70 replies to this topic

[norto]

Alanh
Can you tell me if a Windgard or Omni brand tv aeriels are suitable
for digital reception on a caravan (constantly travelling). If not what should i get
cheers

[alanh]

norto,
Antenna Survey Caravans and Marine
AlanH

[mtv]

Before deciding what is required to provide the best reception, first you must know what signal levels and quality are present at a given location.

The key to digital reception is obtaining signals of adequate power and quality At THE ANTENNA.

Amplifiers should only be used to compensate for distribution losses, not to try and increase signals which are too low/not present.

Over-use of amplifiers without prior knowledge of signal power and Bit Error Rates is almost guaranteed to not only amplify existing problems, but to also create new ones.

Selection of the correct antenna for a particular location, together with accurate digital measurements to locate the best mounting location for the antenna are things which make every installation unique.

A "blanket post" across every regional area DTV forum recommending such bad practice may be considered 'trolling'.

As you are a new member, having only joined the forum today, burnoutking2 perhaps you could share with us your location, what channels you are receiving and from where, and what antennas and amplifiers you are using to achieve this.

I have my suspicions this poster is closely related to recently suspended troll, tyrewarmer20/dodgy

[Roderick]

Adza, on Oct 30 2005, 10:21 PM, said:

This is slightly incorrect.... all digital channels are broadcast on VHF Band 3 only. You will only require a Band 4 horizontal antenna if you still wish to pick up the analogue channels in this band which are 28 for SBS, 31 for WIN and 34 for Prime.

This means I should get rid of my horizontally polarized UHF antenna, as I only view digital channels from Black Mountain.   I can take down the ugly UHF antenna I used with analogue TV, as well as the combiner on the antennae pole.  Yipee!

Is this still true?

Rod

Damn:  Didn't see the bit about SBS still being UHF.  One channel puts a spanner in the works.  I suppose there had be some reason why I kept the UHF antenna when I originally switched to DTV.  We do watch SBS now and again.

[holden caulfield]

I live in O'Connor and last night my digital reception dropped out. The old skool feed through my TV was unaffected. I'm trying to ascertain if this reception issue is related to my Pana DMR-EX75 or did others experience a similar problem last night???

[holden caulfield]

It was a dud unit. I replaced my EX75 from JB Hi-Fi Civic and the replacement unit auto-tuned without problem.

[cagehead]

So I live in the Avenue Apartment block in the city - with an antenna in the roof wired ot my apartment. I've just bought a new plasma with integrated HD tuner and I get pretty poor reception. Would I be better off buying an indoors antenna to use with it?

Cheers in advance...

[alanh]

cagehead,
The best option is to connect this antenna, however if this is not possible, then read the first post in this strand. Click on the indoor antennal link.
Your problem is that the main transmitters use vertical and horizontal polarisation. Rotating the antenna on some channel changes will be a pain.

AlanH

[cagehead]

alanh, on Aug 12 2007, 07:00 PM, said:

cagehead,
The best option is to connect this antenna, however if this is not possible, then read the first post in this strand. Click on the indoor antennal link.
Your problem is that the main transmitters use vertical and horizontal polarisation. Rotating the antenna on some channel changes will be a pain.

AlanH

Sorry Alan I'm not sure I know what you mean. I can't physically change the antenna as I am in an apartment block. Is that what you mean?
Thanks.

[prl]

The ACMA Radio and Television Broadcasting Stations Book and the ABC Reception advice page both list ABC Digital Canberra (Channel 9a, Black Mountain transmiters) as broadcasting at 205.625 MHz, rather than 205.5 MHz, the channel nominal centre frequency. However my Beyonwiz DP-S1 and DP-H1 both say that they scan channel 9a at 205.5 MHz.

Does anyone on the forum know what frequency ABC Digital Black Mountain is actually transmitted on?

I've asked My ABC , but they say: "Due to the number of enquiries we receive, it may be up to 28 days before you receive a reply."

Peter

[alanh]

prl,
Why are you so concerned about the frequency. Channel 9A is infact European channel 9 so all digital tuners will tune it. The ABC's reply is standard for them. When they eventually answer the answer will be of no help. When you do the standard search it should find the signal unless the signal is either the wrong signal strength or contains too many reflected signals. The 125 kHz offset will probably be removed when analog TV is switched off.

AlanH

[prl]

alanh, on Apr 17 2008, 08:59 PM, said:

prl,
Why are you so concerned about the frequency. Channel 9A is infact European channel 9 so all digital tuners will tune it. The ABC's reply is standard for them. When they eventually answer the answer will be of no help. When you do the standard search it should find the signal unless the signal is either the wrong signal strength or contains too many reflected signals. The 125 kHz offset will probably be removed when analog TV is switched off.

AlanH

Hi AlanH.

I'm trying to eliminate it a possible source of reception problems. The tuner tunes to channel 9a, but to 205.5 MHz, not to the frequency that the ACMA & the ABC reception page say that ABC Digital Canberra is broadcasting 205.625 MHz. I'm aware of the adjacent analog channel, but it's not going to be turned off in the immediate future.

Peter

[alanh]

Peter,
What sort of interference do you have?
Is your signal coming from a Master TV antenna system or an individual antenna?
There is another digital ABC transmitter on channel 9A in Bateman's Bay/Moruya. It also has the 125 kHz offset. It is horizontally polarised and Canberra us vertically polarised. This sounds to me like a single frequency network, where the frequencies must be identical.

The most likely cause is a strong FM radio signal overloading your system.

AlanH

[prl]

Occasional uncorrected blocks.

I doubt that the 9a transmitter in Batemans/Moruya is causing interference. I'm 6km from the 50kW vertically polarised transmitter on Black Mountain, and 100 km from the 500W horizontally polarised transmitter at Batemans/Moruya. My antenna is vertically polarised and directed at about 90deg off line-of-sight to the Batemans/Moruya transmitters. The Bateman's/Moruya transmitter has a directional antenna, and from the coverage map on the ABC reception site, its main lobes seem point north and south along the coast and seawards, and up the Araluen valley; all away from Canberra.

I think that FM radio interference is a more likely cause of the problem than the Batemans/Moruya transmitter.

Anyway, it's interesting speculation, but doesn't go near my original question, which was a quite specific one about the actual transmitter frequency of ABC Digital Black Mountain.

[Grampus]

alanh, on Apr 17 2008, 07:59 PM, said:

prl,
Why are you so concerned about the frequency. Channel 9A is infact European channel 9 so all digital tuners will tune it. The ABC's reply is standard for them. When they eventually answer the answer will be of no help. When you do the standard search it should find the signal unless the signal is either the wrong signal strength or contains too many reflected signals. The 125 kHz offset will probably be removed when analog TV is switched off.

AlanH

Alan, I think you are saying that the ABC frequency in Canberra is currnetly at 206.625 Mhz?

I have been chasing a similar question about the Latrobe Valley Txmter with the ABC.
About a month ago, I believe it was transmitting at 627.375 Mhz, and was confirmed by both a PC based app, and the ABC in response to my query.
But currently it it seems that it is transmitting at 627.500 Mhz.

This information was being chased up to see if we could determine the veracity of a PVR's information re the actual freq tuned to.

[alanh]

prl,
You should try an attenuator in the input to the receiver as the signal is likely to be too strong. 1ABCFM is on 102.3 MHz 102.3 * 2 = 204.6 MHz. Channel 9A 205.625 - 204.6 = 1.025 MHz. This frequency is well within the bandwidth of the ABC9A transmissions.

So firstly I would try the attenuator as it is cheaper. If that does not work an FM filter should be tried.

Grampus,
A PVR is not a calibrated frequency meter. he only thing I can add is that GLV42 in the Goulburn Valley and TVT42 East Devonport are both on 627.5 MHz. They are all horizontally polarised.
An offset of -125 kHz is unusual, they are usually +125 kHz.

AlanH

[Grampus]

alanh, on Apr 18 2008, 04:36 PM, said:

Grampus,
A PVR is not a calibrated frequency meter. he only thing I can add is that GLV42 in the Goulburn Valley and TVT42 East Devonport are both on 627.5 MHz. They are all horizontally polarised.
An offset of -125 kHz is unusual, they are usually +125 kHz.

AlanH

Alan, thanks for the advice, I am well aware that a PVR is not the definitive tool.

I had a response from the ABC a month ago to advise me that they were transmitting Ch42 on the Goulbourn Valley txmitter at
627.375 Khz.
This was also seen in the output from a PC app as being 627.375 as well.
Since then it appears that the freq has altered to 627500.

The info below was supplied in 2004 from the Radio and Television Broadcasting Stations 2004 (Internet Edition)
Of course it is well out of date now.  But it showed that the lower offest was being used at the time.

ABLV42  Latrobe Valley  National  627.375  H  OD  400k  -38  24  2  146  33  48  1158094
  ABLV NTL Broadcast Tower MT TASSIE

[alanh]

Grampus,
As of this month it is still 627.375 MHz according to the ACMA

AlanH

[Grampus]

alanh, on Apr 18 2008, 05:34 PM, said:

Grampus,
As of this month it is still 627.375 MHz according to the ACMA

AlanH

Yes its a little confusing.
Maybe someone is a little tardy in updating some tables?

I've just used the DOS based utilty ScanChannelsBDA.exe.
If I try and  scan 627.375 as a unique freq.  The s/w doesn't find it.
But if I use 627500, it does.

It appears that in this mode (single frequency) the utility won't try to use offsets.

Where if I ask it scan all australian frequencies, it will try the base frequency first, then try both upper and lower offset.

[meaghers]

Hi everyone,

I'm new to Canberra and have been reading the blogs on this thread. I am very much a novice in this area and appreciate the information provided. I live in Watson and can see Black Mountain Tower from the roof of my house. Reading the spreadsheet on what type of antenna is recommended for my area, it appears I need a type C Band 3-4 antenna. However, when I checked the other reference for a suitable manufacturer, I couldnt find specifically a Band 3-4 antenna. There were Band 3-4+, but I'm not sure if they do the same job.

Could someone please help.

Regards,
Greg

[kenneth]

Basically you need an antenna that does VHF 6 to 12 (ABC and the commercials have frequencies for digital within this range) and also have one that can do UHF 30 for SBS.

I'm sure one of the antenna guru's will be able to spread some more light on the antenna type, but from what I gather the Band 3-4+ does the same job (although looking at Google, it actually seems to go a bit further to VHF 14 which is a bit interesting/useless).

[alanh]

Meaghers,
Please read the first post in this strand "Get the best reception".
Canberra requires special antennas because the channel 6 - 12 section needs to be on its side and the channels above channel 27 have to be parallel to the ground. This is called a cross polarised antenna.

There is a link to band 3 & 4 antenna in the post mentioned above. you need the crosspolarised type.

AlanH

[meaghers]

alanh, on May 5 2008, 07:34 PM, said:

Meaghers,
Please read the first post in this strand "Get the best reception".
Canberra requires special antennas because the channel 6 - 12 section needs to be on its side and the channels above channel 27 have to be parallel to the ground. This is called a cross polarised antenna.

There is a link to band 3 & 4 antenna in the post mentioned above. you need the crosspolarised type.

AlanH

Thanks for your replies. I did read all of the posts and attachments, but couldnt find specifically a crosspolarised Band 3-4 antenna listed in your antenna manufacturers, only 3-4+ antennas. Thus my question is really;can a cross polarised 3-4+ antenna be used in lieu of a cross polarised 3-4 antenna? Kenneth believes it does.

Kind regards,
Greg

[mtv]

meaghers, on May 5 2008, 10:08 PM, said:

can a cross polarised 3-4+ antenna be used in lieu of a cross polarised 3-4 antenna?

Yes Greg, it can.

The + just means it's UHF receiving capability extends beyond band 4 (eg: it goes part way into band 5).

[(ツ)]

Bearing in mind that if you can see the transmitter site your signal will be strong enough to cope with an antenna that's not 100% perfect. Another good guide for which antenna to use is to look around at what the neighbours are using.

Unless of course they're using an indoor antenna which confirms a very strong signal.

Thankfully "rabbit ears" haven't been banned yet