Book: From Crystal Sets to 405 Line TV

[evingar]

Hi Folks

I wrote the above a while ago. I offered it to the BVWS to serialise in the mag a while ago, and they did publish a few chapters, but I guess it was considered to "dry" in contrast to restoration stories (etc.) - which I can understand completely.

Anyway, it seems pointless to let it languish, so for what it's worth I have set up some Web pages containing it. The introduction page can be found here :-

http://evingar.www.idnet.com//radio_introduction.html

Apologies in advance for the lack of elegance, possible typos, omissions, heinous errors (etc etc) - It's a bit of a "text dump". When I get a round tuit, I plan to make it look nicer. Constructive comments will be gratefully received. I am happy to receive these either via the forum, PM or the email on the site.

[jim_jobe]

What a great effort Chris. Many thanks!
Jim

[chipp1968]

Very good Chris . I will go through it when i have time .

[ppppenguin]

Always good to have useful vintage information available on line. I've skimmed a few chapters, most of it is good sensible stuff but I've noted a few items that need attention.

In chapter 6 (safety):
...shorting negative to earth in this way...
should read
...shorting neutral to earth in this way...

Fig 6b doesn't really show an autotransformer. It's a double wound transformer with one side of the secondary connected to one side of the primary.

Mu Metal

This was frequently used to shield the line output stage of sets and to prevent x-rays from being emitted from the valve E.H.T rectifier. The metal should never be reworked as it may loose its ability to shield

Mu metal is a special alloy used for magnetic shielding. Ordinary steel is good enough for Xray shielding and does not lose this ability when reworked. In any case Xrays were only a problem on early colour sets and projection sets. In neither case was the EHT rectifier the main culprit. It was the shunt stabiliser in CTV, the CRT itself in a projection set.

[Aerodyne]

Hi Chris
Have you considered submitting this material to a suitable publisher? It would need expanding to 'full book' size plus some reworking but some of this expansion could be partly in the form of photographs and 'pen portraits' (of people, set makers, scientists etc). It reads well, so it is surely worth the effort and there's not much on the market at present - though to be fair, it isn't easy to assess the demand level of any such market.
-Tony

[f.cooper]

Hi,

Mu Metal

This was frequently used to shield the line output stage of sets and to prevent x-rays from being emitted from the valve E.H.T rectifier. The metal should never be reworked as it may loose its ability to shield

Was not Mu Metal used a lot in Radar equipment (what used to be called "Indicator units"), for instance type 62A adapted and used by many to construct either a TV receiver or even an oscilloscope. The main use was to shield the CRT from any magnetic fields or otherwise. Reworking this type of metal could destroy its properties.
I believe Jeffrey is quite correct about the shunt stabiliser ( PD510 etc ) in CTV.


Best Regards

Fred ( G0BYU )

[ppppenguin]

Originally Posted by f.cooper

Was not Mu Metal used a lot in Radar equipment (what used to be called "Indicator units"), for instance type 62A adapted and used by many to construct either a TV receiver or even an oscilloscope. The main use was to shield the CRT from any magnetic fields or otherwise. Reworking this type of metal could destroy its properties.
I believe Jeffrey is quite correct about the shunt stabiliser ( PD510 etc ) in CTV.

Mu metal is indeed used to shield CRTs in 'scopes and elsewhere. Also sensitive transformers such as microphone matching types. It is very sensitive to work hardening.

The classic UK shunt stabiliser used in TVs such as the Decca CTV25 was the PD500. http://www.r-type.org/exhib/aah0027.htm

[f.cooper]

Hi Jeffrey,
Sorry about quoting PD510 instead of PD500, I thought it was PD500 but looking through 1979/80 Mullard Data Book could only see PD510, should have taken more trouble and looked at an earlier Data Book (1970 etc).

[evingar]

Hi Guys

Thanks for the feedback.

Jeffrey, I will change the items that you have highlighted when I get a moment - thanks.

Tony, when I originally wrote it, I did approach a number of publishers. A couple liked the material, but their market research showed that the target audience was too small. It may be worth trying again at some point.

[chipp1968]

Yes worth trying to publish .I would be interested in books written this way.Certainly for me ,stuff simply worded is easy to read and more likely to sink in than standard book format. I just cant follow it especially the sudden use of equations with in the first paragraph is a total switch off for me unfortunately , which is why I have not been able to learn repairing from a book as yet.

[Aerodyne]

Tony, when I originally wrote it, I did approach a number of publishers. A couple liked the material, but their market research showed that the target audience was too small. It may be worth trying again at some point.

Unfortunately the market is small and probably grows smaller. I published two books myself. An earlier book was taken on by First and Best but they wouldn't be interested in this type of material. Crowood Press commissioned and published my 'Vintage Radios' book but this was written to order, i.e. it was intended as a collector's guide and I was under orders not to delve into technicalities (other than broadly!)

Newnes/Butterworths - or whatever they call themselves these days - might possibly be interested. Otherwise, you could self-publish but be warned from one who knows; you will not be retiring on the proceeds. I certainly didn't but in truth that was never my aim. In the end I covered all costs and that's probably the best you can hope for.

If you think I might be able to offer any advice about the issues above, feel free to PM me.

-Tony

[G8HQP Dave]

you will not be retiring on the proceeds

I can second that. I once edited a book for Newnes, as the author (Joe Carr) unfortunately died shortly after submitting the manuscript but his widow was happy for publication to proceed. I did the sort of work that the author usually does to knock a bare manuscript into shape for publication. It took me about a month in total. Total royalties to date (about 8 years) roughly correspond to a couple of weeks consultancy fees. You have to pen a best-seller to make any money out of being an author!

However, there is still the non-financial reward of having added to the sum of accessible human knowledge.

[G8HQP Dave]

A couple of points: In Ch 2 you need to mention getters, then you can include white getter as a valve fault when someone has let the vacuum out. In Ch 3 you can use RC coupling up to video frequencies, not just audio. Superhet is an abbreviation of supersonic heterodyne - super heterodyne is not a name normally used?

A general point is to define terms before using them (e.g. potential - where would a new reader discover that this means the same thing as voltage?). Sneaking in calculus terminology (e.g. dVa/dIa) might be a problem for readers who struggle with algebra, but this raises the general issue of how do you explain something which requires maths to people who don't understand maths? I don't have an answer to that one! Incidentally, dVa is not the rate of change of Va (that would be dVa/dt) but an infinitesimal change in Va.

[AlanBeckett]

Originally Posted by G8HQP Dave

.... has let the vacuum out.

Can you let a vacuum out?

Isn't that the same as saying letting the cold in?
The flow is always in one direction - high pressure to low, hot to cold, high voltage to low etc.

Alan

[G8HQP Dave]

Originally Posted by AlanBeckett

Can you let a vacuum out?

Isn't that the same as saying letting the cold in?
The flow is always in one direction - high pressure to low, hot to cold, high voltage to low etc.

Alan

I bet you are a blue smoke denier i.e. you don't believe that components contain a magic blue smoke which enables them to work. When released, typically by sudden overheating, components stop working.

[AlanBeckett]

I still support the Phlogiston theory, flat earth, Aether, transmutation ....
My mother would always say 'shut the door, you'll let the cold in'. I could never persuade her that it was the other way round.
Alan

[murphyv310]

Originally Posted by AlanBeckett

I still support the Phlogiston theory, flat earth, Aether, transmutation ....
My mother would always say 'shut the door, you'll let the cold in'. I could never persuade her that it was the other way round.
Alan

Em !!!!!!!!!!! Perhaps Mummy may have had a point!

[evingar]

Originally Posted by G8HQP Dave

A couple of points: In Ch 2 you need to mention getters, then you can include white getter as a valve fault when someone has let the vacuum out. In Ch 3 you can use RC coupling up to video frequencies, not just audio. Superhet is an abbreviation of supersonic heterodyne - super heterodyne is not a name normally used?

A general point is to define terms before using them (e.g. potential - where would a new reader discover that this means the same thing as voltage?). Sneaking in calculus terminology (e.g. dVa/dIa) might be a problem for readers who struggle with algebra, but this raises the general issue of how do you explain something which requires maths to people who don't understand maths? I don't have an answer to that one! Incidentally, dVa is not the rate of change of Va (that would be dVa/dt) but an infinitesimal change in Va.

Thanks for the specific comments Dave - duly noted.

WRT the general observations, my intention was that the diagrams would make the text clear. From conception, the purpose of the book was to guide someone with little or no knowledge of electronics to attempt the restoration of vintage equipment. In line with that I have tried to keep the use of mathematics to a bare minimum. I would not expect anyone to attempt to design with the information given. There are a host of excellent text already available on that subject of valve technology theory and also texts that give a much more rigorous treatment of the subject, but with an (arguably) less novice friendly style and scope.

As an example of the former I would refer people to the Admiralty "Handbook of Wireless telegraphy" and the latter one of Mr. Millers books. I would recommend both if the reader feels they want to take theory further, but I would hope my effort would be sufficient for someone, not especially interested in theory pe-se, to repair elements of their collection.

Originally Posted by AlanBeckett https://www.vintage-radio.net/forum/...s/viewpost.gif
I still support the Phlogiston theory, flat earth, Aether, transmutation ....
My mother would always say 'shut the door, you'll let the cold in'. I could never persuade her that it was the other way round.
Alan

Em !!!!!!!!!!! Perhaps Mummy may have had a point!

Both may be right if dense cold air entered at the bottom of the door way and hot air exited from the top

[Herald1360]

I have come across "let the vacuum up" which is sort of correct, but letting the vacuum out is more fun!

[wireful3]

Just to pass the time:- letting vacuum out brings electrons and holes to mind, though the book is clearly not intended to cover this sort of stuff.

When a valve leaks, then the pressure outside is reduced - not very much - so I reckon there is nothing wrong in saying let the vacuum out. Similarly for letting cold in.