On Fri, 15 Nov 2019 05:27:27 -0800, Emir Sherbi wrote:

I had a lot of noise issues with the USB ports. Some of them work,
others not. The most practical was to carry a portable powerbank, but is
another thing that you have to remember to charge....

My PNA used to run off an el-cheapo Fleabay cigar-lighter USB charger,
but noise from it was never an issue because it was inside a Maplins[*]
cast metal enclosure, for shielding, and I'd stripped off its plastic
case and soldered on a decent 12 v connection to avoid any 'leaping out
of the socket' syndrome. About two years ago the original USB charger
failed after over 10 years use and was replaced by a 'brick', a solid
state 3A 12v-5v converter, which seems to be working very well indeed.

I've included this link to a similar one that might also suit the OP:
https://www.amazon.co.uk/Converter-A...tor-FlowerPEI/
dp/B07YB17YL7/ref=sr_1_5?
keywords=12v+to+5v+power+converter+3A&qid=15738301 47&sr=8-5

I said similar because this one has two USB sockets already connected to
it, while mine has a single pair of bare output wires. These things are
dirt cheap - under $4 excluding postage.

--
Martin | martin at
Gregorie | gregorie dot org