Re: 🇦🇺 Navy Ship Causes Internet Outage In Parts Of 🇳🇿

Lawrence D'Oliveiro  <ldo@nz.invalid> wrote:

>
<https://www.nzherald.co.nz/nz/australian-navy-ship-hmas-canberra-causes-internet-outage-in-parts-of-nz/EGBPRF5D5NAURF6LTPCXXFWN5Y/>
>
Quote from an official:
>
   “Some spectrum bands are free of charge and available for anyone
   to use – such as the shared spectrum bands for Wi-Fi and
   Bluetooth,” said Dan O’Grady, the ministry’s manager of radio
   spectrum policy and planning.
>
   “The interference that occurred on Wednesday was in one of these
   shared bands.”
>
But those shared bands are not a complete free-for-all: there are
supposed to be limits to the power that transmitters are allowed to
have, precisely to avoid this sort of interference.

Yes, but the ISM bands are dumping grounds for trash in both the US and the
UK, and users operating ISM devices under Part 18 should have no expectation
of reliability.

The ISM bands were located in places that nobody wanted for any other uses,
and they are generally not very desirable spectrum.  Part of why the 2.4 GHz
band is undesirable is that both the military and US civilian aviation
folks have high powered radars above and below that band.

http://www.panix.com/~kludge/2.75ghz.gif

And this is fine... except that a lot of consumer devices that use ISM
frequencies are cost-engineered to be so cheap that they don't really
perform very well, and strong sources on nearby frequencies cause the
receivers to go deaf.  Most people are not going to spend a penny more on
a wifi device to get better RF performance.

Another thing that happens is that.... while the US Army is extremely good
about coordinating frequencies with other organizations and making sure
they aren't causing interference (because interference provides intelligence
to the enemy too).... the US Navy is used to being able to just turn stuff
on or off willy-nilly without regard to other users because they are used to
being in the middle of the ocean.   I live near Norfolk and we frequently
have issues with shared frequencies because nobody on that ship in port
bothered to call the base frequency coordinator before turning something on.

I don't know if the Aussies are as bad as the Americans but I would not be
surprised.

Summary:

1. People trying to use junk spectrum in ways it was never intended for.
2. People buying cheap equipment with poor RF performance.
3. (Possibly) Navy radarmen not doing the right paperwork.

--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."