On Sat, 02 Jun 2018 02:08:15 +0100, Rod Speed wrote:



"Brian Reay" wrote in message
news
On 01/06/2018 18:13, Graham. wrote:
On Fri, 01 Jun 2018 16:21:19 +0100, Graham.
wrote:

This is what I think of as a magnetron, as used in conventional
microwave ovens with a turntable:
http://www.hokuto.co.jp/eng/products...dex_img_01.gif
It's about the size of a fist. So how do they make them flat under
the food cavity in flatbed ovens? Does the magnetron sit under there
and is redesigned to be flat? Or is there some kind of fancy rotating
waveguide, and the magnetron sits at the side as before?


Basically the later I should think.

The one I had in the 1980s had a large aperture covered with mica on
the roof of the cooking cavity. The Magnetron was at the side of the
cavity with a brass wave guide leading up to the top. A squirrel-cage
fan blows air up the wave guide and not only cools the Magnetron, but
also rotates a paddle-wheel at the top, a rotating antenna, carrying
multiple reflectors thar distribute the radiation throughout the
cavity. I imagine modern bottom entry ones do a similar trick, but I
have yet to work on one.

I didn't realise they were available in 1980. So why aren't they all
like that? Does it add a lot to the price?

The one we had is in the last illustration on this page

https://www.photomemorabilia.co.uk/P...iterature.html

I've still got the 170 page hard-back cookery book.


That looks quite a sophisticated one for the early 80s. We bought one
around 1981 and it had just a simple turn and 'run back' timer. It did
last about 17 years, with only a couple of O rings in the turn table
drive. We only disposed of it as it started to look tatty.

I'm still using the Sharp I bought in 73 almost every day.

It does have a proper electronic control and display.

Never had to do a thing to it.

Corse now it will curl up and die and it will be your fault.

Whatever happened to Sharp, they still seem to be in business, but I haven't seen anything made by them for a decade or two.

--
Mr Churchill is reputed to have once said
"It will be long, it will be hard, and there'll be no withdrawal"