America's GMRS in Australia

herrgott · Post by **herrgott** » Mon Apr 28, 2008 12:34 pm

Please be in mind that I only understand the basics of radio communications. I'm fielding this question on behalf of my curious old man.

Right-o. If I were to purchase a US GMRS handheld pair of two-ways [which go for $70 and claim to reach 45km line of sight] for use in Australia, apart from being illegal, what would the effects be?
Would the radios work? Are there other services using the GMRS frequency here in [Western] Australia that would interfere with it? If some ignorant American happened to bring his to this country and start using it, is he going to be chased down by the authorities for this ignorant use / breach of law? I understand that using GMRS in Australia could interfere, but what is the actuality?

My UHFs are 2W and around 10km line of sight, costing around $300 for the pair of handhelds. Comparing that to the GMRS two-ways in use in the US blows me away - is there any reason why the legal boffins decided to limit us to <5W two-ways with short distances, especially considering the size of this country? And the crazy prices in Australia for our handheld UHF's compared to US prices?

Thanks for your time fielding a response for me. I know there's a few questions in there.

herrgott · Post by **herrgott** » Mon Apr 28, 2008 12:48 pm

Perhaps answering my own question here, but looking at the frequency that GMRS runs on [462.550 through 462.750 from wikipedia] and then looking at Uniden's online frequency search tool which is at http://www.uniden.com.au/v3/search_page.htm for WA, it appears that there are some clashes with the frequencies listed [some clash, some aren't listed on Uniden's site so I'm assuming must be 'free']. Would the answer then be definitive that it's a 'maybe' regarding interfering with WA services?
Some frequencies are obviously used by certain agencies and clash with GMRS public and free frequencies that are meant for use in the US which would result in interfering with their services. Others perhaps aren't being used but may be at any time registered to somebody for their own use and would then begin to interfere?

Nick · Post by **Nick** » Mon Apr 28, 2008 4:26 pm

Getting 45 km out of handhelds is being overly optimistic without using a repeater. All these companies claim "upto" so many km from the radios in ideal circumstances. I can get 150 km from my 1 watt handheld if I stand on Bluff knoll and the other is on flat ground. The other problem is power, more power means bigger battery = more expense = more weight = bigger radio's.
The other problem is OH&S. Who wants high RF power against their head.

WPXZBP · Post by **WPXZBP** » Mon Apr 28, 2008 4:47 pm

Check out http://web.acma.gov.au/pls/radcom/regis ... .main_page which is the ACMA's register of licences. Don't make the assumption that if a frequency has nobody listed that the frequency is "free" to use. You could get pinged for using a military, AFP or other organisation's frequenices. You also need to ensure you have a licence to operate on that frequency otherwise you could get pinged for operating without a licence. (Depends on whether it's class, apparatus or spectrum licencing.)

I'm no lawyer but I would give this advice.... don't use them!

Post by **Zebedee** » Mon Apr 28, 2008 5:59 pm

The general situation in Australia is that the use of any radiofrequency spectrum has to be licenced.

CB radios here are covered under a "class licence" - that is, a licence doesn't have to be issued to an indivudual.

But these GMRS radios wouldn't be licenced here under such a system, so unless the operator obtained a licence from ACMA to use the frequencies that the radio transmits on, then it would be illegal to use them here.

That's my (very basic) understanding. I echo Wes' opinion ... don't do it

herrgott · Post by **herrgott** » Tue Apr 29, 2008 5:46 pm

Thank you kindly for your informative replies, guys.

Your suggestions to not use them are needless - I was/am looking for the information out of curiosity, not to purchase some of them for use. I'm not in the business where I can afford to be done for flouting the law, if you know what I mean. But I appreciate it all the same.

Nick, you make a few good points in your post that I hadn't thought about. I guess the American's don't mind pounding their skulls with radio waves.

Any idea why the powers that be have set handhelds at a 5W maximum?

WPXZBP · Post by **WPXZBP** » Tue Apr 29, 2008 6:14 pm

herrgott wrote:Any idea why the powers that be have set handhelds at a 5W maximum?

Methinks it might be due to the limitations of portable battery power. Even if battery power could give out, say, 100W, the heat generated in the process would require you to wear gloves and a face shield to prevent you getting scorched.

Lucas_arts_182 · Post by **Lucas_arts_182** » Tue Apr 29, 2008 7:01 pm

WPXZBP wrote:
herrgott wrote:Any idea why the powers that be have set handhelds at a 5W maximum?
Methinks it might be due to the limitations of portable battery power. Even if battery power could give out, say, 100W, the heat generated in the process would require you to wear gloves and a face shield to prevent you getting scorched.

No it wouldnt.... But it will "warm your feet"

vk6ngs · Post by **vk6ngs** » Wed Apr 30, 2008 8:40 am

100 watts from a handheld would burn you,its called RF burns.Its covered in the amateur regs,safety section.It says the minimum height for base antenna putting out 100watts is 30ft.I can tell you from experience that holding a antenna putting out 100+watts isnt a pleasant feeling

Post by **VK6ZMS** » Thu May 01, 2008 7:01 pm

100 watts into 50 ohms is only 70 volts @ 1.4 amps

Seriously though kids do not try that at home.

Nick · Post by **Nick** » Thu May 01, 2008 9:09 pm

We are dealing with rf. Simple ohms law does not apply. We have to deal with Q factors and impedance points on the antenna. I can easily demonstrate that 100 watts will light a 40w fluorescent light at 1 metre through the air. In fact I do this when ever I demonstrate why the HF antennae used by emergency services/military has a warning to keep at least 2 metres from antenna during transmission. As the frequency increases it takes less power to penetrate the human body. 2450 mHz is the frequency used by microwave ovens. 5mW is the maximum power allowed to leak from an oven. Guess why.........

Post by **VK6ZMS** » Thu May 01, 2008 9:27 pm

ohms law is relevant those other factors will sway results but not to a huge degree. RF is AC current at a high frequency.

WPXZBP · Post by **WPXZBP** » Thu May 01, 2008 10:06 pm

I was actually talking about the heat dissipated by the finals in the hand-held. I wasn't referring to the RF side of things.

Post by **robbage** » Fri May 02, 2008 4:41 pm

Imagine if it was transmitting every now and then while held against your body 16 hours a day (or 24 hours if you're a teen) every day of the year

You could end up like this. Brain dead

WPXZBP · Post by **WPXZBP** » Sat May 03, 2008 12:54 am

Wearing glasses like that (:smt078) would make me think blind also.