but not the VHF/UHF. The VHF/UHF power would be on the masthead amp side of the combiner (i.e. not on the combined signal side, but the leg that only goes to the masthead amp).

From memory, the masthead amp is a DC voltage and the LNB voltage is an AC voltage.

Any suggestions?

Cheers -

[cyril]

Hi Slang, Diplexers for V/UHF and LBand(Sat) are commonly available for around $15 a piece they only pass DC on the Sat leg, however they work well.

So in your roof space (I assume the roof space is where things combine) combine with a Diplexer the Sat/LNB feed and the Antenna feed, then use a splitter (I guess 4way is what you need) to distribute the signal. At each room you will require another Diplexer to split the V/UHF and Sat signals, dont be tempted to not use a diplexer at each room as it can cause termination issues for the sat side.

You could use an all port pass 4way splitter, however I recommend that you use a splitter with one DC pass and just ensure that that port is connected to a satellite STB that will always be present and on (ie the main lounge one). By the way the LNB requires 18V DC not AC.

For the Antenna amp (some are AC some are DC) I suggest that you put a injector in the line between the diplexer and antenna, so somehow you need to get that power into the roof space.

I normally modify a blank PDL plate to accept the two ports of a diplexer are presented for use.

Here (http://www.freeviewshop.co.nz/satellite-terrestrial-diplexer-p-57.html) is a link to diplexers, however you can get them at dick smith and the likes of mastertrade for similar prices.

Cyril

[slang]

Hi Slang, Diplexers for V/UHF and LBand(Sat) are commonly available for around $15 a piece they only pass DC on the Sat leg, however they work well.

So in your roof space (I assume the roof space is where things combine) combine with a Diplexer the Sat/LNB feed and the Antenna feed, then use a splitter (I guess 4way is what you need) to distribute the signal. At each room you will require another Diplexer to split the V/UHF and Sat signals, dont be tempted to not use a diplexer at each room as it can cause termination issues for the sat side.

You could use an all port pass 4way splitter, however I recommend that you use a splitter with one DC pass and just ensure that that port is connected to a satellite STB that will always be present and on (ie the main lounge one). By the way the LNB requires 18V DC not AC.

For the Antenna amp (some are AC some are DC) I suggest that you put a injector in the line between the diplexer and antenna, so somehow you need to get that power into the roof space.

I normally modify a blank PDL plate to accept the two ports of a diplexer are presented for use.

Here (http://www.freeviewshop.co.nz/satellite-terrestrial-diplexer-p-57.html) is a link to diplexers, however you can get them at dick smith and the likes of mastertrade for similar prices.

Cyril

Hiya Cyril.

Thanx, wasn't aware that those diplexers existed specifically for SAT and V/UHF muxing, or that the LNB voltage was DC. I expect that they pass the DC to the LNB, but not the U/VHF, so I could put masthead amp power supply on the U/VHF leg.

Would such a setup limit/inhibit a STB's ability to switch H/V signal?

From what you've described, I'm pretty sure that I have even more options, like run SAT & U/VHF to main TV (with diplexer there to de-mux) and simply U/VHF to everywhere else (don't have set top boxes anywhere else...)

We have all the cabling in a wardrobe, so it's pretty convenient and we have plenty of power access etc.

Cheers -

[cyril]

Such a setup would limit you to only the box with a DC pass to the LNB being able to control the polarity, all the other boxs would loose signal unless the polarity selected was what they were after. But if you are only using this for freeview/Sky its not an issue. If you require more flexibilty in this respect then a dual output LNB and multiswitch like this (http://www.adigitalife.com/product_info.php?product_id=235&cat_link=digital_satellite.html&resultpage=2) is required, there is also a four output one on the same site as you can see most multiswitches also have a built in duplexer on their input side.

No you dont need to have STBs everywhere, however I do recommend using a duplexer at each outlet as some TV's tuners can present an effective short at the Sat Lband, the diplexer will isolate this, same applies if a diplexed multiswitch is used. It would be prudent to put a 75ohm terminations on each unused Sat port, but not entirely nessecary, suck and see.

Place the V/UHF amp power injector on the leg going directly to the antenna, ie in the leg between the diplexer and the antenna.

Cyril