HDTV - experince (tip) - Melbourne Metro

Hi All,

Background =========== I have a little bit of RF and electronics experience and I was called to my friends house to help fix the HDTV signal problems on ABC(HD). The complaint was poor signal or no signal and some pixelation (spelling). [I'm no TV expert].

How could ABC(HD) be poor and the other HD channels and SD channels be OK? Hmmm I said.

When I turn on the VCR and or the DVD player etc the pixelation got worse , but most significantly on ABC(HD). Ahhhh I said, it must be the switch mode power supplies causing interference.

The problem had recently occurred over the last few months.

- Setup External Analog TV antenna and 2way splitter to another room (all HDTV signals good in the other room)

Connection ======== The setup had a Belkin surge protector that protected the RF and mains power.

Hence the antenna RF signal when through the surge protector (probably arrestor inside).

Theory ======== I thought that since the interference was worse with other power devices on... I suspected that the RF surge arestor must be coupling noise/interference in to the RF of the HDTV TV set.

Removing /bypassing the RF surge protection ..... all signals including the ABC(HD) GOOD ! ;-)

==> Problem Solved

Reply to
Joe G (Home)
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Research the actual frequency of the aerial frequency required you are using , I expect there is nothing close to a resonant length on the thing close to that required so it may well need replacing with one more a-tuned

Reply to
atec 77

"Joe G (Home)"

** Yep.

Digital only antennas ( for metropolitan use) are small - cos they have no long elements fitted for receiving channels below ch 6. They also cover the VHF range up to ch 12 which few analogue antennas do - plus the UHF range.

ABC Digital is on VHF ch 12 so can be problematic.

** Post antenna gain will not help.

But a well sited, high gain antenna designed for digital may be essential in some locations.

.... Phil

Reply to
Phil Allison

**For HDTV you need the following:

1) A decent antenna and good signal.

2) Decent, quad shield cable. (VERY important).

BTW: Surge protection devices are bullshit.

--
Trevor Wilson
www.rageaudio.com.au
Reply to
Trevor Wilson

Yeah, abc digital is 226MHz.

Reply to
Joe G (Home)

"Joe G (Home)"

** In reality, ABC Digital transmits THREE signals in the band from 203 to 210 MHz.

... Phil

Reply to
Phil Allison

The you need to determine how far off the resonant frequency the existing aerial is and then replace it with a suitable unit as others have ( cutting most likely wont work )alluded to

Reply to
atec 77

And there is the log-periodic antenna type that, whilst lower in gain, make up for it by having a better frequency response and do not need a balun. So in many cases the log-periodic type can improve your performance.

As is good quality RG6 quad shield coax and F connectors. This is usually the first step in upgrading your antenna system to better support digital.

Dave.

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Reply to
David L. Jones

"David L. Jones"

** Think Dave is alluding to one of these:

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Cheap and small - less than 1 metre square.

Conventional Yagi designs give more gain and directionality, but are somewhat larger and more expensive.

.... Phil

Reply to
Phil Allison

Yup. See:

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I had a noticeable improvement in impulse noise immunity on digital after installing my log-periodic.

Dave.

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Reply to
David L. Jones

Where in the Melbourne metro is your friend located? Have they got a clear line-of-sight of Mt Dandenong? They're not in The Basin, or really close to the foothills somewhere like that are they?

Reply to
dmm

Near South Land

Reply to
Joe G (Home)

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