15 replies to this topic

[spinner]

Hi.
Has anybody heard if (and when) channel 44 will be transmitted from the Uley Rd Craigmore transmitter? This transmitter has really improved reception to the surrounding areas but currently ch 44 is not available. They have some really interesting programs worth watching.

[alanh]

Spinner,
Ask the station http://www.44adelaide.com.au/co.html

AlanH

[CWulf]

 spinner, on 06 January 2012 - 11:15 AM, said:

Hi.
Has anybody heard if (and when) channel 44 will be transmitted from the Uley Rd Craigmore transmitter? This transmitter has really improved reception to the surrounding areas but currently ch 44 is not available. They have some really interesting programs worth watching.

Hi Spinner

I think it is very unlikely. The ACMA and government haven't approved repeaters for community television services anywhere other than on the Como building in Melbourne (which I understand was an exceptional case approved when the Como building services were implemented.

[alanh]

Cwulf,
The MGV64V analog (340 W = other transmitters), MGV66V digital is a tiny 6 Watts (others 85 W). These translators are on top of Como Centre South Yarra. MGV will cease analog transmissions from MGV31 and MGV66 in March this year. Melbourne digital restack cannot occur prior to 2014.

The translators at Uley Rd Elizabeth Downs conform to the new restack allocations. This leaves channel 38 available for allocation.
Keith also uses the same channel allocations except Keith uses horizontal polarisation and Elizabeth Downs is vertical. Keith and Elizabeth Downs are sufficiently far apart because other transmitters on these sites do not interfere.
The real problem is ABNS38 on the Bluff which is 240 kWerp. Horizontally polarisation. To conform to the digital restack ABNS needs a channel change to 43. This will not occur until 1st Jan 2014. ABNS is so powerful it could interfere with a translator on channel 38 in Elizabeth Downs under the right weather conditions.

Capital City Main transmitters Digital Restack
CTS30 will have to move to RF channel 10 like all other community TV stations in 2014 unless SBS is forced to carry their program stream. If channel 10 is used then the LCN 44 can continue to be used, however if SBS is forced to transmit their program the LCN must be 3#. (Restacks in Perth and Brisbane can occur after 30 June 2013)

Spinner in summary, not before 2014, if you want reception now, use a 4 bay UHF phased array and if require, UHF masthead amplifier to receive channel 30 from Mt Lofty.

AlanH

[CWulf]

Hi Alan

A lot of waffle of which I'm well aware, and far more so than you.

I don't see anything in your post that adds to mine or provides any useful advice other than that Spinner continue to try and watch the community service from Mt Lofty!

[alanh]

"The ACMA and government haven't approved repeaters for community television services anywhere other than on the Como building in Melbourne (which I understand was an exceptional case approved when the Como building services were implemented."

Digital transmitters

WTW Perth 200 kW
CTS Adelaide 7.5 kW
MGV Melbourne 15 kW/6 W
TSN Sydney 20 kW
CTQ Brisbane 15 kW

All SBS main capital city transmitters are 200 kW each

Considering that the Adelaide transmitter is half the power of the Melbourne main transmitter and that the ACMA has determined that for reception of other channels that Craigmore would also be an exceptional case, even for a tiny 6 W transmitter!
Since the ACMA has recognised that reception of Mt Lofty is poor how do you expect Spinner to watch Mt Lofty in digital?

If you are so well aware of the interference issues for Craigmore vs The Bluff transmitter why did you not post this as a reason?

Note that there is no channel 31 analog signals transmitted in Perth and Brisbane. Melbourne and Sydney will switch it off in March this year only leaving CTS31 Adelaide.

AlanH

[M'bozo]

WTW Perth 200 kW

Since when?

[alanh]

Mbozo,
It has been that way since West TV started. Prior to that in analog it was 600 kW. The extra costs were born by the WA government.

[CWulf]

As pointed out to Alan before, although he hasn't grasped it, the Perth CTV service is operating using 64QAM while the others are using QPSK!  This means that with these ERPs the community services are actually expected to provide similar coverage to the SBS, or at least the analog CTV services.

[alanh]

CWulf,
As you have not grasped all that changing the modulation type has done is to steepen the slope of the digital cliff. The fact still remains that if there is insufficient signal to lock onto the pilot signals there is no reception regardless of the modulation. The pilot signals are independent of the modulation type as they are just fixed frequencies.

The power of the pilot signals are reduced by 14 dB in Adelaide's case making coverage area less than the only other band 4 high powered station of SBS. If there is sufficient signal for a reliable lock then it will remain error free with QPSK rather than 64 QAM.

I have not mentioned analog at all. When Perth's community analog TV was on air it was 600 kW when compared to Adelaide's 30 kW analog. The modulation characteristics were identical to Adelaide. The ACMA generally makes a digital transmitter 1/4 of its analog equivalent, which is what has happened to community TV. The ACMA has been using the quarter rule for digital to give the same coverage area without interference to analog. All capital city SBS transmitters have gone from around 800 kW to 200 kW as have all band 3 analog transmitters gone from 200 kW to 50 kW for digital.

AlanH

[CWulf]

Really!  It seems the ACMA needs you to point this out to them as I suspect they just based their planning on all the DVB documentation that shows QPSK can provide similar coverage to 64QAM with a 10-12 dB lower C/N requirement (related to the 10-12 dB lower ERP I'd imagine).  You could also contact the eastern states CTV operates and point out that they have been conned and their not achieving the coverage they think they are!

BTW - I don't need you to quote ACMA planning data, restack block or your views on what they may do in the future. I'm not sure what it adds to these discussions.

[alanh]

Cwulf,
All the ACMA has to do with digital is to match the analog coverage. Considering that the analog power is considerably lower than SBS analog, there is no requirement on the ACMA to match SBS or the commercial stations.

In Adelaide case analog SBS 28 798 kW compared to the power 30 kW. This is hardly an equal coverage area with a difference of 14 dB

There is currently talk of converting SBS to 64QAM to increase the data rate from 19 - 23 Mbit/s. Thoughts of putting NITV on SBS??

AlanH

Edited by alanh, 05 March 2012 - 04:57 PM.

[CWulf]

Umm, SBS is already 64QAM.

[DrP]

<snicker>

[alanh]

SBS say that they are transmitting 64QAM with a data rate of 19.358 Mbit/s. Their reduced data rate allows more error correction bits to be inserted.

AlanH

[DrP]

Something that has been said by many forum members over the years.  Congratulations on 'discovering' this information.

Perhaps you should look into the issue of GI and the implications thereof too.  You may 'discover' more.

Edited by DrP, 07 March 2012 - 06:14 AM.