GRN P25 Pt2

[Longreach]

and they bungled the move on mt gibralter by sticking a voice channel the same as a RFS channel 40km away. causes us no end of interference even on XTL/S 5K's. the channel has disappeared off ACMA yet its still in use. might be a call to ACMA soon.
cheers
Matt

[ivahri]

Don't go there... I could tell you a lot of stories about agencies running unlicenced/incorrectly licenced services... I bet there are two sides to this story! 40km is borderline for reuse but spectrum in & around Sydney is so tight that reuse distances are often less than 40km.

Cheers,

Richard

[centralcoastscanman]

you beat me to it richard, i was going to start mentioning the ACMA embargo's as one thing but thought i won't even go there as its not his fault that they cannot manage their licenses properly...

I always thought the rule for radio freq re-use was 100km in the sydney metro area or was that an urban myth...

[Sigint]

I always thought the rule for radio freq re-use was 100km in the sydney metro area or was that an urban myth...

I think that only applies if it is between different licence holders. eg., if Motorola wants to re-use some frequencies within 100K of one of their own Sites, it is OK. But if the opposition wants to use the same frequencies, it is a NO NO.

--
Comint

[Longreach]

hang on, the RFS have had that frequency licenced on Egans hill or Mt Marulan (11km SW of Marulan) for 2 and a half years and heres the link to it
http://web.acma.gov.au/pls/radcom/assig ... ID=2233874
the department of whoever it is now decides we need a channel for our new system and ACMA miraciously picks this frequency on the gib.
amazingly though it was licenced up on the gib and when i went to check to write an email to my local RFS operations manager it had disappeared from ACMA yet to this day it remains in use. its replacement however is licenced and its also in use.
the way i guessing the 40k rule happened is that Egans hill falls under the 2580 postcode some boffin would have said 'oh thats Goulburn' and just did it when in fact its 25km from Goulburn.

Matt

[Sigint]

the way i guessing the 40k rule happened is that Egans hill falls under the 2580 postcode some boffin would have said 'oh thats Goulburn' and just did it when in fact its 25km from Goulburn.

Matt

Yes. Unfortunately, the ACMA seem to place too much reliance on PostCode boundaries.

We have two Sites in my area, which are separated by a roadway, which also happens to be the PostCode boundary. And it seems that when they do their frequency planning for one Site, they don't see the frequencies on the other Site, because it is in another PostCode area, even though it is less than 150 metres away.

--
Sigint

[ivahri]

hang on, the RFS have had that frequency licenced on Egans hill or Mt Marulan (11km SW of Marulan) for 2 and a half years and heres the link to it
http://web.acma.gov.au/pls/radcom/assig ... ID=2233874
the department of whoever it is now decides we need a channel for our new system and ACMA miraciously picks this frequency on the gib.
amazingly though it was licenced up on the gib and when i went to check to write an email to my local RFS operations manager it had disappeared from ACMA yet to this day it remains in use. its replacement however is licenced and its also in use.
the way i guessing the 40k rule happened is that Egans hill falls under the 2580 postcode some boffin would have said 'oh thats Goulburn' and just did it when in fact its 25km from Goulburn.

Matt

Matt,

First, ACMA don't pick the frequency- an assigner does (and they rarely work for ACMA- RFS & GCIO both use private assigners so don't blame ACMA!). That assigner very likely looked at what channel would be least likely to cause a nuisance to another service. The days of 100km reuse distances is long gone- ancient history! Try 40km anywhere with talk now of assigning specific output power/antenna gain to sites to bring that down even further. The bottom line is that there is no guarantee of protection if the other service is more than 40km away. I don't necessarily agree with that view, but that is what we have to work with because spectrum is so scarce. Maybe if RFS & others stopped licencing so much UHF spectrum within GRN areas we mightn't have the problems we have with congestion?

An assigner does not use postcodes to determine protection from other services. They look at location, height ASL, height of antenna, antenna gain & pattern. I've done this kind of planning for more than 20 years so know the process very well!

Again, till I know both sides I don't apportion blame. Both parties involved have installations that aren't in compliance with their licence conditions but I'm not going to give you examples. Nuff said?

Cheers,

Richard

[ivahri]

you beat me to it richard, i was going to start mentioning the ACMA embargo's as one thing but thought i won't even go there as its not his fault that they cannot manage their licenses properly...

I always thought the rule for radio freq re-use was 100km in the sydney metro area or was that an urban myth...

Just ancient history... I can tell you one case where there are two services only 7km apart- licenced, installed but not in compliance with the licences, and they interfere to the point of being unusable! But this was done by an agency & contractor that shall remain nameless- and ACMA would be unaware of the non-compliance. I have plenty of examples where my agency reuse channels 40-60km apart but we use different CTCSSs to reduce the impact. I once had a call from an RFS person 120km away complaining he was hearing our base on "his" channel. Since he was using carrier squelch I told him that it wasn't my problem... if he used CTCSS on his mobile he didn't hear a thing from us. It isn't ideal but if there are no spare channels you do what you have to do.

Richard

[centralcoastscanman]

you beat me to it richard, i was going to start mentioning the ACMA embargo's as one thing but thought i won't even go there as its not his fault that they cannot manage their licenses properly...

I always thought the rule for radio freq re-use was 100km in the sydney metro area or was that an urban myth...

Just ancient history... I can tell you one case where there are two services only 7km apart- licenced, installed but not in compliance with the licences, and they interfere to the point of being unusable! But this was done by an agency & contractor that shall remain nameless- and ACMA would be unaware of the non-compliance. I have plenty of examples where my agency reuse channels 40-60km apart but we use different CTCSSs to reduce the impact. I once had a call from an RFS person 120km away complaining he was hearing our base on "his" channel. Since he was using carrier squelch I told him that it wasn't my problem... if he used CTCSS on his mobile he didn't hear a thing from us. It isn't ideal but if there are no spare channels you do what you have to do.

Richard

Ok thanks for that Richard, you are a wealth of knowledge...
and also thank you for explaining the basics of whats involved in assigning a radio freq as i didn't know it was that involved..

[Longreach]

well maybe the person involved should know his/her job better. a check on ACMA would have told him/her that other services were nearby, and a shift 25khz above would have solved the issue.
as far as im concerned the only person in breach is the GCIO as they are the ones using an unlicenced frequncy. i would have thought first in best dressed?
as for the GRN vs others licencing in that 403-420mhz spectrum i didnt thing the GCIO had exclusive rights on that part of the spectrum and i keep saying its STILL NOT ONE SIZE FITS ALL.
im sure this wouldnt be an issue if both services were using both an analogue channel with a different subtone but given how the digital bleeds thru its definately an issue. im not the only person in my area annoyed by it, Trying to do a job today in Marulan just about proved pointless with this problem at hand.
anyway some in my area have now marked it as a safety issue so they are now taking steps to sort the problem.

cheers
Matt