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I'm developing an open source mini radio transmitter, and need hackers/makers/designers/users to help me to do it! And preferably a radio electronics whizz too.
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0.24 testing: my experience
From what I’ve heard, the testers have received their kits and are underway with hacking. We made use of my 0.24 prototype over christmas, with some mixed results -
Used it at first to transmit sound from my brother’s laptop to the living room stereo. Whereas the sound from the laptop is tinny and quiet, it seems the signal from Niftymitter is too much the other way – quite bassy, which isn’t a great problem except that it seems to clip distort quite easily when things get a bit bassy in the TV soundtrack (we were watching James May’s Lego programme on the laptop).
Also tested it at a greater distance, from the first floor, transmitting a mp3 recording to the radio in the kitchen, and transmitting a digital radio programmed from the kitchen to the living room, distances of 10 – 15m I would guess. There seems to be very little interference in my house, which is a victorian brick building. So better range than I had in the college building in Dundee (modern concrete all the way). The other problem with doing things over a longer distance was with levels: The transmitter requires only a very low signal level, so I generally turn the volume right down on the source, make sure the receiver is tuned in correctly and then gradually raise the source level to an acceptable level. However, when the two are separated by a stair case and several corridors, it soon gets annoying adjusting levels between the two. It would be great if the transmitter automatically reduced the level to just the right volume for transmitting.
So most of the time the transmitter was just sitting next to the source (radio/laptop/PC), and didn’t call for any adaptation that I could think of – basically a passive object, although handy to be able to see the on/off light. I still am a little unsure about the orientation of the unit. i generally like to have it standing up on its end, but its not particularly stable like this, with the cable pulling it over. For these uses, it would be great if the unit was heavier, or had rubber feet or similar to stop slipping. The inaccuracies in the cardboard construcation are still irritating, the slight bulge of the sleeve comoponent making the object a bit unstable on a surface again.
The biggest problem for me however, and I know for one other tester, is in retuning the transmitter. I took delivery of some trim tools from Rapid that reduce the effects of interference of touching the trim cap with a metal screwdriver blade, but curiously, there was still some intereference. So I had to play with the radio receiver to see what the offset was when using the trim tool and then account for that when retuning. Not good. The point was, once I got the transmitter down to Lancashire, radio 2 was very strong on the freq the transmitter was tuned to, so, not wanting to interfere with it, wanted to retune. At first i thought this isn’t something one would want to do often however, you would have to do it whenever you moved the transmitter a significant distance across the country! I think some kind of permanent dial, perhaps glued onto the trimcap, would be a great improvement..
Sorry there are no photos, will remedy next time. So a few of the problems are electronic there, which I can’t do much about, but some nice mechanical issues too. Will put them in as issues on the google code project, but will be intrigued to find out what other peoples’ experiences are.