18-01-2016, 11:41 AM
(17-01-2016, 09:46 PM)Mark Hennessy Wrote: ... my favourites were the deep red/maroon body types from Piher. If you wish to indulge, see here: http://www.mds975.co.uk/Content/george_d...radio.html - page 39 is probably my favourite. The real book is better than the scans, naturally. Just lovely...
Interesting to note how the Piher carbon film types with their curved dog-bone shape are increasing diluted by the RS carbon composition ones with their more austere rectangular as the book progresses!
By the time you get to page 48 the Pihers are being overwhelmed by the RS types!
Interesting also the way that small capacitor values are expressed in ρF whilst the tuning cap is 0.0005µF ... I wonder how many kids visited their 'local radio dealer' for this item, as advised, and got the number of noughts wrong!
Come to that, how many local dealers would have stocked such items as solid dielectric variable caps and ferrite rods as late as 1972? By the time I left the trade in late '69 I'd built up an excellent range of components in my service department and a trade to match - woe betide my newsagent if my copy of the various magazines didn't land on my doorstep on the morning of publication so that I had some inkling of what unusual items the local schoolboys would be asking for in the afternoon* - or their mums the following morning! However, the demand for such capacitors, Repanco coils and the like had completely dried up by then and we were never asked for (or stocked) 'naked' ferrite rods!
* We stocked the full range of E12 resistor values in several ratings, of course, but E24 would have been too much, however, many of the magazine contributors obviously worked for the likes of Marconi where such values were often used. But I wished they could have used a bit of common sense in their designs. It was quite obvious that many values were based on quick mental arithmetic - collector load resistors in small signal circuits, for example, were invariably 10k but those that weren't were 5.1k. Why couldn't they have used 4.7k - after all, resistor component lists always stated ±20% tolerance!
