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Mark Harris

Australian Users: The laws for 2.4ghz

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I sent an email off to ACMA today to find out what the laws and restrictions are on the 2.4ghz spectrum.

My Email:

I am seeking information on the 2.4ghz frequency. Could you please tell me what the legal Effective Isotropic Radiated Power limit is? I’ve heard this is around 10mW, however cannot find any information on your website to this effect. Additionally some websites have mentioned an Effective Radiated Power limit of 4 watts.

I’m hoping to sell 2.4ghz wireless video systems for use on model aircraft. Is there a licence that can be obtained to use more powerful transmitters, if so could you please point me to any information on obtaining one.

Finally, is it legal to sell transmitters more powerful than the limit?

Their response (was not expecting something so detailed from a government department!)

Mark,

With reference to you query below.

The power limits under the class licence refer to EIRP and the gain of any directional antenna and the losses of associated coaxial leads would of course have to be taken into account.

For all the conditions that apply to using 2.4 GHz under a class licence, check out the link below:-

http://www.acma.gov.au/WEB/STANDARD//pc=PC_1278

http://www.acma.gov.au/WEB/STANDARD//pc=PC...spectrumdevices

In the LIPD class licence (at 2.4 GHz)-:

Under item 19, you are allowed 10 mW for any type of modulation, analogue or digital.

Under item 45A you are allowed 4 Watts with restrictions on spectral density.

Under item 52 you are allowed 500 mWatts using a minimum of 15 hopping frequencies.

Under item 53 you are allowed 4 Watts using a minimum of 75 hopping frequencies.

As you can see from above there is some scope for transmitters in the 2.4 GHZ band of greater that 10 mWatts. You have to make sure your transmitters fit the requirements.

If transmitters are scoped in AS 4268 then they would be subject to the Radiocommunications Devices (Compliance Labelling) Notice 2003.

You ask if it is legal to sell transmitters more powerful than the limit.

It is not a breach of the Radiocommunications Act to sell an overpowered transmitter.It may be a breach of another act, eg You may be supplying a device unfit for its intended purpose etc.

If the transmitter is not operated within the class licence limits the transmitter is unlicensed.

If the resultant EIRP of a transmitter in the 2.4 GHz band is detected by ACMA then the responsible entity for the transmission may be in breach of the Radiocommunications Act 1992 Sections 46 and 47. The maximum penalty for an individual is imprisonment for 2 years and if it's a corporation then the maximum penalty is 1500 penalty units, (1 penalty unit = $110). for each section. If this was to happen to an entity or individual they may seek civil redress from the supplier. For any further information I suggest you consult a legal practitioner.

Kind regards, Mick Burgin

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>>with restrictions on spectral density.

aha !

our video transmisions are super wideband !

FM and no sideband suppressions not at all.

so how to calculate the ocupied bandwidth power ?

in what bw do they measure ?

so you can be lucky and get permission to TX 500mW or even 1W

and still be way under the limits,

my wideband telemetry systems on 433MHz use 250mW and can not be heard on a narrowband hamradio receiver even if they are 10m away !

that is exactly due to the ocupied bw is close to zero.

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here in Denmark it is legal to own/sell/purchase all sorts of transmitters, no matter what, no limits.

but to use them ! is up to the individual person,

if they have special license or other permission to that frequency band.

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I found something while looking through the class license, and have emailed good 'ol Mick about it.

Section 26,

Telecommand or telemetry transmitters

1. 2400–2450

2. 5725–5795

3. 5815–5875

1W of power allowed.

The first 3 channels of the Airwave tx's fit into 2400-2450, the fourth is just outside at 2463MHz.

I suggest that the fact we are sending Audio, Video and possibly GPS/other data through it would make it be considered telemetry.

This is 45A/B:

45A

Class of transmitter: Digital modulation transmitters

Permitted operating frequency band:  2400–2483.5

Maximum EIRP: 4 W

Limitation:

1.  The radiated peak power spectral density in any 3 kHz is limited to 25 mW per 3 kHz.

2.  The minimum 6 dB bandwidth must be at least 500 kHz.

45B

Class of transmitter:  Digital modulation transmitters

Permitted operating frequency band:  5725–5850

Maximum EIRP:  4 W

Limitation:

1.  The radiated peak power spectral density in any 3 kHz is limited to 25 mW per 3 kHz.

2.  The minimum 6 dB bandwidth must be at least 500 kHz.

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For both, it states:

Class of transmitter: Digital modulation transmitters

Video TXs use analog modulation, so don't fit in there.

Unfortunately, from what I see from the previous posts is that our usual TXs would only fit in

Under item 19, you are allowed 10 mW for any type of modulation, analogue or digital.

:(

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Well, can't say that without having the details. But I've rarely seen analog telemetry transmitters, so I fear that would have limitations too.

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