Wireless Waffle - A whole spectrum of radio related rubbish
Oooh, Baby Baby!signal strength
Monday 18 June, 2007, 15:31 - Radio Randomness
In a previous entry, I discussed the massive security hole presented to their neighbours like a baboon's bottom, by those still using analogue cordless telephones, as they can be easily received with cheap radio scanners, over quite large distances. However this is as nothing compared to the relatively common practise of bugging one's own house; otherwise known as 'installing a baby monitor'. The majority of these low power (10 mW) transmitters operate using basic analogue FM modulation on frequencies between 49.820 and 49.980 MHz (a low-power, short-range, licence-exempt band in the UK). These devices, like their cordless phone counterparts, can be picked up over several hundred metres, if not further. And whilst the owners often switch off the receivers when their child isn't in range of the monitor, they rarely switch off the transmitter meaning that it's often possible to tune-in to your neighbours going ons all day long (though such activities are strictly illegal in the UK and should not be entered into).

baby monitorAround the wireless waffle HQ, there are several such baby monitors clearly audible on frequencies of 49.830, 49.840, 49.890, 49.930, 49.940, 49.950 and 49.962 MHz (the latter possibly intending to be on 49.960 MHz but is off-tune). There are also carriers on several other frequencies in this range but which are too lost in noise and interference (caused by other transmitters on the same frequency) to clearly make out. Some devices just produce a steady carrier, modulated with audio, others transmit data too, either as a 'warble' every second or so, or as a continous 'chuff-chuff-chuff-chuff' type noise. The latter types typically revert to being audio transmitters once the microphones detect any sound.

As well as allowing anyone with a cheap receiver to tune in to your private moments, many of these devices are poorly designed or built and have the capacity to cause significant amounts of interference to nearby radio frequencies, in particular the 6 metre (50 MHz) amateur band. It was as a result of such interference that my attention was drawn to the use of these 49 MHz frequencies in the first place, as reception from around 50.000 to 50.200 MHz suffers from out-of-band emissions from these devices (especially the warble and chuff-chuff-chuff-chuff models). What effect a 200 Watt SSB transmission on 50.150 MHz has on reception on neighbouring devices, I have no idea but it's to be hoped the receivers are as bad as the transmitters and that mummy and daddy are startled to find their 6 month old baby calling 'CQ'. baby modelIt seems that the power supplies used for these transmitters are often badly regulated or smoothed meaning that there's broadband 50 Hz powerline noise, or worse, switch-mode noise emitted along with the intended transmissions.

There are some newer digital baby monitors available which operate either in the 900 MHz range (US models only, not licenseable in the UK), the 2.4 GHz and 5.8 GHz range. These models are virtually impossible to eavesdrop upon as they use digital modulation and are usually spread-spectrum. That being said, they're not encrypted so I guess it would be possible for some enterprising brainbox to figure out how to listen in, but that's hardly a Sunday afternoon activity (an activity which we do not condone, as it demonstrates utter contempt for people's privacy and is, at least conceptually, even more illegal than listening to the analogue ones). If it were me with a young child, I'd opt for a digital system safe in the knowledge that (a) it offers better features, (b) it's much more difficult to intercept and (c) it causes less noxious emissions that have the capacity to cause severe damage a young humans brain and body tissue. This latter point is exceptionally important, or completely made up, I'm not telling: you decide!
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Wire-More LAN (Part IV)signal strength
Friday 27 April, 2007, 14:51 - Radio Randomness
Another train journey, another chance to run good ole Netstumbler and do a survey of channel occupancy for 2.4 GHz (that's 802.11b, g and n and not 802.11a in case you were wondering) to see whether my previous analysis of which are the best WiFi channels to use still holds.

For those who haven't (or can't be bothered to) read my previous article, I came to the conclusion that if you lived in an area of high WiFi penetration, channel 1 was the best channel to use as it was the least likely to suffer interference from other Wireless LAN users. In areas where there was unlikely to be any other wireless LAN activity, channel 11 (or 12, or 13) would be best, as these are the most free from other interferers (e.g. the military, microwave ovens, radio amateurs and so forth).

wifiscan1

So what are the results of this train journey? I've plotted them above. I've shown the outbound journey separate from my return journey. As it's highly possible that if I picked up a LAN in one direction, I might have equally picked it up in the other, I've filtered the return numbers to take account of this. Also, I kind of half forgot to switch my system on on the outbound journey so, as you can see, the results for the return journey show many more LAN's than the outbound!

The upshot remains exactly the same as before (phew!) Channel 1 continues to be the best channel to use if you are in an area saturated with other users. Remember when looking at the above graph that channels 2 to 5 interfere with channel 1 and as such are not independent - equally they interfere wich channel 6 - only channels 1, 6 and 11 (or 1, 7 and 13) are actually free from interference from each other. My arguments about channel 11, 12 or 13 being the best to use in quiet areas remain unchallenged.

As a postscript, I though you might enjoy one or two of the network SSID's (names) that I found during my journey. Here are my favourites:

ideal cleaning wireless'Bleach2006'
'bombolong'
'GARY BARLOW' (was it really...?!)
'Ideal Cleaning Wireless'
'legal loonies'
'SLAPHEADS NETWORK'
'supermonkey
'the wardrobe'
'TOAST'
':)'

and my absolute favourite: 'FRAUDULENT'...! Also, a few other vaguely interesting facts and figures:

Number of networks called 'BTVOYAGER': 12
Number of networks called 'BTHomeHub': 45
Number of networks called 'SKYxxxxx' (where xxxxx is a 5 digit number): 30
Number of networks called 'Belkin54g': 10 (and 7 of them were open)
Number of networks called 'default': 5 (all of them open)
Number of networks called 'linksys': 10 (4 of them were open)
Number of networks called 'NETGEAR': 16 (10 of them were open)
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Skywave Stripteasesignal strength
Monday 18 December, 2006, 11:46 - Radio Randomness
antenna dollHere at Wireless Waffle, we have spent the last month tracking down the perfect Christmas present for the radio enthusiast. Something classy and stylish that would enhance even the lamest of radio installations and make them sparkle and gleam. Something that will make everyone look at your aerial with amazement, requiring double and triple takes in order to believe the awesomeness (yes, that is a word!) of your antenna.

And after literally minutes of research, we have discovered the 'Antenna Doll' - an authentic plastic pole dancer who is already stripped to her undies and is ready and willing to spruce up the season with her sexy moves. According to the packaging, special features include:

* Fits on Standard Car Antennas
* Heavy Duty Plastic
* Moves with Motion of Vehicle

raven antenna dollWhat's more, this must-have gift for the wireless wayfarer comes in several different variants guaranteed to make your pole stand to attention including the ravishing dark haired damsel 'Raven' and the buxom burlesque blondette bimbo 'Britni'.

britni antenna dollThe Antenna Doll isn't available at all good retailers or radio shops, it can only be bought in specialist outlets such as eBay and your local tat emporium, junk shop or adult outlet.

As well as ensuring you the best possible reception (especially in the car park of the local Womens' Institute) almost 10 pence (20 cents) of the price of every Antenna Doll that is sold goes directly towards its manufacture. So why not give the one you love something tasteful and unique to fill their stocking this Christmas and buy something else instead.
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Antenna Plural Bugbearsignal strength
Tuesday 14 November, 2006, 08:52 - Radio Randomness
Aaaaargh... Why is it that so many people insist on using the wrong plural for antenna? It's soooo annoying. There are two plurals of the word 'antenna':

Antennas - a technical term meaning more than one antenna or aerial
Antennae - a zoological term meaning more than one antenna of an insect nature

Don't confuse the two! I often see articles where people say that they have erected 'antennae' at home. Really? They've spent an afternoon mounting insect feelers on their house? Interestingly the entomological community rarely make the same mistake. It's not common for them to claim to have found a new kind of bug with aerials growing from its head!

antenna

If you don't believe me, take a look at the screen-shot above taken from answers.com which clearly defines the two different plurals and their different meetings.

To avoid all confusion, try using 'aerial' to mean a radio antenna, that way there's no confusion as the plural is quite obviously 'aerials'!
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