MUX C Divis missing (LOG Periodic & full signal)

Dave72

Hi Guys. Sorry if something similar has already been posted but I cannot seem to find a definitive answer.

I have a new set of antenna on my home in Newry&Mourne area, two LOG Periodics actually and no masthead amp needed. Just a Diplexer. One LOG facing Divis and another Clarmont Carn. I am pulling RTE digital at average strength (because of obstructions) though picture is fine and BBC etc. from Divis is top notch. Thing is, I'm missing MUX C (Dave, DaveJaVu etc.) completely.

Now before I had the LOGs installed I had actually used an indoor amplified antenna which picked up some of the Divis transmissions and showed Dave etc. on the EPG though no picture or sound so I know MUX C is there.

As LOGs are wideband and the signal from Divis is really good why no MUX C? Strange.

Any ideas or should I just wait till DSO?

Rick_

Perhaps the diplexer is set to join the wrong channel groups? Did you install this yourself or did an installer do it?

MUX C is one of the strongest signals so it's strange you can't get it. The most troublesome is MUX 2 from what I can find online, it certainly is for me. Divis needs a masthead for me in Armagh so I'm surprised that you find you don't need one in Newry.

Dave72

Installer put the system in and he knows his stuff (does lots of installs in area especially for freeview/sat) so I have no reason to believe the diplexer is an issue.

All other MUXs come in perfectly well and MUX2 is not a problem (UTV/CH4/CH5 etc. all perfect). I live on a hill to the north west of the city so Divis is easily picked up and the signal is really good so no need for a Masthead. The LOGs were easily the best option as they are wideband by nature and reject sideband interference (Newry North/South/Camlough).

Thing is, I've just checked with a few friends - living in the city and surrounding towns who receive Divis - exactly which channels they had and had not got on Freeview and they say the same thing! No Dave / DaveJaVu / Daystar etc. MUXC again!

Just on a side note if anyone is interested. I'm getting SaorView MPEG4 with a LOG vertically polarised. Its a reflection coming off another hillside rather than Clarmont directly and the signal is reasonable. Enough to give an uninterrupted picture - even 1080i RTE2. Gotta love those LOGs!

Vince Cable

Dave72 wrote: »

Installer put the system in and he knows his stuff

Wouldn't stop him using a diplexer that's split at the top of group A, maybe channel 38.
The current Divis muxes will all be contained within the old group after ASO but any additional future services (probably just the RTE 'mini mux' if it happens) may not.

Dave72

Will ask the installer what the diplexer he installed is split at. Hopefully this is just a temporary problem.

lucernarian

The installer probably knew what he was doing but he may have used a less suitable diplexer as perhaps he thought "5 out of 6 muxes ain't bad". There aren't that many diplexers out there that won't affect the reception of either Mux C on channel 48 or Saorview on channel 53.

Vince Cable

The installer could have at least explained the situation, I wonder has he even tried a 50/52 diplexer in the area.

Digifriendly

Strangely, this MUX has always been the weakest for me. Both BBC Muxes are the strongest here in Moira - I'm using a Pro-27 Televes wideband with a set back amp. I have a problem with foliage in the summer and signal on this mux tends to break up during June/July/August. Reason for set back amp is that signal is split between 2 TVS. Even stranger is a strengthening of the signal in my smaller set on Freeview when the masthead amp that boosts ROI signal is turned off and this ensures that Mux C is watchable.

Dave72

Haven't spoken to installer yet but I was thinkin, maybe a different diplexer would cure it? Only thing is, the only one I could find that would adequately cover the channels needed was a Televes 21-48 & 50-69. After trawling through various web pages on the matter I gather that although this type of diplexer may cover the channels needed, there may be significant signal fall off at and around 48 and 50 on the split so maybe of no use. I wouldn't want anything to lessen the RTE signal.

Anyone have a better idea?

Booms

Can you try the Divis aerial directly, without the diplexer? That'll show what signal strength you're getting, if any, for mux C.
And did all the other people you mentioned that don't get the mux have the same aerial system installed?

Dave72

Funnily enough, I have an 18 element wideband (black bung) yagi type aerial in the loft which I'm not using for anything now. Maybe I will rig this directly to one of the TVs and check what comes up.

The friends have various combinations of aerial installations, mostly those budget type yagi, although they all have BBC/RTE antennae on diplexer.

Vince Cable

Dave72 wrote: »

Anyone have a better idea?

First thing to do would be to look at the diplexer already fitted, if you can access it, each leg should be labeled with its passband channels.

Triax do a 50/52 diplexer which supposedly passes channels 2-50 (VHF & UHF) on the low leg & 52-69 on the high. Haven't used one myself.

Peter Rhea

Vince Cable wrote: »

Triax do a 50/52 diplexer which supposedly passes channels 2-50 (VHF & UHF) on the low leg & 52-69 on the high.

Have one of those combining Divis with Monaghan.

I can't be much help in this case though, as I've stuck with the group A aerial for Divis. I don't want to compromise reception of the other muxes in pursuit of what is (to my mind anyway) the poorest in terms of content.

So currently I'm not receiving anything near the splitting frequency but I want to keep as many channels as possible available for Divis & I can fit a wideband aerial if any new services are launched after ASO.