Channel 4HD Free to Air from 10th March

watty

Shannon Hartly 1948

Capacity is related to Signal Power / Noise Power
Thus if you increase the Symbol Rate (more capacity), the "Quality" in digital terms must be lower unless you increase the signal by larger dish or more Transponder power.

But on DVB-S2 all is not equal.

On DVB-S there is only QPSK modulation. So more Symbol Rate means more bandwidth and the bits per symbol is constant.

On DVB-S2 you can vary the bits per symbol too. More bits per symbol needs lower noise or higher power for same "Quality".

Quality isn't signal to noise. It's the amount of errors you have. obviously it's related to SNR (Signal/Noise ratio).

There is FEC (Forward Error Correction).
7/8 means most of the data is real data and very little Error correction is possible. So you need MUCH more power or signal to get the same quality.

1/2 means a lot of the data is cleverly duplicated so that more errors can be corrected.
(Reed Solomon and Viterbi are the guys to look up)

So for SAME transponder power and Symbol rate and Modulation, 7/8 gives more actual data rate, but a much smaller footprint, or needs a giant dish. FEC of 1/2 gives lowest actual data rate for same Symbol Rate and larger footprint or Smaller dish.

Given Satellite Transponder power, Satellite Dish gain, home dish gain, weather, and required bit rate, you can calculate the minimum FEC needed and what the actual foot print vs dish size is.

Everything is inter-related.

example a 10 Watt transmitter with a 1000 SR.
To get the same quality with 10,000 SR you need 10 times the power, because the bandwidth must be 10x more if the modulation is the same. Noise power is same at each band, so 10 times bandwidth is x10 more noise. Or to think of it another way, the 10W if you change from SR 1,000 to SR 10,000 is spread x10 more thinly...

If you use COFDM its more obvious. Instead of 1,000 SR on one QPSK carrier, you can have 10 carriers each 1/10th bandwidth, each at SR = 100. The total data is the same. Each carrier is 1W.
Now using COFDM to get the 10,000 SR you need 100 carriers, each 1W and each SR=100. More obvious that as you increase the Symbol Rate (if all else is the same) the quality must fall, or alternatively you have to increase the power to keep quality the same.

You can see how Analogue SNR is a bit misleading as you need to compare the bandwidths and data rates too. Digital "Quality" measurement takes into account the power, bandwidth, data rate, FEC and noise. Which is why on same satellite with similar Symbol Rate the "quality" of a 7/8 feed is rubbish compared with 2/3 Home TV.
Of course the "feeds" are often lower power too. The Broadcaster's earth Station may be using a 3.7m to 5.6m dish. Hence saving space using 7/8 and saving power too (smaller uplink dish on the mobile van).

DigiDec

Watty.................so knowledgeable!

liamtech

DigiDec wrote: »

Watty.................so knowledgeable!

I agree - 100% - For what its worth I salute you Watty, you know your stuff, and whats more you can make it understandable to a layman....FAIRPLAY:D

I gotta say im looking forward in particular to this one going FTA - if it wont tune in to $ky, it will give many HD fans the nudge they need towards embracing FTA & Freesat -

holidaysong

I can't get this tuned in on my Humax Foxsat HDR, should I be able to? Will I be able to tune it in tomorrow?

muincav

holidaysong wrote: »

I can't get this tuned in on my Humax Foxsat HDR, should I be able to? Will I be able to tune it in tomorrow?

Officially CH4 HD will not be avaiable on Freesat and their boxes until April according to the INFO page on freesat boxes.

Nowso

Ch4 HD (UK)
12.607V SR
27500 FEC 3/4 FTA (DVB-
S2 QPSK) Tagged as 55300
Search for all channels until it goes fta . I got it up on my humax foxsat hd.

Digital Satellite TV

Anyone get CH HD on Free to Air HD box yet? We tried around 7.30am and no joy yet.

Rick_

It may not happen until later today, but it may not happen today at all according to some posters on Digital Spy. Something to do with the ROI versions of C4/E4/M4/F4 being encrypted and Channel 4 HD being FTA.

homer911

Paddy C wrote: »

It may not happen until later today, but it may not happen today at all according to some posters on Digital Spy. Something to do with the ROI versions of C4/E4/M4/F4 being encrypted and Channel 4 HD being FTA.

Surely that would only be on a sky box - a regular FTA box doesnt care where you are..

Digital Satellite TV

Paddy C wrote: »

It may not happen until later today, but it may not happen today at all according to some posters on Digital Spy. Something to do with the ROI versions of C4/E4/M4/F4 being encrypted and Channel 4 HD being FTA.

If it is free in UK it is free here - you can tune in any version you like on a freesat of fta box. Just need the bleedin thing to be available!!!!!!!!

Rick_

I'm just going by what I have read elsewhere.

It was supposed to be going FTA today, but surprise surprise it hasn't. So the people in the know who informed us it mightn't due to ROI issues were correct, just like they were in telling us that the channel was coming in the first place and the dates for it launching, testing etc.

liamtech

Paddy C wrote: »

I'm just going by what I have read elsewhere.

It was supposed to be going FTA today, but surprise surprise it hasn't. So the people in the know who informed us it mightn't due to ROI issues were correct, just like they were in telling us that the channel was coming in the first place and the dates for it launching, testing etc.

Im sorry to say, that is totally incorrect - I have seen the posts on Digital spy and that poster is incorrect - any station broadcasting from astra A B D 28.2, or eurobird 28.5, assuming that station is being broadcast unencrypted, will be receivable in ireland - its impossible to prevent this - thats why i can watch STV HD, which is meant for scotland, or S4C which is meant for wales - Those "in the know" who speculate its to do with ROI users are wrong, and clearly are not "In the know"!

It may yet launch today or the 10th March date could have been incorrect - it is stated on the OFFICIAL FREESAT Website that it will launch on that platform in April - worst case scenario we have to wait till then -

I do understand peoples disappointment, i feel let down myself - fingers crossed for later tonight!

sky23

yeah still encrypted the signal quality is low enough for me too 28%, i hope that won't be too much of a problem

PressTheButton

C4HD meant to be FTA today, but might have been put back one week; this doesn’t affect the expected launch date though - 1st April 2011 (Not April's Fools, BTW). This date isn’t officially confirmed. Source

Video

can anyone give me the exact information of the stream that was working in the tests?

everytime i try the other info i dont get anything just a signal lagging but everyother channel on my reciever works so its not a signal strength issue!

ftakeith

Digital Satellite TV wrote: »

If it is free in UK it is free here - you can tune in any version you like on a freesat of fta box. Just need the bleedin thing to be available!!!!!!!!

april 1st when c4hd is available, its mostly upscaled of c4, so don't panic, everyone can see the hollyoaks in upscaled hd in a few weeks

Minstrel27

ftakeith wrote: »

april 1st when c4hd is available, its mostly upscaled of c4, so don't panic, everyone can see the hollyoaks in upscaled hd in a few weeks

Hollyoaks is actually shown in HD. It's not upscaled.

fat-tony

Video wrote: »

can anyone give me the exact information of the stream that was working in the tests?

everytime i try the other info i dont get anything just a signal lagging but everyother channel on my reciever works so its not a signal strength issue!

I posted the relevant tuning information on the other thread you started http://www.boards.ie/vbulletin/showpost.php?p=71089302&postcount=5

It's still encrypted - have patience, grasshopper:D

PressTheButton

C4DH listed as 55300 is there alright - still encrypted. Parameters: Frequency 12607. Symobol Rate (or SR) 27500. Polarity Vertical. Possibilities are it may go FTA in the next 5 days or exactly 14 days before Freesat launch. In the meantime if you activate the subtitles you get them - confirming encrypted C4HD transmission in progress.

mike2084

Hoping this goes FTA soon - Cheltenham is in Native HD this year

Video

well im not pickin it up at all
when i add it manually i get no subs either

liamtech

slight changes in signal strength at the moment, and two friends have confirmed that - HDRS400 reads a drop from 75% to 67% - no movement of the dish-

My friends system, a SL65 reads this encrypted channel as 62% quality -

I suspect they are tweaking the signal strength to minimize the amount of users outside the UK and Ireland that can pick it up - this is only theory but given the whole Astra 2D, UK Footprint argument, its a definite possibility - i wouldnt be surprised if C4 do something along the lines of what ITV did with the first incarnation of ITV HD - ie Freesat exclusive red button from C4 SD to C4 HD - this might set the launch date back a bit

its a bit stupid really as i know for a fact that my cousin in Marseilles can pick up every 28.2/28.5 station there is - using a bigger dish it has to be said though - i cant remember what box he was using but i know for a fact that it was possible to tune in ITV HD manually

givecredit

Arqiva has secured a satellite distribution deal for Channel 4 HD. The new arrangement facilitates transmission of Channel 4 HD for the first time on Freesat (from April 2011) while maintaining the channel's presence on the Sky platform. Arqiva provides encoding, teleport services and satellite capacity to enable Channel 4 HD to be uplinked simultaneously to both platforms via one transponder.

The service, which began on the 18th February 2011, takes advantage of Arqiva’s technologically advanced DVB-S2 MPEG-4 encoding platform on Eurobird EB1. This enables Channel 4 to more efficiently deliver the high quality HD signal. Arqiva has also installed the necessary compression equipment at Channel 4’s Playout Centre and is providing the necessary Sky adaptation and Freesat EPG insertion

Nowso

epg now showing

200motels

Nowso wrote: »

epg now showing

Can I get this on Sky?

stanley1

Nowso wrote: »

epg now showing

7 day epg now active.

Minstrel27

200motels wrote: »

Can I get this on Sky?

No. The Sky box does not allow you to tune it in.

kaerobe

Minstrel27 wrote: »

No. The Sky box does not allow you to tune it in.

Yet or Ever?

JDxtra

We don't know yet. It has been absent for active Irish Sky subscribers for an unknown reason - maybe this reason remains.

Minstrel27

kaerobe wrote: »

Yet or Ever?

No idea.

Minstrel27

Healy1 wrote: »

so is it up now as FTA, if so can you post frequency etc,

thanks

Post number 1.

muffler

Healy1 wrote: »

so is it up now as FTA, if so can you post frequency etc,

thanks

Minstrel27 wrote: »

Post number 1.

That doesn't work for me

sky23

muffler wrote: »

That doesn't work for me

Its still encrypted. are you not picking it up at all?

muffler

sky23 wrote: »

Its still encrypted. are you not picking it up at all?

Just the "no signal being received" message

muffler

muffler wrote: »

Just the "no signal being received" message

Are you using a Sky HD box? It won't lock on the frequency.

muffler

Karsini wrote: »

Are you using a Sky HD box? It won't lock on the frequency.

Ah!........ thats the problem so


Edit/ But then again what use would it be without a HD box?

.

muffler

muffler wrote: »

Ah!........ thats the problem so


Edit/ But then again what use would it be without a HD box?

.

Same with the non-HD box, it doesn't lock it and isn't capable of either (probably shouldn't be so specific ). The multiplex is being broadcast in DVB-S2 and it seems the Sky HD box won't lock on S2 transponders with manual tuning even though the hardware can do it.

spongerobinson

is everyone able to pick this up now, or is it still not available properly? can't get a signal on the transponder at all on my spiderbox. Definitely have all the correct information entered, but getting no signal whatsoever. Have no problem with any other channels so don't think its my dish. Anyone else with a spiderbox have it working?

Minstrel27

I can tune it in but it is still encrypted.

PressTheButton

Channel ID change - 55300 now Channel 4 HD. Still encrypted. EPG visible. Subtitles available. Same parameters. Frequency 12607. Symbol Rate (or SR) 27500. Polarity Vertical.

Machinehead

55300 still available flagged as HDTV encrypted & "No Service". Channel 4 HD also appears & flagged as pay tv.

Rick_

Sky boxes will now use this for the EPG and next Friday the encryption will be removed and it will go FTA. It will also go onto the Freesat line-up on the same day and will presumably also go on to Sat4Free boxes EPG's as well.

liamtech

Paddy C wrote: »

Sky boxes will now use this for the EPG and next Friday the encryption will be removed and it will go FTA. It will also go onto the Freesat line-up on the same day and will presumably also go on to Sat4Free boxes EPG's as well.

I believe the Sat4free units don't actually update there line-up automatically. Users may have to perform a factory rest, which should do the job

Rick_

That's a bit poo, can't they just perform an update channels scan, or has that been disabled too along with the ability to change the postcode?

clln

Paddy C wrote: »

Sky boxes will now use this for the EPG and next Friday the encryption will be removed and it will go FTA. It will also go onto the Freesat line-up on the same day.

Hi Paddy C,can you confirm that it will go FTA next Friday?

You have me scratching my head now as i have checked the official and unofficial Freesat websites.
i have checked Ch number 999 on Freesat and i have checked DS(were another 'Paddy C' posts! the imposter!;):)

well? link please :pac::)

Rick_

The posters on DS who intially broke the news, as they had knew about it before it was officially announced, confirmed that it would be joining the Freesat lineup on 1st April after someone else on another forum leaked the dates. They have not said anything since to change this, so the plan still is, as far as I can see, for it to go FTA and join Freesat from next Friday.

Oh, and the Paddy C on DS is also me.

fat-tony

Paddy C wrote: »

The posters on DS who intially broke the news, as they had knew about it before it was officially announced, confirmed that it would be joining the Freesat lineup on 1st April after someone else on another forum leaked the dates. They have not said anything since to change this, so the plan still is, as far as I can see, for it to go FTA and join Freesat from next Friday.

Oh, and the Paddy C on DS is also me.

Next Friday? Thought it was due on 1st April, which is Friday week?

MBSnr

spongerobinson wrote: »

is everyone able to pick this up now, or is it still not available properly? can't get a signal on the transponder at all on my spiderbox. Definitely have all the correct information entered, but getting no signal whatsoever. Have no problem with any other channels so don't think its my dish. Anyone else with a spiderbox have it working?

I don't have the same box as you but I was scratching my head for a while on this. I wasn't getting anything on the transponder at all. In the end I stepped through all the transponders and realised I couldn't see any of the newer HD ones. Turns out my box had the original settings for a lot of the transponders of DVB-S QPSK 27500 and not DVB-S2 QPSK 27500. A quick edit and the transponder appeared...

Rick_

fat-tony wrote: »

Next Friday? Thought it was due on 1st April, which is Friday week?

We've already had that discussion on DS regarding different regions and what they mean to be "this coming xxxxday" and "xxxxday next week"!

Where I am from we say "next Friday" and it means 'Friday next week'. If I said "this Friday" it means "the Friday coming this week".

Anyway, it is supposed to launch on Friday 1st April 2011 but Ian-D who is in the know of these things and posts on DS has said that the dates might have been pushed back a little bit but it still will be going FTA in April, just maybe not the 1st April any more.

clln

Paddy C wrote: »

We've already had that discussion on DS regarding different regions and what they mean to be "this coming xxxxday" and "xxxxday next week"!

Where I am from we say "next Friday" and it means 'Friday next week'. If I said "this Friday" it means "the Friday coming this week".

Anyway, it is supposed to launch on Friday 1st April 2011 but Ian-D who is in the know of these things and posts on DS has said that the dates might have been pushed back a little bit but it still will be going FTA in April, just maybe not the 1st April any more.

I for one accept that explanation Paddy C.
thank you for your deliberate mistake and for keeping us on our toes! :D