Thanks a bunch for pointing that out. I'd wondered about the
relationship between beam width, reflector diameter, and frequency.

Now that I think about it, doesn't focal length or focal ratio play a
part as well?

I don't suppose you could point me at a decent reference for this
stuff, could you? I've found that Google (i.e., the web) is somewhat
lacking when it comes to explanations - especially accurate ones - of
where those nifty approximation equations come from.

Depends on the level of detail and backup you want. There's a EW
Handbook at Point Mugu Naval Air Station, you might be able to find it
with google.

W1GHZs online book is at: http://www.w1ghz.org/antbook/preface.htm





There's a little more than this to the whole problem, but, in general,
if what you want to do is measure the distance to the moon, a radar
built with an oven magnetron probably isn't the best way to go about
doing it.


So noted. The goal here is not so much to do it the best way
possible, but rather to see what kind of results I can obtain using
the scrap (i.e., free) materials I have available.

Sure, I understand..

It's just that MO Magnetrons are such ragged edge cost sensitive items
that they spend absolutely nothing on making them good transmitter
components. After all, all they have to do is heat stuff, cheaply.

Even if you have a design from, say, 20-30 years ago, I suspect that
modern tubes aren't going to be as suitable.

I did see a clever design where they took a whole array of MO magnetrons
and injection locked them to build a microwave weed killer. Microwave
Journal, October 2005.

http://www.mwjournal.com/journal/art...p?HH_ID=AR_113

Enjoy...



If I were after accuracy, I'd point a laser at the corner reflectors
left by the Apollo missions. 8^)

Hmmm.. That's a nontrivial thing.. BUT, you could do (maybe the first)
optical EME contact on the 470 THz band.