Proposed GRN Expansion

[ivahri]

Of the roll-out... don't hold your breath for the other.

Cheers

[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....

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

I agree about the cost, especially when as i was told its half the price of a full blown repeater.. wasn't aware of the technical side of it as i didn't need to know at the time but it would not surprise me..

[Bigfella237]

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 ~

As far as price is concerned, I would think they would be more expensive? Twice the number of bases (including the links), multi-couplers and other hardware costs twice as much and there's twice as many frequency licences (if they actually bothered to licence the links) and site costs, the only thing you really save on are the digital lines only having to go to one site instead of four (in the case of Crown Castle)?

Where the advantage lay with the old Type II system is that it allowed you to cover more area without using extra precious ports on a zone controller which, as has already been stated, is a "dead issue" now; so I would say that unless there are locations where it is prohibitively expensive to get landlines to, all these hidden host sites will be converted to stand-alone sites when upgraded to P25?

Remember too that there's four times the number of user radios potentially being crammed onto the one site which means if there's a major incident at one of the shopping centres there's gunna be a lot of radios going "BOOP" because they can't get a channel allocation...

Andrew

P.S. I really hate that "BOOP"!

[system_tech]

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 ~

As far as price is concerned, I would think they would be more expensive? Twice the number of bases (including the links), multi-couplers and other hardware costs twice as much and there's twice as many frequency licences (if they actually bothered to licence the links) and site costs, the only thing you really save on are the digital lines only having to go to one site instead of four (in the case of Crown Castle)?

Where the advantage lay with the old Type II system is that it allowed you to cover more area without using extra precious ports on a zone controller which, as has already been stated, is a "dead issue" now; so I would say that unless there are locations where it is prohibitively expensive to get landlines to, all these hidden host sites will be converted to stand-alone sites when upgraded to P25?

Remember too that there's four times the number of user radios potentially being crammed onto the one site which means if there's a major incident at one of the shopping centres there's gunna be a lot of radios going "BOOP" because they can't get a channel allocation...

Andrew

P.S. I really hate that "BOOP"!

I don't think anyone here quite knows how these are done

1 Motorola Base Station = 30k so a 6ch site just for bat gear .. 180k

or ...

Low power DSP "translator" .. 1 unit / 35k (will do up to 8 channels).
For in building / in tunnel stuff .. you only need low power tx.

Of course you need other equipment but you have saved 150k straight up.

If you think I'm guessing .. no ... my team is commisioning 3 such sites this week.

[see if you can find them ]

And there are already similar sites in existance .. clue go to Central Railway main concourse and see which GRN site your radio affiliates to.



A comment .. actually they are a cost effective way of using underutilised existing sites (ie donor site) with low traffic density!

[Bigfella237]

I don't think anyone here quite knows how these are done

1 Motorola Base Station = 30k so a 6ch site just for bat gear .. 180k

or ...

Low power DSP "translator" .. 1 unit / 35k (will do up to 8 channels).
For in building / in tunnel stuff .. you only need low power tx.

Of course you need other equipment but you have saved 150k straight up.
~
A comment .. actually they are a cost effective way of using underutilised existing sites (ie donor site) with low traffic density!

Not that I doubt you Mal but wouldn't that still make these 'slave' sites more expensive?

Discounting all the other equipment, an actual stand-alone 6 channel site only needs 6 bases (@ $30k each) but a 'slave' site needs 6 bases (for the links) plus a low power 'translator' (an additional $35k)?

I have no idea what it costs to have the digital lines installed or what the rental on them would be but I reckon it'd take a while to add up to $35k?

As for the Mt Clear/Mt Budawang sites (which are hosted by Mt Cowangerong), there's no low power translators involved so you would still have to double the number of bases needed anyway wouldn't you?

BTW, what is Mother's policy on replacing equipment such as bases? Do they replace them at certain intervals whether they need it or not? Or just run 'em till they cook and replace 'em then?

Andrew

[system_tech]

Ah no.

1 "translator" (total 35k) [actually translator is my term, it s really a clever DSP BDA that can do more than a simple BDA] replaces up to 8 bat bases (30k each).

So for your 6ch site you have saved 145k.

Regarding frequencies: the translators are at a site where there is no signal at all from the original site, so reusing the same frequencies is achievable (also neccessary) and is within a tunnel / building and doesnt leak outside (well may be a tiny bit with no detriment) and is in fact clever reuse of existing frquencies rather than needing new ones.

[system_tech]

Cowangeranong is a special case. Quickly: Cowangeranong is a normal site. Budawang and Mt Clear, the 2 slaves that reuse Cow's freqs are low power and solar (from memory, hey its 5.40am) and would NOT support power inefficient bat bases (rule 1: bat bases are no good for solar sites).

There is a reason for everything!

[citabria]

Of the roll-out... don't hold your breath for the other.

Cheers

It's being tested in the USA and the specs are in the preliminary phase - basically the protocol is a mixture of P25 and dPMR style TDMA. I'm sure it will happen one day (might be a long way off though!)

[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 ~

As far as price is concerned, I would think they would be more expensive? Twice the number of bases (including the links), multi-couplers and other hardware costs twice as much and there's twice as many frequency licences (if they actually bothered to licence the links) and site costs, the only thing you really save on are the digital lines only having to go to one site instead of four (in the case of Crown Castle)?

Where the advantage lay with the old Type II system is that it allowed you to cover more area without using extra precious ports on a zone controller which, as has already been stated, is a "dead issue" now; so I would say that unless there are locations where it is prohibitively expensive to get landlines to, all these hidden host sites will be converted to stand-alone sites when upgraded to P25?

Remember too that there's four times the number of user radios potentially being crammed onto the one site which means if there's a major incident at one of the shopping centres there's gunna be a lot of radios going "BOOP" because they can't get a channel allocation...

Andrew

P.S. I really hate that "BOOP"!

I just dug up the quote i was given at the time, and for a 5 channel site fully installed from scratch in an existing building would take 3 months and cost $120k from start to finish with the exception of any costs charged by the people that install the antenna which would be minimal

[ivahri]

Ah no.


Regarding frequencies: the translators are at a site where there is no signal at all from the original site, so reusing the same frequencies is achievable (also neccessary) and is within a tunnel / building and doesnt leak outside (well may be a tiny bit with no detriment) and is in fact clever reuse of existing frquencies rather than needing new ones.

Well that was the case when the tunnel/buildings used leaky coax... but then some genius decided that a coverage problem outside could be fixed if the leaky coax was combined with an external antenna. Those in the know where I am referring to! These systems are great, even if hideously expensive (even with the RFI device) for the load that they carry, so long as those tinkering with them know what they are supposed to do (and based on what I've seen they don't have a clue). Maybe they will fix the audio quality problem & heterodyne issue I've been screaming about for some months... at least before P25 Phase II arrives in Australia.

Cheers,

Richard