Mux with RTE1 has 96% signal strength, 0-15% signal quality

watou

Hi, hopefully this rings a bell for someone here. Our LG TV had strong RTE1 and RTE2, both transmitters were working fine, and then our RTE1 went to hell.

The signal tester shows

UHF Channel 21 (474000 kHz) gives strength/quality as ~ 95%/95% (RTE2 etc.)

UHF Channel 24 (498000 kHz) give strength/quality as ~ 96%/14% (RTE1 etc.)

This is in the Clonakilty, Co. Cork area.

I've powered off both ends of a single wireless handset, powered down a Z-Wave network and my mobile phone, none of it made any difference. The antenna amplifier has solid connections and is doing the job just fine for UHF 21.

What could be the cause of the recently arrived terrible signal quality?

Many thanks!

dxhound2005

Anything on 46 and 48? They are the channels on the local low power Clonakilty transmitter.

watou

https://www.boards.ie/discussion/comment/119529461#Comment_119529461

Thank you very much for your reply. Unfortuntely both come in at 0% signal with the current setup. I didn't realise there was such a nearby transmitter, but the Saorview tool here says the transmitter to serve our location is 45km away. Even though the 46,48 transmitter is only 4km away, could the lay of the land be such that it would be hopeless to install an aerial outside facing the direction of the local transmitter? Our current aerial is in the attic and there is roughly a stone gable end between it and the local transmitter, and possibly a few hills too. Are the transmitters directional?

Is it possible that someone has created a radio noise source at ~498 MHz and they could be found and made to stop?

Sorry for all the further questions but it's maddening that all Saorview channels worked great, and now half of them became rubbish all at once a few weeks ago.

Thanks again.

dxhound2005

That transmitter is only 50 watts against 200,000 watts from Mullaghanish on 21 and 24. If you have any nearby neighbours you could check if they are using outside aerials. As a general rule Saorview recommend outside aerials, but they are not always necessary. Something must have gone wrong with your set up, so it might be time to call in a TV installer.

https://2rn.ie/wp-content/uploads/2022/07/2RN-DTT-Television-Transmission-Network-Sept-2019-Rev.1.2.pdf

The Cush

Yes, something in your installation is at fault here if the setup have worked without fault previously. I would look at all connections and ensure they're secure.

Can you describe the setup from aerial to TV points. What amp is being used and where is it located?

It would be interesting to see those signal figures without the amp in place.

watou

Thank you both for your replies. I have a large rectangular aerial in the attic hanging from two hooks on rafters, to a box in the attic that splits the signal 4 ways down to room drops. The Living Room drop has a "Labgear PSUFC" amplifier plugged into the wall going to the attic, and a coaxial cable to the LG TV. It was all working fine until a few weeks ago.

Late on a Sunday night, UHF 24 is now getting between 23-30% signal quality, much better than earlier daylight times I've tested at around 14%, with same very high signal strength.

Without the amp inline, all signal strength/quality is 0%/0%. I've tightened and jiggled the living room connections with no change noticed.

Thanks for any more thoughts, and your input so far.

The Cush

https://www.boards.ie/discussion/comment/119535277#Comment_119535277

The high signal strength will be there in any case with the amp, so not getting a true reading, quality reading here is the important figure.

I assume the large rectangular aerial is similar to this wideband grid aerial, https://www.freetv.ie/wide-band-grid-uhf-aerial/ ? Not the best aerial for Mullaghanish, especially mounted in the attic with the transmitter 45km away, it would be interesting to get the figures at the aerial before the amp in the attic, I assume they would be borderline. A Group A aerial would be recommended as it's directional and covers just the frequency range for Mullaghanish and not the complete TV frequency range and probably some of the mobile frequency range too depending on its age.

Has anything changed in the attic recently that would have affected reception, stuff moved around etc. or outside, panels on the roof etc? Walls, roofs etc. are a signal attenuator with the amp trying to make up for the losses

Assuming all connections from aerial to TV have been checked and are secure then next thing to check is aerial correctly aligned towards the Mullaghanish transmitter and correctly polarised H like in the picture above. Another possibility could be a fault with the amplifier in the attic or a fault with the cabling, damaged/crushed/etc.

As posted previously an external aerial would be recommended and could eliminate the need for the amp especially for Mullaghanish, at 200 kW the most powerful transmitter in the country. I use it here in NW Co Limerick at about double your distance.

watou

https://www.boards.ie/discussion/comment/119535756#Comment_119535756

The wideband grid aerial you linked is just the type that's up in the attic, probably ca. 20 years old, and for Mullaghanish is oriented almost exactly 90% incorrectly, and polarised V instead of H. I suppose it's no wonder that signal quality is 0% for both UHF 21 and 24 without the amp.

There's a chance that recent enough changes to our Internet and security equipment might have interfered with the RTE 1 etc. signal, but thanks to your insight it's time to get out the ladder and get back up there and orient the aerial properly, as a first step. The next step would be to get a Group A aerial to narrow down the frequencies received.

I think you've given me something practical to attack, so thank you. I will add a reply with any observations.

The Cush

https://www.boards.ie/discussion/comment/119535822#Comment_119535822

20 year old grid aerial would be a wideband UHF 21-69 and iirc they perform better higher up the frequency range. In the last 10 years the TV band has been reduced twice to 21-60 and now 21-48, with the lost spectrum now used for 700/800 MHz mobile broadband. Nearby mobile base stations can cause inward interference to home TV installations with amplified overlapping aerials.

The bow-tie directors in front are the polarising elements of the aerial.

Glaceon

https://www.boards.ie/discussion/comment/119535822#Comment_119535822

It's worth noting that the polarisation of those grid aerials is the opposite of what you might think. The image on freetv.ie is horizontally polarised.

watou

Ladder, torch, moving furniture, cobwebs, 5 minutes to face the aerial towards Mullaghanish and in the correct H orientation (thanks @Glaceon and @The Cush) and with the amplifier in line I now get 100%/100% on both UHF 21 and 24. Interestingly, I get 0%/0% without the amplifier, but with a more suitable/modern high gain antenna I would probably see better.

Everything works so much better when you have a clue what you're doing. Thank you very much for all of your help; it's very much appreciated!

The Cush

https://www.boards.ie/discussion/comment/119536297#Comment_119536297

When you say without the amp, have you completely bypassed the amp and the power supply at the the TV end?

watou

https://www.boards.ie/discussion/comment/119536341#Comment_119536341

Yes, and I just tested it again to verify! The F connector screwed into the TV coaxial cable and plugged into the wall, instead of through the amplifier. Solid 0% strength and quality, per LG TV, as opposed to pure 100% strength and quality with the amp is connected and powered. I'm surprised to see nothing at all without the amp, but as long as the amp works, problem solved!

The Cush

The amplifier is located in the attic beside the aerial, right?

watou

https://www.boards.ie/discussion/comment/119536450#Comment_119536450

No; it's in the living room by the wall socket. I didn't make an effort to get power in the attic where I'd need it, and I only use the living room drop anyway. I think the proper arrangement would have been to put the amp right after the aerial and before the splitter, so all drops would benefit.

The Cush

So you have the amp and power supply (Labgear PSUFC) right beside each other behind the TV?

watou

https://www.boards.ie/discussion/comment/119536570#Comment_119536570

The coaxial cable to the back of the TV extends about 3 metres away from the television, so the power outlet and antenna wall receptacle are next to each other about that far from the TV.

The Cush

The Labgear PSUFC is a power supply for a remote amplifier, where is the amplifier located? Trying to get my head around your setup.

watou

Oh geez, my mistake. I had forgotten that the amplifier is up in the attic in line properly. At some point the power supply for it fried and I ordered a replacement online, and I subsequently forgot about the amplifier in the attic. So my previous posts were the gibberish of a foggy memory. So sorry about that. That probably explains why there was no signal at all with the PSU removed but the amp still in line up in the attic.

At some point I'm going to properly re-connect the pieces properly. Thank you for cajoling me into understanding what's really going on here....

The Cush

Excellent, good to know your own installation, makes it easier to troubleshoot when issues arise.