22 replies to this topic

[Multivits]

Please help why are they turning off the analogue??? Digital is not better than analgoue when dealing with poor weather conditions, who has convinced everyone that digital is better? Digital may be OK in near perfect reception conditions, but when the rain comes down the digital just can't cope and freezes up. But behold in comes analogue like a Knight in shining armour and we can yet again see the Tv. But not for much longer. Modern is not always best : (

[pgdownload]

Digital is fine in most reception conditions. One main benefit is that you continue to get a 100% picture while the signal strength gets worse. Analogue starts showing static and ghosting etc. unless it has perfect reception. However a trade off is that you can still get a poor analogue signal when the digital signal stops. Google "digital cliff"

FWIW when the analogue network is completely shut down, the digital transmitters will be powered up quite a lot so everyone's reception should improve a lot then. But until then it sounds like you need to have your antenna checked by a professional.

Peter

[M'bozo]

but when the rain comes down the digital just can't cope and freezes up.

Under certain specific conditions, yes. Ordinarily, no.

FWIW when the analogue network is completely shut down, the digital transmitters will be powered up quite a lot

There may be certain specific instances of this (where there are adjacent channel/co-channel interfernce issues), but generally speaking, the power level should remain unchanged*.



(*I have no idea if this will be the case after band restack occurs.)


(Edit: Can't help feeling the first post is a troll post.)

Edited by M'bozo, 22 March 2012 - 01:12 PM.

[Tazzy2Heads]

Multivits, on 22 March 2012 - 11:15 AM, said:

Please help why are they turning off the analogue??? Digital is not better than analgoue when dealing with poor weather conditions, who has convinced everyone that digital is better? Digital may be OK in near perfect reception conditions, but when the rain comes down the digital just can't cope and freezes up. But behold in comes analogue like a Knight in shining armour and we can yet again see the Tv. But not for much longer. Modern is not always
best : (

Hi Multivits,
As a matter of interest, where are you located ? As has been already suggested you may have some antenna grief now that is
affecting your tv signals both digital and anologue.This can only be checked by someone with a digital signal meter.
If you are going to loose reliable tv reception when the analogue gets turned off there is the VAST satellite system for people in
your position , which is now in SD and HD widescreen with program guides etc, which is far better than analogue in picture.
The key to it all is where you are and do you have a faulty system now that is not delivering the required signal quality to
maintain tv in the bad weather.
Cheers Tazzy.

[nbound]

Multivits, on 22 March 2012 - 11:15 AM, said:

Please help why are they turning off the analogue??? Digital is not better than analgoue when dealing with poor weather conditions, who has convinced everyone that digital is better? Digital may be OK in near perfect reception conditions, but when the rain comes down the digital just can't cope and freezes up. But behold in comes analogue like a Knight in shining armour and we can yet again see the Tv. But not for much longer. Modern is not always best : (

If your digital reception has issues in poor weather, then in all likelyhood it hasnt been set up correctly*, a good digital system will have no problems whatsoever with almost any amount of rain or even snow. Actually a reasonably good chance, is that the birds have been at your external cabling and waters getting in.

* Note: (Or you are right on the very outer outer limit of the particular transmitter you are currently aiming at)

As Tassy has said, if your system is setup properly and you are still having these issues, than you can get satellite free-to-view digital tv.

[alanh]

Multivits,
This will answer most of your questions http://www.digitalready.gov.au/

Also go to http://www.dtvforum....hp?showforum=82
Select your area and then read "Get the best reception" There may be a repeater near you on other channels. In newly measured black spots some new repeaters are being installed.

AlanH

Edited by alanh, 22 March 2012 - 07:14 PM.

[SDL]

Not to worry it will one day all come down a tube for most and then antennas will be a thing of the past.

[alanh]

SDL,
You could have said this about cable TV which has been around a long time particularly in the USA. It has not taken off here because free to air is cheaper than paying telecom companies. The same will still apply to the NBN.

The NBN has been testing using HD video for Doctors appointments from remote locations (now there is a Medicare item number), legal consultations etc. There is plenty of other applications than just entertainment for the NBN.

Also consider that S3-D HD 50 frame/s video requires around 30 Mbit/s and a dwelling's allocation is 100 Mbit/s. So if three people watch different programs the whole allocation is used at that time. What happens if this is on a large scale. What happens through the network to the playout centre!

Broadcast is a cheaper one way communications system particularly in areas of lower population densities.

AlanH

[M'bozo]

SDL, on 27 March 2012 - 09:54 AM, said:

Not to worry it will one day all come down a tube for most and then antennas will be a thing of the past.

I agree.

In Tasmania's case, looks like this might start around 2015

[SDL]

Agreed Alan there are a lot of applications, entertainment just being one of them, and many of them we haven't even thought of yet. Cable TV was a little different because it was based on the old copper system and because it relied on TV being the only revenue stream pretty much if you ignore the more recent package deals.

[Robbks]

Now where did i put my CDMA phone.......??

if you have drop-outs in bad weather in your area you need to find a way of getting a better signal.
antenna orientation to the correct repeater
correct antenna
correct connections
ensuring you're receiving the RIGHT signal for your antenna (digi channels can be broadcast on either or both UHF and VHF in your area)
amplify the signal at your end

[Multivits]

I am in Berowra NSW, which is officially Sydney Metro region.

Thanks for the replies. The bird cable attack I will check but when I was up on the roof last the connection was fine and dry and we had problems back then (thats why I was up theer on the roof)

I have checked the antenna direction and it is aimed at Gore Hill Sydney.

Channel 9 (GO etc) is the worst we loose the signal daily. But not so much others. Although CH7 can go under extreme heavy rain.

But never ever loose SBS. Is ther any clues in here?

TIA

Multivits

[Robbks]

well SBS should be good.
it has a 200KW transmitter, compared to 50KW of the others
http://ozdigitaltv.c...rmon-Willoughby

you may be better off swinging around to the north east and re-scanning
http://ozdigitaltv.c...s/NSW/32-Bouddi

and teh maps show you teh frequency you should be looking at

NOTE:
if you have a VHF ONLY antenna then any stations over 300MHz will be received properly
and likewise with a UHF only, stations under 300MHz will not be received properly

looking at teh site you're pointing at SBS is at 570MHz (UHF) and all others in the VHF band
so you may only have a UHF antenna

the other site has UHF only signals which may fix your issue

[Malich]

alanh, on 27 March 2012 - 07:01 PM, said:

What happens through the network to the playout centre!

Layer 2 IP multicast.

NBN's media release, multicast technical discussion paper, and invitation for Expressions of Interest.

[nbound]

Robbks, on 02 April 2012 - 01:02 PM, said:

well SBS should be good.
it has a 200KW transmitter, compared to 50KW of the others
http://ozdigitaltv.c...rmon-Willoughby

you may be better off swinging around to the north east and re-scanning
http://ozdigitaltv.c...s/NSW/32-Bouddi

and teh maps show you teh frequency you should be looking at

Incorrect, SBS has to be at 200KW to equal the others as the higher frequency signal does not propagate as well as the VHF signals do.

Robbks, on 02 April 2012 - 01:02 PM, said:

NOTE:
if you have a VHF ONLY antenna then any stations over 300MHz will be received properly
and likewise with a UHF only, stations under 300MHz will not be received properly

looking at teh site you're pointing at SBS is at 570MHz (UHF) and all others in the VHF band
so you may only have a UHF antenna

the other site has UHF only signals which may fix your issue

Incorrect again, aerials are "cut" for a specific range of channels within VHF and UHF for digital thats CH6-12 (VHF) and then 28-69 (UHF), and an aerial may be any subset of those channels. Unless it was a DIY job, Id assume he already has a combination antenna (or 2 separate antennas) that covers the correct frequency ranges (Band 3 and 4) for the Sydney Transmitter, or perhaps already a UHF antenna if he is going for a retransmission site. Most likely is that all his channels are very low, and a couple are just a lil lower than the others hence they are breaking up while the others appear ok. Wont know for certain until he gets someone out to measure signal strengths.

[alanh]

Multivits,
It depends on where in Berowra you are. There are some deep valleys in your area.
Can you receive ABC1 on analog (channel 2)?

I suggest you read http://www.dtvforum....showtopic=11367

From 2014 SBS will move to channel 7 and the 7 Digital will remain on channel 6.
So for this all that is required is one of the antennas in the H3 link in the above link. If you have terrain between you and Artarmon, when viewed from your roof, then the blocked path recommendations apply.

The reason why Nine, Gem, Go! and 9Extra are unreliable is that their transmitter tower if further south than the Mowbray Rd Artarmon one for 7 and Ten networks and the Broadcast Australia tower in Pacific Highway for ABC.

If you want SBS/TVN in the meantime I would add a high gain H4 antenna in the H4 link above.

AlanH

[Tazzy2Heads]

Multivits, on 02 April 2012 - 11:09 AM, said:

I am in Berowra NSW, which is officially Sydney Metro region.

Thanks for the replies. The bird cable attack I will check but when I was up on the roof last the connection was fine and dry and we had problems back then (thats why I was up theer on the roof)

I have checked the antenna direction and it is aimed at Gore Hill Sydney.

Channel 9 (GO etc) is the worst we loose the signal daily. But not so much others. Although CH7 can go under extreme heavy rain.

But never ever loose SBS. Is ther any clues in here?

TIA

Multivits

Hi Multivits'
Have you typed in your address on the 'Myswitch' web sight to see what it says about signals at your place, and /or clicked
on alternate transmitter locations ? If you are high up you may be able to get signals from the Wollongong Knights Hill towers
on UHF.You would need a signal meter to ascertain if the signals are adequate.
Tazzy

[James T Kirk]

alanh, on 02 April 2012 - 05:18 PM, said:

Multivits,
The reason why Nine, Gem, Go! and 9Extra are unreliable is that their transmitter tower if further south than the Mowbray Rd Artarmon one for 7 and Ten networks and the Broadcast Australia tower in Pacific Highway for ABC.

AlanH

My suggestion is not to place value on AlanH's advice, he is commonly in error and surprise surprise he is again, his statement above is wrong.
James

[digital doctor spock]

I have known TV antennas to fail on some channels during rain, I remember one case where the viewer completely lost the Band III channels but not the BI channel and it turned out to be a faulty antenna, I took a lot to convince the viewer mind you. In some areas it has been found that some of the older VHF antennas were cut specifically for channels 7,9 & 10 and function quite poorly on channels 11 & 12 which happen to be the digital channels for 10 & the ABC respectively.
Propagation of RF signals due to rain will not depend on whether it is an analogue or digital transmission because all transmitters operate in the analogue domain irrespective if they are modulated by an analogue signal or a digital signal. Rain cannot differentiate between an analogue TV signal or a digital TV signal but it can have different effects for different frequencies. The same applies to TV antennas, they cannot differentiate between "digital" and "analogue", but they are very frequency conscious.

[Multivits]

Thanks Digi Dr Spock

by "frequency conscious" do you mean multipathing?

This is the top answer for me. : )

I think all things considered I will get a new antennea with some good gain (20db enough?) when I win the lotto!

[digital doctor spock]

Hi Multivits

I was referring more to the resonant nature of antennas and that they are designed and manufacture to work at different frequencies. Some of course are designed to be broadband antennas by having a 'combination" antenna such as a VHF/UHFyagi.

Most antennas I am aware typically have a gain of anywhere from 10 dB to 15 dB. Getting a high gain broadband antenna is a challenge.

Of course Multi-pathing too is frequency conscious (or wavelength dependent)

[nbound]

Multivits, on 04 April 2012 - 03:13 PM, said:

I think all things considered I will get a new antennea with some good gain (20db enough?) when I win the lotto!

You are going to struggle to get an antenna with a gain above 16-17dB.

Theres a good chance its not required anyway, check what your neighbours have, in most circumstances, what they have will do the job equally well at your place.

Spending money on equipment to DIY aerials can quickly turn into a money sink. Get an installer, find out whats wrong. It could end up being cheaper than replacing an aerial anyway.

[andrewlace]

There are many causes for weaker TV signals - trees, rubbish cables, antennas, cheap digital tuners, faulty amplifiers, or external noise.  My personal feeling is that digital will work better with many amplifiers when analogue is taken off air.  Less channels: less noise, less intermod distortion. Personally I'd say why keep analogue for the sake of those with insufficient signal.  Have you had someone look over your system with proper test equipment and skills?

If the antenna has a faulty balun this could be the cause (or one of many) of your problems

Edited by andrewlace, 19 June 2012 - 08:36 PM.