public static RTLDevice[] GetActiveDevices()
{
uint _devicecount = NativeMethods.rtlsdr_get_device_count();
var _result = new RTLDevice[_devicecount];
for (var i = 0u; i < _devicecount; i++)
{
// get device name
string _name = NativeMethods.rtlsdr_get_device_name(i);
// get device pointer
System.IntPtr _dev;
if (NativeMethods.rtlsdr_open(out _dev, i) > 0)
{
throw new InvalidOperationException("Cannot open RTL device. Is the device locked somewhere?");
}
try
{
// get tuner type
RtlSdrTunerType _tunertype;
_tunertype = NativeMethods.rtlsdr_get_tuner_type(_dev);
// get descriptor strings
StringBuilder _manufact = new StringBuilder(256);
StringBuilder _product = new StringBuilder(256);
StringBuilder _serial = new StringBuilder(256);
NativeMethods.rtlsdr_get_usb_strings(_dev, _manufact, _product, _serial);
RTLGainStages _gainstages = new RTLGainStages();
RTLTunerGains _tunergains = new RTLTunerGains();
RtlSdrGainMode _gainmode = RtlSdrGainMode.GAIN_MODE_MANUAL;
double _maxpower = 0;
// try to get all possible gain settings for all stages
// requires special version of rtlsdr.dll
try
{
// iterate through 256 possible stages
for (byte stage = 0; stage < 255; stage++)
{
// get number of gains per stage
int _count = NativeMethods.rtlsdr_get_tuner_stage_gains(_dev, stage, null, null);
// stopop iteration at first stage with no entries or error
if (_count <= 0)
{
break;
}
var _gains = new int[_count];
StringBuilder _desc = new StringBuilder(256);
// get gains
NativeMethods.rtlsdr_get_tuner_stage_gains(_dev, stage, _gains, _desc);
// add new entry to array
_gainstages.AddGains(_desc.ToString(), _gains);
}
}
catch
{
// no gain settings found or wrong version of rtlsdr.dll
}
if (_gainstages.Count > 0)
{
// gain settings per stage were found --> assuming that special version of rtlsdr is loaded
// we can set special settings per stage by ourselves
// save default gain settings to file to ensure that we have at least default settings on a file
SaveDefaultGainSettings(_tunertype, _gainstages);
// try to read gain settings per stage from file
// set gain mode to gain per stage
_gainmode = RtlSdrGainMode.GAIN_MODE_PERSTAGE;
// calculate file name according to tuner type
string filename = Directory.GetCurrentDirectory() + Path.DirectorySeparatorChar + _tunertype.ToString() + ".tun";
try
{
using (StreamReader sr = new StreamReader(filename))
{
while (!sr.EndOfStream)
{
// read a line
string s = sr.ReadLine().Trim();
if (!String.IsNullOrEmpty(s) && !s.StartsWith("//"))
{
// not comment, try to split into single values
try
{
string[] a = s.Split(';');
// check array for length --> must be equal to stages count
if (a.Length != _gainstages.Count)
{
throw (new InvalidOperationException("Tuner type: " + _tunertype + "\n" + "Filename: " + filename + "\n" + "Number of entries does not match number of stages" + " [" + _gainstages.Count.ToString() + "] in line: " + s));
}
// initialize gain arry
int[] gains = new int[_gainstages.Count];
// set gain values
for (int index = 0; index < a.Length; index++)
{
// convert string to int
try
{
gains[index] = System.Convert.ToInt32(a[index].Trim());
}
catch
{
throw (new InvalidOperationException("Tuner type: " + _tunertype + "\n" + "Filename: " + filename + "\n" + "Invalid gain entry in line: " + s));
}
// validate entry with gain stages
if (!_gainstages.ValidateGain(_gainstages[index], gains[index]))
{
throw (new InvalidOperationException("Tuner type: " + _tunertype + "\n" + "Filename: " + filename + "\n" + "Gain entry is not valid for this stage[ " + _gainstages[index] + "] in line: " + s));
}
}
// sum up and correct tuner gains
int _gainsum = 0;
switch (_tunertype)
{
case RtlSdrTunerType.E4000:
_gainsum = _gainstages.GainSumE4000(gains);
break;
case RtlSdrTunerType.R820T:
_gainsum = _gainstages.GainSumR820T(gains);
break;
default:
_gainsum = _gainstages.GainSumDefault(gains);
break;
}
// add them to TunerGains object
_tunergains.AddGains(_gainsum, gains);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message, "Error Reading Tuner Gains from File" + filename);
}
}
}
}
}
catch
{
// do nothing if file not found
}
}
if (_tunergains.Count <= 0)
{
// file read was not successful or old version of rtlsdr.dll is loaded
// try to get per stage settings from DLL
// try to set gain mode to manual
if (NativeMethods.rtlsdr_set_tuner_gain_mode(_dev, RtlSdrGainMode.GAIN_MODE_MANUAL) != 0)
{
throw new InvalidOperationException("Cannot set tuner gain mode: " + RtlSdrGainMode.GAIN_MODE_MANUAL.ToString());
}
if (_tunertype == RtlSdrTunerType.E4000)
{
// OK, we have a E4000 tuner and we will emulate a sensitivity mode
// set emulated gains according to SM5BSZ
int[] _gains = { -250, -200, -150, -100, -50, 0, 50, 100, 150, 200, 250 };
// add each tuner gain to tuner gains, gain settings per stage set to 0 entries (not used)
foreach (int gain in _gains)
{
int[] _dummy = new int[0];
_tunergains.AddGains(gain, _dummy);
}
// store gain mode, we will use it later
_gainmode = RtlSdrGainMode.GAIN_MODE_SENSITIVITY;
}
else
{
// very old or very official version of rtlsdr.dll
// try to get standard stages from DLL
// get size of tuner gain table first
int _count = NativeMethods.rtlsdr_get_tuner_gains(_dev, null);
if (_count < 0)
{
// set count to 0 if fails
_count = 0;
}
// get tuner gain table if count > 0
int[] _gains = new int[_count];
if (_count >= 0)
{
// get tuner gains from dll
if (NativeMethods.rtlsdr_get_tuner_gains(_dev, _gains) < 0)
{
throw new InvalidOperationException("Cannot get tuner gains.");
}
// add each tuner gain to tuner gains, gain settings per stage set to 0 entries (not used)
foreach (int gain in _gains)
{
int[] _dummy = new int[0];
_tunergains.AddGains(gain, _dummy);
}
}
// store gain mode, we will use it later
_gainmode = RtlSdrGainMode.GAIN_MODE_MANUAL;
}
}
// set MaxGain according to tuner type
switch (_tunertype)
{
case RtlSdrTunerType.E4000:
_maxpower = SupportFunctions.ToLinear(50);
break;
case RtlSdrTunerType.R820T:
_maxpower = SupportFunctions.ToLinear(45);
break;
default:
_maxpower = SupportFunctions.ToLinear(50);
break;
}
// initialize new RTLDevice entry
_result[i] = new RTLDevice
{
Index = i,
TunerType = _tunertype,
Name = _name,
Manufacturer = _manufact.ToString(),
Product = _product.ToString(),
Serial = _serial.ToString(),
GainMode = _gainmode,
GainStages = _gainstages,
TunerGains = _tunergains,
MaxPower = _maxpower
};
}
finally
{
// try to close the device anyway
NativeMethods.rtlsdr_close(_dev);
}
}
return(_result);
}
public static extern int rtlsdr_set_tuner_gain_mode(IntPtr dev, RtlSdrGainMode mode);