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Remote antenna switch box.
Alternative to moving antenna cables.

This was the starting point. I wanted to operate in a different location and didn't like the idea of moving or extending all those antenna cables! The solution was to run a single coaxial cable to the new location along with a multicore cable (single Cat 5 UTP cable - 4 pair) used for remote switching the antennas by relays.
The switch box allows the selection of one antenna from four, provides indication of the selected antenna, provides for the reversal of connection of both the outer and inner conductors (as required with inverted coaxial L style antenna). An additional switch was provided, to utilise the spare cable pair, to provide additional remote switching.
 
 
The schematic of the remote and the relay switchbox.
Remote Switchbox Schematic
 
 
Circuit description.

There are two parts to the remote switchbox.
The top part of the schematic shows the wiring of the control box used at the new location. This part supplies the power for the whole circuit and a led is used to indicate that the circuit has power. Switch 1 (SW1) is used to enable/disable a remote relay for transposing both the inner and outer conductors on the main feedline to the antenna, at the remote end. Switch 2 (SW2) is used to select an antenna by providing power to the relay at the remote location and also provides power to the local antenna selector led indicator. Switch 3 (SW3) is used to provide remote switching across the spare cable pair. J1 is connected to a single 4 pair Cat 5 UTP cable and connects to the remote relay box via J2.

The bottom part of the schematic shows the remote relay box which provides the relays and coaxial cable sockets for antenna cable connections. Each relay has a rf bypass capacitor, free-wheeling diode and led indicator. When a particular relay is energised, you will be able to easily determine which relay is active. Each relay isolates both the inner and outer conductors of the bnc sockets from the circuit, when not energised. (i.e. both parts of the connection are isolated and floating, with reference to ground.) A single coaxial cable runs from connecr, P1, to the new location.
 
 
Completed photos.

Photos of the completed units to follow ... soon.
 
 
 
       
    2006 - 2009 S.Spirat 
Another SPIRAT initiative