EF Johnson Challenger Series Information
Contents
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 frequency ranges below are based on practical experience not documented from EFJ.
7151
- Band: VHF
- Channels: 2 Channel
- Output: 25 Watts
- Freq Range: 144-174 mHz
7152
- Band: VHF
- Channels: 8 Channel
- Output: 25 Watts
- Freq Range: 144-174 mHz
7153
- Band: VHF
- Channels: 2 Channel
- Output: 40 Watts
- Freq Range: 144-174 mHz
7154
- Band: VHF
- Channels: 8 Channel
- Output: 40 Watts
- Freq Range: 144-174 mHz
7155
- Band: VHF
- Channels: 20 Channel
- Output: 40 Watts
- Freq Range: 144-174 mHz
7156
- Band: VHF
- Channels: 99 Channel
- Output: 40 Watts
- Freq Range: 144-174 mHz
7157
- Band: VHF
- Channels: 99 Channel
- Output: 100 Watts
- Freq Range: 144-174 mHz
7161
- Band: VHF
- Channels: 2 Channel
- Output: 25 Watts
- Freq Range: 144-174 mHz
7162
- Band: VHF
- Channels: 8 Channel
- Output: 25 Watts
- Freq Range: 144-174 mHz
7163
- Band: VHF
- Channels: 2 Channel
- Output: 40 Watts
- Freq Range: 144-174 mHz
7164
- Band: VHF
- Channels: 8 Channel
- Output: 40 Watts
- Freq Range: 144-174 mHz
7165
- Band: VHF
- Channels: 20 Channel
- Output: 40 Watts
- Freq Range: 144-174 mHz
7166
- Band: VHF
- Channels: 99 Channel
- Output: 40 Watts
- Freq Range: 144-174 mHz
7167
- Band: VHF
- Channels: 99 Channel
- Output: 100 Watts
- Freq Range: 144-174 mHz
7171
- Band: UHF
- Channels: 2 Channel
- Output: 15 Watts
- Freq Range: 440-488 mHz
7172
- Band: UHF
- Channels: 8 Channel
- Output: 15 Watts
- Freq Range: 440-488 mHz
7173
- Band: UHF
- Channels: 2 Channel
- Output: 35 Watts
- Freq Range: 440-488 mHz
7174
- Band: UHF
- Channels: 8 Channel
- Output: 35 Watts
- Freq Range: 440-488 mHz
7175
- Band: UHF
- Channels: 20 Channel
- Output: 35 Watts
- Freq Range: 440-488 mHz
7176
- Band: UHF
- Channels: 99 Channel
- Output: 35 Watts
- Freq Range: 440-488 mHz
7177
- Band: UHF
- Channels: 99 Channel
- Output: 80 Watts
- Freq Range: 440-488 mHz
7181
- Band: UHF
- Channels: 2 Channel
- Output: 15 Watts
- Freq Range: 440-488 mHz
7182
- Band: UHF
- Channels: 8 Channel
- Output: 15 Watts
- Freq Range: 440-488 mHz
7183
- Band: UHF
- Channels: 2 Channel
- Output: 35 Watts
- Freq Range: 440-488 mHz
7184
- Band: UHF
- Channels: 8 Channel
- Output: 35 Watts
- Freq Range: 440-488 mHz
7185
- Band: UHF
- Channels: 20 Channel
- Output: 35 Watts
- Freq Range: 440-488 mHz
7186
- Band: UHF
- Channels: 99 Channel
- Output: 35 Watts
- Freq Range: 440-488 mHz
7187
- Band: UHF
- Channels: 99 Channel
- Output: 80 Watts
- Freq Range: 440-488 mHz
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.
UHF Cover Plate
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)
UHF-80 Watts / VHF-110 Watts
UHF-35 Watts / VHF-40 Watts
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)
2 Channel Non-remote
20 or 99 Channel Non-remote
99 Channel Remote
