digital aerials

Submitted: Friday, Jul 09, 2010 at 18:52
ThreadID: 79962 Views:3617 Replies:2 FollowUps:6
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just wanted to know if anyone finds they need digital aerial to receive digital TV.. not sure if we need to buy one to get rid of a lot of pixilation.. we have digital TV so are not running through a settop box.. any input would be good
ta muchly
Mieke
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Reply By: Member - Rod N (QLD) - Friday, Jul 09, 2010 at 18:58

Friday, Jul 09, 2010 at 18:58
There is no such thing as a 'digital' antenna. TV is either VHF (antenna with long elements) or UHF (antenna with shot elements). Digital TV is UHF, but there are some analog channels that are UHF. If you are on the road a combination antenna such as Digimatch works for me.
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Follow Up By: paulnsw - Saturday, Jul 10, 2010 at 10:19

Saturday, Jul 10, 2010 at 10:19
There *IS* such a thing as a digital antenna.
Analogue antenna did bands 1,2,3,4 & 5

Digital antenna does bands 3,4 & 5 and band 3 has been extended and the aerials are made to cater for frequencies of digital TV.

Band 3 now goes from channel 6 to 12. Digital aerials are made to receive those frequencies. Previously Band 3 only went to channel 10.

Digimatch Explorer is best caravan digital TV aerial you can buy for reception and portability. Digimatch Explorer will do horizontal and vertical and cross polarisation. Available Dick Smith and Jaycar.
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Follow Up By: Member - Rod N (QLD) - Saturday, Jul 10, 2010 at 15:42

Saturday, Jul 10, 2010 at 15:42
Thanks for the clarification, paulnsw.
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Follow Up By: Nomadic Navara - Saturday, Jul 10, 2010 at 21:03

Saturday, Jul 10, 2010 at 21:03
"Band 3 now goes from channel 6 to 12. Digital aerials are made to receive those frequencies. Previously Band 3 only went to channel 10."

The extra channels were available long before digital TV came along. Their spectrum was previously occupied by the civil aviation DME beacons. These were started to be cleared in the late 70s. There currently 51 CH 11 and 6 CH 12 analogue channels in this spectrum.

So we go back to Rod's statement "There is no such thing as a 'digital' antenna." There are just TV antennas that cover different ranges of channels. In the early days there were different models produced for different areas. For example, there were antennas constructed to receive channels 1 & 8 that were sold in the Orange TV area. Other areas had antennas concentrating on other channels

The next introduction was the introduction of SBS. Viewers then had to add UHF antennas to their systems. When aggregation arrived, the extra commercial channels were located adjacent to the local SBS channel so the same UHF antenna would suffice (band 4 or 5.)

The new arrival, digital TV, was located on channels adjacent to the existing analogue channels. This was so the existing antennas again could be used and new antennas would not be needed. These narrow band older antennas are thus suitable for digital TV.

Rather than looking for these mythical digital TV antennas, we should be looking for antennas suitable for caravans. As we travel widely what we should be looking for is an antenna that will cover the whole of bands 3, 4 & 5 rather than antennas cut for the particular suite of channels where we live.

The main classes of people who claim there is a special class of digital antenna are the TV antenna installers and retailers attempting to con consumers into purchasing something they don't need.
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Follow Up By: Fiona & Paul - Sunday, Jul 11, 2010 at 00:42

Sunday, Jul 11, 2010 at 00:42
Just the bloke I need Nomadic Navara

Have you got a suggestion for a combo one, we use one of those T bar aerials that can be changed from horizontal to verticl, etc. Seem to work OK but in some areas like Bourke we could only get one channel. Missing getting beaten by Queensland does not go down well in our van.

Regards
paul H

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Follow Up By: Member - Rod N (QLD) - Sunday, Jul 11, 2010 at 07:56

Sunday, Jul 11, 2010 at 07:56
As Nomadic Navara said, when aggregation arrived in Towwomba the ABC was moved from VHF channel 3 to a UHF channel. Also other channels were available on UHF. I had to get a UHF antenna for those which also works for the digital channels.
As was said before, the Digimatch Explorer is one of the better ones for travellers. I also use a mast top amplifier. In the end though a lot depends on the actual area and what transmitters are available. For example at Barwon Heads, not that far from Melbourne we, and others, had a lot of trouble getting a good reception.
Rod
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Reply By: Bazooka - Friday, Jul 09, 2010 at 22:58

Friday, Jul 09, 2010 at 22:58
Mieke - more info required if you want good replies. Home? Caravan? What is your current setup? There are possibly better forums for this question though eg http://www.dtvforum.info/.

I guess that you are probably talking about 'mobile' TV, but what the heck noone has replied so this may be of some help.

I am not an expert but reception is a function of more than just an aerial. New cabling can make a huge difference. We had to replace our fixed (home) roof aerial recently in order to get good HD digital TV for a number of the available channels (others were clear as a bell). The original aerial was UHF/VHF capable (for most local frequencies) but replacing old wiring with new coaxial cables and better connectors, better aerial positioning and new aerial tech/design has turned 'fuzz' into clarity for not a lot of $.

Cheers
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Follow Up By: Nomadic Navara - Friday, Jul 09, 2010 at 23:56

Friday, Jul 09, 2010 at 23:56
Your antenna was probably OK but whilst they were replacing the cable it was probably worth the expense of replacing it with one that would last the life of the new cable.

Your big problem most likely was the poorly screened cable used in the original installation. Up till the introduction of digital TV the cable used only had a single braid for the outer conductor/shield. This is not a very good shield that will prevent interfering signals from getting into the cable or signal from radiating out from the cable.

The newer cables have aluminium outer shielding as well as the braid. This better shielding gives rise to far less interference getting into the cable. It also stops signal in the cable from escaping, which in turn makes the cable less lossy for any signal passing down it (ie the new cable has less attenuation than your old cable.) I would reckon that the poor channels you were receiving with your old installation were suffering some sort of interference entering your long run of cable (this is a very common problem with old antenna installations.)

For domestic installations with their longer cable runs you definitely need double or triple shielded cable to keep interference at bay. For caravan installations with their shorter cable runs it is not so important but if you are purchasing new cable for your van then go for the better cable.

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