The amazing development of electronics over 50 years.
(A republication of a post first shown on the 13th August, 2009)
The calendar reliably informs me that this is my 65th year. My brain, of course, lags somewhat in accepting this!
My step-father during my early teenage years worked for Elliott Brothers (the link goes to an interesting history of the firm that started in 1804) in Borehamwood, just north of London. He encouraged me to fiddle with ‘steam’ radios and
try and understand how these basic circuits worked. It was then a small step to deciding to become a radio amateur, popularly known as a radio ham! In those days it was a case of some pretty intensive studying to pass a Theory exam as well as being able to pass an exam in sending and receiving Morse code.
So joining the local radio society seemed like a sensible idea. That was (and still is!) called the Radio Society of Harrow. That it is still in existence after all these years is truly delightful. Those Friday night sessions at the Society and extra-curricular classes on Sunday morning at Ron Ray’s (G2TA) house, an hour’s bicycle ride away from home, ensured that shortly after my 16th birthday I was granted a Licence, G3PUK. It was a very proud moment.
Anyway, once granted a licence it was time to build my own radio transmitter. Most of the details have been lost in the mists of time but what is recalled was that the final amplifier was a pair of 803s driving an 813 (These are radio valve numbers). It sounds like something from the ark! But again ploughing the inexhaustible files of the Web, it’s possible to see what these radio valves looked like. Thanks to the National Valve Museum.
Here are pictures, courtesy of the National Valve Museum of those two radio valves:
803 – The substantial wide glass tube envelope is 58 mm in diameter (2 1/4 in) and, excluding the special five pin base pins, is 216 mm tall (8 1/2 in).
813 The classic envelope is substantial at 60 mm diameter (2 1/3 in) and 170 mm (6 2/3 in) long excluding the special base pins. The anode is 53 mm long and 48 mm wide. The metal is 1 mm thick.
It’s difficult, today, to imagine devices which are essentially diodes (well, technically the 803 was a pentode and the 813 a tetrode) being between 6 and 8 inches tall!
My own self-build transmitter had not really been successful emitting more heat than light, so to speak. Literally, in the sense that these large radio valves kept me warm in my converted garden shed at the bottom of the garden. They also completely wiped out TV reception for those households with a 1/4 mile range that had invested in early television sets! It was time to move on to the R1155.
Around this era, less than 20 years after the end of the War in Europe in 1945, war-surplus equipment was widely available including ‘compact’ transmitter-receiver units.
One popular one was the RAF R1155 which had been fitted to RAF Lancaster bombers and RAF marine craft. It was also fitted to the Sunderland flying boat. This information plus the photos below is from this fascinating web site for those wishing to be ‘geeky’ about this.
Just compare the view on the right to the inside of your domestic radio or your cell phone.
A lot happens in 50 years!
My personal journey now leaps to 1978 and I have just left IBM UK having had 8 fabulous years with them as an Office Products salesman. My fledging company, Dataview Ltd, has just become the 8th Commodore Computer (CBM) dealer in the UK, based in a small office in Colchester, Essex, about 50 miles north-east of London.
The CBM PET (Personal Electronic Transactor) released in 1977 initially with a calculator type keyboard was useless for any business application but soon came out with a typewriter sized keyboard, making it a more viable business
machine. Today, as this is typed on an ‘old’ laptop with 2GB RAM, it seems unbelievable that these CBMs were sold with between 4k and 96k of RAM (memory) and no hard disk, although one could purchase an add-on that comprised dual 5 1/2 inch floppy disk drives.
YouTube obligingly finds a short video on the Commodore PET for those really wishing to enjoy the nostalgia!
So to turn to the 21st century and to run out of understanding. We appear to live in a world of multi-later printed circuit boards of unimaginable (to me) component density, assuming that the word ‘component’ is even relevant today.
What an amazing period it has been!
Now let me see was it Pin 920 to Pin 140, or Pin14 to Pin 860 connected to Pin 56 ………?