Southcoast TV apply for digital licence

BrianD

I note from todays Irish Times that SCTV have applied to Comreg for a digital TV distribution licence. It is likely now that we ave a network of independent local DTT suppliers as opposed to the national platform as originally proposed.

The move is likely to annoy BSkyB as their may be frequency clashes between DTT and Sky signals.

It's good to see the start of DTT even on a local basis. Plus it will increase competition and ultimately benefit the TV consumer Any thoughts?

BTW anybody got a web address for South Coast TV?

watty

The original SCTV scheme clashes with over 30 Satellites. Not just Sky.

I don't think the original scheme will (or ought) be allowed.

They may get a Terrestrial frequecny allocation though.

ShaneOC

Here you go but it is way out of date.

BrianD

Perhaps we are lookingat this the wrong way round...satellite feqa clash with our DTT freqs.

To be honest, when Sky Digital allow themselves to be regulated in this country they can complain about frequency allocations.

Mike 1972

Actually there is a lot of disagreement among engineers as to whether 11GHz terrestrial and satellite services can co-exist

Seems like theres two options here

1) UHF DTT
the deflectors are allowed to use some of themultiplexes (excpt one reserved nationally for RTE/TV3 unless/until an "Irish freeview" network can be established
2) 11GHz "hypercable"
deflector allowed to use the 11GHz band for TV and broadband provision on a secondary basis i.e. any interference to someones satellite reception and they have to find enother frequency or failing that close down

watty

Where do you get that Mke.

I haven't heard ANY qualified Comms Engineer suggest that 11GHz DTT is sensible.

There are a lot more than Two options.

The main limiting factors is existing agreed use of radio spectrum and propagation.

As you go above 1GHz the "Line of Sight" and blocking by trees gets more critical.

The 11.7GHz was chosen by them simply on cost. The equipment is cheap. But such use is:
* Poor due to trees and much more defined LOS than even MMDS
* Illegal under International treaties we have signed
* Interfere with a wide range of Satellite service (not just Sky)
* Possibly hazards near transmitter sites (RF more dangerous the higher the frequency. If Mobile Masts are a a risk, then these transmitters would be 10 times more dangerous.

Mike 1972

I haven't heard ANY qualified Comms Engineer suggest that 11GHz DTT is sensible

A Mr Eddie O Gorman advised the Dept of Communications years ago to use 11GHZ for analouge MMDS but it was turned down (mainly for economic reasons as smaller cells/more transmitters would be needed) 11GHz In the UK 11Hz "MVDS" was proposed by the DTI/RA/ITC in the UK but there wasnt any takers as it was felt there wasnt the market for it

There are a lot more than Two options

Maybe but speaking in the context where the continued use of deflectors is envisaged I cant think of any (maybe you can) apart from "do nothing" (the worst but most likely option)

As you go above 1GHz the "Line of Sight" and blocking by trees gets more critical

This is true and actually is to some degree even an issue at UHF frequencies and (in extreme cases) Band 3 as well !

The 11.7GHz was chosen by them simply on cost. The equipment is cheap. But such use is: Poor due to trees and much more defined LOS than even MMDS

True but given the local nature of most deflector groups only a small coverage area ("cell size") is envisaged anyway so it is (or at least Southcoast claim it is) doable in most cases

Illegal under International treaties we have signed

I seem to remember the same argument being used against legalising deflectors or even introducing commercial local radio in the UK until it was shown that international treaties are not as rigid/inflexiable as often appears initially
Most international treaties have clauses on low power secondary use which effictively mean that as long as harmful interference is not caused to users in other countries COMREG can more or less licence whoever they like

Interfere with a wide range of Satellite service (not just Sky)

A point that experts disagree on. Some argue that due to the very directional nature of recieve dishes at these frequencies low power terrestral transmissions can co-exist

Possibly hazards near transmitter sites If Mobile Masts are a a risk, then these transmitters would be 10 times more dangerous

Not necessairly
As frequency rises transmissions become even more directional
The ground level RF field strengths at phone mast sites and even high power UHF transmitter sites is often suprisingly low

RF more dangerous the higher the frequency

Just an assumption (based on thermal effects etc) Knowledge about the hazardous (or even beneficial) health effects of RF is very sketchy (comparable to the understanding of gamma ray hazards in Marie Curies time) and the biggest concerns that have been expressed so far relate to fields from domestic wiring and appliances which in most cases involve frequencies in the 50-60 Hz range

As for phone masts I dont think there is a problem but I wouldnt be sure about handsets (inverse square law and all that) On the other hand I wouldnt like to live beside a 400Kv ESB/NIE transmission line. -The field strength from electric blankets and hairdriers may be higher but I never use those items !

watty

Yes a Phone handset is much, much more dangerous than any mast.

The more masts there are for mobile phones, the lower the power and the safer. That's ironic given usual protests about new masts!


It is because it is more directional, it is more dangerous. You don't look into wave guide of a 20mW transmitter unless you like getting cateracts. This is proven.

A Mr Eddie O Gorman advised the Dept of Communications years ago to use 11GHZ for analouge MMDS but it was turned down (mainly for economic reasons as smaller cells/more transmitters would be needed) 11GHz In the UK 11Hz "MVDS" was proposed by the DTI/RA/ITC in the UK but there wasnt any takers as it was felt there wasnt the market for it

.......... And rejected due to inference, safety of transmitters, poor perforamce in trees or buildings, needing direct visibel line of sight etc.

It was a stupid idea then and a stupid one now. 4Ghz to 200GHz is FINE for point to point links (enginnerd Masts) and for Satellite as there are no obstructions. Useless for Domestic Terrestrial distribution in Rural OR Urban Ireland. The 2.4 GHz (MMDS or Wireless LAN) is tricky enough in majority of cases. Poor analog Signals and "freezing" crashing Digital MMDS.

Mike 1972

It is because it is more directional, it is more dangerous.

true but only if its pointing at someone. When youre talking about signals fom tall masts pointed at (or slightly above/below) the horizon the only way anyone is going to get exposed to a significant amount of RF is if theyre stupid enough to climb the mast and look into a transmitting aerial/waveguide

Some interesting claims made here

LMDS @ 28GHZ and MVDS @ 40GHz