Answered Experts in rf modulation

daftpunk1

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Hoping to find someone educated in this, if not please can someone recommend a site or business who can advise me.

Basically my question is on rf distribution. I can have two sky hd boxes running through a diplexer and into my rf splitter box which distributes both sky boxes all around my home without issues.

Now if i replace one of the sky boxes with a dreambox or any linux box for that matter I need to make use of a scart rf modulator. I use the triax tri link as it gives me magic eye function but when i set it up the magic eye function does not work..

So Im thinking an issue with diplexer so I try 3 different brands but then i realise the sky hd box has no issue sending power through for magic eye function so the difference must lay with the modulator itself. What is different about the modulator built within sky box and that of the triax tri link.

Im hoping to be able to get two dream boxes going through a rf modulator/diplexer/rf splitter with magic eye function as a result...

Anyone got any ideas,....
 
No need for a diplexer. or splitter. Simply chain the rf via the in and out sockets on each modulator. The Trilink that provides the power for the magic eye and processes the magic eye remote signals has to be the last in the chain, this unit uses the VHF modulated remote control codes to provide infra red output to the stick on emitters. The same signal is passed on to the Sky box which works as normal. Nothing special about the modulator in a sky box other than the extra circuitry to provide 9V power and a built in VHF demodulator to recover the remote control signals sent back down the coax by the magic eyes. The chain would be the two dream boxes first then the Sky box and lastly the Triax trilink unit. Of course the output channels of all of them will have to be chosen to not conflict with your terrestrial aerial and each other. Not sure what you have connected to the Tri-link scart.

For two dream boxes and a sky box you would only need one extra modulator, the other can connect to the tri-link unit.
 
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But surely one rf splitter is required. I'm referring to the aerial distribution box in attic that takes analogue signal to all rooms.

I want to run one sky HD box and one dreambox but I fail to understand how I can get both boxes tuned in without making use of a diplexer to get both coax cables coming from rf2 9v into the input of the 8 way coax splitter.

I've also looked for splitters that have two inputs but they don't exist lol
 
But surely one rf splitter is required. I'm referring to the aerial distribution box in attic that takes analogue signal to all rooms.

I want to run one sky HD box and one dreambox but I fail to understand how I can get both boxes tuned in without making use of a diplexer to get both coax cables coming from rf2 9v into the input of the 8 way coax splitter.

I've also looked for splitters that have two inputs but they don't exist lol

Your Sky HD box either has a built in modulator or needs a io link unit. Coax from aerial goes to either Sky box RF1 in (or same socket on iolink unit). RF1 out on iolink goes to local TV, RF2 out on iolink goes to trilink rf1 in, trilink rf out goes to remote skylink splitter (return cable). Dreambox analogue output to trilink analogue in (scart or CVBS and analogue audio).

Triax Link RF Output for Sky HD Box: Amazon.co.uk: TV

TRIAX TRI-LINK Kit Control Sky, Freesat, Freeview: Amazon.co.uk: Electronics

If you want another box, connect it's modulator between aerial and io link(Sky box) rf1 in.

Here's how it works for the two box arrangement. Incoming cable carries the digital mux from your aerial (In my case Lark Stoke using UHF channels 26 23 30 41 44 47) the modulator adds a PAL analogue channel from the analogue video and audio input using the UHF channel it's set to use (say 68, it modulates UHF 68 to create a analogue channel). It's output now has in my case 6 digital mux plus one analogue PAL channel. The second modulator (the trilink unit) adds a second analogue channel using a different UHF carrier (say 58). It/s output now has 6 digital and two analogue channels your remote TV's can tune to.

These days you can buy a digital modulator that will create a HD digital channel you can add to the mix using a hdmi input.
 
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I think the Diplexer you are referring to is something similar to the Global SPC4 RF2 combiner. If you are taking a Sky box out, then sending your Dreambox around the house with a Tri-link modulator then you won't need it. The combination of the RF's will be done at the Tri-Link modulator. Then on from there to your amp.
 
There's an echo round here, here, here:rotfl:
 
And a Troll...

Sorry Grahamlthompson if you think I have copied you. I think my comment was of some use establishing what diplexer was being used as the thread starter has tried 3 (maybe wrong ones) and should help him understand why it's failing.
 
Ok I'm still not in understanding. I do not want to use the Sky HD box. I want to use just two dreamboxes and have two triax trilinks.

How do I pair these up so I have both boxes distributed around house with magic eye function?
 
Ok I'm still not in understanding. I do not want to use the Sky HD box. I want to use just two dreamboxes and have two triax trilinks.

How do I pair these up so I have both boxes distributed around house with magic eye function?

You don't need two trilink units. Just one to convert magic eye RF control signals back to infra red.

Does one of the Dreamboxes have a built in TV modulator ? The clue is it will have a output terrestrial type socket and a menu option to set the UHF output channel used and probably a setting to select PAL I output.

EDIT do you want the remote TV's to use Freeview (using their own tuners) as well as satellite ?
 
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Neither dreambox has RF, only scart. So I was under the assumption I need two triax tri links to convert scart to RF.

My two dreamboxes are in a wiring closet beside my RF amp, no tv is in this location.

I do not have a free view aerial so do not need to add terrestrial tv into the equation.

The way I was thinking you were trying to put across is each dreambox scart into separate triax tri links then chain the tri links together from Rf1 which is out to Aerial In on the second triax trilink. Then just on the second trilink coax from rf2 9v to RF amp. Then I use infrared sensors, one on each dreambox

Am I close lol...?
 
Close but the modulator at the start of the chain doesn't need to be a expensive tr-link modulator.

Any modulator will do. (all it has to do is modulate the video and audio onto a UHF carrier, it does not need to understand Magic Eye control commands).

eg

https://www.amazon.co.uk/Mercury-350-111-12V-250mA-Modulator/dp/B000M6SMKW

You will of course need to set different UHF carriers for each modulator. Hint use low channels (in the 20's) as the lower frequency isn't attenuated as much in the coax cabling as the higher frequencies). Ideally use WF100 sat grade cable.
 
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Believe it or not but that was my next question. I have a Mercury RF modulator as they are the best modulators I believe when you don't require magic eye.

Ok I will test this out and see if it works.

And what if I did want to use one sky plus box and one dreambox. I presume I still need the expensive triax tri link but how do I get the magic eyes to work with the sky plus box if the rf2 on sky plus box is not being used. Do I just add an infrared sensor from the triax trilink modulator onto the sky plus box IR
 
The tri-link unit doesn't need the stick on IR emitters when used with a Sky box. The TriLink passes on the magic eye commands via the coax cable so it works as normal when using a Sky remote. Just make the Sky box the last link using rf1 in and rf2 out to the trilink unit so the return signal goes straight to the rf2 out on the Sky box. The scart from the dreambox connects to the tri-link modulator. The Sky box has it's own modulator (or a special io link one if it's a newer box).
 
So are you saying that if i used two dreamboxes and a sky box I could actually get away with using just two mercury rf modulators without the need to buy expensive triax tri link at all..??
 
So are you saying that if i used two dreamboxes and a sky box I could actually get away with using just two mercury rf modulators without the need to buy expensive triax tri link at all..??

No - The tri-link converts the control codes sent down the coax to infra red and emits this from the stick on emitters. These are required for non sky kit as they don't have the internal capability to understand the control codes directly from the coax. Basically magic eyes are also a modulator. They use a VHF carrier rather than UHF so essentially a VHF channel carrying the infra red controls is put on to the coax return cable. The sky box demodulates this carrier internally recovering the sky remote control codes. The Tri-Link demodulates the same and emits the infra red from the emitters. Essentially it's the reverse of a magic eye.

It's the same process in reverse as used for the Video and Audio. The modulator modulates a UHF carrier with the video and audio info, creating a PAL analogue TV channel. The analogue tuners in the remote TV's demodulate this to recover the video and audio data to sennd to the screen.

If you used a cheaper wireless infra red control repeater system then you wouldn't need the trilink and magic eyes.
 
I think you need to draw a diagram or two GLT.:D
 
I think you need to draw a diagram or two GLT.:D

At the moment helping to knock down the wall between our kitchen and the utility extention to make one large room. :)

If the OP didn't keep changing the question I might find time to oblige :)

Perm any combination of two Dreamboxes and a Sky box. :D
 
Yea, sorry for changing the scenario so much.

But big thank you for your help, got two dream boxes going around the house with magic eye function without having to use a diplexer..

Out of curiosity if i did have a freeview aerial would that go into the aerial socket of the first rf modulator that being the mercury non magic eye modulator...

Or if i was using one sky plus box and one dream box, would the freeview aerial just go into the aerial socket of the sky plus box?
 
Freeview Aerial into Mercury RF In.

If using two Dreamboxes, Mercury RF out to Trilink RF in, Trilink RF out to return cable to sky link amp,

If using One dreambox and one Sky box. Mercury RF Out to Sky RF1 in, Sky RF2 out to Trilink RF in. Trilink RF out to return cable to sky link amp, Sky RF1 out to local TV

Or just connect aerial to Sky box RF1 in, RF2 out to trilink RF in, RF1 out to local TV. TRilink rf out to amp.
 
All tested and all working. Thank you.

So what benefit is a diplexer, what I've been using to combine rf2, what I've seen professionals use to chain two sky boxes to distribute through the home.

if the diplexer/combiner is not needed then why use them..

Can you offer a genuine use for them before i bin a couple?
 
Hi again, Ive just a VCR as a rf modulator in the past. Ive just come across an old sky box that has VCR and TV scart. The new sky hd boxes don't have that.

But on this old sky box I'm thinking i can use it as a rf modulator with a dreambox. Ive connected scart from my dream box to VCR scart of sky box and rf2 out from sky box to my tv amp...

But the only thing I pick up on my tvs is the actual picture of the sky digibox, I've no scart connected to tv or satellite connected to box at all. just scart from dream box to VCR scart and rf2 to tv amp...

Can you offer any advice?
 
You can't use the built in modulator on a sky box to show anything but the built in tuner. There's no way to switch an external input to the modulator as you could with a vcr. The new boxes have a special socket to provide the same capability.

Triax IO Link FOR USE With SKY HD Receivers Restores RF2 Functionality | eBay

You will need a seperate modulator for the Dreambox. You can chain the dreambox modulator to the Sky box one to provide both pictures using two different output channels.
 
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The Sky box cannot be used in this way, the VCR scart is an output...
Not strictly true - at least on SD boxes the VCR scart has a pass through to the TV scart when box is in standby BUT input has no connection to RF modulator. So you can view Sky box and VCR on Tvs with only one scart input without the need for scart switches/adapters.
 

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