diff --git a/main.cpp b/main.cpp
index 7fa5fde..3c22add 100644
--- a/main.cpp
+++ b/main.cpp
@@ -97,6 +97,31 @@ static void poh_thread()
     }
 }
 
+static std::atomic<bool> ls_accept_input;
+static std::binary_semaphore ls_input_ready{0};
+static std::complex<float> ls_input_block[block_len];
+static std::mutex wf_ls_mutex;
+static unsigned int wf_ls[wf_width*wf_height];
+
+static void ls_thread()
+{
+    std::vector<float> block_mag(block_len);
+
+    while(!shutdown_threads) {
+        ls_accept_input = true;
+        ls_input_ready.acquire();
+        fft_mag(ls_input_block, block_mag.data(), block_len);
+        {
+            std::lock_guard<std::mutex> guard(wf_ls_mutex);
+            std::memmove(&wf_ls[wf_width], &wf_ls[0], sizeof(int)*wf_width*(wf_height - 1));
+            for(int i=0;i<wf_width;i++) {
+                int j = i*block_len/wf_width;
+                wf_ls[i] = 0xff000000 | 0x010101*std::min(int(block_mag[j]/900.0f), 255);
+            }
+        }
+    }
+}
+
 static std::atomic<int> frames_processed;
 static std::atomic<int> frames_dropped;
 
@@ -107,15 +132,16 @@ static int brf_frames_dropped_cnt = 0;
 static void* brf_dispatch(struct bladerf* dev, struct bladerf_stream* stream,
     struct bladerf_metadata* meta, void* samples_v, size_t num_samples, void* user_data)
 {
-    if(poh_accept_input) {
+    if(poh_accept_input && ls_accept_input) {
         std::complex<int16_t>* samples = (std::complex<int16_t>*)samples_v;
-
         for(size_t i=0;i<block_len;i++) {
             poh_input_block[i] = samples[2*i];
+            ls_input_block[i] = samples[2*i+1];
         }
-
         poh_accept_input = false;
         poh_input_ready.release();
+        ls_accept_input = false;
+        ls_input_ready.release();
         brf_frames_processed_cnt++;
     } else
         brf_frames_dropped_cnt++;
@@ -261,6 +287,12 @@ int main(int argc, char* argv[])
     };
     std::atexit(JoinPOH);
 
+    static std::thread ls_thread_h = std::thread(ls_thread);
+    static auto JoinLS = []() {
+        ls_thread_h.join();
+    };
+    std::atexit(JoinLS);
+
     static std::thread tec_thread_h = std::thread(tec_thread);
     static auto JoinTEC = []() {
         tec_thread_h.join();
@@ -294,8 +326,8 @@ int main(int argc, char* argv[])
             }
             glBindTexture(GL_TEXTURE_2D, wftex[1]);
             {
-                std::lock_guard<std::mutex> guard(wf_poh_mutex);
-                glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, wf_width, wf_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, wf_poh);
+                std::lock_guard<std::mutex> guard(wf_ls_mutex);
+                glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, wf_width, wf_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, wf_ls);
             }
         }