Saturday, 25 June 2016

Don't be scared of the scrap

Ive been doing a bit of skip-ratting recently. The main purpose of this is to womble up some more sheet aluminium. 19" rack mount equipment will often yield at least one nice big sheet of aluminium, or sometimes galvanised steel, from the covers. All very useful for making boxes and chassis for projects.

Most of the 19" racks units I end up with these days are, even when nominally of 'radio' equipment, digital beasts inside. And almost invariably all SMT! You might think that such things would be of little use in amateur radio.

But thats not the case. Take just one of these units, a now obsolete MPEG2 encoder. Lets take a 'walk' around the unit...

Theres a filtered mains input socket, lots of 75ohm BNC sockets, D type sockets, lots of push buttons and LEDs on the front panel, a very nice big backlit LCD unit. Hundreds of ceramic and electrolytic SMT capacitors, various crystals and crystal oscillator modules, voltage regulators, EMC filters.  On the boards there are SMT ICs that are useful - dual op-amps, SMT fuses and holders, latching relays. There are also numerous broadband RF transformers. So, just because its essentially a load of VLSI digital chips, theres still plenty of parts of use in old fashioned analogue radio building. And, of course, the hardware - M3 nuts, bolts, washers and spacers. Ali sheet, some plain, some perforated. Theres of course very useful high power and EMC clean SMPSUs, theres cooling fans, heatsinks, and connectors. Even some lengths of coax and ribbon cables.

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