Monday 18 December, 2006, 11:46 - Radio RandomnessHere 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
What'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'.
The 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.
Tuesday 14 November, 2006, 08:52 - Radio RandomnessAaaaargh... 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!
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'!
Wednesday 8 November, 2006, 15:29 - Amateur RadioWhen I'm at home, my receiver is usually switched on monitoring one frequency or another, commonly 145.500 or the local 70 cm repeater. Yesterday I was doing the latter and it soon became apparent that there was some active tropogation around. In addition to my local repeater, other amateur repeaters from typically 300km distant were fading in and out with regularity. What I noticed, however, was that the audio for all these distant repeaters (and, mysteriously, the local ones too) was accompanied by a rather annoying crackle.
My first thought was that the coax cable feeding the antenna must have a dry joint in it somewhere and the gentle wind blowing it back and forth was causing an intermittent connection. But I checked reception of repeaters on 2 metres and these were clear of the crackling noise which indicated that the effect was real, and was being received right across the 430-440 MHz band.
The next port of call was the various items of household equipment that could cause such relatively focussed wide-band noise; thermostats, fluorescent lights, computers, vacuum cleaners and similar devices being the typical culprits. But wandering around the house with a hand-held UHF receiver, it soon became apparent that none of these were the problem, nor could the crackle now be heard at all on the local repeater, though it was still there on more distant stations.
Then I remembered the BMEWS radar at Fylingdales near Scarborough and Whitby on the North Yorkshire Moors. This operates from 420 to 450 MHz and is renowned for producing interference resembling a crackling sound right across this frequency range. Obviously the tropogation was carrying the BMEWS signal the 350 km across the UK to my receiver.
Having now heard the kind of noise that this early warning radar produces, it amazes me that radio amateurs anywhere in Yorkshire or Durham can use the 70 cm band at all, but apparently they do! But this isn't the only noisy noise that annoys users of this band.
On several channels (including repeater input frequency 434.600, 433.900, 433.525 and repeater output 433.050 MHz) in my area is the familiar buzzing of low-power, licence exempt data links. Such links are commonly used for cheap wireless devices such as weather stations, doorbells, key-fobs and more. According to Recommendation 70-03 of the European Radiocommunications Office (ERO), which details which frequencies must be made available on a licence-exempt basis in European countries, such links are free to use the frequency range 433.050 to 434.790 MHz (centre frequency 433.920 MHz) with powers of up to 10 mW. What a stupid range of frequencies to choose as this coincides with many 70 cm repeater output and input frequencies as well as common FM working channels SU20, SU21 and so on. One can only assume that someone at the ERO (an agency of CEPT) has it in for radio amateurs. Why not limit the range to, say, 434.000 to 434.500 MHz, frequencies which are rarely used.
Recommendation 70-03 largely prohibits the use of voice or audio signals in this sub-band, but that doesn't stop (cheap) equipment being produced that is capable of doing just that. And if cheap equipment is available, someone will buy it. Monitoring 433.925 MHz in my area yields what sounds like a wirless audio link being used to relay television sound from one room to another, as well as occasional walkie-talkie like conversations. But who is going to stop this equipment being used illegally like this? Ofcom? They can't even keep obvious spectrum miscreants such as pirate radio operators down, so they're unlikely to be bothered about people who are using voice in a non-voice band.
So can anything be done to recover the band for radio amateurs? Well the old adage 'use it or lose it' has never been more applicable. If the band were full of transmissions, the ERO would never have considered it for such low-power devices. But it's not too late. A good 20 Watt transmitter on 433.925 MHz should wipe-out key-fobs, freezer failure detectors and other mindless devices over a good few hundred or more metre radius. So next time you want to chat with a local amateur, why not go simplex on 70 cm on, say, 433.925 MHz just for the hell of it?! Antisocial? Me? It's legal. It's simple and it's worthwhile. See you on 70 cm then...
Wednesday 1 November, 2006, 16:47 - Radio RandomnessAs if this site isn't littered with enough useless information already, here's a load more. Having travelled to and from the various London airports on a number of occasions, I thought it would be nice to have an up-to-date list of the various air traffic control frequencies used at them (so that whilst en-route to the airport or waiting in the lounge I could tune-in to see exactly how delayed my flight is). Using the all-knowing Google proved rather confusing as lots and lots of differing lists appeared, so I decided to compile the lists together and then take a listen to see which channels were clearly active and which were now obsolete.
The results are posted below and only those frequencies heard to be active during random monitoring sessions in October 2006 are listed. The frequencies shown in italics were listed on a number of sites (sufficient to believe that they are for real) but monitoring showed that there was no activity, so they're listed just in case! All frequencies are in MHz.
London Heathrow Airport
Approach 119.725 134.975
Tower 118.500 (Departures) 118.700 (Arrivals)
Ground 121.900 121.700
ATIS 121.850 (Departures) 128.075 (Arrivals)
London Gatwick Airport
London City Airport
Other London Airports/Frequencies
Battersea Heliport 122.900
Thames Radar 132.700 (also used as Approach for London City Airport)
London VFR 125.625 (Visual Flight Rules)
London FIS 124.600 124.750 (Flight Information Service)
So there you have it. Together with a cheap airband scanner, you now have the knowledge required to depress yourself by listening in to flight controllers and discovering exactly how late your flight really is!