Hi All,
For anyone that wants to use the 60 dbm.com 100W SWR bridge for the DE platform, here's the list of stuff you'll need:
1 x 100W SWR Bridge from 60dbm.com
1 x ATtiny 85 PIC
2 x 100k multiturn potentiometers (or other value)
3 x 0.1 uf capacitor (~16V)
1 x 4-pin 90¡ã female header
1 x 2-pin 90¡ã male header
small pcb
wire and mounting hardware
The trickiest part (for me) was carefully removing the existing BNC antenna connector and routing shielded cable to and from the SWR bridge.? I stacked two stand-offs to solidly groung the bridge and to provide local antenna ground to the bridge.
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Carefully desolder the center BNC connection (I pulled the entire connector from the board).? Use needle nose pliers to pull the center conductor away from the PCB.? Form the pulled connection up and away from the PCB.? Insert a suitible wire (I used solid core coax) into the now vacated PCB connection and route to the input side of the SWR Bridge.? Connect the output of the bridge to the BNC center connection.? It's hard to see but in the detail of the BNC, the shield is not grounded and the center conductor is solidly bonded to the BNC center.? I grounded the coax shield to the case by soldering on the braid a small ring terminal.
The ATtiny 85 is connected to the I2C bus via the real time clock.? A 4-pin female connector from the ATtiny 85 interface board makes all connections to the sBitx.? The FWD and REV signals from the SWR bridge are terminated on the interface board.
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You can probably make this for around $30.? I had most of the parts so I did it for the cost of the bridge and the Tiny 85.? Oh, and programming the Tiny 85 is pretty easy if you have an Arduino.
I have to admit that I got a bunch of help from the guys in this group but if anyone jumps into this project, I'll be happy to assist.
Cheers, Scott
