"Rod Speed" wrote in
:



"Jimmy Wilkinson Knife" wrote in message
news
On Sat, 02 Jun 2018 12:01:14 +0100, Rod Speed
wrote:



"Jimmy Wilkinson Knife" wrote in message
news 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...img/index_img_
0
1.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
I recall a Phillips one in the 70's which had the controls and
presumably the magnetron above the cavity. I don't think it had a
turntable. One would suit me now as it woual be narrower.