Proposed GRN Expansion

[ivahri]

Hi Mal,

Actually the 420-430MHz bandplan has not to my knowledge been gazetted yet (I don't think it has even has been even discussed in detail yet), but the initial allocations made in this band have used a 7MHz split. There are no problems with a 7MHz split for P25 (trunking or conventional) to my knowledge, it is TETRA that uses 10MHz but then it can't be implemented in 400-430Mhz here anyway!

I thought Russell's finger slipped... heck people will start carrying on with 6.25, they still can't cope with 12.5 in the good ol' USA... the world will end if they have to move from 25kHz!

Cheers,

Richard

[Sigint]

Maybe they will follow the debacle in Victoria, which is the MMR, where they are using 6, 5.5, and 4 MHz splits in the 420-430 MHz Band.

--
Sigint

[system_tech]

I think NSW (and anyone else) is better off with the 9 to 10 MHz split. This is a technical thing where it is easier to make duplexers and multi-coupling with the larger split. However smaller splits are achievable but the cost is greater and perhaps not quite as good separation but still quite usable. (eg 470 - 510 use 5.2 MHz split, amateurs use 5MHz split 433 - 440 MHz)

Reading the new 400 Mhz plan, I'n not sure that NSW GRN will expand out of 400 - 420, the ACMA has designated a "government sub-band" within 400 - 420 (as with 450 -470) and I think GRN will stay within that sub-band although, or course that is not certain.

420 - 430 is an interesting band, with some legacy amateur allocations still in use, they will probably go in the longer term.

Many of the so called GRN frequencies are just being "parked" at that site for a number of reasons, and may not eventuate as an actual site, although yes as Richard and others indicate there will be a a Northern Expansion.

S T

[matthewn1983]

not sure if this has anything to do with the last post, but i noticed a CC in the 500mhz area, i think it was 500.900? or there abouts ill have to check the scanner again, came up with site id 7D3D i think. was tracking grn tgids, but obviously my scanner hasnt been setup for that in the bandplan.

[cartman]

500Mhz sites are the so-called hidden host sites for shopping centres and other hard to get at places - harbour tunnel, parramatta justice centre etc
7d3d is Horsley Park on 500.9500 that links into Parramatta, Blacktown and Penrith shopping precincts + parramatta justice centre
The other one on 500Mhz is GPT on 500.2625 with 3a0d
Basically so emergency services have good comms inside these mega complexes
There are folk better qualified here to explain the ins and outs of how the hidden hosts sites work, except to say there is a 500mhz link to the target site which is then translated back to 400mhz to boost the signal .. the grn radios are obvilious to it



Grant

[Bigfella237]

500Mhz sites are the so-called hidden host sites for shopping centres and other hard to get at places - harbour tunnel, parramatta justice centre etc
7d3d is Horsley Park on 500.9500 that links into Parramatta, Blacktown and Penrith shopping precincts + parramatta justice centre
The other one on 500Mhz is GPT on 500.2625 with 3a0d ~ Grant

The ACMA licences are a mess for both the Crown Castle and the GPT hidden hosts too... both of these sites have the 500MHz frequencies licenced but they're not linked to anywhere; there are no 510MHz freqs licenced at any of the slave sites?

The only hidden host that is licenced properly is the Mt Cowangerong site that links Mt Clear & Mt Budawang.

Not sure who is in charge of keeping the ACMA up-to-date but it seems they could use some help?

Andrew

[centralcoastscanman]

the donor sites are a great way of setting up limited grn capacity for sites that could not justify the expense of having a full blown repeater setup...

I was looking at recomending one to my boss at work, but when i saw the price i didn't go much further as i was lead to believe its half the price of a full repeater I thought against it was I didn't want to be laughed out of my bosses office.

not sure how the donor sites are going to be affected when the grn goes p25....

[ivahri]

Oh bugger, you are right!

Cheers,


Richard

[ivahri]

the donor sites are a great way of setting up limited grn capacity for sites that could not justify the expense of having a full blown repeater setup...

I was looking at recomending one to my boss at work, but when i saw the price i didn't go much further as i was lead to believe its half the price of a full repeater I thought against it was I didn't want to be laughed out of my bosses office.

not sure how the donor sites are going to be affected when the grn goes p25....

It's a hideously expensive & spectrum inefficient system designed to get around the lack of additional 400-420MHz channels.

They will be changed over but not until after phase II.

Cheers,


Richard

[citabria]

When you say Phase II, are you referring to Phase two of the rollut plan, or P25 Phase 2 6.25kHz modulation?

Cheers,
Matt