Hello Osmocom community, I have a contact in Australia who reached out to me with a desire to set up his own personal GSM/2G network. Australia is a nasty anti- retrotechnology country, even worse than USA, where all official 2G networks were shut down back in 2018. As most of you know, I run my own pirate-radio GSM cell in USA, and I tried reaching out to other Vintage Mobile Phone communities, promoting the idea that people can run their own networks using Osmocom CNI plus suitable hw plus my ThemWi add-ons for outside PSTN interconnection, and offering to teach others how to copy what I am doing. When I made the latter offer to the community, I was expecting people from other parts of USA - but right now the only person with an active interest is in Australia. I am currently teaching my Australian contact the "pure physics" aspects of running your own GSM network: what frequencies are usable for GSM, dB and dBm units of measurements, how to use a handheld spectrum analyzer etc. These are all "physics" topics that are independent of where one happens to be geopolitically. But there is another key aspect which I feel he needs to know, but which I won't be able to teach him: country-specific spectrum-political aspects. I know the spectrum-political landscape in USA: how FCC has divvied up PCS1900 and GSM850 bands (or B2 & B5 in modern parlance) between carriers, which spots in these bands are completely unused and thus reasonably safe to squat in, and how one can exploit the overlap between EGSM900 DL and USA ISM band to run a BTS with low probability of getting into trouble. But I have absolutely no such knowledge for any other country in the world, let alone one as remote and foreign to me as Australia. Is there anyone in this community who is based in Australia and knows this topic? I would greatly appreciate any advice from an AU-knowing person that I could pass to my GSM-enthusiast contact: out of the 4 frequency bands that are in-principle suitable for GSM, which is the safest one to squat in for a pirate operator, and which ARFCN range(s)? Obviously I will teach my contact that he needs to pick a spot where the spectrum analyzer shows nothing but noise floor, but just because a spot "looks blank" on an SA doesn't mean that the spot is safe to squat on, without knowing anything at all about the country's spectrum-political landscape... TIA, Mychaela