what I have learned today.

[Kim]

Right enough, I ran into SWG around 65 years ago, making a coil for a crystal set. 3" former and N hundred turns.

I'm fairly sure (as sure as you can be after >50 years) that SWG was specified in Ladybird book instructing brother how to build a transistor radio...

Second mention of that book in a couple of weeks. lkingscott, from the hardcore brompton fettling thread, said it was a childhood influence.

I had it too. OC71. Jumpers for goal posts.

Online version here: https://worldradiohistory.com/BOOKSHELF-ARH/Technology/Making-a-Transistor-Radio-Ladybird%20Books-1972.pdf

Cor, PNP.  You oldies did everything standing on your head...


I molished a crystal set with a germanium diode and a bog roll tube when I was a small, but transistor radios were mostly something you took apart rather than built from first principles.  Closest I got was the now legendary Tandy 75-in-1 project kit, with those ghastly coil spring connectors that made it more of a lesson in carefully following instructions than actually understanding electronics.

[MattH]

I remember that book. I didn't realise it was written by the Rev George Dobbs, G3RJV, though he was a very prolific author of QRP (low power) radio books.

[Clare]

This morning I have purchased an SWG.

[T42]

Cor, PNP.  You oldies did everything standing on your head...

I loved valves, hot-cathode ones in particular.  I could perfectly imagine the electrons boiling off and zooming across the vacuum to impact on the anode, and the dastardly grid trying to waylay them halfway.  You could write adventure stories based on that.  Transistors, bleh, nasty little knobby things and we were supposed to believe there were holes moving round inside them.  The only positive hole I could envisage was between the ears of the pervert who dreamt that one up.

[Kim]

Yes, well, I never really encountered those JFET-with-a-pilot-light things until I was old enough to know better...  Shame really, as you say there's something about being able to see what's going on...

[Diver300]

What about compass for use on the equator?

IGMC

Good question! The deeper I look into the compass question, the more interesting it gets. It appears that compass manufactures consider three zones: northern, southern and equitorial. Presumably the "equitorial" versions do not have any bias weighting at either end of the needle.

It is all rather accademic since Silva do what they call "global" models (for use in both hemispheres) for about £60.

I'm pretty sure that compasses as used in the yachting world are made differently (in some way) if being used in high latitudes, something to do with the magnetic field applying less torque to the needle (or something).

Once you get into large boats, the magnetic field of the boat has to be compensated for, allowing for all directions of the boat may be pointing, as well as a wide range of angles of heel. I think it's witchcraft, personally, but apparently science and not incantations are used in making binnacles. https://en.wikipedia.org/wiki/Binnacle

Add into that the problems of the changing inclination of the earth's magnetic field, and I can see the whole process being very difficult.

[T42]

Yes, well, I never really encountered those JFET-with-a-pilot-light things until I was old enough to know better...  Shame really, as you say there's something about being able to see what's going on...

Confession: during exams involving transistors I did all the thinking in valvish then translated it to transistorish to write the answers.

[PaulF]

I'm trying to remember if I've knowingly come across SWG for actual wire.  Normally it's either AWG for the small stuff, or - more sensibly, because it's the value you're most likely to need for strength or resistance calculations - the cross-sectional area is quoted in square millimetres.

I've come across it when specifying enameled copper wire for building ferrite rod antennas.

(The Ladybird Book 'Making a Transistor Radio' uses 50 turns of 36 SWG on a 3/8" ferrite rod...)

I built that radio! Don't think I finished all the stages but IIRC you started with a crystal set then added a transistor and then more transistors but each stage left you with a working radio

[Zipperhead]

I have learnt two things already today, and frankly I'm not sure which is most disturbing.

The first is that one man, Thomas Midgley Jr., is responsible for the invention of both leaded fuel and CFC's (Freon). If there's an Oppenheimer scale then he's got to be right up there.

Oh, the other thing?

Gwyneth Paltrow is shooting ozone up her but for the sake of "wellness"

[Mr Larrington]

Paltrow wins that one pants hands down.

[pcolbeck]

That if you suspend a stretched slinky vertically in the air then release the top the bottom of the slinky stays suspended in mid air not moving until a lot of the slinky has compressed again. The centre of mass of the entire slinky falls at 9.8 m/s/s but the bottom spends a relatively long time hovering in mid air. Quite a lot of non intuitive physics going on with several interpretations of what's happing out there.

Nice slow mo film of a huge slinky falling:

https://youtu.be/JsytnJ_pSf8

[Feanor]

You lot probably all know this, but...

Kings Cross has a platform zero.

[Basil]

You lot probably all know this, but...

Kings Cross has a platform zero.

As does Cardiff Central.

Eta.  It also has no platform 5, although there are platforms 6, 7 and 8

[Kim]

You lot probably all know this, but...

Kings Cross has a platform zero.

As does Cardiff Central.

And Stockport.


Actually, I bet someone's made a list on Wikipedia....
There we are: https://en.wikipedia.org/wiki/Platform_0

Wonder if anywhere has a Platform -1?

[bhoot]

I was about to add Gravesend having caught a train there last weekend!

[hatler]

What about compass for use on the equator?

IGMC

Good question! The deeper I look into the compass question, the more interesting it gets. It appears that compass manufactures consider three zones: northern, southern and equitorial. Presumably the "equitorial" versions do not have any bias weighting at either end of the needle.

It is all rather accademic since Silva do what they call "global" models (for use in both hemispheres) for about £60.

I'm pretty sure that compasses as used in the yachting world are made differently (in some way) if being used in high latitudes, something to do with the magnetic field applying less torque to the needle (or something).

Once you get into large boats, the magnetic field of the boat has to be compensated for, allowing for all directions of the boat may be pointing, as well as a wide range of angles of heel. I think it's witchcraft, personally, but apparently science and not incantations are used in making binnacles.https://en.wikipedia.org/wiki/Binnacle

Add into that the problems of the changing inclination of the earth's magnetic field, and I can see the whole process being very difficult.

I've been aboard a couple of craft where they've swung the compass. Fascinating task (even if I didn't really understand how they do it).

I think I recall our doing this on a 34' plastic yacht after a new engine fitment, but I could be wrong.

[yorkie]

You lot probably all know this, but...

Kings Cross has a platform zero.

As does Cardiff Central.

And Stockport.


Actually, I bet someone's made a list on Wikipedia....
There we are: https://en.wikipedia.org/wiki/Platform_0

Wonder if anywhere has a Platform -1?

Not yet*, but if the tentatively proposed work to install 2 new platforms on the north west side of Leeds station** goes ahead, they could well be -1 and -2.


* In the UK - other jurisdictions may differ!
** Next to platform 0

[JellyLegs]

There a video on YouTube about visiting all the Platform Zeros in one day by train. https://youtu.be/TTHOyTypNs8.  Don’t ask why I found that interesting.  For some reason I find most of Geoff Marshall’s videos fascinating which is odd as other than that I have no interest in trains or railways.

[Basil]

You lot probably all know this, but...

Kings Cross has a platform zero.

As does Cardiff Central.

And Stockport.


Actually, I bet someone's made a list on Wikipedia....
There we are: https://en.wikipedia.org/wiki/Platform_0

Wonder if anywhere has a Platform -1?

Not yet*, but if the tentatively proposed work to install 2 new platforms on the north west side of Leeds station** goes ahead, they could well be -1 and -2.


* In the UK - other jurisdictions may differ!
** Next to platform 0

Don't know about -1 & -2. I reckon A & B is more likely.

[yorkie]

You lot probably all know this, but...

Kings Cross has a platform zero.

As does Cardiff Central.

And Stockport.


Actually, I bet someone's made a list on Wikipedia....
There we are: https://en.wikipedia.org/wiki/Platform_0

Wonder if anywhere has a Platform -1?

Not yet*, but if the tentatively proposed work to install 2 new platforms on the north west side of Leeds station** goes ahead, they could well be -1 and -2.


* In the UK - other jurisdictions may differ!
** Next to platform 0

Don't know about -1 & -2. I reckon A & B is more likely.

GPWM

Given it's that side of Leeds, they could well be 00 and 000 (or absolutely anything else for that matter!) 

Of course, Network Rail could have persuaded the DfT to pay for a full re-signalling of the Leeds area by then and the station renumbered as platforms 1 to 20! (Was that a porcine aviation squadron I just saw fly over??) 

[ian]

I have learnt two things already today, and frankly I'm not sure which is most disturbing.

The first is that one man, Thomas Midgley Jr., is responsible for the invention of both leaded fuel and CFC's (Freon). If there's an Oppenheimer scale then he's got to be right up there.

Oh, the other thing?

Gwyneth Paltrow is shooting ozone up her but for the sake of "wellness"

There's nothing our Gwen won't shoot up her butt. You don't want to be stuck in a lift with her. It's probably dark up there.

Midgley is famous for that double misfortune. He didn't know about CFCs, but it was well-known that organic lead was poisonous and adding it to petrol was really a very bad thing. He died when he got caught up in the mechanism of his own device designed to get him out of bed (he had been left severely disabled by polio).

[robgul]

When you buy plywood, chipboard, OSB etc from B&Q or other timber supplying emporia the items usally have a sticky label placed in the middle of the sheet - with glur of the "shit to a blanket" variety . . .

I've discovered, courtesy of YT, that gentle heat from a heat gun (or even a hairdrier) and gentle scraping eases the label from the surface leaving minimal glue residue which can then be gently sanded away.

[T42]

Possibly works on other items too - hardware, crockery etc.

[rafletcher]

That there is a 5000 mile wide “blob” of Sargassum seaweeds stretching from Africa to the Caribbean. And that it can wash ashore in drifts 2m high, emits Hydrogen Sulphide and contains Arsenic.

[T42]

That there is a 5000 mile wide “blob” of Sargassum seaweeds stretching from Africa to the Caribbean. And that it can wash ashore in drifts 2m high, emits Hydrogen Sulphide and contains Arsenic.

A few years ago the H2S from washed-up seaweed killed a horse in Brittany.