Monday, 27 January 2014

Making with MeSquares

Having been directed to come directly home after work, instead of getting my few jobs done, because Tom wasnt feeling  too good, I decided i'd get the two-tone generator built. To accomplish this I decided to use some of QRPme's 'MeSquares', these are 5mm pre-etched and tinned little squares of PCB material, which are superglued down to a larger piece of plain PCB in Manhattan Island style construction. My board was cut to fit into an Altoids tin, along with a PP3 battery

I slightly mucked up my parts layout, which resulted in a more 'circular' arrangement of the 10nF capacitors, but both oscillators did work first time. Although when measured on my frequency counter the actual frequencies were a bit off what I wanted. I changed the 3k3 resistors in one side for 2k7's to change the frequency a little

Once tested, Installation into the Altoids tin began. I didnt bother seriously measuring things here so its all a bit of a squeeze, and the holes are rather rough. A phono socket was selected for the output. Both the phono and the level control pot will need gluing in place as they were originally PCB mount types. A bit of foam or velcro will be needed to keep the battery in place.

Whilst trying to get the LED into its bezel, there was an immense sound of jet engines, a rush outside revealed the culprit - a Typhoon (or possibly an F18?), a scan of the UHF airband, hoping to turn up an active air defence exercise, failed to do so, but instead picked up, albeit rather weakly, a training sortie by the Red Arrows!

Rather unfortunately though, as I was soldering the power wiring, I found the solder wouldnt melt. My soldering iron element has failed! To be fair that 18w Antex iron has served me very well, ive had it for about 20years! A replacement is on order, this time a 25w iron. I could possibly complete this job with my 40w iron, but its an el-cheapo and suited more to plugs and cable than component level work.

All the while, ive had the DX-70 sat on 10m PSK-31. 10m looks to be rather dead today, although for a brief moment part of a QSO was decoded that clearly hinted at an Isreali origin.

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