Power Spectral Density?

[j7r4]

I am currently testing a Pico2 HP with the supplied 6dB omni antenna.

LIPD Licence requirements in my country are summarised as follows:

1. Permitted operating Frequency Band: 2400 - 2483.5 MHz
2. Maximum EIRP: 4W (36dBm)
3. The radiated peak power spectral density in any 3 kHz is limited to 25 mW per 3 kHz
4. The minimum 6 dB bandwidth must be at least 500 kHz

I'm comfortable with requirements 1 and 2 but how do I verify requirements 3 and 4?

If I change the channel spectrum width from the default 20MHz to 10 or 5 MHz, how will this effect requirements 3 and 4? AirOs manual suggests it would increase PSD but by how much?

Thanks

[j7r4]

OK, I have done some more research and I think I can answer some of my questions.

The radio is certified to FCC Part 15 so I downloaded the compliance test report from the FCC web site.

Requirement 4 is duplicated in FCC Part 15.247 (a) and the test report shows a measured 6 dB bandwidth in the range of 10 - 15 MHz in b and g modes and across all channels. So the radio is compliant.

Requirement 3 is a little different. FCC Part 15.247 (e) requires that: "the peak power spectral density conducted from the intentional radiator to the antenna shall not be greater then 8 dBm in any 3 KHz band". So the US requirement appears to be 8 dBm (6.31 mW) whereas the Australian requirement appears to be 14 dBm (25 mW). So either the US are more strict or the US measure is at the feed line and the Australian requirement is at the (presumably 6 dBi) antenna. Either way, the FCC test report shows a measured peak power spectral density in the range of -4.953 to 0.137 dBm. So the radio is compliant.

I'm still not sure how reducing the channel spectrum width would effect the measurements. The AirOS manual says it will increase the spectral density but by how much?

Does the "obey regulatory power" option automatically account for the channel spectrum width setting?

Any thoughts?

[kijoma]

Hi,

i cant see how 3 or 4 are affected by channel width.. they are merely stating that in a 3khz bandwidth the power level must be less than 25mw and that the smallest channel width is 500 khz..

UBNT smallest channel is 5 Mhz, which will easily meet the 25mw/3khz spec you give..

you sure it is 3khz?

[j7r4]

Hi Bill, thanks for taking an interest in my question :)

It's definitely 3kHz as listed in Item 45A of the Radiocommunications (LIPD) Class Licence 2000. See here: http://www.comlaw.gov.au/ComLaw/Legislation/LegislativeInstrumentCompilation1.nsf/0/58DA61C0685CFB85CA2575ED0032C733/$file/RadcomLIPDClassLic2000.pdf

My assumption is that for a given output power (eg 20 dBm), if you were to halve the channel width then you would double the PSD. Is this correct?

But, as you say, it would appear to be nowhere near the limit even at a 5MHz channel spacing.