Attention Greater Geelong Viewers

[Guest Malich]

Another typo for you to fix, Alan...

Garyv5758. My second last post uses the first harmonic which is double the frequency.

No, that'd be the 2nd harmonic. The "first harmonic" is the fundamental frequency.

---

Does someone know the simple maths to derive harmonics? No need to deploy Fourier Analysis I hope.

An aside - and this isn't particularly directed at you, garyv5758.

I realise that most "become a government accredited antenna installer in just 14 days!" courses are probably little more than 'try not to fall off the roof, and don't drill a hole in your own foot' training, but I'm surprised if they don't teach such a ... ahem, "fundamental" ... concept.

No maths beyond the ability to multiply by 2, 3, etc is required e.g. for a given frequency f the harmonics are :

1st harmonic =

f

x 1 (i.e. the same as the original frequency, typically called the

fundamental

)

2nd harmonic =

f

x 2

3rd harmonic =

f

x 3

... and so on. The level (amplitude) of each harmonic is related to the amplitude of the fundamental, and (typically, at least in simple cases) decreases as the harmonic number increases i.e. the 2nd harmonic has a lower amplitude than the fundamental, the 3rd has a lower amplitude than the 2nd, etc...

Other things (e.g. waveform shape, modulation, how/where the harmonics are generated, etc) complicate the exact calculations - and that's where Fourier transforms / analysis are helpful. But for typical AM / FM (& probably even DVB-T) interference, basic approximation from the above calculations are fine. Actual installers can probably correct me, but unless something else is terribly wrong (i.e. transmitter problems, IM, etc) you probably don't need to consider harmonic interference from anything beyond 2nd or 3rd harmonics.

(Yes, that's all probably over-simplified. Sue me...)

Edited July 24, 2013 by Malich

[alanh]

Already explained. Fourier transforms have nothing to do with harmonic distortion. Your smoke screen.

[Guest Malich]

Already explained.

As I pointed out, "explained" incorrectly.

Are you going to fix your "typo"? You haven't yet.

Fourier transforms have nothing to do with harmonic distortion.

I find this odd coming from someone who claims to be technically educated, and most probably a sign that the technical education claimed is grossly inadequate or woefully out-of-date. How else do you calculate the frequency and amplitude of the harmonics, or detect them if they exist?

(Don't say "tuned or swept narrowband filters" - they're just simplistic implementations of a binned or continuous Fourier analysis...)

Regardless, I answered the question as asked - "Does someone know the simple maths to derive harmonics? No need to deploy Fourier Analysis I hope" - and explained why, in this and other typical cases, Fourier analysis is unnecessary.

Your smoke screen.

And what "smoke screen"? If you disagree with my comment, explain your disagreement.

If you can't, we'll just have to assume you're disagreeable...

(edit: many additions)

Edited July 24, 2013 by Malich

[MLXXX]

Another typo for you to fix, Alan...

Garyv5758. My second last post uses the first harmonic which is double the frequency.

No, that'd be the 2nd harmonic. The "first harmonic" is the fundamental frequency.

Alanh,

here is yet another opportunity for you to correct your own error (this time in relation to naming the 2nd harmonic), and

Already explained. Fourier transforms have nothing to do with harmonic distortion. Your smoke screen.

to withdraw an instance of unfounded criticism of a fellow forum member (this time the impolite and inaccurate reference to smoke screen).

____________

Edit 29/7/13: This claim now appears as entry 005 in the alanh "facts".

Edited July 29, 2013 by MLXXX

[garyv5758]

The new Geelong transmitter has already been a bonus as a problem solver.

The masts and antennas will be smaller ( and less expensive) but we'll still sell amps because of the cable losses with UHF.

As soon as I'd posted I looked at the relevant frequencies and realised it was x2 but thanks anyway.

As I said if Mt Dandenong SBS goes to 7 we will need the Geelong transmitter as a robust alternative.

It's just a pity there is little coverage behind and to the side, such is life.

[crusty1503560570]

Did a signal test with the speccy on Frid from Mcdonalds

reserve Reynolds rd Belmont

LP 4/5 and PHASED ARRAY

Good signal, but you are bang on with the need for amps with the cable loss on the higher UHF freqs

Come across this quite a bit when doing Ballarat installs.

Crusty

[Soap]

I could imagine some fun will be had for viewers who want Geelong translator channels on UHF Band V, and C31 from MtD on UHF Band IV. Might be some opportunities for installing Band 4&5 diplexers...

[garyv5758]

Yes, I've done this on one install and it worked really well.

It was a good geographic location to combine the Geelong translator and MtD CH31(32)

Making sure that I had the correct diplexer to allow for the restack.

It did occur to me that if CH31 goes to VHF it could all be a waste of effort.

I've read the restack forum

Any thoughts ?

[beeblebrox]

last time I talked to 31 they had no plans to move.

[garyv5758]

Thanks, personally I'd be happy if it stayed where it is.

I'll press on and offer it as an option where applicable.

We'll see what happens.

[alanh]

On their website they describe themselves as "We are Melbourne and Geelong". They have a low powered transmitter on Mt Dandenong 94 km away. Hardly a local transmitter. Now that there are new Geelong greater coverage translators where is the MGV translator? Like the other translator sites in Anglesea/Airey's Inlet, Warburton, Marysville, Selby, Upwey, Monbulk, Ferntree Gully, Melbourne Inner Suburbs, Ocean Grove, Rosebud & Safety Beach. Only South Yarra has a tiny translator. They are so out of touch technically that they after 16 months they have not changed their name from channel 31. Their viewers have to select channel 44 to receive their program. Why haven't they changed their name to one not containing a channel number or use channel 44 like the other community broadcasters? Other community broadcasters lobbied to move to channel 10 but were unsuccessful. If that had happened all the receiving antennas could have been cheaper being band 3 only. Lastly all the community broadcast licences expire next year. Interesting to see what new conditions will be placed on any renewals. Alanh

[Guest Malich]

On their website they describe themselves as "We are Melbourne and Geelong". They have a low powered transmitter on Mt Dandenong 94 km away. Hardly a local transmitter.

Well, that's the power of QPSK/4QAM for you...

They are so out of touch technically that they after 16 months they have not changed their name from channel 31. Their viewers have to select channel 44 to receive their program. Why haven't they changed their name to one not containing a channel number or use channel 44 like the other community broadcasters?

Like Briz31 / 31Digital? As far as I know 44Adelaide is the only one to have changed their station name to match their LCN, while TVS & WTV were always that under their current licencees.

It's hardly a technical decision anyway, it's marketing.

Other community broadcasters lobbied to move to channel 10 but were unsuccessful.

Which ones? I know Briz31 / 31Digital didn't...

If you ignore the temporary licencees, that leaves only one - TVS in Sydney - who may or may not have lobbied to move.

But I'm pretty sure we've been over all this last time, when you tried to convince us that

Channel 10 has been allocated in all mainland capital cities by the ACMA along with all broadcaster funded translators

not because you'd misread and misunderstood ACMA's published TLAPs, PDs, and FAPs, but because

I was alerted to the VHF allocation of Main community TV transmitters by the Head of Community TV at the ACMA, not some random ACMA engineers.

(Amusingy enough, both myself and nbound predicted back then that you'd refuse to back down from your claim, would slink away without ever admitting your mistake, and would pop back up at some later time ignoring contradicting your earlier ridiculous statements. Looks like we were right.

He's not here to gloat, but I am...)

Edited August 26, 2013 by Malich

[GoForMoe]

C31 actually changed their logo after they started their simulcast.

General brand recognition of 'Channel 31' for community television is stronger than either the term 'community television' or the number 44.

[Guest Malich]

C31 actually changed their logo after they started their simulcast.

Briz31 / 31Digital did something similar. I think initial trials used a name I forget, but they became Briz31 at or just after their official analogue launch. They then changed their name to Channel 31, became QCTV for a while - and then changed their name to 31Digital when they officially started digital transmission on LCN44 / UHF Ch32...

General brand recognition of 'Channel 31' for community television is stronger than either the term 'community television' or the number 44.

Bingo. Despite Alan's baseless belief that keeping 31 in the name marks them as "out of touch technically", brand recognition trumps technical accuracy.

[GoForMoe]

Mind you, this is the guy who would rename Channel Seven to 'West' and Ten to 'Eye' just so people don't get confused by LCNs.

[Guest Malich]

Actually, I don't think he's completely wrong there - or, more precisely, it will probably happen in the future for reasons not related to anything going on inside his head.

Now that the precedent has been set years ago by radio (i.e. names not related to frequency or callsign), and with the majority of TV stations being network and the channel names not related to anything other than LCNs (which are allocated by Free TV Australia), there's not really any point for branding to be tied to RF channel.

It's already happened with the secondary channels (e.g. GEM, Go!, Extra); all that's needed for it to happen with the main channels is a compelling reason to relaunch/rebrand. An eventual move to HD? That might be impetus enough.

[MLXXX]

They are so out of touch technically that they after 16 months they have not changed their name from channel 31.

Another "reckless insult" from alanh, I see.

As Malich has explained:

Like Briz31 / 31Digital? As far as I know 44Adelaide is the only one to have changed their station name to match their LCN, while TVS & WTV were always that under their current licencees.

It's hardly a technical decision anyway, it's marketing.

Yes, indeed, it is a question of marketing.

I know who Briz31 [31Digital] are, as would many other Brisbaneites. As for "44", I only know that as the digital TV LCN corresponding to 31Digital, because of taking a particular interest.

Bris31/31Digital are much more recognisable as branding. "31" dates back to 19 years ago (1994) when the service commenced on analogue as UHF channel 31.

[GoForMoe]

It seems the Ocean Grove transmitter idea has been dropped - with MySwitch now just referencing the Safety Beach transmitter which it implies has increased coverage as of last week.

Broadcasters have indicated that digital TV transmissions broadcast from Safety Beach are available in parts of the Ocean Grove area from 23 August 2013.

The new predicted coverage from the Safety Beach transmitter is now available in mySwitch.

If you currently do not receive adequate reception from the Melbourne transmission site on Mount Dandenong, you may wish to attempt to receive the digital services from Safety Beach. Should you wish to do so, you may be required to make modifications to your antenna setup (such as repointing and/or replacing antenna equipment and possibly the removal of any boosting devices) should you wish to receive services.

No parts of Ocean Grove are getting 'Good' coverage from the Safety Beach transmitter, so I'm not sure if it will be more reliable than Mt Dandenong in the area, which also nominally covers most of there with the variable coverage.

[beeblebrox]

yes they upgraded the arthurs seat transmitters last week... given the power and radiation patterns I think arthurs seat to ocean grove would be hopeful...... how's the geelong coverage there though?

[alanh]

Community TV naming: Brisbane "Briz 31 commenced transmission on July 31, 1994 under temporary licences. A permanent licence was granted on August 1, 2004 for a period of five years. In October 2006, Briz 31 changed its name to Channel 31 to reflect its expansion into other parts of Queensland. In July 2008, Channel 31 announced it would be rebranding itself as QCTV, for Queensland Community Television. In early 2010 it was announced that QCTV would once again rebrand as 31 Digital to go with the launch of the 31 Digital broadcast channel." Funny that their relaunch was on transmission channel 38 and LCN 44 and also that they have only had a licence for the Brisbane area and not the rest of Queensland. Since the restack they have not re-lanched themselves now that they are on transmission channel 28 still with LCN 44. So they did use QCTV with no channel numbering. Sydney TVS has always been its name with no channel number; Melbourne: It has always called itself C31. Adelaide: Changed its name to channel 44 3 years ago. Perth: When the new licence was issued it is called West TV or WTV, no channel numbers mentioned. Alanh

[Guest Malich]

Yeah we know that, Alan; I pointed out most of it before.

In July 2008, Channel 31 announced it would be rebranding itself as QCTV, for Queensland Community Television ... So they did use QCTV with no channel numbering.

No, you're wrong. At that time their on-air ident was "31 QCTV", and that's how they were listed in printed guides etc. That was when they were angling to be an umbrella for further/future CTV licencees in regional Queensland, hence the "QCTV" part of the branding; the "31" was kept to differentiate them as the original Brisbane Ch31. That didn't eventuate (for a couple of reasons), they dropped the QCTV altogether for a month or two and were just "31", then when they started digital broadcasts they rebranded themselves as "31 Digital"

In other words, they have always had 31 in their name, and have never used "QCTV with no channel numbering" like you claim. As I said, you're wrong.

(edit: Here's their old Twitter account from the time, which still retains the branding...)

(edit2, 3 days later: Hear that sound? ... no, not that one, the other one ... that "chirrupp ... chirrup ... chirrup"? Sounds like crickets saying "I only post facts" and "I admit when I am wrong".

It must be crickets, because it can't be Alanh...)

Edited September 4, 2013 by Malich

[garyv5758]

I did an install yesterday at Blackwell crt , Ocean grove,

The signal level from the Geelong transmitter 76-79dbuv at the antenna.

I removed the old masthead and still had plenty at the three outlets.

The owner had patiently waited to have a poorly installed

Mt Dandenong antenna system replaced.

He said they wern't concered about CH31.

He did say he felt like the odd one out surrounded by masted dual antenna systems.

I think residents should be able to get either Geelong or Mt Dandenong without to much

of a problem in most parts of Ocean grove.

Although I stand to be corrected.

[Guest Fact Checker]

Long time lurker, first time poster. There's so much concentrated nonsense in this post that I just felt I had to respond with some knowledge.

On their website they describe themselves as "We are Melbourne and Geelong".

That's because the station is aimed at Melbourne and Geelong. The station is licensed to serve the Melbourne TV1 licence area, which, as you can see here, includes Geelong.

They have a low powered transmitter on Mt Dandenong 94 km away. Hardly a local transmitter.

Now, I know that Alan doesn't believe in the greater penetrative power of QPSK, but fortunately physics thinks otherwise and the C31 signal reaches much of Geelong. In fact, it even reaches parts where the SBS reception is dodgy, such is the robustness of QPSK. Those boffins in the DBCDE sure knew what they were doing when they mandated QPSK as a low power and therefore low cost solution to reaching the whole of the licence area.

If the signal didn't reach Geelong, do you think that the volunteers down there would be producing News Geelong each week? Or that The Pulse, a Geelong radio station, would have started up a program last week?

Now that there are new Geelong greater coverage translators where is the MGV translator? Like the other translator sites in Anglesea/Airey's Inlet, Warburton, Marysville, Selby, Upwey, Monbulk, Ferntree Gully, Melbourne Inner Suburbs, Ocean Grove, Rosebud & Safety Beach. Only South Yarra has a tiny translator.

The ACMA isn't issuing any licences for the extra infill sites at this time. They're waiting until the federal government makes a permanent decision about the future of CTV. So you can't blame C31 for that. (And yes, the South Yarra translator is tiny, but again, QPSK...)

They are so out of touch technically that they after 16 months they have not changed their name from channel 31. Their viewers have to select channel 44 to receive their program. Why haven't they changed their name to one not containing a channel number or use channel 44 like the other community broadcasters?

Oh, Alan, are you miffed because you've written to them a couple of times about this and they brushed you off? The reason that "C31" is still used is because, as another poster has noted, it has high brand recognition in Melbourne (and Geelong). Viewers aren't dumb. Just as they can work out that you press 73 to get 7Mate, or 99 for Go!, they've also twigged that you press 44 for C31. (And that's assuming that they don't just scroll through the channels with channel up and down on their remote.)

The other reason not to change to 44 is that there's no guarantee that that's what the LCN will be in the future. Heck, it could be 4 or 40 or 41 or 31 or goodness knows what, depending on what the government ultimately decides. A successful business doesn't undertake rebranding lightly, and so you'd only do it once you were sure what it was going to be - or indeed if you were sure you'd have a future beyond the end of 2014.

Other community broadcasters lobbied to move to channel 10 but were unsuccessful. If that had happened all the receiving antennas could have been cheaper being band 3 only.

I've no idea what you mean by this, Alan. No CTV station has lobbied to be moved into the sixth channel by itself. That would be folly. It would require new VHF transmitters (= money that the stations don't have). It would cause interference problems when (or if) the sixth channel multiplex proper was rolled out. It sounds like something you've made up.

Remember, you can't split a 7MHz TV channel into little bits and divvy it up amongst transmitters. It's all or nothing, multiplexed together into one signal.

What the CTV sector has been lobbying for is to be included as one of the channels carried on the sixth channel multiplex when/if it is finally commissioned. The Convergence Review recommended this as a course of action; and the Explanatory Memorandum to the Broadcasting Legislation Amendment (Convergence Review and Other Measures) Bill 2013 specifically noted that:

the proposed statutory cap on the number of commercial television broadcasting services in a licence area is designed to ensure that the remaining capacity in the television broadcasting services bands is made available for other types of broadcasting services – including (but not limited to) community television broadcasting services – as well as being available to test new broadcasting technologies as they emerge.

So there clearly are intentions that this might happen. It's just getting the government of the day to do something about it and making the sixth channel actually happen.

Lastly all the community broadcast licences expire next year. Interesting to see what new conditions will be placed on any renewals.

If you mean the broadcasting services licences, it is highly unlikely that any new conditions will be placed on the licensees. What rationale would ACMA have?

On the other hand, if you mean the apparatus licences, they come up for renewal every year and are re-issued with exactly the same conditions: QPSK modulation, only to be used for a single SD channel, etc. The ACMA are hardly likely to do something like saying "It's a new condition that you have to be rebroadcast at the infill sites" when they aren't issuing any apparatus licences for the infill sites.

Melbourne: It has always called itself C31.

No, from 1994 to 2002, it was always referred to both on-air and off as "Channel 31". "C31" was introduced in 2002.

[alanh]

Fact checker! It sounds as if DrP is back!

[Guest Malich]

Or somebody else with a clue and a dislike of idiots who post crap...