October 21, 2007
At the W4RM contest station, we manually selected receiving antennas (beverages) by moving a patch cord between connectors on a wall-mounted box. It was tough to keep up with the propagation changes, DX spots and random calls. So I designed and built an antenna switch, which gives us the capability of switching antennas from our operating positions. The control is mounted next to the operators keyboard and the antenna matrix is mounted in the back room.
Click through the pictures and diagrams below or visit the project discussion page for a write up of all the details.
I spent about 120 hours learning, building and testing. Maybe more. I really didn't keep track. Thanks to generous junk boxes, the project cost about $180. Most of that was for the PC Board expenditure ($65,) which I'm not sure I would do again.
- Relay board - hamfest find!
- PIC 16F628(a) - PIC for the remotes
- PIC 16F876 - PIC for the master
- Allegro AS6801 - Current sink latches
- MAX RS-233A - RS-232 Drivers
- Modtronix LCD Display
- W4RM Contest Station - Three operating positions ready to go.
- Station Closeup - Closeup of an operating postion, note the remote in the lower right hand side of picr
- Master - All the modules for the master, including the controller board, inteface board,LCD module and latch board
- Controller board - Close up of the master controller board, built using a pre-fabbed board from Basic Micro
- Inteface Board - Connects the Master controller to the RS-232 cables. Used for the terminal strips
- Latch Board - Used to latch the relays. I designed this PCB.
- Relay Board - Relays used to connect the antennas to the radios. Every thing goes into driving this board.
- Remote - Close up of a remote, after the lables were applied
- Remotes before labels - Four remote controllers, before the lables were added.
- Master Mounted - Boards added to the box and mounted on the wall
- Backboard - All of the hardware mounted on the wall
- Under the Workbench - After the project was done.
- My Shack - After the project was done - what a mess!