Re[2]: [HomeBrew] UHF SWR meters

[Steven Weber]

Hello Elliot,

I'm new to this list..

The ARRL Antenna handbook has plans for a VHF/UHF directional coupler made
from common copper pipe couplings, but looks like a project. 

I have an old (1968) VHF handbook with an interesting VHF/UHF bridge. It
uses a 7 1/2" lenght of RG-58 with a pick up wire inserted between the
braid and center conductor. A 47 ohm resistor is placed at the exact center
of the pick up wire to ground, and the froward/reverse detectors are on the
opposite ends of the pick up wire. (and come out from the shield a little
before the ends of the coax)  It's claimed to work from 50 to 450 MHz. If
you only want 430 operation, you could shorten the length of the coax by at
least half. 

The main trick is feeding the pick up wire between the shield and center
conductor. Remove the outer jacket of the coax, lossen up the braid by
pushing it towards the center and insert the pick up wire from the center
point of the coax, leaving a small loop to attach the 47 ohm resistor to. 

Finally, I would think you could make a coupler on a small piece of printed
circuit board stock using strip line techniques. 


72,
Steve, KD1JV
"Melt Solder"
White Mountains of New Hampshire
http://www.qsl.net/kd1jv/