rtl_power: doc corrections

src/rtl_power.c

@@ -156,6 +156,7 @@ void usage(void)
 		"Use:\trtl_power -f freq_range [-options] [-f freq2 -opts2] [filename]\n"
 		"\t-f lower:upper:bin_size [Hz]\n"
 		"\t  valid range for bin_size is 1Hz - 2.8MHz\n"
+		"\t  multiple frequency ranges are supported\n"
 		"\t[-i integration_interval (default: 10 seconds)]\n"
 		"\t  buggy if a full sweep takes longer than the interval\n"
 		"\t[-1 enables single-shot mode (default: off)]\n"
@@ -179,8 +180,9 @@ void usage(void)
 		"\t[-F fir_size (default: disabled)]\n"
 		"\t  enables low-leakage downsample filter,\n"
 		"\t  fir_size can be 0 or 9.  0 has bad roll off,\n"
-		"\t try with '-c 50%%'\n"
+		"\t  try -F 0 with '-c 50%%' to hide the roll off\n"
 		"\t[-r max_sample_rate (default: 2.4M)]\n"
+		"\t  possible values are 2M to 3.2M\n"
 		"\t[-P enables peak hold (default: off/averaging)]\n"
 		"\t[-L enable linear output (default: off/dB)]\n"
 		"\t[-D direct_sampling_mode, 0 (default/off), 1 (I), 2 (Q), 3 (no-mod)]\n"
@@ -198,6 +200,8 @@ void usage(void)
 		"\t  integrate for 15 minutes and exit afterwards\n"
 		"\trtl_power -f ... -e 1h | gzip > log.csv.gz\n"
 		"\t  collect data for one hour and compress it on the fly\n\n"
+		"\tIf you have issues writing +2GB logs on a 32bit platform\n"
+		"\tuse redirection (rtl_power ... > filename.csv) instead\n\n "
 		"Convert CSV to a waterfall graphic with:\n"
 		"  https://github.com/keenerd/rtl-sdr-misc/blob/master/heatmap/heatmap.py \n"
 		"More examples at http://kmkeen.com/rtl-power/\n");