[AusNOG] AirFibre

[Paul Wallace]

On the discussion surrounding the intelligent use of 24GHz class license in Australia ..

The ACMA states that in fact there is no such thing in Australia as 'license free' or 'unlicensed'.
I.E. All spectrum in Australia is controlled by license conditions.

In the case of the particular 24GHz spectrum mentioned, the prevailing license is called a 'class license'. 'Class license' means that you are not required to seek an individual license (that's where people get the idea it's unlicensed), however you must at all times operate within the terms of the class license, the primary conditions of which are severe transit power limitations (set out as 'EIRP'), and frequency use.

The EIRP limit in this case is 20dBm.
EIRP is calculated by adding the tx power to the antenna gain, then subtract the losses.
Therefore to comply in Australian 24GHz class license this UBNT microwave kit operates in, you'd need to set the tx power to -15dBm, (assuming antenna gain of 35dBi).
(yes that's minus 15dB transmit power)
Carrier class licensed kit operating in licensed 23GHz band transmits up to 28dB, therefore a 43dB difference.
A rule of thumb is that 6dB will double your effective distance so 43dB the diff is a massive difference.

Also be aware of the following:

Most of the larger operators of 'licensed' 23GHz microwave systems (the large mobile voice carriers) wont deploy 23GHz past around 5kms, and that's with a 43dB advantage so I'm a little surprised by these claims of 13kms. We think 700 metres is the rough safe working distance in NSW & Qld rain rates. A little further in Victoria.

Bear in mind there's a chance that in theory you could actually successfully form a link at 13kms, ... on the basis that 24GHz does not completely dissipate over that distance, however rain would cause serious failures.

Happy hump day
-P





From: AusNOG [mailto:ausnog-bounces at lists.ausnog.net] On Behalf Of Joshua D'Alton
Sent: Thursday, 28 November 2013 1:41 PM
To: John Edwards
Cc: ausnog at ausnog.net (ausnog at lists.ausnog.net)
Subject: Re: [AusNOG] AirFibre

That's heavy!

Regarding OP, you could talk to BigAir they do contracting not just with their own system, they might be able to help you bring together a solution.

On Thu, Nov 28, 2013 at 2:31 PM, John Edwards <jaedwards at gmail.com<mailto:jaedwards at gmail.com>> wrote:
Those of you concerned with OHS might be interested to know that when these are powered on with defaults and the dishes pointed into a concrete floor for config, they set off RadMan RF safety detectors nearby. That probably won't stop anybody from using them, but try not to have one on your desk!

John


On Thu, Nov 28, 2013 at 1:50 PM, James Andrewartha <trs80 at ucc.gu.uwa.edu.au<mailto:trs80 at ucc.gu.uwa.edu.au>> wrote:
On Thu, 28 Nov 2013, Joe Saxton wrote:

> As I was doing some research on opportunities on ways our company can improve our bandwidth across our sites I can along this
> product called AirFibre.
>
> http://www.ubnt.com/airfiber
>
> Its described that over the licence free 24Ghz band it can carry 1.4Gbps+ data throughput upto 13km range with the airFibre24.
> The airFibre5 operates on the lower 5Ghz band (which may or may not require licencing) which can carry upto 1Gbs data throughput
> within a 100Km range.
>
> For a point to point link at ~$4k it seems like a cost effective way to deploy an alternate FTTP link.
Be aware that the licensing of this band in Australia means the distances
it can achieve are much shorter - see
http://store.freenet-antennas.com.au/product_info.php?products_id=534 for
theoretical and real-world examples.

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