I don't have a scanner, so if you help Stéphane here he'll get something
useful.

"Tom Bruhns" wrote in message
m...
Hi Stéphane,

Just so you don't confuse people you talk with, "stripline" is a line
sandwiched between two ground planes (could be air dielectric or
circuit board dielectric), but if it's a PC board with ground plane on
one side and a trace on the other, that's "microstrip."

I think 1.6mm thick fiberglass epoxy, with a 50 ohm microstrip line on
it at about 3mm line width, will handle 100 W at 450MHz just fine.

You can make a stripline or microstrip coupler that's shorter than 1/4
wave, and it should still have good directionality. It just won't
have as much coupling as it does at 1/4 wave. The coupling at 1/4,
3/4, 5/4, etc., is all the same, and there are nulls at DC, 1/2 wave,
2/2, 3/3, etc. The maxima are rather broad, rounded, and not sharp
peaks. I think I found a plot of the response on the web recently,
but perhaps I made it from formulas.

If you don't get it somewhere else, I can scan and send the ARRL
article on making an SWR meter using copper pipe fittings. I suppose
they are US-standard fittings, but there should be reasonable
equivalents in the civilized metric world.

Cheers,
Tom