* Posts by PolarPerson

4 posts • joined 5 Apr 2011

Royal Navy halts Highlands GPS jamming

PolarPerson
Boffin

GPS and Distress calls

Although distress calls are (of course) transmitted in a vastly different part of the EM spectrum from GPS, disabling GPS disables a crucial part of the Global distress system (GMDSS). A VHF technology called DSC provides the capability to broadcast digital message containing latitude and longitude; these are used heavily in distress messages that are provided on pushing a Big Red Button. Of course, the latitude and longitude are normally provided by a GPS system; other types of electronic position finding are rarely used.

Automated distress beacons also provide positions from GPS; again, although the communications technology is not compromised, the GPS is. In this case, there is no alternative technology feasible.

However, the other side of the coin is that I, an amateur yachtsman who happens not to have gone to sea for a couple of months, knew all about these tests. I really don't understand why the fishermen didn't know about them - they are routinely notified through a wide variety of channels. What do the fishermen want? Personal visits from HRH?

Scientists reveal eight-legged Jurassic beast

PolarPerson
Boffin

Re: A bigger one (Maybe?)

No, it MAY be a Eurypterid - which is a marine relation to a spider, anyway. And if it is a Eurypterid, it is an anomalous one - I am no expert in the Chelicerae, but I understand there are problems with identifying it as a Eurypterid, just as there are problems with it being a spider! So, it is either an anomalous spider or an anomalous Eurypterid.

PolarPerson

A bigger one (Maybe?)

The Sedgwick Museum in Cambridge has a specimen that MAY be a spider, but which is a LOT bigger - see http://www.sedgwickmuseum.org/about/news/05spider.html. OK, it might not be a spider - but it certainly looks like one (I've seen it). And the generic name means "Big Spider".

The Osborne 1: 30 years old this month

PolarPerson

Memory Lane

I used one of these in the 1980s as a portable development system for developing real time logging software. I re-wrote the I/O component of one system in the middle of the Greenland ice-cap using our trusty Osborne 1, following the failure of the primary recording device.

Hey-ho - the joys of writing complete systems to fit in 2k of EPROM! But the Osborne's suit of programs did the business; it came with an editor and an assembler, and Kermit would transfer stuff to the EPROM writer.

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