UPC: Triax trilink to distribute digital and analogue stations

derekwallace

Hi,
We have UPC digital (and the original 17 analogue stations).
I use a splitter to split UPC input. One goes to UPC box and on to 1st Tv and the other to the 2nd TV. Upto now we watch the the digital stations on one TV and the analogue stations on the other TV.

I would now like to also get the UPC digital channels on the 2nd TV, AND the original 17 analogue stations.

I purchased a Triax Trilink thinking it would do the job.
The setup is below (if you can make out the ascii drawing).
The 1st TV is fine. Digital TV is perfect.
The 2nd TV is the problem.
If i disconnect the RF In, the 2nd TV is fine. I just have the 1 "UPC digital" i.e. the Scart signal. The magic eye remote works fine.
If i connect in the RF In, the picture quality becomes very grainy on 2nd TV for the UPC Digital station and the 17 analogue stations.

The Trilink has a gain control on it.
When i set it to minimum, the UPC digital signal on 2nd TV improves but the analogue stations are too grainy to watch.
When i set to a maximum he UPC analogue signals on 2nd TV improves but the UPC digital station is too grainy to watch.
There is no in-between gain level that makes both acceptable.

ScreenShot027.gif


Anyone any suggestions as to why this doesnt work?
Has anyone tried something similar i.e. have analoge and digital on a 2nd TV?

Thx
Derek

Peter Rhea

The modulated output from the digital box is more than likely being interfered with. You could try selecting a different channel for the modulator, though I'm not sure where you would find a clear frequency on a UPC feed: might need filtering.

The analogue channels are another matter: assuming the Tri-Link passes all the relevant frequencies, you could get rid of the splitter & feed the UPC box from RF1. Might provide an improvement at the 2nd TV. Or maybe you don't want to mess with what is between the UPC point & box. (And you couldn't do this if you had to filter the input to find a clear channel for the modulator.)

The Cush

Peter Rhea wrote: »

The modulated output from the digital box is more than likely being interfered with. You could try selecting a different channel for the modulator, though I'm not sure where you would find a clear frequency on a UPC feed: might need filtering.

Somewhere in the UHF 40s, away from the UPC, Three Rock, Kippure and 4G frequencies.

Peter Rhea

Where do the UPC digital channels fit in?

derekwallace

There is NO modulated output from the UPC Mediabox, only the SCART which connects to the Trlink box.

The RF In (UPC Analogue and UPC digital channels) is coming from a splitter which is directly fed by the UPC cable that comes into the house.

The Trilink is modulating the SCART (output from UPC Mediabox) on channel 36 which is free (im sure).

There is a good video explaining the trilink here.
One of the reasons i bought it was that it accepted the RF In and effectively added the scart as a RF channel.

http://www.youtube.com/watch?v=_q01Fb89tP4


Thx
Derek

The Cush

Peter Rhea wrote: »

Where do the UPC digital channels fit in?

I always assumed they used frequencies below UHF but assumptions aren't facts so I checked the technical conditions for digital cable.

Digital cable is allowed to use frequencies from 5 - 862MHz with certain frequencies prohibited/restricted. In the UHF band this applies to frequencies used for DTT in cabled areas. Similar to DTT 47/77 dBμV min/max carrier level at socket outlet which would of course cause co-channel interference.

It would be interesting to know which UHF frequencies are used and if the 4g band will continue to be used.

Peter Rhea

derekwallace wrote: »

. . . The Trilink is modulating the SCART (output from UPC Mediabox) on channel 36 which is free (im sure).

That is what I was referring to as 'the modulated output from the digital box' (Because that is what it is or, actually the baseband output of the box modulates the UHF carriers.)

How are you sure UPC don't use ch. 36?

derekwallace

CH 36 is typically used for VCRs etc.
On an analogue TV CH36 is just white noise.

id be very surprised if UPC put some digital info on that channel.

I also tried a range of channels from 20 to 40 all with the same response.

The Cush

derekwallace wrote: »

CH 36 is typically used for VCRs etc.
On an analogue TV CH36 is just white noise.

id be very surprised if UPC put some digital info on that channel.

I also tried a range of channels from 20 to 40 all with the same response.

Do any of your TVs have a DVB-C (digital-cable) tuner, if so try a manual scan on each frequency. I don't think you'll notice any difference with an analogue tuner.

Peter Rhea

derekwallace wrote: »

CH 36 is typically used for VCRs etc.
On an analogue TV CH36 is just white noise.

id be very surprised if UPC put some digital info on that channel.

Channel 35 & 37 used typically to be used for VCRs & other devices with modulators too but, it didn't stop Channel 5 using them for their analogue terrestrial network in the UK, although they did publicise it & carry out a retuning campaign. (But this was in the days when VCRs were still in widespread use.)

UPC cables have to carry all the TV & internet traffic (& FM radio but the wall box would filter that out), so I wouldn't think there is much free space.

Peter Rhea

I'm not sure where you would find a clear frequency on a UPC feed: might need filtering.

Example of filter here: passes from 5-694 mHz (694 mHz is top of UHF ch. 48). Fitted to the Tri-Link input, it would allow all the UPC analogue channels to pass, & certainly all channels from 52-68 would be well clear of interference & could be used for the Tri-Link modulator output.

ted1

for a 5er a month why not just get a 2nd box?
no need for analogue channels, watch different channels in each room. no issue with poor signals.

The tax man

Just tried the analogue channels through one of these units and they came through fine for me. We only use them for modulating the output of STB's to RF,tend not to put the analogue through them.
CH 36 is not free but that won't affect the analogue channels,only the modulated output from the scart source would be affected.Checked this with a signal meter,no degradation of analogue signal quality.
The only channels we use are 62 63 64 66 67 68.
What type of splitter are you using?
The only two things that might cause your issue would be a problem with the RF feed going to the unit or there's something up with the unit itself.

Antenna

derekwallace wrote: »

CH 36 is typically used for VCRs etc.
On an analogue TV CH36 is just white noise.

id be very surprised if UPC put some digital info on that channel.

I also tried a range of channels from 20 to 40 all with the same response.

Digital signals will look just like white noise on an analogue TV (if the TV doesn't mute the picture in the absence of a valid signal!)

I recall another thread where someone's modulator on Ch36 suddenly became unuseable with noise on UPC cable.

Try Ch 65 which should be a clear channel.


A potential problem with your setup is that if you use HDMI out from the UPC box in the future, the SCART reportedly becomes disabled!!! (not a problem with Sky)

The tax man

Ch65 isn't free.

Antenna

The tax man wrote: »

Ch65 isn't free.

Whats on it? You are referring to something on UPC cable?

BTW UHF Chs 62 63 64 are allocated for 4G 800MHz band base stations, and 66 67 68 (+69) to handsets (the latter channels would be lower risk of interference for modulators)

The tax man

Yes, it's a used channel for network purposes. Those channels I mentioned are free of anything transmitted on the cable network.