Grounding pin 14 on the rear panel accessory connector will extend
the frequency ranges to: 
Band    - Extended coverage - Factory coverage
----------------------------------------------
160m    -   1.0 -  3.0 MHz  -   1.8  -  2.0 MHz
 80m    -   3.0 -  5.0 MHz  -   3.5  -  4.0 MHz
 40m    -   7.0 -  9.0 MHz  -   7.0  -  7.5 MHz 
                                7.3  -  7.5 MHz Receive Only
 
 20m    -  14.0 - 16.0 MHz  -  14.0  - 15.2 MHz 
                               14.35 - 15.2 MHz Receive Only
 
 15m    -  21.0 - 22.0 MHz  -  21.0  - 21.5 MHz
 
 10m    -  28.0 - 30.0 MHz  -  28.0  - 30.0 MHz 
                               29.7  - 30.0 MHz Receive Only
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