[MAMS] 47 GHz

[Dr. Gerald N. Johnson]

On 10/31/2011 11:47 AM, Zack Widup wrote:
> If I had to drive 23 miles I might have considered McMaster-Carr. As it
> was, I only had to drive a half mile.
> :-)
>
> Also, I have been told by several people that WR-34 and WR-42 can be butted
> up against each other with virtually no loss at 24 GHz. They are both the
> same height and the waveguide flanges use the same hole spacings.

I hadn't realized they were the same height. But they are. And some 
others don't have the width exactly twice the height, like the inside 
dimensions of WR90. The only good argument for width twice the height is 
that gives the widest bandwidth without the chance of exciting higher 
order modes with the greatest power handling capacity. Where we have 
hambands a tiny fraction of any waveguide bandwidth we could use any 
ratio of height to width so long as we can control (or use) the high 
order waveguide modes. Low height lowers Z0 which can make matching 
easier as was used in some G4GVL (IIRC) transverters a decade or two ago 
in the days before MMICs. I have a TWT with waveguide ports less than a 
quarter inch high by 1-1/2" wide about. Probably 6 GHz, I need to learn 
more about it.
>
> I had a course in engineering probability taught by an EE professor who
> taught the course because he wanted to learn more about it! It was an
> interesting course. He was learning along with the rest of us.

I admit to not being a good teacher, so I refrain from teaching. I've 
tried a couple times, and I'm sure I learned more than the students both 
times. I claim to be more honest than some of the professors I've had. I 
don't do what I'm bad at. They did. But part of graduate school is 
learning to learn without being spoon fed, to learn what no one else 
cares to know so maybe having bad professors is part of that training, 
though the bad cost the same per credit hour as the good. They took up 
more hours with homework learning what the professor didn't know to tell 
and to do the homework assignments.

73, Jerry, K0CQ
>
> 73, Zack W9SZ
>
>
>