It was the same in the analogue days with the VHF channels. ABC on Ch 3 and commercial on Ch 7. That is until the Rockhampton ABC moved to Ch 9.
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Thanks, never knew ABC Rockhampton was once on VHF 3. Do you know when that was changed?
From what I can cross-reference through old ABC annual reports, the change wouldâve occurred around 1991-92.
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Are they (and were they) the same polarisation? Surely that wouldâve been an issue during tropo openings?
They are the same polarity, but directionality of UHF antennas and that itâs over 600 km between the two sites would help minimise issues.
Itâs a bit different to Newcastle and Wollongong that are only about 200 km apart.
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The strange thing about polarisation is that the United States and Canada only uses horizontal polarisation for all of their TV broadcasters. One wonders how they manage all that with the potential interference.
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Iâm guessing because a lot of Americans get local FTA through cable so not many people notice it?
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IIRC Townsvilleâs ABNQ 3 have a very significant offset from the channel centre frequency compared to Rockhampton. ABNT 3 Launceston was also offset. I assumed it was for this reason.
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ABTQ3 87.27/92.77 MHz
ABNT3 86.2/91.7 MHz
Also TNT9 was offset as well due to GTV9. It was one of the worst broadcast planning decisions.
196.223975/201.723975 MHz
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Thanks - thatâs what I remembers - a full MHz difference. Of course, there was also ABDQ 3 Darling Downs to content with ion Queensland.
Brisbane and Grafton on Ch 2 used to interfere with each other in summer. And despite the opposite polarities 6/8 from Wide Bay and Richmond/Tweed has some issues.
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I believe the further the signal travels, the difference between vertical and horizontal blends out.
Yes, because the atmosphere & other physical objects in the path can cause the signal to spin, but unless itâs a mixed polarised signal to start with like most of our FMâs, itâll still only be polarised in one plane, just mightnât be the same one it left the transmit antenna in.
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There are many places that are much closer that have channels on same frequencies, but on the VHF band. The channels would be on the same frequencies except that the spare channel may be different in each location e.g.:
Melbourne and Upper Murray - about 225 Km apart
Melbourne and Western Victoria - about 300 Km apart
Western Victoria and Mildura/Sunraysia - about 350 Km apart
Mildura/Sunraysia and Adelaide - about 325 Km apart
Western Victoria and Adelaide - around 400 Km apart
All of these are horizontally polarised and high power (though some are less high powered than others. All of these pairs are in different markets from each other.
There are also other instances of VHF channels are separated by similar distances but with different polarity (e.g. Sydney and Canberra).
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They tend to have a lot less translators/repeaters (at least within metropolitan areas, not sure about rural areas). But then again, they have a lot more channels in many metro areas which are often closer together than ours. For example, there are channels in Los Angeles and San Diego that are on the same VHF frequency as each other even though theyâre around 100 miles apart (160 Km). Yet the US can fit all those extra channels and less polarity choices into only a few more channels than we have (35 in the US vs. 30 in Australia).
All of the 7QLD channels are now in MPEG4. Seven was the last MPEG2 channel on the network but that has changed now.
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Make it happen nationally.
I reckon Nine has kept 9Gem and 9Go in SD temporarily for the Olympics and will remove them soon after.
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I think Nine wonât remove SD channels of 9Gem and 9GO! until after the Paris Paralympic Games finish in September.
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Picture quality on 7HD is very soft - with a bitrate of just 2.5 Mbps for the picture.
7Bravo is 4.4 and 7Mate 5.1 - crazy IMO - currently running the analyser over several hours.
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Bit rates 7 Sunshine Coast
| 7 HD | 4.0 |
| 7Two HD | 4.3 |
| 7Mate HD | 4.7 |
| 7Bravo HD | 3.7 |
| 7Flix | 1.6 |
| 7Race | 2.4 |
| TVSN | 1.1 |
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Hopefully they plan on having 7Flix HD.
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