Foundations of Amateur Radio As radio amateurs we learn which frequencies we're allowed to transmit on, where stuff lives and who has priority when there's a signal on the frequency you're operating on and when you need to contact your regulator if you hear an illegal station on the air. Some of that information arrives in your brain by way of the education process that eventually becomes your license after a test. Depending on which country your license is valid, determines which region of the International Amateur Radio Union your activities fall. Here in Australia, I'm part of the IARU Region 3, together with the rest of the Asia - Pacific region. In the Americas you're part of Region 2 and Europe, Africa, the Middle East and Northern Asia fall into Region 1. As amateur population sizes go, Region 2 and 3 each cover about 40% of all radio amateurs. Region 1 is about 20%. Each of these IARU regions has a specific band-plan that is updated regularly as member countries adapt and negotiate different frequencies for different users. The band-edges might not change that often, but bands come and go, segments are added and removed as needs change. For example, here in Australia or VK, the 6m band has been changing because analogue TV has been changing. Information about band-plans is not easy to come by. For example if I look at IARU Region 2, their documentation is pretty sparse. I've never managed to actually load their website and by the looks of it, neither has the Internet Archive. Given that Region 2 is all of the Americas and represents pretty much two fifths of all amateurs on planet Earth, that's a big hole. There is some availability in Region 1 and 3, but those too leave to be desired. There does not appear to be any formal method of archiving or naming and the transient nature of the Internet all but guarantees that historic information like this is being lost at a high rate. Even with those limitations in mind, there is plenty of information to be found. Let's look at Australia, for no other reason than that I was able to pull some of the historic information out of the bit-bucket. You might be surprised to learn that there is much more change under the hood that far exceeds the band edges and segment changes. The Wireless Institute of Australia publishes the Australian Amateur Band Plan. Using the Internet Archive I was able to count that between November 2007 and November 2019 there were at least 25 different versions of that band plan published, for example in 2008 alone there were at least five different versions. I managed to download 11 of those band plans which show the introduction of the 2200 meter band, the 630 meter band, changes to mode frequencies, DX frequencies, the allocation of emergency frequencies, changes to FM bandwidth from 6 kHz to 8 kHz on bands below 10m, the formalisation of WSPR frequencies, JT65, FT8 and JT9. Now I must point out that the information I'm presenting here is incomplete. There are many more changes, just in VK alone. I'm relying on the Internet Archive which only sampled the WIA website 162 times between March 2008 and January 2020. Within those pages there were only 11 copies of the actual band plan and I've only compared three of them, August 2009, March 2015 and October 2019, and of those only a few changes that stood out. And this is for Australia alone. This is on the HF bands. I've not even looked at the veritable feast of changes associated with the VHF and UHF bands, let alone the cm, mm and higher bands. Even with this massive disclaimer, my point should be pretty clear. A band-plan is a living document. It changes regularly. Likely much more often than you realise. I'll leave you with one burning question. When was the last time you got yourself a copy of the band-plan? Seriously, when was it? I'm Onno VK6FLAB