Saorview from Mullaghanish - getting UK channels because of the high pressure?

2 Wheels Good

Hi, down in west Cork on the coast. We've had issues with our Saorview box losing the Saorview signal and if i do a rescan it tunes in what seems to be the UK freeview set of channels. We used get the English channels this time of year back in the day so do we have the same problem now? Any suggestions how to fix it? We have a TV Star Saorview box. Thanks

The Cush

2 Wheels Good wrote: »

We used get the English channels this time of year back in the day so do we have the same problem now?

Yes, tropospheric ducting. This means that interference signals from other countries or other Irish transmitters that share the same frequency are travelling further than usual and are being picked up by your aerial. Has always occured but more noticeable now with digital. Indoor or inadequate outdoor installations can be susceptible to interference.

Carandon Hill in Cornwall is the likely culprit in relation to Mullaghanish.

A good outdoor aerial installation will help eleminate or reduce the interference.

marno21

Looks like some heavy tropo on the way for the weekend too, so expect more interference

http://www.dxinfocentre.com/tropo_nwe.html

SRB

It travels far, the analogue signal from that tx used to appear here in Portaferry during the summer months the odd time too, have only ever had one rx of the digi signal though.

excollier

What high pressure would that be? It's lashing down outside

2 Wheels Good

So are there people on boards.co.uk in Cornwall complaining about rte blocking out their bbc?

Antenna

Beware many common 'contract' yagi aerials have an undersized reflector for Ch21 (Mullaghanish) as well as Ch22 and Ch23. (the 3 lowest UHF TV channels)

This means at the low end of UHF they will easily pick up possible interfering signals arriving to the 'back' of the aerial, on ch21 especially

read this

http://www.wrightsaerials.tv/articles/whatsat-short-reflector-syndrome.pdf

The Cush

Notice on the 2RN website recently

03 Jul 2013

A period of stable high pressure may cause interference

A period of stable high pressure may cause interference to SaorView signals over the coming days, do not adjust your receive equipment.

http://www.2rn.ie/a-period-of-stable-high-pressure-may-cause-interfe/

Rippy

I have seem it a lot lately in Garretstown /Old head of Kinsale area. Saorview from Mullaganish here is poor enough in parts as looking into a hillside and easily swamped during a lift by BBC from Clarendon Cairn in Cornwall, also on Ch21.
I have changed a couple of aerials here for log periodics as they have inherently good rejection from the rear .

A good polar response comparison here
http://www.aerialsandtv.com/polardiagrams.html

Rippy

Antenna wrote: »

Beware many common 'contract' yagi aerials have an undersized reflector for Ch21 (Mullaghanish) as well as Ch22 and Ch23. (the 3 lowest UHF TV channels)

This means at the low end of UHF they will easily pick up possible interfering signals arriving to the 'back' of the aerial, on ch21 especially

read this

http://www.wrightsaerials.tv/articles/whatsat-short-reflector-syndrome.pdf

Very true, however particularly bad lately , and have seen it on decent aerials like the Triax HG5 ( huge reflector) and and also grids and colour kings .

Peter Rhea

Rippy wrote: »

and have seen it on decent aerials like the Triax HG5 ( huge reflector)

No, you haven't seen 'short reflector syndrome' on an aerial with a 'huge reflector'.

There isn't any tv aerial that is at its best at the bottom or top of the band. I wonder does Antenna have any evidence of the presence in this country of the dodgy contract aerials Bill Wright refers to?

Rippy

Peter Rhea wrote: »

No, you haven't seen 'short reflector syndrome' on an aerial with a 'huge reflector'.

There isn't any tv aerial that is at its best at the bottom or top of the band. I wonder does Antenna have any evidence of the presence in this country of the dodgy contract aerials Bill Wright refers to?

I meant I have seen CCI with intrference fron the rear on different aerials , lately , not just cheaply contracts .

whitebriar

Rippy wrote: »

I meant I have seen CCI with intrference fron the rear on different aerials , lately , not just cheaply contracts .

yeah.CCI in lifts like the monster that's coming this week will not care how good the set up is,it might cause mahem in waves in certain areas at different times.

I've seen tropo here over the years in the southeast to make a signal visit so strong that its ambient,coming in the sides,rear front and everywhere .
Tropo can sometimes really reduce your home(wanted) signal too,scoop it up and bounce it god knows where,France probably.
That's a double whammy.

Great from a geek like me's point of view though,I love dx'ing tv and radio.

marno21

Should be plenty of interference there todya especially this morning.

Able to drive around Co. Kerry with BBC R4 on 92.5 with full RDS this morning with little or no interruption. It was clearer than some of the local stations on the same route

Peter Rhea

Rippy wrote: »

I meant I have seen CCI with intrference fron the rear on different aerials , lately , not just cheaply contracts .

Any aerial used for terrestrial tv reception will have a response lobe to the rear. As you say above, log periodics have a pretty small one.

Ronnie Raygun

whitebriar wrote: »

I've seen tropo here over the years in the southeast to make a signal visit so strong that its ambient,coming in the sides,rear front and everywhere .

And electromagnetic energy isn't "ambient" the rest of the time? How does that work then?

whitebriar

Ronnie Raygun wrote: »

And electromagnetic energy isn't "ambient" the rest of the time? How does that work then?

I think you know what I mean but you wouldn't use the same kind of description.
Equality of ambience or full ambience,if you want me to clarify,ie the tropo is so strong delivering a signal so strong that if you swung the aerial around 360,your meter would read the same in any direction as opposed to the directional ambience you're referring to,when a visitor is only strong enough to leak in the back or side.
Flooded in visiting signal basically.
Doesn't happen often but it can happen

Ronnie Raygun

whitebriar wrote: »

I think you know what I mean

No I don't. What's "directional ambience"?

whitebriar

Ronnie Raygun wrote: »

No I don't. What's "directional ambience"?

I think you might be over reading me,but anyway,I look at it as follows.
Signal in the ambient athmosphere that can be received from any location in the area as long as you direct an aerial at its source.
As opposed to signal that's so strong,you could point at the ground and receive.*


*please note these are my own practical descriptions not from university text books,I've been experiencing tropo for 40 odd years and I enjoy its fruits (sometimes) If any further clarification is needed,I'll oblige but it may be after beer o clock

Ronnie Raygun

So a strong signal as opposed to a weaker one? Why didn't you just say that?

hju6

Peter Rhea wrote: »

No, you haven't seen 'short reflector syndrome' on an aerial with a 'huge reflector'.

There isn't any tv aerial that is at its best at the bottom or top of the band. I wonder does Antenna have any evidence of the presence in this country of the dodgy contract aerials Bill Wright refers to?

Yes he has, and
..,
have you or Ronnie Raygun proof that not one "dodgey contract aerial" has been installed in this country?

MiCr0

hju6 wrote: »

:cool:

Whats wrong with this forum that almost every topic gets dragged off topic and name calling and eye-rolling starts?
I'm completely feed up with it.
From now on each and every OT post will be removed.

MiCr0

Also, I'm banning people to a month who continue to do this.

whitebriar

Ronnie Raygun wrote: »

So a strong signal as opposed to a weaker one? Why didn't you just say that?

Because,having been talked about up thread,I wanted to give some kind of classification difference between a visiting strong signal or even aless strong one that can leak in the back or side of a less well aligned aerial or a badly maintained aerial or a cheap aerial and a sometimes whopper of a visitor signal in a lift that behaves like it's omnidirectional thanks to the magic of tropo.

The latter and some of the former would test even the best set up,nothings immune.

Being able to discuss these things at length and share these interesting experiences is what made this forum a wonderful place since it started pre it's move to boards in 2001.
It's where I came to talk about my on digital subscription back then,a subscription set up over the phone with the UK call centre with a wexford address and no problems.
Mostly still analogue tropo visitors still then though.

On a side note but related,this weather also brings fog,something sea path signals hate and may mitigate the tropo effects somewhat.

Ronnie Raygun

whitebriar wrote: »

Because,having been talked about up thread,I wanted to give some kind of classification difference between a visiting strong signal or even aless strong one that can leak in the back or side of a less well aligned aerial or a badly maintained aerial or a cheap aerial and a sometimes whopper of a visitor signal in a lift that behaves like it's omnidirectional thanks to the magic of tropo.

Dunno about that. I've heard of super-refraction, but I'd doubt it can "bend" radio waves to that extent.

whitebriar

Ronnie Raygun wrote: »

Dunno about that. I've heard of super-refraction, but I'd doubt it can "bend" radio waves to that extent.

well if you don't believe me,I suppose that's your prerogative,it makes no odd's.

marno21

Interference to Mullaghanish tonight on C21 here in North Cork, first break up I've had in ages..

Must be strong enough bursts if it's interfering on a VHF Band III attic aerial 23km from the TX

Antenna

2 Wheels Good wrote: »

So are there people on boards.co.uk in Cornwall complaining about rte blocking out their bbc?

If it were a problem, it would be a MUX (they have 6 MUXs) carrying less important channels that would be affected, so not affecting the main BBC ITV C4 etc

http://en.wikipedia.org/wiki/Caradon_Hill_transmitting_station

BTW TV3 analogue from Mullaghanish had been on the same UHF channel (27) as another identical powered (since 9 Sept 2009) MUX from over there. Did you ever notice any deterioration of TV3 analogue in recent years during similar weather ??
Digital to analogue CCI interference would have resulted in 'snow' as if the analogue had gone weak.

Rippy

Antenna wrote: »

If it were a problem, it would be a MUX (they have 6 MUXs) carrying less important channels that would be affected, so not affecting the main BBC ITV C4 etc

http://en.wikipedia.org/wiki/Caradon_Hill_transmitting_station

BTW TV3 analogue from Mullaghanish had been on the same UHF channel (27) as another identical powered (since 9 Sept 2009) MUX from over there. Did you ever notice any deterioration of TV3 analogue in recent years during similar weather ??
Digital to analogue CCI interference would have resulted in 'snow' as if the analogue had gone weak.

Yes it was seen and noted on occasions . Though lifts to this scale were rare enough .
This is what the lower end of the UHF spectrum looked like in Garretstown , near Kinsale, a couple of weeks ago . BBC MUX CCI with Saorview on 21, and pefectly watchable reception of muxes on 22, 24,25,27&28 from Clarendon .
It really is a case of bad channel planning.
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Ronnie Raygun

Rippy wrote: »

This is what the lower end of the UHF spectrum looked like in Garretstown , near Kinsale

... It really is a case of bad channel planning.

Notice a lot of white on the coverage map in that area.

It can't be easy to provide a signal something like 20dB above the interference at all times, to all those places near the coast from an inland transmitter, even a very high site like Mulla.

Peter Rhea

marno21 wrote: »

. . . Must be strong enough bursts if it's interfering on a VHF Band III attic aerial 23km from the TX

What counts is if the receiver can sort out the wanted signal from everything else in the channel. You give it a better chance if you maximise the wanted signal with the right aerial.