Converting Dash Mount EF Johnson Challenger Radios to Remote Mount

the Ef johnson Challenger series radios are quite flexible for older technology. You can take a dash mount radio and convert it to remote mount if you have the remote head and junction box.

These are connected to the junction box via a n 8 pin modular connector, that resembles an RJ45, but its just a little smaller. You can easily file down the sides of an RJ45 and make it fit perfectly.

Challenger Remote Components

although the image is clearly of an 86xx series, the remote heads are the same

Choosing the Proper Radio

Not all challenger series radios have the necessary configuration or parts to convert to a remote. The main item to look for are the additional mounting holes for the relay and the presence of other parts on the bottom of the board.

OK to Convert

Not OK to Convert

Cable Connections

The connection cable between the radio and the remote junction box is an 8 pin modular plug, much like an RJ45. The standard RJ45 (network cable) wont fit directly, but you can file down each side a bit and it will work fine. I usually take a 'flexible' 8 ft network patch cable and cut one connector off, then hard wire this cable into the radio. Although the factory has a modular plug installed at the radio, they just really add an additional failure point.

The colors in the table correspond to the images below. In EF Johnson service manuals they refer to the connections as A123456B, however they are just pins 1-8 for the plug. I have included the EF Johnson designation in parenthesis.

• Cable Connections
  • 1 - (A) Orange - Receive Data
  • 2 - (1) Ground Braid
  • 3 - (2) Red - Mic audio
  • 4 - (3) Green - Power Control
  • 5 - (4) Yellow - PTT
  • 6 - (5) Blue - 13.4 volt source
  • 7 - (6) White - Receive Audio
  • 8 - (B) Brown - Transmit Data