2 UHF aerials - Freeview / Saorview

aquascrotum

Hi - am over the border in Co. Down and know that I have good Saorview coverage from Clermont Carn nr Carlingford.

I've an existing UHF aerial for Freeview from Divis (Belfast) and want to install the 2nd aerial to pick up Saorview. My freeview feed is into a powered amplified UHF/VHF diplexer (VHF is unused, think its for DAB radio) that splits to 6 feeds. My understanding (i think) is that I'd need a UHF-UHF diplexer to combine the FV/SV aerial feeds, but I can't find such a thing - they're all VHF-UHF for combo sat and aerial etc. Does that matter, if I use the VHF inlet on my ex. amp for the Saorview aerial am I likely to get the RTE channels and/or interference on the Freeview channels?

What component do I need to combine these feeds?

Any help appreciated!

L1011

UHF combiners exist, people used them for analogue for ages. But you need to have your two inputs quite seperate - a few channels between the Saorview and Freeview muxes won't be possible. And for some reason Google is failing me on finding them right now.

Your existing combiner shouldn't let appreciable UHF through the VHF input. It may still work if the signals are extremely high power.

You'd combine the signals before putting in to the UHF input on your distribution amp

byte

This is the list I found for the Freeview Divis TX: https://ukfree.tv/transmitters/tv/Divis which is mostly Gr A, except for COM7 and NIMM muxes which will be a problem when you use a diplexer.

Clermont Carn uses Ch 42 and 45, Vertical polarisation.

You could use a Gr A/B diplexer like this: https://www.freetv.ie/uhf-diplexer/ but I wouldn't be keen on the board not being screened and appears to cover all the way up to C68 which may introduce mobile interference issues.

There is a possibly better one here: https://atcsupplies.ie/product.php?id=003506 which is in a screened enclosure.

With either diplexer you'll have issues with COM7 and NIMM muxes due to them being way up on Ch 55 and 48 respectively.

TAFKAlawhec

The NIMM mux from Divis on E48 is a very low powered (10 watts) filler for parts of Belfast. The main NIMM mux for much of East of the Bann is transmitted from Black Mountain (next door to Divis) on E33 (with the Armagh & Newcastle relays also transmitting the NIMM on E48 themselves with vertical polarisation).

A UHF-UHF diplexer with one input covering E21 to E37 and the other covering E39 or E40 upwards would be ideal to combine two aerials aimed at Divis & Clermont Carn respectively - you'll likely lose reception of the COM7 multiplex in case there's anything on there you're interested in, but it's a transmission that's on borrowed time anyway as its transmission is guaranteed only until the end of June this year - after that it can be switched off at short notice (a month, I think) as the EE mobile network won UK rights to the spectrum that currently covers E55.

As for diplexers themselves, the Fringe ones sold by Free TV that byte's linked to is one I've used with good results though as he says if interference is a potential issue, get a screened one (like the Labgear model from the ATC supplies link).

wodeda67

yes of course this will work. you see it on aerial masts all the time.

you can daisy chain diplexers if you really want com7 too.

don't understand why you'd want nimm if you have saorview, that's kind of the point.

Digifriendly

https://www.boards.ie/discussion/comment/118753416#Comment_118753416

Only advantage of NIMM over Saorview is that picture quality on TG4 is slightly better on NIMM due to compression method.

Iderown

Just a suggestion. Mybe try the Divis aerial as only input to rest of your system. OK. Clermont Carn is vertically polarised but there may be enough of its signal getting through the other part of the system for it to function well. Just a suggestion which should be easy to try.