, or

For QRP work a resistive (lossy -6dB) type that you switch out after use is the best. However I don't think these are made commercially! You sometimes see the simple circuit with QRP rigs & I suggest you get a local to build it, possibly a novice! The circuit uses a double pole changeover switch (measure operate), a SWR C/O switch Forward & Reverse, 3 50Ohm Rs rated at 1/4 RF power, 1 RF diode (OA81), 2 caps, series meter cal variable R (10K) & a meter(100uA). Best made from an old CB meter as you get the Box, Meter SWR scale, sockets and switches. Sensitivites are down to about 0.2V of RF which is about 0.8mW.
Depending on the layout and components used, the meter could be accuate to VHF.

                      OPERATE
TX Socket o------.-->o----------------------o<--.------o Load Socket
             MEASURE o--------50R-----------o MEASURE
                     !                    !
                    50R  Diode    1n      !
                     !----!>!----!!---.-->o SWR
                     !         !          o CAL
                    50R     Cal Pot       !
                     !         !          !
                     !         !----      !
                     !       Meter  !     !
                     !         !   === 1n !
                     !         !    !     !
          Gnd------------------------------------------Gnd

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However, We accept no responsibility for damage or injury, however caused, due to the use of this data.
This design was originally posted on Packet radio by John G8MNY - Jan 2001.