From: bill.sloman@ieee.org   
      
   On 2/01/2026 7:53 pm, Liz Tuddenham wrote:   
   > Bill Sloman  wrote:   
   >   
   >> On 1/01/2026 4:35 am, Liz Tuddenham wrote:   
   >>> Bill Sloman  wrote:   
   >>>   
   >>>> On 1/01/2026 12:39 am, Liz Tuddenham wrote:   
   >>>>> Bill Sloman  wrote:   
   >>>>>   
   >>>>>> On 31/12/2025 8:31 pm, Liz Tuddenham wrote:   
   >>>>>>> Bill Sloman  wrote:   
   >>>>>>> [...]   
   >>>>>>>   
   >>>>>>>> Driven shields have been around forever.   
   >>>>>>>   
   >>>>>>> Since the mid 1930s, invented by Blumlein.   
   >>>>>>   
   >>>>>> I worked at EMI Central Research for a couple of years (1976-1979), but   
   >>>>>> I'd heard of the Blumlein bridge even before that.   
   >>>>>>   
   >>>>>> https://en.wikipedia.org/wiki/Alan_Blumlein   
   >>>>>>   
   >>>>>> He died at age 38, and had his name on 128 patents. The IET has   
   >>>>>> published a biography, but it doesn't do him justice.   
   >>>>>>   
   >>>>>> "The Life and Times of A.D. Blumlein" by Russel Burns ISBN 0 85296 773 X   
   >>>>>> and 978-0-85296-773-7   
   >>>>>   
   >>>>> That is an excellent book - but be aware there is another book with a   
   >>>>> very similar title which is a complete load of rubbish.   
   >>>>>   
   >>>>> I was priviledged to have met Alan Blumlein's son, Simon, on several   
   >>>>> occasions and chatted to him about his father.  Simon died about a year   
   >>>>> ago; he was a lovely character with a similar sense of humour to his   
   >>>>> dad.   
   >>>>   
   >>>> I envy you the personal acquaintance.   
   >>>   
   >>> I was very lucky.  Simon Blumlein was a patron of the City of London   
   >>> Phonograph and Gramophone Society and he attended their AGMs (and spoke   
   >>> at some of them).  I happened to see him killing time before the evening   
   >>> meal and we fell into conversation.  After that, we often had a quick   
   >>> chat when time permitted.   
   >>>   
   >>> I managed to record two of his talks, one on his researches into his   
   >>> father's life and the other on his own life (he was deeply involved in   
   >>> optical design, loved a wide range of music and was also a ballet dancer   
   >>> in his spare time!).   
   >>>   
   >>>   
   >>>> I wasn't all that impressed by the   
   >>>> book. I don't think the author knew much about the electronics that   
   >>>> Blumlein worked on (few people do - he worked in a lot of different   
   >>>> areas) and it struck me as rather superficial in consequence.   
   >>>   
   >>> I thought the IET book wasn't too bad, are you sure that was the book   
   >>> you read?   
   >>   
   >> It's on my booKshelf and I posted both it's 10 and 13 digit ISBN numbers.   
   >>   
   >>> The other Book (whose name I have forgotten) was much much worse.  The   
   >>> author knew less than nothing about electronics or anything remotely   
   >>> scientific i.e. he thought he understood but obviously didn't have a   
   >>> clue.  For the benefit of less expert readers than himself, he provided   
   >>> explanations of the technical details in pseudo-scientific gobbledeygook   
   >>> using technical terms he had read in the source material but clearly   
   >>> failed to understand.   
   >>>   
   >>> It is one of the few books I have read where the author has added   
   >>> negative value to his source material.   
   >>   
   >> The Russel Burns book wasn't that bad - it was just weak on the   
   >> technical content.   
   >   
   > Yes, the technical content in Russel Burns' book wasn't too deep but it   
   > was accurate and logical - unlike the other book which went into great   
   > detail and got it wrong.   
   >   
   >> I've just re-read the last chapter, on the H2S radar whose flight trial   
   >> killed Blumlein, and the technical analysis doesn't go deeper than   
   >> distinguishing between klystons and magnetrons. It's remarkably superficial.   
   >   
   > Similarly the section on Blumlein's improved recorder isn't very deep.   
   > In fact almost any book which attempted to cover all of Blumlein's   
   > inventions would have to draw a line somewhere, otherwise it would   
   > become completely unwieldy.   
      
   That's where you need an author like Tracy Kidder, who can capture some   
   of the complexity without losing the reader's attention.   
      
   > I have read his notes (elsewhere) on the design of the cutterhead   
   > equaliser, it took me several days to understand the way he was thinking   
   > about it.  He eventually gave up the detailed analysis and basically   
   > said "I'm not sure exactly why, but it just works".   
      
   Empirical assertions, backed up by thorough analysis, can be convincing.   
   Before modern computers, numerical analysis ran out of puff pretty quickly.   
      
   Well constructed experimental tests can explore the edges of the   
   performance limits in an informative way.   
      
   --   
   Bill Sloman, Sydney   
      
   --- SoupGate-DOS v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)