Travelling with a portable radio can be a lot of fun, especially for us who are mostly on UHF/VHF and don't get to contact too many people outside of Australia. For an upcoming US trip I had a quick look on the FCC site to see how to correctly operate in the USA. Notably, the way that the calling works. This is all specified in 47 C.F.R. § 97.119.
For example, an Australian travelling in Massachusetts would use /W1 a the end of their call sign. In my case I would call as "VK2NET/W1".
But then (shock, horror!) I noticed that little sentence there highlighted in yellow (click the image to expand): "No United States citizen, regardless of any other citizenship also held, is eligible for reciprocal operating authority." 47 C.F.R. § 97.5(d)(1)
Well there are many reasons someone can be a US Citizen with only very tenuous links to the US, for example even being born overseas to a single parent who is a US Citizen is enough. Often these people are called Accidental Americans.
So the answer is that such people, like myself, need to get an FCC license. While there is nothing that I could find in Part 97 about requiring a US mailing address, you do need a postal address. You also need a photo ID issued by a U.S. government agency.
I contacted the FCC directly and got this reply (click to enlarge) and noticed that little section about "or show that you meet the requirements..." so I went to the link of VECs provided and contacted most of them. Surprisingly none of them were familiar with this expat problem and they all suggested that I just need to take a test (but also provide a US Mailing address). One of them did say that he would accept my Australian CoP along with US Photo ID, a US address and proof of my Australian license as well as evidence of what my Australian License was equivalent to in the USA. Fortunately there is a great table on the ACMA site with just that! There is a US$35 fee which must be paid with a credit card from a US bank. I also had to apply for a FRN (FCC Registration Number) and complete the 1-page NCVEC Form 605 2020.
Once the process is kicked off, it's very quick. The VEC sent a form in, within a few hours I got an e-mail from the FCC to pay the US$35 fee which I did online with a credit card. In under 12 hours, I got the full license e-mailed to me. This license lasts for 10 years (much cheaper than the Australian license!)
From now on, I will be known not only as VK2NET but when travelling in the US as....