53 replies to this topic

[debruis]

alanh, on Nov 11 2010, 06:29 PM, said:

Viewer,
If only 6 houses require a signal then it is not worthwhile to install 5 translators.

The only appropriate antenna for you for Mt Moombil, is the Fracarro PU16F phased array antenna, which is available in Coffs Harbour. This antenna should be atleast 10 m above the ground.
The most appropriate amplifier is Kingray's new MHU42FS

All of your digital signals are UHF.

AlanH

A 10 metre antenna tower sound like a waste of time to me. If the installer has the right meter SNR BER/MER etc you should be able to find a sweetspot for the antenna. I have found that many installation have better signal quality or it makes no difference/ when the antenna is mounted at a lower height.

Also viewer has your installer mate tried stacking two phased array antenna to try and improve your reception. I have found it works well in the Upper Hunter in an area surrounded by hills.

Edited by debruis, 12 November 2010 - 07:30 AM.

[DrP]

Obviously a skilled installer with practical real world experience would try to get reception at various locations and heights and should reception not fall within the minimum guidelines (ie after a decent site survey being done it is discovered that acceptable reception can not be achieved even when the antenna is located 10 metres high) the site would hopefully be eligible for 'black spot' DTH coverage.

Edited by DrP, 12 November 2010 - 07:38 AM.

[alanh]

M'Bozo,
Next time you get a large brick or concrete wall, in the right place, try it out and measure the signal increase.

AlanH

[alanh]

debruis and DrP,
BelloTV was complaining about generic responses, you should read further back prior to commenting.
This has already been done, but there was no published readings.

Alanh

[DrP]

Oh someone needs to read back and stop making generic comments, that's for sure.  

[viewer]

The antenna is 9.6 meters from the top of it, to the ground.

I still have the phased array gutter mounted pointing at the mountain directly east to me, and I connected up to it just now. It is not amplified, antenna cable is one run, no cuts or splices.

Connected to it I can get picture on 10 and Prime, but others all choppy, SBS hopeless. It was mounted the normal way, like this crude drawing
                                                                                                                                                                        [........    ]
                                                                                                                                                                        [ ........   ]
                                                                                                                                                                        [ ........   ]
                                                                                                                                                                        [ ........   ]
                                                                                                                                                                        [ ........   ]
                                                                                                                                                                            


When I put it horizontally, like this
----------------------------
i .................................i
i .................................i
----------------------------

          

then I lost everything...
  

My google reference point is
Latitude  30° 6'1.42"S
Longitude 153° 0'0.84"E
I am nestled between the Conglomerate State Forest (where the phased array gets a reflected signal from), and the Bagawa State Forest behind me to the west.
I am 3.95Km North of the township of Nana Glen, off of the Orara Way

The installer fixed antenna points to Moombil ( south - west)....Bruxner unavailable here...Nardi not seen

Plenty of signal...plenty of woes getting it

[gordon_s1942]

10 metres sound good but then why not 5 or 15 ??
Of course a 10 metre or 30 foot mast is reasonably manageable by one person unless its very windy but thats about all its got in its favour.
My VERTICAL UHF Digital antenna isnt 3 metres high and that was found by a very competent installer using a quality FSM.
I tried various heights from 3 to 10 meters before cementing a mast in place and got bugger all except where it is now.
I still have a pair of phased array VHF antenna's mounted over 80 feet high back when I used to receive TV directly from Sydney and from both experience and person knowledge of this location, 10 metres dont receive diddly squat !!!

[debruis]

viewer, on Nov 12 2010, 03:36 PM, said:

The antenna is 9.6 meters from the top of it, to the ground.

I still have the phased array gutter mounted pointing at the mountain directly east to me, and I connected up to it just now. It is not amplified, antenna cable is one run, no cuts or splices.

Connected to it I can get picture on 10 and Prime, but others all choppy, SBS hopeless. It was mounted the normal way, like this crude drawing
                                                                                                                                                                        [........    ]
                                                                                                                                                                        [ ........   ]
                                                                                                                                                                        [ ........   ]
                                                                                                                                                                        [ ........   ]
                                                                                                                                                                        [ ........   ]
                                                                                                                                                                            


When I put it horizontally, like this
----------------------------
i .................................i
i .................................i
----------------------------

          

then I lost everything...
  

My google reference point is
Latitude  30° 6'1.42"S
Longitude 153° 0'0.84"E
I am nestled between the Conglomerate State Forest (where the phased array gets a reflected signal from), and the Bagawa State Forest behind me to the west.
I am 3.95Km North of the township of Nana Glen, off of the Orara Way

The installer fixed antenna points to Moombil ( south - west)....Bruxner unavailable here...Nardi not seen

Plenty of signal...plenty of woes getting it

Sound like signal to noise ratio is low on all but 2 channels you mention. Reflected signal sometimes requires a broader receiving area on the antenna/e hence why I asked if any installer has tried a stacked phase array which is 2 of the phased arrays antenna( 2 of crude drawing vertical) side by side diplexed or coupled. This can be quite tricky to set up unless you have the correct digital tv meter so you can adjust the array to provide the most gain to the frequencies required. If that did not work then you may have to get VAST

[viewer]

Thanks debruis...yep VAST in 2 years...time should go quickly shouldn't it?

Ta for the tips.

[alanh]

All,
Nana Glen - Mt Moombil path plot
The azimuth is 211 degrees and the path length 27 km.

As you can see the terrain blocks the signal and it will be diffracted in that area by the Bagawa State Forest.

If you were to draw a line between the transmitter antenna, clearing the obstruction, you can then see the height required for reception.

Using vertically polarised antenna will only give any signal if it is pointed at reflections on the opposite side of the valley (Conglomerate State Forest).

I agree that you are in a blackspot and that VAST is your best option.

AlanH

[viewer]

alanh, on Nov 12 2010, 05:25 PM, said:

All,
Nana Glen - Mt Moombil path plot
The azimuth is 211 degrees and the path length 27 km.

As you can see the terrain blocks the signal and it will be diffracted in that area by the Bagawa State Forest.

If you were to draw a line between the transmitter antenna, clearing the obstruction, you can then see the height required for reception.

Using vertically polarised antenna will only give any signal if it is pointed at reflections on the opposite side of the valley (Conglomerate State Forest).

I agree that you are in a blackspot and that VAST is your best option.

AlanH

Thanks for that information.

For the layman like myself, can you advise if that program can be used (is it available) by us, or is this a resticted access type program?

I see it as a useful tool for any person looking to see how they fair?

Using that path, if I said you wanted a total unimpeded path from the transmitter to the end line, my calculations say the tower would have to be at a height of 1400 on the graph...is that right, or am I reading it wrong?

Thanks

Edited by viewer, 12 November 2010 - 05:50 PM.

[debruis]

alanh, on Nov 12 2010, 05:25 PM, said:

All,
Nana Glen - Mt Moombil path plot
The azimuth is 211 degrees and the path length 27 km.

As you can see the terrain blocks the signal and it will be diffracted in that area by the Bagawa State Forest.

If you were to draw a line between the transmitter antenna, clearing the obstruction, you can then see the height required for reception.

Using vertically polarised antenna will only give any signal if it is pointed at reflections on the opposite side of the valley (Conglomerate State Forest).

I agree that you are in a blackspot and that VAST is your best option.

AlanH

I do not agree you are in Blackspot just because the terrain blocks your antenna's line of sight to the tower unless you have had a site survey and  readings done by an installer using a meter that reads SNR/BER and signal levels. I have had installations where the house has been located at the base of hill directly in front of the tower and they are receiving all channels. This is only after a site survey using multiple types of antenna,combinations of antennas and different types of mast head amplifiers.

Edited by debruis, 12 November 2010 - 06:11 PM.

[viewer]

I agree with your logic...lots and lots of places (majority) don't have line of sight.

I have no problem at all getting it measured, it's just that at this stage, it wouldn't even help...the 2 year wait is in force...been there done that when I got Aurora put on.

Edited by viewer, 12 November 2010 - 06:16 PM.

[debruis]

viewer, on Nov 12 2010, 07:16 PM, said:

I agree with your logic...lots and lots of places (majority) don't have line of sight.

I have no problem at all getting it measured, it's just that at this stage, it wouldn't even help...the 2 year wait is in force...been there done that when I got Aurora put on.

Do you have any idea what the signal readings are that you are receiving currently. Levels and Signal to noise ratio if possible. I still think with the correct antenna array you could receive all channels where you are located. Is the whole area in the same situation as yourself?

Edited by debruis, 12 November 2010 - 06:55 PM.

[viewer]

debruis, on Nov 12 2010, 07:55 PM, said:

Do you have any idea what the signal readings are that you are receiving currently. Levels and Signal to noise ratio if possible. I still think with the correct antenna array you could receive all channels where you are located. Is the whole area in the same situation as yourself?

I don't have access to a meter or have a mate to do same.

Not all around me are the same...one 500 metres away used rabbit ears ! My immediate neighbour is about 3 mtrs lower, and all is good except his Prime.

As the crow flies, 1 km opposite me in Morrows Rd, another Aurora user, three about 500mtrs behind me on Ellems Quarry road, another on Aurora in Sherwood Forest Rd.....they are dotted around everywhere, dairyville, Karangi, Coramba, Glenreagh. Lot's of neighbours just gave up and went Austar, but alas, no fta on them.

In the end, I will just do the wrong thing...find someone to use their address in an authorised/no checking area, order the goods, and relocate the receivers. It's just an absurd situation to have to do it this way, but in the end, it's my easiest and cheapest alternative,as all the dishes and infrastructure is in place for my 2 Aurora receivers now. Unbelievable in this day and age to have to resort to this mentality, but tell me a better option...there is none..this is the cheapest and easiest, bar the stupid regulation.

Edited by viewer, 12 November 2010 - 07:08 PM.

[M'bozo]

bellotv, on Nov 11 2010, 08:24 PM, said:

Give viewer a brake .The guy he gets from Wollgoolga knows his stuff. If he can't get it to work ,it isn't going to work .

viewer, on Nov 12 2010, 06:20 PM, said:

For the layman like myself, can you advise if that program can be used (is it available) by us, or is this a resticted access type program?

It's not restricted, I'll give it to you.

click.

[viewer]

M'bozo, on Nov 12 2010, 08:17 PM, said:

It's not restricted, I'll give it to you.

click.

Thanks...never knew that existed...things are slow getting into this blackhole....now to play and learn how to pilot it...got the graph thingi up..

Ta M'bozo

[alanh]

debruis,
Whether a blocked path is important depends on the following factors;
Path length,
Frequency of transmission
The transmitter power radiated in that direction
The depth and length of the blockage
The surface of the blockage eg is it smooth eg over water and the horizon, or forrest
The shape of the blockage for example if it is thin compared to the wavelength diffraction will occur. This is where the exact position of the antenna is important.
The antenna gain
Any amplifier gain
Cable losses
Receiver sensitivity

Also the signal level on the opposite side of the "viewer's" valley is not blocked at all hence some of these people can use rabbits ears.

Marc,
I have ignored Fresnel zone clearances because of the high transmitter power and the comparitively short path.

AlanH

[debruis]

alanh, on Nov 12 2010, 08:50 PM, said:

debruis,
Whether a blocked path is important depends on the following factors;
Path length,
Frequency of transmission
The transmitter power radiated in that direction
The depth and length of the blockage
The surface of the blockage eg is it smooth eg over water and the horizon, or forrest
The shape of the blockage for example if it is thin compared to the wavelength diffraction will occur. This is where the exact position of the antenna is important.
The antenna gain
Any amplifier gain
Cable losses
Receiver sensitivity

Also the signal level on the opposite side of the "viewer's" valley is not blocked at all hence some of these people can use rabbits ears.

Marc,
I have ignored Fresnel zone clearances because of the high transmitter power and the comparitively short path.

AlanH

What the &%$ In the real world you are not really  what is in the way of the transmitter in a difficult reception areas once you are on site just what your meter is telling you and your field experience with similar type installations. If you are a half decent installer you are stating the obvious and they would already know the above losses you mentioned  and would not be concerned if the installation was done correctly. All this information does is confuse the end user. Especially when you contradict the experienced installers on this forum. In my experience in difficult reception area there are only a couple of types of antennas or combinations that you would bother to install or at least have half a chance of receiving anything. The gain on both of these is around the same with one being used for line of sight and one for undulating terrain. Mast head amplifiers there is only a couple you would bother using in areas with difficult reception. Cable losses are pretty none existent if the cable is RG6 up to around 25mts. What you get at the antenna/mast head amplifier is what you get at the outlet/tuner. This is another thing that is not at concern is most domestic installation cable run are not that long. The main concern is antenna position on the site. In a difficult area
/undulating terrain you will find that one antenna position will receive 2-3 channels 2,7,9 then moved slightly 2-3 channel but of different call sign. Hence why I suggested stacked phased array as it would increase antenna receiving area and hopefully enough signal level and SNR etc to be amplified or be high enough for the TV without any amplification. A lot of the advice you give works for analogue reception but digital is a whole different ball game. Antenna height does not mean brilliant reception as I notice a lot of your advice is.
Another example of flawed advice in a different part of the forum was that in a certain location on the  Sydney Nth Beaches you adviced an antenna type to be used would be different even though both towers that we the most suitable were UHF and available in that location. Usually same antenna but diferent mast head amplifier depending on location. Sorry to the other installers as I must sound like a broken record

Edited by debruis, 12 November 2010 - 08:45 PM.

[DrP]

debruis, on Nov 12 2010, 07:54 PM, said:

What the

I wouldn't put too much thought into it.  alanh has a demonstrable history of addressing posts to the wrong person; claiming that person A is in reality person B or person C or person D or all of the above; or just making off the wall unrelated posts and addressing them to anyone and everyone at random.

[debruis]

DrP, on Nov 12 2010, 09:44 PM, said:

I wouldn't put too much thought into it.  alanh has a demonstrable history of addressing posts to the wrong person; claiming that person A is in reality person B or person C or person D or all of the above; or just making off the wall unrelated posts and addressing them to anyone and everyone at random.

Just edited post as I had too much thought too give. He has supplied me with some very interesting reading while reading this forum over the past couple of years

[mtv]

debruis, on Nov 12 2010, 09:48 PM, said:

Just edited post as I had too much thought too give. He has supplied me with some very interesting reading while reading this forum over the past couple of years

debruis,

As far as everyone here knows, alanh is not and has never been, a professional antenna installer.

I have repeatedly asked him to correct us if that is incorrect, but he has never responded to that question, so you can draw your own conclusions.

His recommendations are based purely on theory and manufacturer specifications.

It is understood he once worked in the transmission side of things with the ABC, many years ago, all in the analoge-only era, which fits with lot of advice he sprouts, not being relevant for digital.

Without real-world practical experience and current in-the-field knowledge and without digital-signal test equipment, the level of advice given is seriously questionable.

Once again. alanh is welcome to set the record straight if any 'facts' about his inexperience, past and present, are not accurate.

[alanh]

Debruis,
My previous post was aimed at you, when you said you have done installations which were not line of sight.

Antenna installer are not the only ones who need to know about the characteristics of TV propagation. The broadcasters need to know what the likely coverage areas are for any transmitter. These are all predicted using geographic and altitude data, the typical losses are then calculated. It is not possible to measure every possible location using a digital field strength meters. The ACMA is currently surveying all analog switchover areas to do spot verifications of field strengths ahead of switchoffs.

You keep going on about using a digital field strength meter. I have always recommended them in all my "Get the best reception" posts. When I first started posting in 2003 these were very uncommon.

The measurement of the signal strength will just tell you if there is enough signal when connected to the antenna being used.
The digital field strength reading should be used with simple calculations to work out how much gain is required and an amplifier selected to match this value.  As far as losses go, I have calculated and graphed the losses for 3 types of cables Cable losses
Amplifiers should be selected for the filter matching the frequency range of the transmissions to be received, gain and noise figure.

"antenna receiving area" of phased arrays is a common misconception. The reason why phased arrays are used for long distance (blocked paths due to the horizon) and other blocked paths is not the receiving area. For horizontally polarised signals a phased array is directional in the vertical direction and is not very directional in the horizontal direction. When a signal comes over the horizon it acts the same as light in a sunrise. The strongest signal is right on the horizon and is much wider than it is high. This matches the characteristics of a phased array. A high gain Yagi-Uda or a Log Periodic antenna is very directional in the horizontal plane but is not very directional in the vertical direction. This is good for rejecting reflected signals in strong signal areas but will give poor results in the over the horizon reception.

For vertically polarised signals the characteristics swap over, so phased arrays are best in the strong signal areas because they can reject reflected signals either side of the antenna. Yagi-Uda antennas are best for over the horizon reception.

As far as Sydney's northern beaches goes, the Bouddi transmitters are a low powered 1.25 kW each and are vertically polarised UHF. The terrain in the area has a lot of hills. So there is a choice of Bouddi and the Artarmon/Willoughby triangle of around 50 kW VHF or 200 kW UHF each. This is an area where the digital field strength meter comes into its own. Not only to measure the signal strength and error rates but also to determining the timing and strength of reflected signals.

As for analog vs digital. I am well known for opposing antennas designed for channels 0 - 5A which are commonly still installed in Sydney. As far as band 3 - 5 digital goes, the RF propagation is unchanged, the main change is that the reception criteria is more critical. Where viewers may have put up with some dots of noise or some ghosting, digital will not show these effects until the digital cliff has been reached. Then the customers complain because the error correction in the receiver is unable to stop the pixellation and the sound breakups.

Some of the above information is in Antenna design Basics and amplifications I wrote in 2004. The "Get the best reception" post were commenced around then and has been kept updated.

This topic is more appropriately discussed in "Antenna & Distribution" systems strand

AlanH

[DrP]

alanh, on Nov 12 2010, 10:54 PM, said:

As for analog vs digital. I am well known for opposing antennas designed for channels 0 - 5A which are commonly still installed in Sydney.

Actually you are well known on this forum for opposing such antennas, regardless of the outcomes desired by the eventual user of that antenna.  There is no point recommending an particular antenna if it does not do what is required, this was explained to you on multiple occasions yet you continued to recommend inappropriate antennas.  In fact, with your typical mistaken reading of things, you then claimed that people were attacking and vilifying you!

[Smacca]

alanh, on Nov 12 2010, 08:54 PM, said:

Debruis,
My previous post was aimed at you...

I swear Alan, you just make life harder for everyone. http://www.snappoll....poll/349606.php