Added the ability to use RTL AGC in rtl_sdr

README

@@ -4,3 +4,25 @@ turns your Realtek RTL2832 based DVB dongle into a SDR receiver
 
 For more information see:
 http://sdr.osmocom.org/trac/wiki/rtl-sdr
+
+======================================================================
+
+Features added by me (MichelinoK):
+
+- Ability to enable RTL AGC in rtl_sdr
+- Ability to enable RTL AGC in rtl_tcp (for those apps that doesn't support enabling it)
+
+Now in rtl_sdr and rtl_tcp you can use the "-X" switch to enable RTL AGC
+
+======================================================================
+
+Suggested to compile this way:
+
+git clone https://github.com/michelinok/rtl-sdr.git
+cd rtl-sdr
+mkdir build
+cd build
+cmake ../ -DDETACH_KERNEL_DRIVER=ON -DINSTALL_UDEV_RULES=ON
+make
+sudo make install
+sudo ldconfig

src/convenience/convenience.c

@@ -136,6 +136,18 @@ int nearest_gain(rtlsdr_dev_t *dev, int target_gain)
 	return nearest;
 }
 
+int verbose_set_rtlagc(rtlsdr_dev_t *dev)
+{
+	int r;
+	r = rtlsdr_set_agc_mode(dev, 1);
+	if (r < 0) {
+		fprintf(stderr, "WARNING: Failed to set RTL AGC\n");
+	} else {
+		fprintf(stderr, "RTL AGC enabled\n");
+	}
+	return r;
+}
+
 int verbose_set_frequency(rtlsdr_dev_t *dev, uint32_t frequency)
 {
 	int r;

src/convenience/convenience.h

@@ -149,3 +149,10 @@ int verbose_reset_buffer(rtlsdr_dev_t *dev);
 
 int verbose_device_search(char *s);
 
+/*!
+* Enable RTL AGC
+* Mod by MichelinoK
+* email: [email protected]
+*/
+
+int verbose_set_rtlagc(rtlsdr_dev_t *dev);

src/rtl_sdr.c

@@ -57,6 +57,7 @@ void usage(void)
 		"\t[-S force sync output (default: async)]\n"
 		"\t[-D direct_sampling_mode, 0 (default/off), 1 (I), 2 (Q), 3 (no-mod)]\n"
 		"\t[-N no dithering (default: use dithering)]\n"
+		"\t[-X enable RTL AGC]\n"
 		"\tfilename (a '-' dumps samples to stdout)\n\n");
 	exit(1);
 }
@@ -115,6 +116,7 @@ int main(int argc, char **argv)
 	int gain = 0;
 	int ppm_error = 0;
 	int sync_mode = 0;
+	int rtlagc = 1;
 	int direct_sampling = 0;
 	int dithering = 1;
 	FILE *file;
@@ -125,12 +127,15 @@ int main(int argc, char **argv)
 	uint32_t samp_rate = DEFAULT_SAMPLE_RATE;
 	uint32_t out_block_size = DEFAULT_BUF_LENGTH;
 
-	while ((opt = getopt(argc, argv, "d:f:g:s:b:n:p:D:SN")) != -1) {
+	while ((opt = getopt(argc, argv, "d:f:g:s:b:n:p:D:SNX")) != -1) {
 		switch (opt) {
 		case 'd':
 			dev_index = verbose_device_search(optarg);
 			dev_given = 1;
 			break;
+		case 'X':
+			rtlagc = 0;
+			break;
 		case 'f':
 			frequency = (uint32_t)atofs(optarg);
 			break;
@@ -222,6 +227,12 @@ int main(int argc, char **argv)
 		verbose_direct_sampling(dev, direct_sampling);
 	}
 
+	/* enable RTL_AGC */
+	if (!rtlagc) {
+		fprintf(stderr,"Enabling RTL AGC\n");
+		verbose_set_rtlagc(dev);
+	}
+
 	/* Set the sample rate */
 	verbose_set_sample_rate(dev, samp_rate);
 

src/rtl_tcp.c

@@ -95,7 +95,8 @@ void usage(void)
 		"\t[-b number of buffers (default: 15, set by library)]\n"
 		"\t[-n max number of linked list buffers to keep (default: 500)]\n"
 		"\t[-d device index (default: 0)]\n"
-		"\t[-P ppm_error (default: 0)]\n");
+		"\t[-P ppm_error (default: 0)]\n"
+		 "\t[-X enable RTL AGC]\n");
 	exit(1);
 }
 
@@ -369,6 +370,7 @@ int main(int argc, char **argv)
 	int dev_index = 0;
 	int dev_given = 0;
 	int gain = 0;
+	int rtlagc = 0;
 	int ppm_error = 0;
 	int custom_ppm = 0;
 	struct llist *curelem,*prev;
@@ -388,12 +390,15 @@ int main(int argc, char **argv)
 	struct sigaction sigact, sigign;
 #endif
 
-	while ((opt = getopt(argc, argv, "a:p:f:g:s:b:n:d:P:")) != -1) {
+	while ((opt = getopt(argc, argv, "a:p:f:g:s:b:n:d:P:X")) != -1) {
 		switch (opt) {
 		case 'd':
 			dev_index = verbose_device_search(optarg);
 			dev_given = 1;
 			break;
+		case 'X':
+			rtlagc = 1;
+                        break;
 		case 'f':
 			frequency = (uint32_t)atofs(optarg);
 			break;
@@ -473,6 +478,14 @@ int main(int argc, char **argv)
 	else
 		fprintf(stderr, "Tuned to %i Hz.\n", frequency);
 
+       /* enable RTL_AGC */
+        if (rtlagc) {
+                fprintf(stderr,"Enabling RTL AGC\n");
+                verbose_set_rtlagc(dev);
+        }
+
+
+
 	if (0 == gain) {
 		 /* Enable automatic gain */
 		r = rtlsdr_set_tuner_gain_mode(dev, 0);