If the range of the BL600 is much shorter than expected, there are a few possible causes:
The BL600 license key is invalid. The simple way to verify this is to use send the command AT I 4 to the BL600, and it will respond with its MAC address. If this response contains the word COFFEE, then the module has an invalid license key, of which one symptom of this is reduced output power. Additionally, the BL600 cannot autorun scripts without a valid key. Laird support can generate your key from the MAC address, which you can retrieve using the command AT I 14. To recover your license key, run the AT I 14 command to get the MAC address, provide the MAC address to Support and we will provide your key back to you. You can then enter it using the AT+LIC “” command.
Another possible cause comes if you are directly using the Nordic's softdevice stack with Nordic sample applications instead of smartBASIC on the BL600. In this scenario, in your Nordic application you must set Nordic GPIO 20 as an output and to logic low in order to enable the RF tx power circuitry.