Reg Hardware

Comments on: Blue Sky squeezes GPS onto a SIM

I wonder how long it took them to work this out.... 

Posted Thursday 26th April 2007 13:47 GMT

".....but when we take away the battery, take the SIM out of the phone, the signal is no longer there."

I hate to piss on their picnic, but they seem to have invented yet another mobile device that (cue "ta-da" sound) stops working when you remove the battery.

I'd like to see the testing methods that they used to narrow the cause of this behaviour down to their secret antenna technology.

Dur 

Posted Thursday 26th April 2007 16:25 GMT

You don't think that maybe they use the phone body (if metal) or just a ground as the antenna?

Phone chassis as ariel 

Posted Thursday 26th April 2007 17:04 GMT

".....but when we take away the battery, take the SIM out of the phone, the signal is no longer there."

What I think he's trying to say is the SIM is inductively coupled to the phone's metal chassis (via an air-gap), and thus is using the chassis as an ariel. If the SIM is connected to the phone with a bit of ribbon cable, or a case-less dev-board phone is used, then the SIM won't work correctly, as it hasn't metal plate near it to use as an ariel.

AERIAL! 

Posted Thursday 26th April 2007 19:00 GMT

Ariel is a washing powder (women know such things).

An aerial is an English antenna (the Americans changed the word because they couldn't spell it either).

No metal chassis 

Posted Friday 27th April 2007 05:09 GMT

The last mobile phone with a metal chassis was dropped from high altitude to destroy a gun emplacement during the second Gulf war.

Modern phones simply do not usually have a metal chassis, the absence of which contributes to their light weight.

If you remove the battery from your phone you will typically discover that it has four electrical connectors, not the two that one would expect. The extra two are used for battery management.

From this we can conclude that mobile phone batteries contain WIRES, which if one is terribly smart and does not upset the circuitry, can be used as an antenna. This is similar to the technique for using headphone connecting leads as an aerial in small radios.

Risto Savolainen is doubtless biting his tongue, at least gently.

That's my guess.

Not "dur" but "ha-ha" actually 

Posted Friday 27th April 2007 08:34 GMT

Personally I thought that my original comment was so obviously a gag that I didn't need to grace it with anything as unsubtle as a smiley.

It's like trying to raise a laugh in a Trappist Monastery round here these days........

Ariel... 

Posted Friday 27th April 2007 10:57 GMT

Don't think they had washing powder in Shakespeare's day (qf The Tempest)