diff --git a/firmware/hackrf_usb/usb_api_sweep.c b/firmware/hackrf_usb/usb_api_sweep.c
index 503e7f6a..35656e81 100644
--- a/firmware/hackrf_usb/usb_api_sweep.c
+++ b/firmware/hackrf_usb/usb_api_sweep.c
@@ -31,31 +31,53 @@
 #define MIN(x,y)       ((x)<(y)?(x):(y))
 #define MAX(x,y)       ((x)>(y)?(x):(y))
 #define FREQ_GRANULARITY 1000000
-#define MIN_FREQ 1
-#define MAX_FREQ 6000
-#define MAX_FREQ_COUNT 1000
+#define MAX_RANGES 10
 #define THROWAWAY_BUFFERS 2
 
 volatile bool start_sweep_mode = false;
 static uint64_t sweep_freq;
-bool odd = true;
-static uint16_t frequencies[MAX_FREQ_COUNT];
-static uint16_t frequency_count = 0;
+static uint16_t frequencies[MAX_RANGES * 2];
+static unsigned char data[9 + MAX_RANGES * 2 * sizeof(frequencies[0])];
+static uint16_t num_ranges = 0;
 static uint32_t dwell_blocks = 0;
+static uint32_t step_width = 0;
+static uint32_t offset = 0;
+static enum sweep_style style = LINEAR;
 
 usb_request_status_t usb_vendor_request_init_sweep(
 		usb_endpoint_t* const endpoint, const usb_transfer_stage_t stage)
 {
-	uint32_t dwell_time;
+	uint32_t num_samples;
+	int i;
 	if (stage == USB_TRANSFER_STAGE_SETUP) {
-		dwell_time = (endpoint->setup.index << 16) | endpoint->setup.value;
-		dwell_blocks = dwell_time / 0x4000;
-		frequency_count = endpoint->setup.length / sizeof(uint16_t);
-		usb_transfer_schedule_block(endpoint->out, &frequencies,
-									endpoint->setup.length, NULL, NULL);
+		num_samples = (endpoint->setup.index << 16) | endpoint->setup.value;
+		dwell_blocks = num_samples / 0x4000;
+		if(1 > dwell_blocks) {
+			return USB_REQUEST_STATUS_STALL;
+		}
+		num_ranges = (endpoint->setup.length - 9) / (2 * sizeof(frequencies[0]));
+		if((1 > num_ranges) || (MAX_RANGES < num_ranges)) {
+			return USB_REQUEST_STATUS_STALL;
+		}
+		usb_transfer_schedule_block(endpoint->out, &data,
+				endpoint->setup.length, NULL, NULL);
 	} else if (stage == USB_TRANSFER_STAGE_DATA) {
-		sweep_freq = frequencies[0];
-		set_freq(sweep_freq*FREQ_GRANULARITY);
+		step_width = ((uint32_t)(data[3]) << 24) | ((uint32_t)(data[2]) << 16)
+				| ((uint32_t)(data[1]) << 8) | data[0];
+		if(1 > step_width) {
+			return USB_REQUEST_STATUS_STALL;
+		}
+		offset = ((uint32_t)(data[7]) << 24) | ((uint32_t)(data[6]) << 16)
+				| ((uint32_t)(data[5]) << 8) | data[4];
+		style = data[8];
+		if(INTERLEAVED < style) {
+			return USB_REQUEST_STATUS_STALL;
+		}
+		for(i=0; i<(num_ranges*2); i++) {
+			frequencies[i] = ((uint16_t)(data[10+i*2]) << 8) + data[9+i*2];
+		}
+		sweep_freq = (uint64_t)frequencies[0] * FREQ_GRANULARITY;
+		set_freq(sweep_freq + offset);
 		start_sweep_mode = true;
 		usb_transfer_schedule_ack(endpoint->in);
 	}
@@ -64,8 +86,9 @@ usb_request_status_t usb_vendor_request_init_sweep(
 
 void sweep_mode(void) {
 	unsigned int blocks_queued = 0;
-	unsigned int phase = 0;
-	unsigned int ifreq = 0;
+	unsigned int phase = 1;
+	bool odd = true;
+	uint16_t range = 0;
 
 	uint8_t *buffer;
 	bool transfer = false;
@@ -88,8 +111,16 @@ void sweep_mode(void) {
 		}
 
 		if (transfer) {
-			*(uint16_t*)buffer = 0x7F7F;
-			*(uint16_t*)(buffer+2) = sweep_freq;
+			*buffer = 0x7f;
+			*(buffer+1) = 0x7f;
+			*(buffer+2) = sweep_freq & 0xff;
+			*(buffer+3) = (sweep_freq >> 8) & 0xff;
+			*(buffer+4) = (sweep_freq >> 16) & 0xff;
+			*(buffer+5) = (sweep_freq >> 24) & 0xff;
+			*(buffer+6) = (sweep_freq >> 32) & 0xff;
+			*(buffer+7) = (sweep_freq >> 40) & 0xff;
+			*(buffer+8) = (sweep_freq >> 48) & 0xff;
+			*(buffer+9) = (sweep_freq >> 56) & 0xff;
 			if (blocks_queued > THROWAWAY_BUFFERS) {
 				usb_transfer_schedule_block(
 					&usb_endpoint_bulk_in,
@@ -102,10 +133,27 @@ void sweep_mode(void) {
 		}
 
 		if ((dwell_blocks + THROWAWAY_BUFFERS) <= blocks_queued) {
-			if(++ifreq >= frequency_count)
-				ifreq = 0;
-			sweep_freq = frequencies[ifreq];
-			set_freq(sweep_freq*FREQ_GRANULARITY);
+			if(INTERLEAVED == style) {
+				if(!odd && ((sweep_freq + step_width) >= ((uint64_t)frequencies[1+range*2] * FREQ_GRANULARITY))) {
+					range = (range + 1) % num_ranges;
+					sweep_freq = (uint64_t)frequencies[range*2] * FREQ_GRANULARITY;
+				} else {
+					if(odd) {
+						sweep_freq += step_width/4;
+					} else {
+						sweep_freq += 3*step_width/4;
+					}
+				}
+				odd = !odd;
+			} else {
+				if((sweep_freq + step_width) >= ((uint64_t)frequencies[1+range*2] * FREQ_GRANULARITY)) {
+					range = (range + 1) % num_ranges;
+					sweep_freq = (uint64_t)frequencies[range*2] * FREQ_GRANULARITY;
+				} else {
+					sweep_freq += step_width;
+				}
+			}
+			set_freq(sweep_freq + offset);
 			blocks_queued = 0;
 		}
 	}
diff --git a/firmware/hackrf_usb/usb_api_sweep.h b/firmware/hackrf_usb/usb_api_sweep.h
index 828647cd..20c27859 100644
--- a/firmware/hackrf_usb/usb_api_sweep.h
+++ b/firmware/hackrf_usb/usb_api_sweep.h
@@ -19,8 +19,8 @@
  * Boston, MA 02110-1301, USA.
  */
 
-#ifndef __USB_API_SCAN_H__
-#define __USB_API_SCAN_H__
+#ifndef __USB_API_SWEEP_H__
+#define __USB_API_SWEEP_H__
 
 #include <stdbool.h>
 #include <usb_type.h>
@@ -28,9 +28,14 @@
 
 extern volatile bool start_sweep_mode;
 
+enum sweep_style {
+	LINEAR = 0,
+	INTERLEAVED = 1,
+};
+
 usb_request_status_t usb_vendor_request_init_sweep(
 	usb_endpoint_t* const endpoint, const usb_transfer_stage_t stage);
 
 void sweep_mode(void);
 
-#endif /* __USB_API_SPCAN_H__ */
+#endif /* __USB_API_SWEEP_H__ */
diff --git a/host/hackrf-tools/src/hackrf_sweep.c b/host/hackrf-tools/src/hackrf_sweep.c
index dca716cf..2edd68cf 100644
--- a/host/hackrf-tools/src/hackrf_sweep.c
+++ b/host/hackrf-tools/src/hackrf_sweep.c
@@ -1,6 +1,7 @@
 /*
  * Copyright 2016 Dominic Spill <dominicgs@gmail.com>
  * Copyright 2016 Mike Walters <mike@flomp.net>
+ * Copyright 2017 Michael Ossmann <mike@ossmann.com>
  *
  * This file is part of HackRF.
  *
@@ -34,6 +35,7 @@
 #include <errno.h>
 #include <fftw3.h>
 #include <math.h>
+#include <inttypes.h>
 
 #define _FILE_OFFSET_BITS 64
 
@@ -87,21 +89,25 @@ int gettimeofday(struct timeval *tv, void* ignored) {
 
 #define FREQ_ONE_MHZ (1000000ull)
 
-#define FREQ_MIN_HZ	(0ull) /* 0 Hz */
-#define FREQ_MAX_HZ	(7250000000ull) /* 7250MHz */
+#define FREQ_MIN_MHZ (0)    /*    0 MHz */
+#define FREQ_MAX_MHZ (7250) /* 7250 MHz */
 
 #define DEFAULT_SAMPLE_RATE_HZ (20000000) /* 20MHz default sample rate */
 #define DEFAULT_BASEBAND_FILTER_BANDWIDTH (15000000) /* 5MHz default */
 
-#define FREQ_STEP (DEFAULT_SAMPLE_RATE_HZ / FREQ_ONE_MHZ)
-#define MAX_FREQ_COUNT 1000
+#define TUNE_STEP (DEFAULT_SAMPLE_RATE_HZ / FREQ_ONE_MHZ)
+#define OFFSET 7500000
 
 #define DEFAULT_SAMPLE_COUNT 0x4000
+#define BLOCKS_PER_TRANSFER 16
 
 #if defined _WIN32
 	#define sleep(a) Sleep( (a*1000) )
 #endif
 
+int num_ranges = 0;
+uint16_t frequencies[MAX_SWEEP_RANGES*2];
+
 static float TimevalDiff(const struct timeval *a, const struct timeval *b) {
    return (a->tv_sec - b->tv_sec) + 1e-6f * (a->tv_usec - b->tv_usec);
 }
@@ -166,15 +172,20 @@ uint32_t amp_enable;
 bool antenna = false;
 uint32_t antenna_enable;
 
-uint32_t freq_min;
-uint32_t freq_max;
+bool binary_output = false;
+bool one_shot = false;
+volatile bool sweep_started = false;
 
-int fftSize;
+int fftSize = 20;
+uint32_t fft_bin_width;
 fftwf_complex *fftwIn = NULL;
 fftwf_complex *fftwOut = NULL;
 fftwf_plan fftwPlan = NULL;
 float* pwr;
 float* window;
+time_t time_now;
+struct tm *fft_time;
+char time_str[50];
 
 float logPower(fftwf_complex in, float scale)
 {
@@ -185,64 +196,112 @@ float logPower(fftwf_complex in, float scale)
 }
 
 int rx_callback(hackrf_transfer* transfer) {
-	/* This is where we need to do interesting things with the samples
-	 * FFT
-	 * Throw away unused bins
-	 * write output to pipe
-	 */
-	ssize_t bytes_to_write;
-	ssize_t bytes_written;
 	int8_t* buf;
-	float frequency;
+	uint8_t* ubuf;
+	uint64_t frequency; /* in Hz */
+	float float_freq;
 	int i, j;
 
-	if( fd != NULL ) {
-		byte_count += transfer->valid_length;
-		bytes_to_write = transfer->valid_length;
-		buf = (int8_t*) transfer->buffer;
-		for(j=0; j<16; j++) {
-			if(buf[0] == 0x7F && buf[1] == 0x7F) {
-				frequency = *(uint16_t*)&buf[2];
-			}
-			/* copy to fftwIn as floats */
-			buf += 16384 - (fftSize * 2);
-			for(i=0; i < fftSize; i++) {
-				fftwIn[i][0] = buf[i*2] * window[i] * 1.0f / 128.0f;
-				fftwIn[i][1] = buf[i*2+1] * window[i] * 1.0f / 128.0f;
-			}
-			buf += fftSize * 2;
-			fftwf_execute(fftwPlan);
-			for (i=0; i < fftSize; i++) {
-				// Start from the middle of the FFTW array and wrap
-				// to rearrange the data
-				int k = i ^ (fftSize >> 1);
-				pwr[i] = logPower(fftwOut[k], 1.0f / fftSize);
-			}
-			fwrite(&frequency, sizeof(float), 1, stdout);
-			fwrite(pwr, sizeof(float), fftSize, stdout);
-		}
-
-		bytes_written = fwrite(transfer->buffer, 1, bytes_to_write, fd);
-		if (bytes_written != bytes_to_write) {
-			return -1;
-		} else {
-			return 0;
-		}
-	} else {
+	if(NULL == fd) {
 		return -1;
 	}
+
+	byte_count += transfer->valid_length;
+	buf = (int8_t*) transfer->buffer;
+	for(j=0; j<BLOCKS_PER_TRANSFER; j++) {
+		if(do_exit) {
+			return 0;
+		}
+		ubuf = (uint8_t*) buf;
+		if(ubuf[0] == 0x7F && ubuf[1] == 0x7F) {
+			frequency = ((uint64_t)(ubuf[9]) << 56) | ((uint64_t)(ubuf[8]) << 48) | ((uint64_t)(ubuf[7]) << 40)
+					| ((uint64_t)(ubuf[6]) << 32) | ((uint64_t)(ubuf[5]) << 24) | ((uint64_t)(ubuf[4]) << 16)
+					| ((uint64_t)(ubuf[3]) << 8) | ubuf[2];
+		} else {
+			buf += SAMPLES_PER_BLOCK;
+			continue;
+		}
+		if(!sweep_started) {
+			if (frequency == (uint64_t)(FREQ_ONE_MHZ*frequencies[0])) {
+				sweep_started = true;
+			} else {
+				buf += SAMPLES_PER_BLOCK;
+				continue;
+			}
+		}
+		if((FREQ_MAX_MHZ * FREQ_ONE_MHZ) < frequency) {
+			buf += SAMPLES_PER_BLOCK;
+			continue;
+		}
+		/* copy to fftwIn as floats */
+		buf += SAMPLES_PER_BLOCK - (fftSize * 2);
+		for(i=0; i < fftSize; i++) {
+			fftwIn[i][0] = buf[i*2] * window[i] * 1.0f / 128.0f;
+			fftwIn[i][1] = buf[i*2+1] * window[i] * 1.0f / 128.0f;
+		}
+		buf += fftSize * 2;
+		fftwf_execute(fftwPlan);
+		for (i=0; i < fftSize; i++) {
+			pwr[i] = logPower(fftwOut[i], 1.0f / fftSize);
+		}
+		if(binary_output) {
+			float_freq = frequency + DEFAULT_SAMPLE_RATE_HZ / 4;
+			float_freq /= FREQ_ONE_MHZ;
+			fwrite(&float_freq, sizeof(float), 1, stdout);
+			fwrite(&pwr[1+(fftSize*5)/8], sizeof(float), fftSize/4, stdout);
+			float_freq = frequency + DEFAULT_SAMPLE_RATE_HZ / 2;
+			float_freq /= FREQ_ONE_MHZ;
+			fwrite(&float_freq, sizeof(float), 1, stdout);
+			fwrite(&pwr[1+fftSize/8], sizeof(float), fftSize/4, stdout);
+		} else {
+			time_now = time(NULL);
+			fft_time = localtime(&time_now);
+			strftime(time_str, 50, "%Y-%m-%d, %H:%M:%S", fft_time);
+			printf("%s, %" PRIu64 ", %" PRIu64 ", %.2f, %u",
+					time_str,
+					(uint64_t)(frequency),
+					(uint64_t)(frequency+DEFAULT_SAMPLE_RATE_HZ/4),
+					(float)fft_bin_width,
+					fftSize);
+			for(i=1+(fftSize*5)/8; (1+(fftSize*7)/8) > i; i++) {
+				printf(", %.2f", pwr[i]);
+			}
+			printf("\n");
+			printf("%s, %" PRIu64 ", %" PRIu64 ", %.2f, %u",
+					time_str,
+					(uint64_t)(frequency+(DEFAULT_SAMPLE_RATE_HZ/2)),
+					(uint64_t)(frequency+((DEFAULT_SAMPLE_RATE_HZ*3)/4)),
+					(float)fft_bin_width,
+					fftSize);
+			for(i=1+fftSize/8; (1+(fftSize*3)/8) > i; i++) {
+				printf(", %.2f", pwr[i]);
+			}
+			printf("\n");
+		}
+		if(one_shot && ((uint64_t)(frequency+((DEFAULT_SAMPLE_RATE_HZ*3)/4))
+				>= (uint64_t)(FREQ_ONE_MHZ*frequencies[num_ranges*2-1]))) {
+			do_exit = true;
+		}
+	}
+	return 0;
 }
 
 static void usage() {
 	fprintf(stderr, "Usage:\n");
 	fprintf(stderr, "\t[-h] # this help\n");
-	fprintf(stderr, "\t[-d serial_number] # Serial number of desired HackRF.\n");
-	fprintf(stderr, "\t[-a amp_enable] # RX RF amplifier 1=Enable, 0=Disable.\n");
-	fprintf(stderr, "\t[-f freq_min:freq_max # Specify minimum & maximum sweep frequencies (MHz).\n");
-	fprintf(stderr, "\t[-p antenna_enable] # Antenna port power, 1=Enable, 0=Disable.\n");
+	fprintf(stderr, "\t[-d serial_number] # Serial number of desired HackRF\n");
+	fprintf(stderr, "\t[-a amp_enable] # RX RF amplifier 1=Enable, 0=Disable\n");
+	fprintf(stderr, "\t[-f freq_min:freq_max] # minimum and maximum frequencies in MHz\n");
+	fprintf(stderr, "\t[-p antenna_enable] # Antenna port power, 1=Enable, 0=Disable\n");
 	fprintf(stderr, "\t[-l gain_db] # RX LNA (IF) gain, 0-40dB, 8dB steps\n");
 	fprintf(stderr, "\t[-g gain_db] # RX VGA (baseband) gain, 0-62dB, 2dB steps\n");
 	fprintf(stderr, "\t[-n num_samples] # Number of samples per frequency, 16384-4294967296\n");
+	fprintf(stderr, "\t[-w bin_width] # FFT bin width (frequency resolution) in Hz\n");
+	fprintf(stderr, "\t[-1] # one shot mode\n");
+	fprintf(stderr, "\t[-B] # binary output\n");
+	fprintf(stderr, "\n");
+	fprintf(stderr, "Output fields:\n");
+	fprintf(stderr, "\tdate, time, hz_low, hz_high, hz_bin_width, num_samples, dB, dB, . . .\n");
 }
 
 static hackrf_device* device = NULL;
@@ -265,18 +324,20 @@ void sigint_callback_handler(int signum)  {
 #endif
 
 int main(int argc, char** argv) {
-	int opt, i, result, ifreq = 0;
-	bool odd;
+	int opt, i, result = 0;
 	const char* path = "/dev/null";
 	const char* serial_number = NULL;
 	int exit_code = EXIT_SUCCESS;
 	struct timeval t_end;
 	float time_diff;
 	unsigned int lna_gain=16, vga_gain=20;
-	uint16_t frequencies[MAX_FREQ_COUNT];
 	uint32_t num_samples = DEFAULT_SAMPLE_COUNT;
+	int step_count;
+	uint32_t freq_min = 0;
+	uint32_t freq_max = 6000;
 
-	while( (opt = getopt(argc, argv, "a:f:p:l:g:d:n:h?")) != EOF ) {
+
+	while( (opt = getopt(argc, argv, "a:f:p:l:g:d:n:w:1Bh?")) != EOF ) {
 		result = HACKRF_SUCCESS;
 		switch( opt ) 
 		{
@@ -291,17 +352,29 @@ int main(int argc, char** argv) {
 
 		case 'f':
 			result = parse_u32_range(optarg, &freq_min, &freq_max);
-			fprintf(stderr, "Scanning %uMHz to %uMHz\n", freq_min, freq_max);
-			frequencies[ifreq++] = freq_min;
-			odd = true;
-			while(frequencies[ifreq-1] <= freq_max) {
-				if (odd)
-					frequencies[ifreq] = frequencies[ifreq-1] + FREQ_STEP / 4;
-				else
-					frequencies[ifreq] = frequencies[ifreq-1] + 3*(FREQ_STEP/4);
-				ifreq++;
-				odd = !odd;
+			if(freq_min >= freq_max) {
+				fprintf(stderr,
+						"argument error: freq_max must be greater than freq_min.\n");
+				usage();
+				return EXIT_FAILURE;
 			}
+			if(FREQ_MAX_MHZ <freq_max) {
+				fprintf(stderr,
+						"argument error: freq_max may not be higher than %u.\n",
+						FREQ_MAX_MHZ);
+				usage();
+				return EXIT_FAILURE;
+			}
+			if(MAX_SWEEP_RANGES <= num_ranges) {
+				fprintf(stderr,
+						"argument error: specify a maximum of %u frequency ranges.\n",
+						MAX_SWEEP_RANGES);
+				usage();
+				return EXIT_FAILURE;
+			}
+			frequencies[2*num_ranges] = (uint16_t)freq_min;
+			frequencies[2*num_ranges+1] = (uint16_t)freq_max;
+			num_ranges++;
 			break;
 
 		case 'p':
@@ -321,6 +394,19 @@ int main(int argc, char** argv) {
 			result = parse_u32(optarg, &num_samples);
 			break;
 
+		case 'w':
+			result = parse_u32(optarg, &fft_bin_width);
+			fftSize = DEFAULT_SAMPLE_RATE_HZ / fft_bin_width;
+			break;
+
+		case '1':
+			one_shot = true;
+			break;
+
+		case 'B':
+			binary_output = true;
+			break;
+
 		case 'h':
 		case '?':
 			usage();
@@ -345,12 +431,12 @@ int main(int argc, char** argv) {
 	if (vga_gain % 2)
 		fprintf(stderr, "warning: vga_gain (-g) must be a multiple of 2\n");
 
-	if (num_samples % 0x4000) {
+	if (num_samples % SAMPLES_PER_BLOCK) {
 		fprintf(stderr, "warning: num_samples (-n) must be a multiple of 16384\n");
 		return EXIT_FAILURE;
 	}
 
-	if (num_samples < 0x4000) {
+	if (num_samples < SAMPLES_PER_BLOCK) {
 		fprintf(stderr, "warning: num_samples (-n) must be at least 16384\n");
 		return EXIT_FAILURE;
 	}
@@ -371,16 +457,36 @@ int main(int argc, char** argv) {
 		}
 	}
 
-	if (ifreq == 0) {
-		fprintf(stderr, "argument error: must specify sweep frequency range (-f).\n");
-		usage();
+	if (0 == num_ranges) {
+		frequencies[0] = (uint16_t)freq_min;
+		frequencies[1] = (uint16_t)freq_max;
+		num_ranges++;
+	}
+
+	if(4 > fftSize) {
+		fprintf(stderr,
+				"argument error: FFT bin width (-w) must be no more than one quarter the sample rate\n");
 		return EXIT_FAILURE;
 	}
-	
-	fftSize = 64;
-    fftwIn = (fftwf_complex*)fftwf_malloc(sizeof(fftwf_complex) * fftSize);
-    fftwOut = (fftwf_complex*)fftwf_malloc(sizeof(fftwf_complex) * fftSize);
-    fftwPlan = fftwf_plan_dft_1d(fftSize, fftwIn, fftwOut, FFTW_FORWARD, FFTW_MEASURE);
+
+	if(16368 < fftSize) {
+		fprintf(stderr,
+				"argument error: FFT bin width (-w) too small, resulted in more than 16368 FFT bins\n");
+		return EXIT_FAILURE;
+	}
+
+	/* In interleaved mode, the FFT bin selection works best if the total
+	 * number of FFT bins is equal to an odd multiple of four.
+	 * (e.g. 4, 12, 20, 28, 36, . . .)
+	 */
+	while((fftSize + 4) % 8) {
+		fftSize++;
+	}
+
+	fft_bin_width = DEFAULT_SAMPLE_RATE_HZ / fftSize;
+	fftwIn = (fftwf_complex*)fftwf_malloc(sizeof(fftwf_complex) * fftSize);
+	fftwOut = (fftwf_complex*)fftwf_malloc(sizeof(fftwf_complex) * fftSize);
+	fftwPlan = fftwf_plan_dft_1d(fftSize, fftwIn, fftwOut, FFTW_FORWARD, FFTW_MEASURE);
 	pwr = (float*)fftwf_malloc(sizeof(float) * fftSize);
 	window = (float*)fftwf_malloc(sizeof(float) * fftSize);
 	for (i = 0; i < fftSize; i++) {
@@ -453,7 +559,21 @@ int main(int argc, char** argv) {
 		return EXIT_FAILURE;
 	}
 
-	result = hackrf_init_sweep(device, frequencies, ifreq, num_samples);
+	/*
+	 * For each range, plan a whole number of tuning steps of a certain
+	 * bandwidth. Increase high end of range if necessary to accommodate a
+	 * whole number of steps, minimum 1.
+	 */
+	for(i = 0; i < num_ranges; i++) {
+		step_count = 1 + (frequencies[2*i+1] - frequencies[2*i] - 1)
+				/ TUNE_STEP;
+		frequencies[2*i+1] = frequencies[2*i] + step_count * TUNE_STEP;
+		fprintf(stderr, "Sweeping from %u MHz to %u MHz\n",
+				frequencies[2*i], frequencies[2*i+1]);
+	}
+
+	result = hackrf_init_sweep(device, frequencies, num_ranges, num_samples,
+			TUNE_STEP * FREQ_ONE_MHZ, OFFSET, INTERLEAVED);
 	if( result != HACKRF_SUCCESS ) {
 		fprintf(stderr, "hackrf_init_sweep() failed: %s (%d)\n",
 			   hackrf_error_name(result), result);
diff --git a/host/libhackrf/src/hackrf.c b/host/libhackrf/src/hackrf.c
index 5bb71dc6..61de081d 100644
--- a/host/libhackrf/src/hackrf.c
+++ b/host/libhackrf/src/hackrf.c
@@ -1810,23 +1810,70 @@ int ADDCALL hackrf_set_hw_sync_mode(hackrf_device* device, const uint8_t value)
 	}
 }
 
-/* Initialise sweep mode with alist of frequencies and dwell time in samples */
-int ADDCALL hackrf_init_sweep(hackrf_device* device, uint16_t* frequency_list, int length, uint32_t dwell_time)
-{
+/*
+ * Initialize sweep mode:
+ * frequency_list is a list of start/stop pairs of frequencies in MHz.
+ * num_ranges is the number of pairs in frequency_list (1 to 10)
+ * num_samples is the number of samples to capture after each tuning.
+ * step_width is the width in Hz of the tuning step.
+ * offset is a number of Hz added to every tuning frequency.
+ *     Use to select center frequency based on the expected usable bandwidth.
+ * sweep_mode
+ *     LINEAR means step_width is added to the current frequency at each step.
+ *     INTERLEAVED invokes a scheme in which each step is divided into two
+ *         interleaved sub-steps, allowing the host to select the best portions
+ *         of the FFT of each sub-step and discard the rest.
+ */
+int ADDCALL hackrf_init_sweep(hackrf_device* device,
+		const uint16_t* frequency_list, const int num_ranges,
+		const uint32_t num_samples, const uint32_t step_width,
+		const uint32_t offset, const enum sweep_style style) {
 	USB_API_REQUIRED(device, 0x0102)
 	int result, i;
-	int size = length * sizeof(frequency_list[0]);
+	unsigned char data[9 + MAX_SWEEP_RANGES * 2 * sizeof(frequency_list[0])];
+	int size = 9 + num_ranges * 2 * sizeof(frequency_list[0]);
 
-	for(i=0; i<length; i++)
-		frequency_list[i] = TO_LE(frequency_list[i]);
+	if((num_ranges < 1) || (num_ranges > MAX_SWEEP_RANGES)){
+		return HACKRF_ERROR_INVALID_PARAM;
+	}
+
+	if(num_samples % SAMPLES_PER_BLOCK) {
+		return HACKRF_ERROR_INVALID_PARAM;
+	}
+
+	if(SAMPLES_PER_BLOCK < num_samples) {
+		return HACKRF_ERROR_INVALID_PARAM;
+	}
+
+	if(1 > step_width) {
+		return HACKRF_ERROR_INVALID_PARAM;
+	}
+
+	if(INTERLEAVED < style) {
+		return HACKRF_ERROR_INVALID_PARAM;
+	}
+
+	data[0] = step_width & 0xff;
+	data[1] = (step_width >> 8) & 0xff;
+	data[2] = (step_width >> 16) & 0xff;
+	data[3] = (step_width >> 24) & 0xff;
+	data[4] = offset & 0xff;
+	data[5] = (offset >> 8) & 0xff;
+	data[6] = (offset >> 16) & 0xff;
+	data[7] = (offset >> 24) & 0xff;
+	data[8] = style;
+	for(i=0; i<(num_ranges*2); i++) {
+		data[9+i*2] = frequency_list[i] & 0xff;
+		data[10+i*2] = (frequency_list[i] >> 8) & 0xff;
+	}
 
 	result = libusb_control_transfer(
 		device->usb_device,
 		LIBUSB_ENDPOINT_OUT | LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_RECIPIENT_DEVICE,
 		HACKRF_VENDOR_REQUEST_INIT_SWEEP,
-		dwell_time & 0xffff,
-		(dwell_time >> 16) & 0xffff,
-		(unsigned char*)frequency_list,
+		num_samples & 0xffff,
+		(num_samples >> 16) & 0xffff,
+		data,
 		size,
 		0
 	);
diff --git a/host/libhackrf/src/hackrf.h b/host/libhackrf/src/hackrf.h
index 904207e0..a92f5051 100644
--- a/host/libhackrf/src/hackrf.h
+++ b/host/libhackrf/src/hackrf.h
@@ -47,6 +47,9 @@ ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSI
 
 #endif
 
+#define SAMPLES_PER_BLOCK 16384
+#define MAX_SWEEP_RANGES 10
+
 enum hackrf_error {
 	HACKRF_SUCCESS = 0,
 	HACKRF_TRUE = 1,
@@ -95,6 +98,11 @@ enum operacake_ports {
 	OPERACAKE_PB4 = 7,
 };
 
+enum sweep_style {
+	LINEAR = 0,
+	INTERLEAVED = 1,
+};
+
 typedef struct hackrf_device hackrf_device;
 
 typedef struct {
@@ -218,10 +226,11 @@ extern ADDAPI uint32_t ADDCALL hackrf_compute_baseband_filter_bw(const uint32_t
 /* set hardware sync mode  */
 extern ADDAPI int ADDCALL hackrf_set_hw_sync_mode(hackrf_device* device, const uint8_t value);
 
-/* Start scan mode */
+/* Start sweep mode */
 extern ADDAPI int ADDCALL hackrf_init_sweep(hackrf_device* device,
-											uint16_t* frequency_list,
-											int length, uint32_t dwell_time);
+		const uint16_t* frequency_list, const int num_ranges,
+		const uint32_t num_samples, const uint32_t step_width,
+		const uint32_t offset, const enum sweep_style style);
 
 /* Operacake functions */
 extern ADDAPI int ADDCALL hackrf_get_operacake_boards(hackrf_device* device, uint8_t* boards);