Euros unwatchable in South Kildare.

PeterTheEighth

When I first moved in to my current house near Kilcullen, I got up on the roof and got signal perfect for all channels. I bolted a lump of metal to the side of the house and fix the aerial to it. this was done in summer with same humidity/foliage/weather etc etc. But recently I have noticed that the RTE TWO coverage has gone to hell. And I was in a store in Naas today and noticed their TV (which was also on the Euros) was WORSE than mine.

So I did a scan and noticed that though I am pulling my signal from Kippure (as I initially directed it towards), different TV stations are coming in on different frequencies. RTE ONE and other are coming in on 770MHz and my signal quality for these is almost 100%. RTE TWO and some other channels are coming in on 738MHz and they are completely unwatchable. The Saorview Coverage Checker says that both of these frequencies are transmitted by Kippure, so I am getting my signal from the same location.

I can only presume that the lower frequency signal is not making the journey as well. Does anybody have any suggestions on this before I get out the damned drill again. Why couldnt they just leave it alone ffs. !! :mad::mad:

Thurston?

Seriously doubt 'they' have done anything, & a transmitter fault won't go unnoticed for any length of time.

More than likely your own installation was delivering 'just good enough' reception, with slightly poorer signal on the RTE2 multiplex, & it would only take a slight deterioration for it to fall over the 'digital cliff'.

Ten Pin

Any chance there's a new 4g mast gone live nearby, some of them use 800MHz, is that close enough to the Kippure freq to be an issue??

Mt Leinster channels are on 490 and 514, may need to adjust antenna or change to another group antenna if the current one is not wideband. I think Mt Leinster has a much further range than Kippure.

PeterTheEighth

Ten Pin wrote: »

Mt Leinster channels are on 490 and 514, may need to adjust antenna or change to another group antenna if the current one is not wideband. I think Mt Leinster has a much further range than Kippure.

Yeah I tried moving the antenna but there is a HUGE tree directly in the way that direction. But I see to have got some sort of solution even though I cant explain it.

I fix TVs as a hobby, so I had a spare set top box, which is about a year old. I swopped this in place of my existing set top box. All channels are now perfect. I've checked and it's still pulling the RTE TWO HD from the 738MHz.

So the channels that are sent in 770MHz works fine on both set top boxes, but the channels on 738MHz (that's the HD RTE TWO and other SD channels) only work on the new box.

The Cush

PeterTheEighth wrote: »

I fix TVs as a hobby, so I had a spare set top box, which is about a year old. I swopped this in place of my existing set top box. All channels are now perfect. I've checked and it's still pulling the RTE TWO HD from the 738MHz.

So the channels that are sent in 770MHz works fine on both set top boxes, but the channels on 738MHz (that's the HD RTE TWO and other SD channels) only work on the new box.

Appears to me that one of the tuners is more capable of handling a weaker signal than the other.

Do you have a terrestrial digital signal meter to hand to check the input signal strength/quality at the TV point? If not what are the signal strength/quality readings for the 2 frequencies using the boxes' own internal signal meters, not always the most accurate but will give you an indication of what's happening in relation to the signal.

A weak signal on one frequency could also be down to bad connections, cable problem etc.

Thurston?

PeterTheEighth wrote: »

... So the channels that are sent in 770MHz works fine on both set top boxes, but the channels on 738MHz (that's the HD RTE TWO and other SD channels) only work on the new box.

As mentioned already, that would be typical of a borderline signal, in that some tuners will handle it better than others.

Also some would be better at handling interference (possibly causing overload too) if that's the issue, so if there's a phone mast, particularly if it's right in the signal path, that could be worth investigating if you can't find a fault or improve the signal, say by resiting the aerial.

exaisle

You don't mention what kind of antenna you have...is it a raster-type ("colour king") or a more directional one?

Yes...Kippure transmitter power is 63kw while Mount Leinster is 160kw...however, Kilcullen is about twice as far away from Mount Leinster than it is from Kippure (as the crow flies).

I think your best bet is to use a masthead amp (you'll have to get the ladder out to do that though) ...

I won't recommend a supplier but google is your friend...they're easy enough to find....

PeterTheEighth

exaisle wrote: »

You don't mention what kind of antenna you have...is it a raster-type ("colour king") or a more directional one?

This is the aerial, which I got from B&Q a few years back.

http://www.diy.com/departments/tristar-silver-outdoor-digital-tv-aerial/571699_BQ.prd

I think your best bet is to use a masthead amp (you'll have to get the ladder out to do that though) ... I won't recommend a supplier but google is your friend...they're easy enough to find....

It was fine after last night, barely a glitch. It seems like the old set top box has a problem with the 738MHz signal. I would have thought it would have had an issue with the higher frequency if anything!

Thurston?

exaisle wrote: »

I think your best bet is to use a masthead amp

Might be a solution, but I know I'd like a bit more info. 1st, try & rule out something like water ingress.

PeterTheEighth wrote: »

This is the aerial, which I got from B&Q a few years back.

http://www.diy.com/departments/tristar-silver-outdoor-digital-tv-aerial/571699_BQ.prd

If it's like the similar type sold in other DIY places, the connection box/dipole assembly is very flimsy & would need attention to stay waterproof & even remain in place properly.

PeterTheEighth wrote: »

It seems like the old set top box has a problem with the 738MHz signal. I would have thought it would have had an issue with the higher frequency if anything!

I'd say both frequencies have poor signal, the 738 MHz wouldn't be as much worse off as onscreen appearences suggest.

The Cush

exaisle wrote: »

I think your best bet is to use a masthead amp (you'll have to get the ladder out to do that though) ...

I wouldn't recommend a masthead amp at this stage without finding the source of the problem, aerial fault, cabling etc. Could end up causing overload on the other frequency or 4g issues. Signal strength/quality numbers would be a good start.

PeterTheEighth

Just something interesting. I had been up on the roof yesterday and left the aerial sitting on the highest point on the roof... (i.e. not where I had it fixed to the house). I noticed today that it had fallen slightly so that the aerial was point towards the ground. While in this position, the RTE TWO on 738MHz was unwatchable, but again RTE ONE on 770 MHz was perfect.

So I think I can conclude that for whatever reason the 738MHz signal is just not as strong as the 770MHz signal.

Thurston?

PeterTheEighth wrote: »

... So I think I can conclude that for whatever reason the 738MHz signal is just not as strong as the 770MHz signal.

Yeah, but it shouldn't be causing problems. There's a pretty wide signal strength range over which tuners will function, & all that needs to be done is to keep the signal within these limits, neither too weak nor too strong.

On my own TVs there's a difference in the levels between the 2 muxes, & if I attenuate the signal to the point where the weaker is unwatchable, the stronger is still glitch-free, the same as your own. The difference is this situation never arises without my purposely weakening the signal (a lot), as I've set things up with a healthy level of extra margin above the bare minimum signal level needed.

What length is the cable from your aerial to receiver?

The Cush

PeterTheEighth wrote: »

So I think I can conclude that for whatever reason the 738MHz signal is just not as strong as the 770MHz signal.

The power output will be the same for both frequencies and no issues reported by the transmitter operator.

Because there are two frequencies a misaligned aerial can receive one frequency better than the other. An aerial must be optimised to receive both as close as possible at the same level. This is where a meter would be useful when aligning an aerial as you can see how good the signal strength and quality being received is or how close the two frequencies are to the so called digital cliff before it falls over. What are the internal meters in the receivers saying about the signal?

Posts here over the years where this was happening and usually resolved by realigning the aerial or repairing bad connections but as you can expect each install can be different and difficult to troubleshoot over the internet.

STB.

The Cush wrote: »

The power output will be the same for both frequencies and no issues reported by the transmitter operator.

RTE were not allowed all their channels on the one mux as the first set of mux frequencies were the optimized ones.

The OP's description of symptoms point to the most common question asked here in very guises. Why am I receiving only one mux ?

The usual reason for the signal loss is that the aerial is misaligned, the cable run is too long, or the connections are terminated incorrectly or a combination of both.

The fact that one box doesn't work but another internal tuner does is purely down to the wide range of tuner types (Sharp Serit etc) and their associated sensitivity. This symptom shows the low margin of error and more importantly he getting barely enough signal.

Meter readings off boxes can be very flakey (the ALI chipset boxes meter are atrocious). Might better to try and optimise the signal using the IDTV's signal meter if you dont have an actual handheld signal meter.

Thurston?

STB. wrote: »

RTE were not allowed all their channels on the one mux as the first set of mux frequencies were the optimized ones.

I think the above was posted in the past. On what is this notion based of there being 1 set of 'optimised' frequencies or where does this info. come from?

STB.

Thurston? wrote: »

I think the above was posted in the past. On what is this notion based of there being 1 set of 'optimised' frequencies or where does this info. come from?

Notion; a conception of or belief about something.

It was something that was mentioned to me in a conversation that I had with someone who was involved in the frequency planning at the outset.

As far as I recall, a scenario as close as possible to matching existing grouped aerials previously used for analogue was part of such planning for first mux on.

Also, the performance of wideband aerials differs according to frequency.

Thurston?

STB. wrote: »

... It was something that was mentioned to me in a conversation that I had with someone who was involved in the frequency planning at the outset.

As far as I recall, a scenario as close as possible to matching existing grouped aerials previously used for analogue was part of such planning for first mux on.

Well I suppose I can't argue with the actual frequency planners, but anyway it's the supposed 'optimised' frequency the OP is having trouble with.

deezell

I assume you have the aerial polarity correct, horizontal. You should be able to see kippure mast from kilcullen, so alignment should be easy. Are there any large objects, sheds, buildings in the path of the signal, even a good distance away. One reason for big differential in strength and quality of two close in frequency signals is multipath reception. This is where the aerial picks up a direct and indirect (reflected ) version of the signal. These mixed signals play havoc with the error correction of the receiver demux. In the analogue days it would manifest as a strong ( not ' snowy') but unwatchable picture with repeated images. Due to the difference in the channel frequencies and their wavelengths, it's possible one channel is more severely affected than the other. A misaligned aerial in a strong signal zone can have a similar issue. If the aerial is receiving it's signal from the side rather than directly in front, the attenuation characteristics will differ for the two frequencies. Finally, incorrect cable, bad terminations at the aerial or aerial socket, or aerial wall socket if that where your cable goes can cause impedance mismatch, reflections in the cable and can act like a comb filter at certain frequencies and can cause a drop in level which is channel dependent. Unless you're stuck in a hollow or in a forest, you should be able to get passable signals on a coat hanger that close to kippure, let alone the multi element antenna you have. It doesn't say on the link if it is a group c/d uhf aerial or a wideband. Check it from top to bottom. Alignment, polarity, cable terminations, water ingress, cut kinked or damaged cable, taps or joints not made with the correct connector and splitters.

STB.

Thurston? wrote: »

Well I suppose I can't argue with the actual frequency planners, but anyway it's the supposed 'optimised' frequency the OP is having trouble with.

I thought it a very simplistic explanation myself. But I suppose it avoided too many situations whereby people trying to pick up high UHF frequencies with a Group A aerial, during switchover.

I can see a measurable difference between mux 1 and 2 with a wideband off Mt Leinster. It wouldn't be too difficult to replicate the few db's in difference at the lower threshold that I could make one mux disappear with a less sensitive tuner.

The Cush

STB. wrote: »

It was something that was mentioned to me in a conversation that I had with someone who was involved in the frequency planning at the outset.

As far as I recall, a scenario as close as possible to matching existing grouped aerials previously used for analogue was part of such planning for first mux on.

RTÉ and others have said publically in the past that during the DTT frequency planning process, except in certain circumstances, the DTT muxes would occupy the same aerial group as the existing analogue channels and have the same or greater coverage so as to have as little impact on viewers with regards to aerials. This would apply to at least the first 4 muxes.

That would match the number of frequencies used for analogue but the next 2 and any further muxes licensed may have reduced coverage due to directional restrictions to avoid interference to other transmitters within the planning area, the planning area being Ireland and the UK. This point was made at an Oireachtas discussion with RTÉ many years ago now.

With regards to the OP's problem there should little to no reduction with a properly aligned aerial optimised for the 2 existing muxes (other issues excepted). I remember here when the second mux was launched quiet a few posts from people either getting a bad signal or no signal at all as many of the aerials had initially been installed for the then one mux, realigning the aerial generally restored the full Saorview lineup.

Just to extend this further, in relation to the replanning for the release of the 700MHz band Comreg had to replan for a 6 mux network as per existing legislation but I assume if we get to see the coordinated plan only 3 or 4 of these muxes will have near full coverage with the others highly restricted. RTÉ have said in recent times only 3 and maybe 4 muxes is all that's likely to be required in future but the law requires 6.

Thurston?

deezell wrote: »

... These mixed signals play havoc with the error correction of the receiver demux.

What about the guard interval between the transmitted symbols, so all but really long delay echoes should be ignored by the receiver?

The guard can also be made longer than the Saorview specs use, say for Single Frequency Networks (SFN), where long-delay echoes probably would be encountered, from other transmitters.

We're talking about a system that was designed to combat multipath (think radio reception in moving vehicles) right from the outset.

The Cush

Thurston? wrote: »

The guard can also be made longer than the Saorview specs use, say for Single Frequency Networks (SFN), where long-delay echoes probably would be encountered, from other transmitters.

We're talking about a system that was designed to combat multipath (think radio reception in moving vehicles) right from the outset.

The advantage of DVB over the effects of analogue ghosting. During the initial DTT spectrum process these islands decided on parameters for fixed reception (RCP1) instead of in-car/mobile reception (RCP2), capacity vs. robust mobile/portable coverage (24 Mbps vs. 13-14 Mbps for example as used in Germany).

Regarding SFNs, looking like we might see them return as part of the new national DTT plan but maybe not for the primary muxes.

deezell

Thurston? wrote: »

What about the guard interval between the transmitted symbols, so all but really long delay echoes should be ignored by the receiver?

The guard can also be made longer than the Saorview specs use, say for Single Frequency Networks (SFN), where long-delay echoes probably would be encountered, from other transmitters.

We're talking about a system that was designed to combat multipath (think radio reception in moving vehicles) right from the outset.

And it does that in spades, I personally receive dtt from kippure or 3rock, and the analogue signal from the latter was unwatchable due to multipath and marginal signal strength due to trees, yet the digital is more or less perfect, with the odd evening of occasional marginal reception. I was more inclined towards the idea of signal strength cancellation due to the subtractive effect of an out of phase signal. A weakened signal with many of its mini channels within the band on the cliff of receiver sensitivity will start to break up. A misaligned antenna or a big steel shed giving a half wavelength of delay can be enough. Also, a home made tap of the cable to a bedroom say, left unterminated and you have reflections on the line causing attenuation. I'm aware that this should affect the 770mhz carrier equally as the frequencies are so close, but it's possible a combination of signal degradations can affect one channel more severely as STB points out. Kilcullen is line of sight to kippure unless you're in a hole or a quarry or a forest. My advise is double check the full path from aerial to set, aerial alignment, and I'd check that box at another known good location, friend or families house,as he's stated an alternate box he owns is perfect.