NSWGRN is now Phase 2, and has 467MHz bandplan added

citabria
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NSWGRN is now Phase 2, and has 467MHz bandplan added

Post by citabria » Mon Dec 17, 2018 11:56 am

Hi Guys,

A user on here noticed that the bandplans on his local GRN site have changed. A quick check of Horsely Park GRN site reveals the same changes have been made on this site too.

Of note is the 467.5125MHz (with a -10MHz offset) bandplan being added in as well.

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Longreach
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Re: NSWGRN is Phase 2, and has 467MHz bandplan added!

Post by Longreach » Mon Dec 17, 2018 12:25 pm

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Hi all, it's only been recent too. Unitrunker shows the following and my TRX-1 has captured it already.

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VK2MRC

Longreach
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Re: NSWGRN is Phase 2, and has 467MHz bandplan added!

Post by Longreach » Mon Dec 17, 2018 12:26 pm

Interesting change though
VK2MRC

citabria
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Re: NSWGRN is now Phase 2, and has 467MHz bandplan added!

Post by citabria » Mon Dec 17, 2018 12:29 pm

Yeah, great find Longreach. This probably means that even more changes are on the way now too.

PS - I fixed up the photo links in your post.

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Bigfella237
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Re: NSWGRN is Phase 2, and has 467MHz bandplan added!

Post by Bigfella237 » Mon Dec 17, 2018 2:39 pm

citabria wrote: ~ Of note is the 467.5125MHz (with a -10MHz offset) bandplan being added in as well.
I can't see your image for some reason but how can you tell what the offset is from UT?

The bandplans have been like that for a while (see the "Notes" section of the site list).

Andrew

citabria
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Re: NSWGRN is Phase 2, and has 467MHz bandplan added!

Post by citabria » Mon Dec 17, 2018 2:52 pm

Bigfella237 wrote:
citabria wrote: ~ Of note is the 467.5125MHz (with a -10MHz offset) bandplan being added in as well.
I can't see your image for some reason but how can you tell what the offset is from UT?
I'm not using Unitrunker in this particular instance - Pro96com calculates and displays the offset for me.
Bigfella237 wrote: The bandplans have been like that for a while (see the "Notes" section of the site list).

Andrew
Ah yes - first time I have noticed it. If you can manage to see the attachment in my first post it shows all the ranges as reported by Pro96com.

citabria
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Re: NSWGRN is now Phase 2, and has 467MHz bandplan added

Post by citabria » Mon Dec 17, 2018 3:00 pm

Andrew, try clicking on the attachment in the first post - hopefully that works for you.

Another thing that has been noticed (by cartman) is that bandplan 5 never actually gets used either. All the 420MHz channels are accessed by extending the 04 - 412.475MHz bandplan up into that frequency range.

I have confirmed this on multiple sites as well. Even the channel grants that come up are in the 04 bandplan as well.

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Bigfella237
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Re: NSWGRN is now Phase 2, and has 467MHz bandplan added

Post by Bigfella237 » Mon Dec 17, 2018 5:02 pm

Thanks, I should've tried clicking the attachment to begin with, I see the image now. I recall Unitrunker used to display the offset too but that feature disappeared quite some time ago.
citabria wrote: ~ Another thing that has been noticed (by cartman) is that bandplan 5 never actually gets used either. All the 420MHz channels are accessed by extending the 04 - 412.475MHz bandplan up into that frequency range. ~
If those higher LCNs are being transmitted incorrectly then the TELCO has a BIG problem! If a radio is told to use an LCN in bandplan 04 it WILL offset the Base TX frequency by -9.45MHz and transmit back to the site.

The problem is, all freqs above 420MHz are licenced on the ACMA with +5.2MHz offsets as per the Government Spectrum assignments.

That means, every radio responding to a bandplan 04 LCN allocation above 04-1205 is TRANSMITTING ON UNLICENCED FREQUENCIES!

For example, site 001-071 at Parramatta has a CC of 422.2875MHz, if you go to the ACMA page, and then into the assignment details for that frequency, it clearly states that the paired (Base RX) frequency is 427.4875MHz, an offset of +5.2MHz as the spectrum says it should be.

*IF* the CC data stream is actually mislabeling this frequency as LCN 04-1570 (instead of 05-0366) then the radio must be calculating the offset based on bandplan 04, and must be transmitting it's response on 412.8375 instead of 427.4875

412.8375MHz is NOT LICENCED at that ACMA site, therefore the NSW TELCO is forcing user radios to transmit on unlicenced frequencies!

This would be a major screw up, it also means the wrong receive freqs would have to have been programmed into the repeaters themselves, and the combiners/diplexers tuned to the wrong frequencies? I just can't see them making such a huge mistake?

Or if the hardware was setup correctly and just the LCNs entered wrongly, then the site would never see any use as it would never hear affiliation requests?

Andrew

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Re: NSWGRN is now Phase 2, and has 467MHz bandplan added

Post by citabria » Mon Dec 17, 2018 5:15 pm

I had the exact same thoughts, but the sites do appear to be working ok - there's no way they tuned up the receivers at the GRN sites for the wrong channels. I guarantee that there's some intricacy we have missed. I'm not sure where, but I'm pretty sure a problem that big would get noticed - the GTR8000s and Quantars are configured on a per channel basis, so they would have to deliberately mis tune those too.

I think I'll park my SDR on the inputs for some of these sites and see what comes up.

Anyway, here's some screenshots from Pro96com. I have asked others to chime in with their info as well.

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Looking at the channel grant log entry is particularly interesting - I whipped up an Excel spreadsheet that confirms that 04-1898 lines up with the frequency in question (424.3375MHz)

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citabria
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Re: NSWGRN is now Phase 2, and has 467MHz bandplan added

Post by citabria » Mon Dec 17, 2018 5:28 pm

So, naturally the bandplans are incorrect, and of course there is another kludge that has been put in place to work around it.

Check out the channel grant opcodes from the sites control channel, and you can see that it's explicitly giving the input frequency as an extension of bandplan 4 as well.

The radios are getting the correct input/uplink freq form the SU to the base using the explicit grants.

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