EF Johnson Challenger Series Information

EF Johnson Series Radio Information

these are very versatile radios, they will easily move into the ham bands VHF and UHF models. The logic boards can be swapped between models and reprogrammed so that you can make a 2 Channel VHF a 99 channel by just replacing the logic board and reprogramming. The boards between UHF and VHF are fully interchangeable. I have also converted non-remote models to remote and vice versa. Converting Dash Mount EF Johnson Challenger Radios to Remote Mount

Model Number Decoding

In a posting on the EFJ yahoogroup a gentleman reported that the model numbers in the 71xx series of Challengers were organized such that: The VHF units were 715x and 716x (the 5x were 1st generation and 6x were 2nd generation)

The UHF units were 717x and 718x (the 7x were 1st generation and 8x were 2nd generation)

The following numbers replace the x as mentioned above:

1 = 2 Channel 25 watts (VHF) 15 watts (UHF)

2 = 8 Channel 25 watts (VHF) 15 watts (UHF)

3 = 2 Channel 40 watts (VHF) 35 watts (UHF)

4 = 8 Channel 40 watts (VHF) 35 watts (UHF)

5 = 20 Channel 40 watts (VHF) 35 watts (UHF)

6 = 99 Channel 40 watts (VHF) 35 watts (UHF)

7 = 99 Channel 100 watts (VHF) 80 watts (UHF)

If it had a -5 after the number it was a remote mount system

Radio Identification by Images

you can easily identify the band of the radio by looking at the inside. the UHF has two small cover plates the the VHF has on large one.

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  UHF Cover Plate

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  VHF Cover Plate

Power output of the radio can be determined by the size of the rear heatsink. the max power is also determined by the band (UHF/VHF)

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  UHF-80 Watts / VHF-110 Watts

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  UHF-35 Watts / VHF-40 Watts

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  UHF-15 Watts / VHF-25 Watts

Determining the number of Channels

(I'm missing an 8 channel image, but its easy, it only has one digit)

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  2 Channel Non-remote

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  20 or 99 Channel Non-remote

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  99 Channel Remote