Posts by Paul Crawford

Antenna gain

You don't get anything for free, if you have a given power flux density at the Earth (you know, a fixed transmitter power and coverage area) then going up in frequency achieves nothing - the increase in directivity gain for a fixed effective aperture is NOT producing an increase in power, and going to a smaller antenna for a fixed 'gain' is not helping - in fact it is counter-productive. The reason why "free space loss" in link budgets includes wavelength instead of simply being inverse-square is specifically to reconcile the relationship between an antenna's effective area and directivity gain.

The only benefit you get in that scenario from higher frequency use is the directivity gain allows you to separate sources (.e.g. satellites) that are close together. But you pay for it by having to steer the beam very accurately (mechanical or phased array). Also rain losses are massive at W-band so for some users in some areas they won't be seeing better then 95%-ish connectivity.

It makes some sense for users in really sparse areas, but not for high density cities, etc, where putting in some fibre and a few mobile base stations operating at frequencies that penetrate building is going to work much better. The real question (beyond pollution of space when those reach end of life and can't be de-orbited from 2000km altitude for millennia) is the economics of doing so for a large number of very poor users. Yes, I feel they should benefit, but I do wonder if the companies behind this can make money. Iridium went bust because the advent GSM, etc, stole its most profitable user base in the big cities and densely populated areas of wealthy countries.

When is a BIOS not a BIOS?

When if it root-kitting you machine obviously.

But the more serious question is why are open/replicable BIOS not more widely demanded? Are our gov departments happy to buy mass-market PCs with such crap-ware (or even foreign spyware) pre-installed? If not, what are they doing about it? When do we start to see contracts for gov PCs that demand open source BIOS without any shit-ware installed? Only then will there be enough of a commercial pressure for suppliers to make enough details available for reliable 3rd party BIOS to be used.

Sadly I can believe it. But then a lot of Americans believe the world is 6000 years old and evolution is less likely. Apparently a National Geographic survey found 77 percent of all Americans “believe there are signs that aliens have visited Earth”, and according to a recent Harris poll only 68 percent of all Americans believe that Jesus is God or the Son of God.

If we simply took the majority's views as always right then the world is flat and slavery is something that is good for business so keep it going.

Salutations to Tesla

For once we see a car company reacting sensibly to the holes in their systems. Of course, this should have all been done before the cars were leaving the factory, but at least Tesla has the balls to realise they did not, and are apparently taking it seriously enough to do something about it. OK, bounty is not so big as some other companies, but its a damn sight better than most auto companies.

Battery life?

How long do the 4 * CR123 cells last? It could become an expensive toy to feed if its not for 6 months or so.

Also, and I guess its out of the scope of a quick review, how secure are any of these? Have any been subject to a proper penetration test? Given the on going crap about home NAS being insecure, etc, I would be very weary of letting and of these products loose in my home/work.

Mind you, who would be foolish enough to trust the communication 'pipe' to implement security & authentication? Damn, that was a dumb question!

End-to-end or no cigar...

Temp difference also matters

I was once installing stuff in Egypt a long long time ago and the IT/computer room/office was set to 18C when outside it was 35-40C. This room was mostly workstations and some photographic plotters, etc, not a data centre.

They had to wear extra cloths / coats indoors and complained about fingers going numb. Despite being used to much colder in the UK I also found it uncomfortable when dressed for that sort of region so set the A/C controls to 25C as no one there felt they had the authority to do so. End result was a much happier work force and greatly reduced electricity bill!

Damn, looks like I will have to study that list in case I am missing something. Other than scruples, that is.

Still, I didn't know there was a web site stiflersmom.com but I guess having seen it mentioned in India Today I will check it out later, and not at work. Look, its bound to be NSFW...

Sounds like a good idea

Firstly I must thank you for cheering my day up with the description " the rancid free-for-all of today’s clickbait-infested swamp", it is spot-on!

It remains to be seen how well the system works, but for a lot of commercial sites I can see it would be a great advantage if photos and other materiel could be licensed for a small fee more-or-less instantly. Even for some of us who choose to put things up for free, it would be nice to track its popularity (particularly if your funding is based on "public impact" factors).

However, the issue of meta-data stripping is more complex as it can reveal information about the person they really don't want public. For example, the lat/lon of their home, or a personal identifier if its a crime they reported. Having an agree copyright metadata field that is not stripped by web sites on pain of legal action is much better, so long as phones, etc, always confirm you want it sent in sensitive cases.

Ofcom report

It is worth a read of the report, in particular section 6.7 is damning of the quality and consistency of the DAB radios out there.

I am not surprised really, and having read parts of the DVB-S2 standard you can see why it is a high risk to implement and of these sort of systems in silicon for space projects etc - the standard is so damn long (from memory about 1000 pages in the various pdf documents) and complex that the chances of someone implementing all of it correctly is quite small.

Really, when you compare DAB in practice to FM and factor in receiver availability, battery life, coverage, etc, there is not a good case for DAB. The suggestion of killing it off and leaving FM and IP radio is a worth considering.

Amusing concidence

Funny when I read the article the last part was:

Have also fired 12-bore shotguns on a few occasions and was once even present at a grouse shoot.

Sponsored: How to deal with Windows Server 2003 end of support

Related I wonder?