WMS you'll like this...

So, I'm at work, I drive a cab btw, and I am having a technical nightmare. I can't get any work done 'cos I can't get a GPS fix, the computer doesn't know where I am so it won't give me any work.

After an hour of cussin' and swearin' I decide enough is enough, I'm going to go into the office and insist that my transponder be replaced, which is what had to happen the last time I had this problem.

As I drive away I realise that I've been parked next to (like 50 yards from...) this honkin' great Warship (HDMS Absalon if anyone cares) that was running one of it's RADAR arrays all last night. Hmmm, thinks I, perhaps this is my problem. I put some distance between us but to no avail, still no GPS signal.

This however has started the cogs turning and I finally notice the deliberate mistake...

I've moved my Ipod.

Only from the center console to the vent to the right of the steering wheel (RHD in the UK). Not much really, only about a meter.

Of course that meant that my iTrip was only 6 inches from the transponder instead of 4 feet. One over D squared, thinks I, and turns off the iTrip.

Bingo! We have lift-off!!

So I park up, whip out the laptop and HSDPA modem and check out GPS on wikipedia. A little squinting at an image of the carrier wave reveals that GPS is transmitted at 1575 Mhz, exactly 18 times the frequency my stupid dongle is randomly set to (220 settings this thing has and I randomly pick 87.5 )

So now I know how to really annoy Geo-cachers and protect myself from GPS guided cruise missiles...

What's really amazing about that is how sensitive the data stream is to interference. One in 18 is only about 6% of the signal being corrupted but that is enough to completely knacker the transmission. Goodness knows how you would go about detecting a jamming signal like that, it appears completely innocuous at first glance.

I toubleshot Wireless Network Connections for "Average Computer Users" for a major Cable company, as a "Combo Unit" for their Cable Internet Service.

The sheer number of things I could tell you causes issues...

One of the few Field Techs I liked talking to told me of his favourite.

Baby Monitors. Old baby monitors were the worst for "Spamming" the waves, and would jam *EVERYTHING*!

I've had XBox 360's screw everything up, believe it or not. I wouldn't be surprised if the Wii is dangerous for that too.

i do 2nd level techsupport for 2 big Phone Company's/ISP's and the biggest cable provider/phone company in Germany . .
the things i learned about wireless stuff are incredible . . once it did not work when the user sat before his computer . . as soon as he moved out of the way, voila, conenction to everything close enough . . WLAN, Blue-tooth, HSDPA, his wireless headphones . . EVERYTHING . .
every frigging little thing disturbes radio frequency . . why do you think they build the radio-telescopes way up in the mountain? even those terra-herz thingies get upset by clouds . .

"It's hard to pick them up clearly at this time in the morning. It has to do with the ionosphere."

"Get the ionosphere the hell off the air and get them on!"
- Kelly's Heroes.

Damn but I love to quote movies it appears.

This is the best thing ever.

I'm totally going to build a jammer into my namesake character's commlink--just so he can jam things with his music player.

That's the thing that I was saying earlier about jammers -- it's actually harder to make something that doesn't jam signals than it is to make a jammer. They're just illegal to make or use, at least intentionally. There was also a cool way to use a radio to listen in to cell phone calls, but I'm not sure it works anymore, and it's also pretty illegal (though easy).

Yeah, and even earlier than that, Baby Monitors picked up Cell Phones. The old analog Cell Phones, the Digital ones work on a different system, IIRC.

This is part of the cause for "PRANK CALL PRANK CALL!" in Pulp Fiction.

The trick is figuring out how to strap the jammer to the gps guided bomb....

Hobbyist miniature helicopter?

First Generation Drone Rigging anyone?

Frequency in radio waves does not refer to their period of broadcast. Different frequency EM waves (like radio waves, and microwaves, and visible light) don't interfere with each other. Instead, you ought to look at the signal profiles of the devices; some electronics receive other signals too easily and if they were only 6 inches away then there's the possibility of induction straight into the aerial of the GPS. Also check your iTrip signal profile; it might be outputting a really low power signal in the frequency band of the GPS but be close enough in distance to be enough. However the fact that the two are broadcasting primarily in frequencies that are some integer multiplier of each is not really an issue.

However, it raises an interesting point for the wireless matrix.

i thought it was those analog wireless phones, because both used the unlicenced range. same that now things like wifi and bluetooth operate on, and that your microwave may well generate. yep, that means that you can turn a microwave into a jammer for wireless networks. hell, even wet dogs can have a effect there at times from what i have heard.

I can confirm all of those, along with fishtanks, cats, rats, gerbils running old metal wheels.

Already mentioned baby monitors being the bane of existance to Wireless.

Oh, yeah, and a Stainless Steel Refridgerator.

I'll tell you that story later!

in the U.S. atleast, I blame the FCC. Read the little notes that come along with any piece of consumer electronics. The FCC REQUIRES them to be affected by interference. Sure they could shield things and make it all work better but the damn FCC wont allow it.

I still say this is part of the push to digital. The digital thing is a nightmare. The signal strength is crap.

damn government

Ah, the FCC are always being bastards--that's their job.

There used to be this great independent (read: pirate) radio station where I live. Some local news magazine did a story about how awesome they were...

...and some jerk from the FCC down in Santa Barbra read the article and drove all the way up here just to bust them and steal their equipment--leaving us with nothing but Clearchannel bullcrap to listen to. I didn't even think that mag circulated in SB.

Back on topic, read the rest of that tag:



It's fragging newspeak. If nothing's allowed to produce interference, then the second point would be moot--but everything produces interference.

Also, I'm not really one for conspiracy theories, but can you think of any reason to outlaw jammers and shielding other than to make it so the government can walk up and fry every electronic device you own?

Well first I think it's not really useful to consider such things...
I mean, it'd be like saying "oh yeah but we can't have wired reflexes because... [insert some biotechnical fact here]". I'm sure most people will accept to suspend their disbelief for such a problem.

Secondly, if every wireless device use the same protocol, it all becomes much easier. You just have to use correct multiplexing/spread spectrum/anti-collision techs.

Useful is debatable because it's objective, interesting is opinion.

Those bastards with their black copters.
Good thing I have my foiled tin protective hat!