AFAIK the gap between 9 and 10 was not large enough for a full channel. To add in 9A, 10 and 11 had to be moved “up” by 1 MHz with the introduction of digital TV.
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Interesting, as when NBN was asked to vacate VHF 3 in the early 90s to free up the FM band, one of the options they put forward was to move to Channel 9A.
The ABT (as it was at the time) only said no because it would interfere with Sydney TV reception in the area.
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Because I am not technical, I don’t understand how we didn’t all need to get our TVs retuned for this? How did it work?
Becasue there was a gap between 9 and 10 it was possible to have analogue stations on adjacent channels. But normally you couldn’t and tow adjacent channels too close together. Sandwiched between 9 and 10 wouldn’t have been ideal for both markets.
AFAIK it didn’t make any difference because it was the new digital channels that were on the new frequencies - so minimal impact on analogue reception. So channel 10 analogue stayed the same - areas where channel 10 was used for digital got the new frequency and of course metro areas that had 10 analogue got digital 10 on channel 11.
But Channel 9A was used for some late-arriving analogue services?
Pannawonica SBS9A
Port Hedland WOW9A
Borroloola QQQ9A
Broken Hill SCN9A
Pannawonica and Port Hedland also had Channel 11s, but I guess there was a gap to prevent interference between 9A and 11, and 11 (analogue) wasn’t altered? Just as long as TV sets could receive 9A I guess. I remember my ‘last’ analogue TV (circa 2002) had 9A on it, but I don’t know when 9A became installed on analogue TVs?
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As long as the stations were one channel apart, it would be ok. Most TVs had switched to digital tuning and didn’t have channel dials by then.
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I bodged this wee diagram several years ago, it might help explain the channel spacings graphically… or muddy the waters! Ignore the NZ related stuff.
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NZ was wise not to put any TV services between 88-108 MHz. Australia mucked that up for itself!
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More info about channels 5a and 9a here:
https://www.austech.info/showthread.php/92057-Channel-9-amp-9A-amp-Channel-5-amp-5A
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And NZ was smart to wait for MPEG4 with DVB-T as well… And here we are in Oz getting close to 25 years of digital TV and STILL a lot of MPEG2 
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Regarding channel 5A and 9A, I remember reading an Electronics Australia article a long time ago about the upcoming introduction of 9A and 12.
According to the article, 9A was introduced to replace 5A, since 9A was with other VHF channels (i.e… between 9 and 10), while 5A was off on its own. I think it said that the frequencies between 9 and 10 were used by the military and that they would be moved over to where 5A was, but not 100% sure. They also mentioned moving 10 and 11 up by 1 MHz.
They also talked about the reason for introducing channel 12. I don’t remember exactly what it was, but it might have been for moving channels on lower VHF channel numbers to higher numbers, and they may have mentioned ABC3 Canberra as an example, but don’t quote me on that.
I don’t think things turned out that way, e.g. many stations on 5A stayed there until digital transition, while some were moved to other channels, including UHF channels. Also, ABC3 Canberra moved to 9, not 12.
As to why TVs didn’t need a complete retune when 10 & 11 were moved up by 1 MHz, there could be several reasons:
- Channel 10’s and 11’s didn’t necessarily move up by 1 MHz. For example, new transmitters might have been on the new frequency from the start (e.g. when AMV4 Albury moved to AMV11). I’m not sure if any existing analog channel 10’s or 11’s actually moved up 1 MHz. Many analog stations remained on the old frequencies.
- Digital channel 10’s and 11’s were on the new frequencies to begin with (with some stations being 125 KHz higher as was the case with other channels).
If any analog channels did change frequencies, then
- Fine tuning could have been all that was needed since it’s only 1 MHz.
- If the TV had automatic fine tuning, the TV could have tuned the channel automatically without anyone noticing (unless fine tuning was turned off).
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I’d love to know what issue that article was in. I could potentially find it.
This just reminded me, we watched some videos on YouTube on the weekend and some included the Test Patterns. I explained to the kids what that was and why there are all the squares and the lines and manual tuning and fine tuning etc… and they simply didn’t believe how difficult things were back then… or how little there was with only 2 TV channels and not even 24 hours!
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There were several analogue TV stations that ran on Channel 9A too. I have a copy of the 2004 TV station list to prove it. Even after the restack, there are several DTV stations still on 9A, especially in Rural and Remote WA.
Channel 5A was introduced as part of 13 channel VHF allocations in the early 1960s. i.e. The addition of Channel 0, 5A, and 11, with 3, 4, 5 moved to the FM band. In 1956-1960 there was just Channels 1 - 10. Some early TV sets have these on their selector dials.
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I should also mention that the original channel allocations changed:
Channel 1 was 49 - 56 MHz, changed to 56-63 MHz.
Channel 4 was 132-139 MHz, changed to 94-101 MHz
Channel 5 was 139 - 146 MHz, changed to 101-108 MHz.
Note that old TVs with 1 - 10 selectors could receive 5A (137-144 MHz) with fine tuning, hence another reason it became named “5A”. (And Channel 6 stayed as it was).
Details on Page 36 here: https://www.worldradiohistory.com/Archive-ABCB/abcb_-_annual_report_-_13_-_1960-1961.pdf
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I noticed a couple of things regarding Sydney vs Wollongong TV:
- 7 Wollongong is about 6 seconds behind 7 Sydney. Other subchannels are less different in time.
- 9 Wollongong seems noticeably louder than 9 Sydney (heard on Today, not sure about other shows). You’d think this wouldn’t be an issue given that everything’s digital these days but I guess there are still local variations.
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I hope you told them the test patterns were for the engineers at the transmitter site, they weren’t for tuning/fine tuning receivers by viewers.
Things in the old analogue TV transmitters would drift between when they were cold (off overnight) & warm/hot (normal operating temperatures), engineers would run the test patterns first thing in the morning after turning the transmitter on while it was warming up, then they’d check everything was aligned properly, so you wouldn’t have incorrect chrominance or colour mixing/saturation (after colour TV came in), also for things like the transmit frequency hadn’t drifted & among other important picture qualities like the shades of grey (B&W days) or colours were correct & that lines were crisp edges, not blurred/feathered & that the vision & audio hadn’t drifted & were still in sync, as the vision & audio were from 2 totally separate transmitters combined together, an AM transmitter for the vision & an FM transmitter for the audio.
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Might have something to do with the way they have the Dolby sound set up. I think 9HD an 10HD use 5.1 Dolby. If WIN doesn’t that could sound louder.
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That’s still a lot better than when Prime7 playout was in Canberra in the mid 10s It used to be a whopping 23 seconds behind Sydney here in Newcastle.
That all changed when playour moved to Meduahub.
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I remember in the analogue days in the 1990s, Wollongong was about 0.5 seconds behind Sydney.
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