Source of BRIGHT red LEDs

Some have asked me what LEDs I've been using so far for my optical experiments. Well, these are 10mm diameter "conventional" style LEDs from a source in Hong Kong. They are 1W devices capable of 280000mcd output and look like a normal LED on steroids in that they come in a standard looking clear package with 2 thick leads.

They are available via eBay at £9.30 for 10 off from Hi Tech LED World.  The supplier delivers promptly and with good packaging (and a nice collection of attractive stamps on the package). They also have a range of other devices available.

Use the link http://www.ebay.co.uk/itm/350347623711 .

As mentioned before, I also have some even more powerful LEDs called Phlatlights which are intended for overhead projectors. I've still to fire these up. These are about 10dB more powerful than the 1W LEDs, so are potentially dangerous.

More optical comms tests

A few days ago I received some 10000mcd 5mm "high brightness" Toshiba TLSH180P LEDs from Maplins.  Today I did some tests without optics using these. Still using just my NE555 1kHz oscillator output directly driving the LED the signal is considerably brighter. It should be some 10dB better than the high brightness LED used before. Using the Toshiba LED both as TX and (unbiased) RX detector the signal could be detected over a range of around 20m in daylight. The beamwidth of the LEDs is narrower (8 degrees) so aiming is quite critical. Further may well be possible with very careful beam alignment.

So, with 100mm lenses at each end (24dB minimum gain each) 5km should be possible and maybe up to 20km.  Progress on the full FM/SSB systems has slowed as Christmas approaches with other activities taking priorities in the family, but the 481THz work is my main priority ham radio-wise.