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Apartment Block Antenna Systems. Why No Digital


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#1 alanh

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Posted 11 December 2005 - 11:05 AM

.

Edited by alanh, 25 March 2013 - 11:56 AM.


#2 dig2all

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Posted 11 December 2005 - 06:52 PM

All,
Most MATV systems use an amplifier for each channel.

bidong - wrong assumption! if you were to replace most with some you would be more accurate.
however most 1 channel filters pass more like 3 channels at once, making regulation of adjacent channels virtually impossible. one successful exception is Fracarro K series. cannot agree with AlanH's simplified assumptions, perhaps they are an example of why apartment blocks need to be very careful about who they call.

#3 alanh

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Posted 12 December 2005 - 03:49 AM

dig2all,

Firstly STBs have to separate a digital channel between 2 analog ones eg channels 7,8 & 9! In addition the digital signal is 6 dB down.

PolytronMK filters

Matchmaster Look in the catalog for Johannson Profiler 14MM-Pro2

Judging by the amount of people in apartments that complain, this must be true. Remember that older systems were not as linear causing intermodulation distortion which gets worse as the number of channels amplifed increases. This is made much worse when the signals from each channel are uneven.

The newer Galium Arsnide Field Effect transistors are much better in their linearity.

AlanH

#4 dig2all

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Posted 12 December 2005 - 06:59 PM

the products you mention are simply not in the same class for selectivity, the vital specification if you are 2 regulate the levels of adjacent channels, funnily enough about which most manufacturers are quite coy.

let's not jump to output power or flatness - quite different subjects.

you wrote:

All,
Most MATV systems use an amplifier for each channel.
AlanH


and that's what i took exception to. don't mind someone who doesn't know asking questions, but someone pretending knowledge is an offence to those with a little understanding and an unecessary smoke screen to those who don't.

#5 banora

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Posted 17 January 2006 - 08:53 PM

All,
Most MATV systems use an amplifier for each channel. So where analog TV is used, the equivalent digital program is on a different channel. Only the installation menu of the Set Top Box will show you the real channel being used.

For example ABC in all capital cities uses channel 2 for analog and channel 12 for digital. The STB will show the transmitted channel number of a number starting with 2.

What are the options for you?

The best option is to modify the MATV system. Home Unit antenna systems

The only other option is click on Geographical Viewers' Forums. Subforums Select your geographic subforum and then open Get the best reception. Which transmitter and which antenna
Post any further posts on this topic in your geographic viewers’ forum.

Towards the end of each of the above posts there is a reference to indoor antennas which applies in that area.

AlanH

hey just a quick question what suburb are you in ???? i have a couple od place's on the lower twd west area that have lost ch 53 ---- seven

#6 DoktorDigital

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Posted 08 May 2006 - 05:11 PM

dig2all,

Firstly STBs have to separate a digital channel between 2 analog ones eg channels 7,8 & 9! In addition the digital signal is 6 dB down.

PolytronMK filters

Matchmaster Look in the catalog for Johannson Profiler 14MM-Pro2

Judging by the amount of people in apartments that complain, this must be true. Remember that older systems were not as linear causing intermodulation distortion which gets worse as the number of channels amplifed increases. This is made much worse when the signals from each channel are uneven.

The newer Galium Arsnide Field Effect transistors are much better in their linearity.

AlanH



AlanH,
Unfortunately you seem to missunderst what is being said here. What dig2all is saying is CORRECT!
But your note on Galium Arsenide Field Effect Transistors has nothing to do with this point.
Also Older systems that exist, usually have a headend that is 10 years old and has the selectivity or narrowness of a barn door! passing more than 2 channels per module which is incorrect and giving problems to end users because of distortion and overlapping. Also the way that old systems were designed and installed in the past were more favourable to product quantity instead of quality. Note that many earlier systems installed used 1 trunk amplifier per level/floor. There are also problems of not enough signal or too much signal. Remember that at the outlet much be no less than 60dBuV or no greater than 77dBuV. In most earlier installations the levels are never anywhere near the figures given. The figures given are taken from the CENELEC or Australian standard for PAL Analogue.
Also there are problems with Phase noise and some earlier single channel amplifiers and channel processors had these problems and therefore were not suitable for digital distribution.

There are many single channel amplifiers on the market today, and I agree can be quite confusing. However, as dig2all noted, the best single channel amplifier headend on the market today (comparing apples with apples and not comparing it with channel processors) is the Fracarro KF or K120 series. They pass 8MHz through each filter and are the best for equalization of headends that require reticulation of both Analogue and Digital carriers.
Yes you could use those brands that you have mentioned but 99.999% exactly the same bad problem will happen because the inferior brands do not have the selectivity required to pass/amplify only one carrier.

People think that by using any old single channel heandend will do the job. Sure this would have been true before digital was introduced because there was no adjacent channeling! However now that digital has been introduced and that they have been allocated (in metro area) in adjacent channel config.
This means that 6,8,11,12 & 29 Digital channels are now together with the existing analogue channels 2,7,9,10,28 & 31. In all cases, except for channel 2 and 31 are adjacent. (this is obviously different for regional areas)
This also means that in order to equalise each channel, you cannot use inferior channel filters/amplifiers because all they will do is amplify the adjacent channel and then mix them together again at the output linking stage. This means that if you used a single channel filter (note the term SINGLE) that passes more than one channel, you are not getting what you paid for and ultimately means that you are doubling up or mixing the same channel with different modules at the output stage only to end up with massive distortion because of overlapping the same carrier twice or in some instances 3 times. You might as well use a broadband amplifier if this is the case but is not the correct thing to do.

It is important to use a quality SINGLE channel amplifier or processor to equalise each channel. Again it is especially important to equalise each channel to eliminate adjacent digital carrier or adjacent analogue carrier interference.

I hope this has cleared the smoke for you but if you wish for me to go into greater detail I could arrange for that.

#7 alanh

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Posted 08 May 2006 - 08:16 PM

Docktor Digital
Thank you for your comments
I think you need both linearity and excellent filtering. Unfortunately as you point out many older systems have neither.

I have referred to the DBA Website specifications. What do you think of them?
The biggest problem is to get landlords to upgrade systems. I suppose this will not happen until analog disappears.

AlanH

#8 DoktorDigital

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Posted 09 May 2006 - 12:26 AM

Docktor Digital
Thank you for your comments
I think you need both linearity and excellent filtering. Unfortunately as you point out many older systems have neither.

I have referred to the DBA Website specifications. What do you think of them?
The biggest problem is to get landlords to upgrade systems. I suppose this will not happen until analog disappears.

AlanH


AlanH, Yes this is true, both linearity and filtering are important. However, with regards to linearity, it usually starts at the antenna. In MATV systems (usually in Metro Areas or where buildings are) there is a high occurance of multipathing or ghosting. They mean both the same thing where the same signal arrives at the antenna at different time intervals. Usually we are talking about 10ms or 20ms or even 30ms (ms=mili seconds). Also Antenna beamwidth and rear signal rejection are also important.
I have found in most cases, Log Periodic Antennas to work the best in these situations as they give the most linear response (incoming signal).

However I don't understand what you mean by you have referred to the DBA website specifications, so I cannot answer your question. Please can you elaborate on this?

In any case, some DBA specifications (ie: on the DBA website) are INCORRECT!
For example, I had read quite some time ago that the signal levels recommended for Digital Carriers would be in the 65dBuV range. That is between 60dBuV to 70dBuV. This is actually INCORRECT because:

IN REALITY AND ON PAPER, an ANALOGUE carrier should not have a channel power Less than 60dBuV or Greater than 77dBuV.
However in the real word, when it comes to digital carriers, the actual ADJACENT CARRIER MUST BE at least 12dB LESS THAN the ADJACENT Analogue Carrier otherwise you will get Digital Channel Interference (ie: Sharp White Dots) on your Analogue picture.
The correct equalization or configuration should be:
Analogue Carriers: No less than 60dBuV and no greater than 77dBuV
Digital Carriers: Must be at least 12dB below the Adjacent Analogue Carrier which will equate to:
Digital Carriers: No less than 48dBuV and No Greater Than 65dBuV but remembering that at any time MUST be 12dB less than the adjacent analogue carrier and no more greater than 16dB less than the adjacent analogue carrier.
Remember, if the Digital Channel has too much channel power, the adjacent analogue carrier will suffer digital interference (ie: Sharp white dots) and if the Digital Channel power is too low proportional to the adjacent analogue carrier, the digital carrier will suffer Analogue interference (ie: pixelation, dropouts etc...)
And... if anyone thinks otherwise I challenge them to prove me wrong!

In any case, MATV systems must be configured and installed with great care and the whole system must be calculated to reflect the given standards for continuous operation.

#9 DoktorDigital

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Posted 09 May 2006 - 12:27 AM

Docktor Digital
Thank you for your comments
I think you need both linearity and excellent filtering. Unfortunately as you point out many older systems have neither.

I have referred to the DBA Website specifications. What do you think of them?
The biggest problem is to get landlords to upgrade systems. I suppose this will not happen until analog disappears.

AlanH


AlanH, Yes this is true, both linearity and filtering are important. However, with regards to linearity, it usually starts at the antenna. In MATV systems (usually in Metro Areas or where buildings are) there is a high occurance of multipathing or ghosting. They mean both the same thing where the same signal arrives at the antenna at different time intervals. Usually we are talking about 10ms or 20ms or even 30ms (ms=mili seconds). Also Antenna beamwidth and rear signal rejection are also important.
I have found in most cases, Log Periodic Antennas to work the best in these situations as they give the most linear response (incoming signal).

However I don't understand what you mean by you have referred to the DBA website specifications, so I cannot answer your question. Please can you elaborate on this?

In any case, some DBA specifications (ie: on the DBA website) are INCORRECT!
For example, I had read quite some time ago that the signal levels recommended for Digital Carriers would be in the 65dBuV range. That is between 60dBuV to 70dBuV. This is actually INCORRECT because:

IN REALITY AND ON PAPER, an ANALOGUE carrier should not have a channel power Less than 60dBuV or Greater than 77dBuV.
However in the real word, when it comes to digital carriers, the actual ADJACENT CARRIER MUST BE at least 12dB LESS THAN the ADJACENT Analogue Carrier otherwise you will get Digital Channel Interference (ie: Sharp White Dots) on your Analogue picture.
The correct equalization or configuration should be:
Analogue Carriers: No less than 60dBuV and no greater than 77dBuV
Digital Carriers: Must be at least 12dB below the Adjacent Analogue Carrier which will equate to:
Digital Carriers: No less than 48dBuV and No Greater Than 65dBuV but remembering that at any time MUST be 12dB less than the adjacent analogue carrier and no more greater than 16dB less than the adjacent analogue carrier.
Remember, if the Digital Channel has too much channel power, the adjacent analogue carrier will suffer digital interference (ie: Sharp white dots) and if the Digital Channel power is too low proportional to the adjacent analogue carrier, the digital carrier will suffer Analogue interference (ie: pixelation, dropouts etc...)
And... if anyone thinks otherwise I challenge them to prove me wrong!

In any case, MATV systems must be configured and installed with great care and the whole system must be calculated to reflect the given standards for continuous operation.

#10 M'bozo

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Posted 09 May 2006 - 05:06 AM

G'day to all the folks at pcl.tv :blink:

Edited by marcj, 09 May 2006 - 06:33 AM.


#11 GrayPerth

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Posted 19 October 2006 - 04:09 PM

There is the possiblity tha tI may be wrong however.

I have just moved to an apartment block in Wembley Perth WA

As you'll see from previous threads I was a bit concerned about not getting digital, due to the posts here about the lack of availablilty for unit complex's. Also after speaking to the people that do the antenna maintenance on our block they said specifically that our system is old (about 15years) and I wouldnt get digital.

So this leaves me wondering howI have got it?
I get the program channel guides for 7 & 10 and multiple channels per channel. Hidef 7,9 & 10...so what the?!?

Can anyone explain this?

#12 bellotv

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Posted 19 October 2006 - 09:08 PM

There is the possiblity tha tI may be wrong however.

I have just moved to an apartment block in Wembley Perth WA

As you'll see from previous threads I was a bit concerned about not getting digital, due to the posts here about the lack of availablilty for unit complex's. Also after speaking to the people that do the antenna maintenance on our block they said specifically that our system is old (about 15years) and I wouldnt get digital.

So this leaves me wondering howI have got it?
I get the program channel guides for 7 & 10 and multiple channels per channel. Hidef 7,9 & 10...so what the?!?

Can anyone explain this?


You are getting it through arse rather than class.
More likely than not your apartment has an antenna and a distribution amplifier that then splits and feeds a block of units .This type will amplify and distribute any Digital channels picked up by the antenna.So long as this Distribution amp isn't overloaded by the extra channels going into it (and obviously it isn't or tenants would have complained about it on Analog years ago when Digital was turned on ) then you will get digital channels in your apartment.

The question is how well ?
If the 15 year old antenna doesn't have the right bandwidth to pick up new digital channels then those at the extemities will be lower than ideal.If the cabling,splitters,wall plates etc aren,t optimal for Digital then brake up is possable due to mis-matches and interferrance ingress.
This doesn't mean that it won't work but that you may be operating your Digital reciever close to the limit and it may fail (picture break up /sound plops) as the reception changes or interferrance levels increase.

If your antenna guy said "YES ,you can get digital " then this implies that the system has been set up to guarantee reliable Digital .

Some apartments ,usually BIG ONES with hundreds of units will have single channel amplifier systems that if set up pre digital era would not be able to distribute anything other than Analog channels .

Hope that helped a bit

#13 dean_gc

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Posted 22 October 2006 - 10:24 PM

Matchmaster Look in the catalog for Johannson Profiler 14MM-Pro2


i use one of these to stop my brisbane antenna (for briz31) from interfering with my gold coast antenna (for everything else) and it works great. unfortunately i do have a small problem with 'drop-outs' between adjacent channels so i ended up having to use the profiler just for 31 and pass the other antenna directly through. this is a rather expensive way to do it but then again i did get the profiler for nothing so i cannot complain :blink:

more free-to-air choice for nothing. definately can't complain.

#14 GrayPerth

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Posted 31 October 2006 - 04:31 PM

You are getting it through arse rather than class.
More likely than not your apartment has an antenna and a distribution amplifier that then splits and feeds a block of units .This type will amplify and distribute any Digital channels picked up by the antenna.So long as this Distribution amp isn't overloaded by the extra channels going into it (and obviously it isn't or tenants would have complained about it on Analog years ago when Digital was turned on ) then you will get digital channels in your apartment.

The question is how well ?
If the 15 year old antenna doesn't have the right bandwidth to pick up new digital channels then those at the extemities will be lower than ideal.If the cabling,splitters,wall plates etc aren,t optimal for Digital then brake up is possable due to mis-matches and interferrance ingress.
This doesn't mean that it won't work but that you may be operating your Digital reciever close to the limit and it may fail (picture break up /sound plops) as the reception changes or interferrance levels increase.

If your antenna guy said "YES ,you can get digital " then this implies that the system has been set up to guarantee reliable Digital .

Some apartments ,usually BIG ONES with hundreds of units will have single channel amplifier systems that if set up pre digital era would not be able to distribute anything other than Analog channels .

Hope that helped a bit


The guy that does the complex maintenance said "NO the system won't get digital" and yet i have crystal clear digital :blink:
I don't have the CH9 guide though...
As for all the connections, my mate who is a telecom tech did the extension, all f connections etc with quad extension.

You are getting it through arse rather than class.



Your prolly right :D makes me laugh!

I guess you can theorise all you want but it's not always going to be true!

either way im happy, once i get my new notebook ill be trying out the HTPC functionality :P

Gray

#15 Biggs

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Posted 31 October 2006 - 09:01 PM

alanH,

This thread is the most confusing ever. Mate!! Please leave it to others to explains then in and outs!

Please, leave the headends to the experienced. New DRAFT AU/NZ standards will help you understand the theory, but practical will still have you confused. :blink: Yes it will. It's very hard to get right.

dean gc--they work OK with analogue. They don't work with digital. Adjacent channel with the profiler does not work


DBA should remove sticky on this thread. It serves no purpose oter than to confuse.

#16 alanh

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Posted 01 November 2006 - 12:21 AM

Biggs,
Which particular points are confusing?

AlanH

#17 M'bozo

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Posted 01 November 2006 - 04:28 AM

New DRAFT AU/NZ standards will help you understand the theory, but practical will still have you confused.


Which have been around for a while and are available here.

#18 alanh

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Posted 19 April 2007 - 01:10 AM

Has anyone heard of any progress in the AS/NZ standard for Master Antenna Systems?

AlanH

#19 stevoboy

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Posted 18 September 2007 - 12:35 AM

G'day,

I am new to Australia and trying to set up my DVB-T. I tried to get reception with the conventional antenna that came along with the stick. However, the reception is kind of dodgy.

Well, my housemate told me that she is getting the standard channels through our roof antenna which is connected to the plug sockets in our rooms. However, those plug sockets do not look like for the standard coax connectors but rather like the ones I know from satellite TV where you screw the plug-in on - or like for your cable internet.

My question now - can I get digital TV through these wall sockets and if yes how to I convert the cable from a screw-on connector to a standard push-on connector?

#20 charlesc

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Posted 18 September 2007 - 06:30 AM

My question now - can I get digital TV through these wall sockets and if yes how to I convert the cable from a screw-on connector to a standard push-on connector?

stevoboy, your question is buried away in a specialised thread. And I see this is your first post. The note below may help.

'Until you make 5 posts, you cannot start a new thread. Have a look here, make some test posts in the Red Thread, and then post a new topic in the relevant area. It may stand out better than being buried on the end of an existing thread'.

Although your post clearly relates to Apartment building problems, you'd be better posting it in the Geographical Viewers Forum area, for your area.

The conventional antenna that comes with USB stick type DVB-T tuners is hardly ever very effective, unless you are right on top of the transmitters, and they are transmitting the higher UHF frequencies (smaller antenna elements needed). You would be better off using an external antenna, like your flatmate.

The screw in connectors that you see are most likely F-connectors (like you will see for Foxtel here). You should be able to get a converter/adapter for that at most Dick Smith Electronics or Jaycar stores (not sure where you live, but they are in most areas). Just explain what you are trying to do. It is just a simple metal plug adapter. Or maybe they will have a short lead that converts the same way.
If the wall connectors are F type, then that is maybe promising, as it could mean the installation is a newer one. In any case, your flatmate seems to have success.

EDIT: One other point. You say your flatmate is getting 'standard' channels through the wall sockets. You will be after digital channels for your USB device, your flatmate may be receiving analogue channels through the shared antenna system. Digital channels are not always passed through the shared antenna system, unless it has been designed to do that. Perhaps have a look here for some more info.

Edited by charlesc, 18 September 2007 - 06:37 AM.


#21 theyallexist

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Posted 29 July 2009 - 12:06 PM

Hi Guys,

I'm in an unit complex and have been having digital reception issues for ~3 months.
We currently get all channels on their native frequencies ( I assume this means we don't have a headend).
We have had a quote to replace the existing system with a headend and new antenna, we have ~100 units.

What are similar sized complex's running?

#22 theyallexist

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Posted 29 July 2009 - 06:49 PM

Also if we do head down the headend path is there something we should be looking for in a unit.
I have read from a number of posts that some antenna mobs are very quick to head down the headend path for unit complex's.

Cheers

#23 beeblebrox

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Posted 30 July 2009 - 05:40 PM

Also if we do head down the headend path is there something we should be looking for in a unit.
I have read from a number of posts that some antenna mobs are very quick to head down the headend path for unit complex's.

Cheers

For 100 units it's very likely you already have a headend!! (though I have seen this many units running off wideband amps) This will likely comprise single channel amplifiers for each of your analogue channels. The reason you may receive some digital with them is often they're not very tightly tuned thus allowing through some of digital channels to sneak through. In fact some are designed to amplify two channels.

Depending on the system installed it may just be a case of getting them retuned, and in some cases it's throw them out and start from scratch. You need to get some who is experienced and does regular MATV work to check it out and make some recommendations.

#24 theyallexist

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Posted 30 July 2009 - 06:15 PM

Thanks Beeblebrox,
I think this may be a case where wideband amps have been used, building is approx 20years old.

Cheers.

#25 charlesc

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Posted 22 August 2009 - 04:53 PM

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