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This is a question The best thing I've built

Wehttamman asks: My dad and I once built a go-kart from chipboard, pram wheels and an engine from a lawn mower. It didn't work... so tell us about your favourite things you've made, and whether they were a triumph or complete failure.

(, Thu 11 Oct 2012, 12:00)
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meccano and a broken radio controlled car
I made a radio controlled bedroom door opener at the age of 12, as I was too lazy to open and close my bedroom door.

I also was interested in radio about that time and realised using my Chinese walky talkies and a copper wire attached to the telephone poll at the end of the garden, which was wrapped around the aerial of the walky talky, would extend the range..I lived on top of a big hill.. my friends and I could run a pirate radio station from my bedroom and destroy what everyone was listening to around the classic fm range..within a certain distance of my house..hahaha until a neighbour complained...

I worked as a technician for the NEC in B'ham for a while and everything we had to make there was held together with gaffer tape or ratchet straps.. most things generally only survived a few hours. Best thing i made there in down time over the summer when we were meant to be doing repairs was A cross bow, also a hover craft.
(, Sat 13 Oct 2012, 0:59, 6 replies)
This is the kind of story I had in mind when I suggested this QOTW
(, Sat 13 Oct 2012, 2:25, closed)
How exactly did you amplify a 100MHz FM transmission with a random wire antenna?
I don't want to call bullshit or owt but even a basic grasp of how RF works suggests that this is ... unusual.
(, Sat 13 Oct 2012, 13:59, closed)
If it's not resonant...
... it'll radiate pretty well along its length. So if you're within about 20-30m of the wire you'll have a good strong signal.

If you want to go any distance you want the aerial to be resonant. There's a whole bunch of stuff that involves fiddly stuff with Maxwell's equations that explains all this, but I'm not in the mood for maths.
(, Sat 13 Oct 2012, 15:34, closed)
If you're tired of maths you're tired of life.

(, Sat 13 Oct 2012, 16:18, closed)
all i know and remember
back then was wrapping around the end of the wire around the antenna, the wire ran out to the top of a telegraph poll at the end of the garden and the range of the walky talky was bigger.. who the hell knows it worked and i got in trouble...that's all that matters as I pissed off Mr Brian who listened to classic fm in his shed, as he complained to my mum that all he could hear was me and my friends over his radio... awaits backlash for annoying shed owners...
(, Sat 13 Oct 2012, 20:14, closed)
Two way radios don't transmit at the same frequency as FM broadcasts.
And the thing you wrapped wire around would have been the outside of a coaxial antenna. I don't know what you think you did, but you definitely didn't talk to the radio in Mr Brian's shed. Soz for being a spoilsport.
(, Sun 14 Oct 2012, 15:26, closed)

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