Add bias_t parameter to build_ism_command()

Same fix as build_fm_demod_command() - the parameter was being
passed but not defined in the method signatures.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

utils/sdr/airspy.py

@@ -126,7 +126,8 @@ class AirspyCommandBuilder(CommandBuilder):
         device: SDRDevice,
         frequency_mhz: float = 433.92,
         gain: Optional[float] = None,
-        ppm: Optional[int] = None
+        ppm: Optional[int] = None,
+        bias_t: bool = False
     ) -> list[str]:
         """
         Build rtl_433 command with SoapySDR support for ISM band decoding.
@@ -145,6 +146,9 @@ class AirspyCommandBuilder(CommandBuilder):
         if gain is not None and gain > 0:
             cmd.extend(['-g', str(int(gain))])
 
+        if bias_t:
+            cmd.extend(['-T'])
+
         return cmd
 
     def get_capabilities(self) -> SDRCapabilities:

utils/sdr/base.py

@@ -138,7 +138,8 @@ class CommandBuilder(ABC):
         device: SDRDevice,
         frequency_mhz: float = 433.92,
         gain: Optional[float] = None,
-        ppm: Optional[int] = None
+        ppm: Optional[int] = None,
+        bias_t: bool = False
     ) -> list[str]:
         """
         Build ISM band decoder command (433MHz sensors).
@@ -148,6 +149,7 @@ class CommandBuilder(ABC):
             frequency_mhz: Center frequency in MHz (default 433.92)
             gain: Gain in dB (None for auto)
             ppm: PPM frequency correction
+            bias_t: Enable bias-T power (for active antennas)
 
         Returns:
             Command as list of strings for subprocess

utils/sdr/hackrf.py

@@ -123,7 +123,8 @@ class HackRFCommandBuilder(CommandBuilder):
         device: SDRDevice,
         frequency_mhz: float = 433.92,
         gain: Optional[float] = None,
-        ppm: Optional[int] = None
+        ppm: Optional[int] = None,
+        bias_t: bool = False
     ) -> list[str]:
         """
         Build rtl_433 command with SoapySDR support for ISM band decoding.
@@ -142,6 +143,9 @@ class HackRFCommandBuilder(CommandBuilder):
         if gain is not None and gain > 0:
             cmd.extend(['-g', str(int(gain))])
 
+        if bias_t:
+            cmd.extend(['-T'])
+
         return cmd
 
     def get_capabilities(self) -> SDRCapabilities:

utils/sdr/limesdr.py

@@ -104,12 +104,14 @@ class LimeSDRCommandBuilder(CommandBuilder):
         device: SDRDevice,
         frequency_mhz: float = 433.92,
         gain: Optional[float] = None,
-        ppm: Optional[int] = None
+        ppm: Optional[int] = None,
+        bias_t: bool = False
     ) -> list[str]:
         """
         Build rtl_433 command with SoapySDR support for ISM band decoding.
 
         rtl_433 has native SoapySDR support via -d flag.
+        Note: LimeSDR does not support bias-T, parameter is ignored.
         """
         device_str = self._build_device_string(device)
 

utils/sdr/rtlsdr.py

@@ -115,7 +115,8 @@ class RTLSDRCommandBuilder(CommandBuilder):
         device: SDRDevice,
         frequency_mhz: float = 433.92,
         gain: Optional[float] = None,
-        ppm: Optional[int] = None
+        ppm: Optional[int] = None,
+        bias_t: bool = False
     ) -> list[str]:
         """
         Build rtl_433 command for ISM band sensor decoding.
@@ -135,6 +136,9 @@ class RTLSDRCommandBuilder(CommandBuilder):
         if ppm is not None and ppm != 0:
             cmd.extend(['-p', str(ppm)])
 
+        if bias_t:
+            cmd.extend(['-T'])
+
         return cmd
 
     def get_capabilities(self) -> SDRCapabilities: