This SWR has a classic balanced schema for measuring power of forward and reflected waves.
Balancing is set by trimmer capacitor C3
|C2, C4||2||105||Unpolarized capacitor|
|J1||1||Antenna||coaxial connector, SO239|
|J2||1||RX||coaxial connector, SMA female|
|J3||1||TX||coaxial connector, SMA female|
|J9||1||Conn_01x03||Generic connector, single row, 01x03|
|R3, R4, R5, R6||4||68R||Resistor|
|T1||1||1:10:10||Transformer, single turn primary, split by 10 turns secondary|
|3D Model||Front PCB||Back PCB|
It has a slightly unusual design and mounted on the back wall of transceiver. I used sandwich from the TRX wall, one-sided PCB boards which serves as isolator and SWR meter board. SWR meter board has a hole for SO 239 connector and relay to switch between reception and transmission. Also I installed SMA connectors to connect the main transceiver board and amplifier with filters. I used T50-6 carbonyl iron ring transformer and a loop made from central core of 50 ohm coax cable.
I plan to shield the board when I will finish tuning. This little loop picks up the noise from power supply really well therefore I have to shield it.
Checkout my design of Band Switch.