LIPD type approval??

[VK2CJC]

This subject may have been covered already on this forum. If so, my apologies for repeating it.

I've been reading the spec for Low Interference Potential Devices (LIPD)
http://www.comlaw.gov.au/Details/F2011C00543

It keeps talking about transmitters complying with this spec and that spec. But do they have any type approval system on LIPDs?

What I am asking is, is it legal to build or modify transceivers to work within the LIPD bands?

I'm looking at the 1w max power band at 40MHz and thinking it could be a good place to experiment.

[VK2AVR]

I'm not a legal expert by any means but this is my understanding as far as developing under a class licence such as LIPDs..

The ACMA requirements for developing LIPDs are that you keep a compliance folder demonstrating the level of compliance you are required to for the particular device. The level required is set based on the type of device. Some devices just need a self-certification document, other devices need to pass an applicable standard for the device type, for example AS/NZS 4268 which is a short range device standard.

Many devices need to be fully tested at an OATS site with a calibrated measurement system and rotating table such that EIRP of the device can be measured at all values of rotation. Then the strength of the fundamental and harmonics can be plotted against the legal limit and Pass/Fail determined. The result of all of this has to go into your compliance folder and ACMA can knock on your door at any time and ask to see it. Once you have done this process you need to register with ACMA for an approval number ('N' number) and then display the C-Tick logo along with this N number on every device. That way, if there's a complaint, ACMA knows whose door to knock on Other electronic devices eg laptops and gadgets also need to be C-Ticked to demonstrate that they don't unintentionally emit excessive amounts of RF, they have their own IT-related standard to adhere to.

I'm not sure what the requirements are if you're doing this yourself. There's a lot of detail in Australian standards documents, not just the LIPD document you referenced. Unfortunately, you have to pay for Australian Standards documents they're not freely available as the LIPD class licence is.

[VK2CJC]

Somehow I knew the answer wasnt going to be simple

And I did think this wasnt an area where home brew was encouraged.

I was just watching how much fun the young lads had with 0.5w UHF CB hand helds. And thinking how they might like to try 40MHz where there was some construction required. And other modes such as digital modes could be tried out.

Needs further investigation methinks.

[VK3YE]

All this sounds terribly complicated and there should be much simpler means to guarantee you're within the EIRP limit.

Measure final stage collector current. Multiply by voltage. This will give a DC power input figure.

Make sure this is under 100mW (the limit on most of the lower VHF LIPD bands - no need to bother with bands with under 100mW limit).

Unless you have just invented perpetual motion (in the shape of an RF power amplifier stage that's over 100% efficient) there's no way your transmitter will output more than the legal limit if the input power is under limit.

Something like a 2N2222 as a final transistor might give 20 - 50mW out in the lower VHF range and is both safely within the limit but still enough for a good range.

As for the antenna, stick with anything that's roughly the same as an isotropic radiator. Eg a quarter wave, magnetic loop, halo or at most a dipole. OK, so a dipole might be 2dB more than an isotropic radiator but if you're conservative with the power out you'll still be fine. An interesting thing is there seems to be no limit to the height you can place your dipole, etc.

As for frequency stablity and spurious output go for a crystal that requires no multiplication, or maybe x 2 only. Put a pi filter on the output. 18.432 MHz is a common xtal frequency and double that is in a wide LIPD band. You might even be able to get xtals that put you directly on 36.864 MHz, though with the 18 MHz xtal you can VXO it over quite a good range.

Provided your output isn't on frequencies it shouldn't be and you stick within the class licence limits, I don't see any problems.

[VK2CJC]

Provided your output isn't on frequencies it shouldn't be and you stick within the class licence limits, I don't see any problems.

I realise building equipment within spec wont be difficult (I've watched your youtube videos) but my question was whether this was legally allowed. Or is there type approval to comply with.

[VK5ZD]

Hi

I would suggest you complete form R052 "Request for advice on operation of radiocommunications devices (class licences)" and submit it to the ACMA.
They will then tell you whether or not you can use the device.

73
Iain

[VK3XRI]

i had a look at the freq spectum for the uhf 434 lipds the other day , being bored ,,,, and found that a number of them are on the input to some of our 70cm repeaters , as i had knowen for some time just not to the extent of what they were ,,

although the power is limited to somthing like 25 mw , in an open area these could have some wide coverage or from a hill top , to asside form the obviose ,

how does one differentiate the two ,, ie some one listening on a simplex freq , tell that this is not a VK user and an lipd user , like i said apart form the obviose , like no calls or ids and prob a huge amount of language .... it leaves it a bit open does it not !!!!

[VK2AVR]

just means you should use CTCSS to keep rif-raff off the repeater

Geoff

[VK2AAH]

Exactly Geoff! CTCSS on base receive should be mandatory, particularly on 70cm.

Cheers,

Richard
VK2AAH

[VK2AVR]

My local club doesn't have CTCSS on 2m, because several members have old radios that aren't capable and putting CTCSS on would force them to modify their radio or upgrade it. However, completely agree with using it on 70cm - I'd be surprised if there is much gear around that can't handle a tone.

[VK3RX]

I recall a fuss with the ACMA when LIPDs were approved.

Interference to the input of some repeaters, WIA having to shift repeater frequencies, ACMA then charging a fee for a frequency change, threats to invert some repeaters so the sites transmitted on the LIPD freqs. etc.

I also recall something about the then honcho of the ACMA signing an Instrument that legally declared LIPDs do not cause interference.

Someone knows the complete story ......

[VK2AAH]

I know some clubs & repeater licensees are hostile to being compelled to fit CTCSS but for a sector of the community that prides itself on an image of being technology leaders this attitude seems troglodytic to me! The RF environment has changed for ever and it is only becoming noisier. Anything that provides a degree (we all know CTCSS is not absolute protection) of protection against noise is better than carrier detection. I was at Maddens Plain (a major site near Sydney) and it was great to see the bank of D Star repeaters combined with home brew filtering that has been there for decades. The days of back to back carrier operated FM828s with just physical antenna isolation is over in most urban areas- out in the bush it may be fine...

Cheers,

Richard
VK2AAH