All posts by PaulN
Below are all of PaulN's postings, with the most recent are at the bottom of the page.Ahh - some good info there... a couple more questions for clarification then.
1 - On the assumption that the RF mode of the NIMM needs 'one tenth of the power' - did I see it right that NIMM power from Black Mountain is touted at a paltry 1 or 2 kW - versus the shocking 100kW that I see forecast for DSO at Divis (I suspect that 100kW is a total for all the muxes - not each one or the sky would surely melt) ?
2 - Did I also not see that Black Mountain transmits with Vertical polarisation today versus the Horizontal from Divis - hence a 2nd aerial required - or is the NIMM planned to go out on Horizontal as well ?
Apologies if I am reading too much confusion into some of the headline numbers I have seen referenced on the site - this RF stuff is a mad black art but I have enough grasp of the fundamentals to still be confused. Lord knows how the average non-techie bloke or granny is going to get their head round some of the DSO issues.
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Thanks for the clarifications... It will be interesting to see if NIMM can be received in East Antrim with a single aerial pointed vaguely at Divis come DSO day.
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@Peter - I am Larne area. Much of Islandmagee seems to have patchy coverage for Freeview from Divis today due to the geography, and much of Whitehead sits in a dip that will see most folk needing a dish for DSO.
I have never bothered to check if my house aerial is the correct type - the previous owner was a complete dullard / cheapskate so will have certainly applied no braincells to the solution. But I digress. Sometimes bad weather causes some channels to be heavily errored - usually on the BBC1/2 mux for some odd reason... must be the most sensitive / borderline to my hokey S/N ratio on the outer limits of Divis footprint.
Are you suggesting that SaorView signals will be receivable across NI cos I didn't think that was the plan - although its fair to expect some overspill near the border which folk might need a 2nd aerial to pick up.
I will perhaps investigate the Scottish option as well, though clearly I was looking in the wrong parts of this site to try and find the nearest Freeview mast across the water that will stay active for DSO.
I probably need to find a friendly neighbourhood aerial man to help with some tests as I don't fancy hanging off the roof waggling an aerial with a signal strength meter in the other hand.
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So then... the plot thickens - in theory at least.
According to the SaorView site - parts of East Antrim should indeed be able to receive the signal from Clarmont Cairn.
As for the works required by RTE at Black Mountain for activation of the NIMM - is that to be done by professional DVB-T2 receivers/turnaround for the signal from Clarmont Cairn and then retransmitting the RTE channels into the NIMM or is there something more complicated ?
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So a quick update from partially successful testing at the weekend.
I bought a Labgear 450W aerial last week (triple decker wideband yagi with 16.5dB gain) and hooked it up to a SaorView TV (powered off an AC inverter in the car) via a DVB-T signal strength meter on some high ground (on an adjustable 6ft pole) near whitehead lighthouse and aimed it vaguely south to see if I could pickup SaorView.
Setup with Vertical polarisation I positioned it halfway between the points where signal strength fell to 50dBuV so I had a solid reading of 60dBuV on the meter (two lights)... Then performed a channel scan and was a bit surprised to see the TV pickup a lot of UK Freeview channels - which I wasn't expecting on VERTICAL - it must have been working off a Freeview repeater in range (but I thought they were very limited range).
The TV couldn't find anything at channels 52 (RTE1) or 53 (SaorView) as I expected from Clermont Cairn, but it did find RTE1, TV3 and TG4 on analog elsewhere in the spectrum. I was too busy holding the aerial in the stiff breeze to see where it found them.
So... is it worth me trying a mast-head amplifier along with a filter that blocks channels 21-48 to give me a better chance of latching onto the Clermont Cairn feed so far North or am I way too optimistic ?
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Funny - I assumed it was Vertical as well... Considered this to be a relay of some sort.
Note to self... slow down on the next daylight run up/down the M1 near the border to see what folks aerials are doing !
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It means you will be able to enjoy our wonderful local productions, enthralling news & documentary programs as well as fantastic local adverts - all in glorious HD. Freesat & Sky HD subscriptions will be soaring as a result. LOL...
Its pretty much same line-up ITV except with the usual regional variations now and again plus local ads/news - great for expats who like to keep in touch with things or anyone else wishing to speak proper NornIron accent like :)
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@Tracey - do a postcode based search on this site to find your best freeview transmitter. Also look at neighbours aerials to see what they are doing. You will need a filtered combiner for two aerials if you wish to receive freeview and saorview on the same devices. There are some stbs which work with both.
Paul
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Can someone confirm that clermont carn is actively transmitting saorview 24/7 these days ?
I challenged myself to see if I can receive saorview in BT40. I bought a decent aerial and masthead amp and a filtered combiner to mix with freeview signals. I bought a triax official saorview decoder and no joy yet.
Quick summary of results so far:
Receiving four analog channels ok - rte1 is barely watchable. Tv3 and tg4 are grand while rte is a bit furry.
The decoder is seeing signal on channel 53 and 57 - but it never indicates any decent "quality" metric and never successfully finds channels in the mux at C53.
I am using decent PF100 cable everywhere, fresh f connectors etc. The aerial has 18dB gain while the amp is 27dB.
I have another tv that has mpeg4 DVB-T2 receiver although not official soarview - it has same behaviour.
Is it simply cos the launch power at clermont carn is so weak that the decoder is unable to extract any meaningful data from it - despite all the gain I have ?
The aerial was aimed live while viewing worst channel.
Some questions - is it worth trying the aerial with a lot more elevation above the roofline as I kept it quite low to reduce impact of wind loading as its quite a hefty aerial - labgear 450W.
The weird thing is that the triax decoder picks up the uk freeview signals just fine - and it reports similar signal strength on some of the uk muxes as it does the Irish ones.
It gets weirder as some uk muxes report much higher strength than other. Best example is C33 which reports 15% while C34 is 90%. My other decoders do not see such diffierence in strength while they all receive at same lovely quality.
Bit perplexed so keen for any expert advice. I may yet rent a specialised measurement set.
Paul
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Monday 20 February 2012 1:42PM
Larne
This looks like a resourceful site, with some good techies on board... I had hoped to find more solid information about NIMM. Confusion still reigns for me at least.
The bit that confuses me the most is how to rationalise the notion that Divis will become the main source of DVB-T/T2 content in NI for the vast majority of its population so how then is the RTE content on the NIMM only applicable to Black Mountain, Carnmoney & Brougher.
I don't understand why NIMM doesn't have a place on Divis. What am I missing ?
I work in the IPTV industry so all of these spectral issue and other technical aspects of antennae planning don't really come into my field of knowledge - so please don't bamboozle me with umpteen RF related acronyms - or I'll be forced to retaliate with umpteen instances of IP jargon.