RadioBanter - View Single Post

Gudmundur · January 22nd 08, 10:06 PM posted to rec.radio.amateur.homebrew

In article ,
says...

Does anyone in the group know anything about magnetrons? I planning to
do some experiments in transmitting microwaves.

I would like to use standard magnetrons from a microwave oven and
believe I can beam further if operated at the same frequency and
with the outputs in phase. I have no idea on how to do this. Please
advise

Cheers,
Bert

Kind of a strange side note to the syncing issue,
There are commercial microwave ovens that use 2 magnetrons.
These ovens are usually in food courts of large business
offices or factories. They are 220vac powered of course.
Since a single mag oven produces power only on a small
portion of one half of an a.c. line cycle they did a neat
trick in the twin mag ovens and switched the line connections
to one power transformer. (the ovens have two complete and
separate h.v. supplies) So one mag makes power on the positive
half of the line cycle and the other makes power on the
negative half of the line cycle. Strangely enough I have
run into several units having the same 'in phase' line
connection (by accident or tampering I guess) and they
still work fine. Both mags tightly coupled to the cavity
producing power at the same time on the same half of the
line cycle. Talk about injection locking!!! 2 mags looking
right at each other, and I have not found their service
life to be any shorter but they take longer to pop popcorn.
Probably several reasons for that, but a differance you can
see and measure with a watch. Just by switching the primary
transformer leads back to the 'normal' out of phase condition
popcorn gets done faster.