diff --git a/src/ch.c b/src/ch.c
index 57411bd9b..89f7a2b4e 100644
--- a/src/ch.c
+++ b/src/ch.c
@@ -87,8 +87,10 @@ int main(int argc, char *argv[])
     float          hf_gain;
     COMP          *ch_fdm_delay = NULL, aspread, aspread_2ms, delayed, direct;
     float          tx_pwr, tx_pwr_fade, noise_pwr, user_multipath_delay;
-    int            frames, i, j, k, Fs, ret, nclipped, noutclipped, ssbfilt_en, complex_out, ctest;
-    float          sam, peak, clip, papr, CNo, snr3k, gain;
+    int            frames, i, j, k, Fs, ret, nclipped, noutclipped, ssbfilt_en,
+                   complex_out, ctest, impulse_en, impulse_clock, impulse_wait_samples,
+                   impulse_state;
+    float          sam, peak, clip, papr, CNo, snr3k, gain, impulse_period;
 
     if (argc < 3) {
     helpmsg:
@@ -97,7 +99,7 @@ int main(int argc, char *argv[])
                         "usage: %s InputRealModemRawFile OutputRealModemRawFile [Options]\n"
                         "\n"
                         "  real int16 input -> Gain -> Hilbert Transform -> clipper -> freq shift ->\n"
-                        "  Multipath -> AWGN noise -> SSB filter -> real int16 output\n"
+                        "  Multipath -> AWGN+impulse noise -> SSB filter -> real int16 output\n"
                         "\n"
                         "[--clip int16]         Hilbert clipper (clip complex signal magnitude, default 32767)\n"
                         "[--complexout]         Optional int16 IQ complex output (default real int16)\n"
@@ -111,7 +113,8 @@ int main(int argc, char *argv[])
                         "[--mpd]                Multipath disturbed 2.0Hz Doppler, 4.0ms delay\n"
                         "[--ssbfilt 0|1]        SSB bandwidth filter (default 1 on)\n"
                         "[--mulipath_delay ms]  Optionally adjust multipath delay\n"
-                        "[--No dBHz]            AWGN Noise density dB/Hz (default -100)"
+                        "[--No dBHz]            AWGN Noise density dB/Hz (default -100)\n"
+                        "[--impulse ms]         simulate impulse noise with mean ms\n"
                         "\n"
                 , argv[0]);
         exit(1);
@@ -135,6 +138,7 @@ int main(int argc, char *argv[])
     Fs = 8000; foff_hz = 0.0; fading_en = 0; ctest = 0;
     clip =32767; gain = 1.0;
     ssbfilt_en = 1; complex_out = 0;
+    impulse_en = 0; impulse_period = 0.0; impulse_state = 0;    
     fading_dir = strdup(DEFAULT_FADING_DIR); user_multipath_delay = -1.0;
 
     int o = 0;
@@ -155,10 +159,11 @@ int main(int argc, char *argv[])
             {"mpd",             no_argument,        0, 'd'},
             {"multipath_delay", required_argument,  0, 'm'},
             {"No",              required_argument,  0, 'n'},
-            {0, 0, 0, 0}
+            {"impulse",         required_argument,  0, 'j'},
+           {0, 0, 0, 0}
         };
 
-        o = getopt_long(argc,argv,"c:df:g:im:n:opr:s:tu:h",long_opts,&opt_idx);
+        o = getopt_long(argc,argv,"c:df:g:im:n:opr:s:tu:hj:",long_opts,&opt_idx);
         
         switch(o) {
         case 'c':
@@ -200,6 +205,10 @@ int main(int argc, char *argv[])
         case 'u':
             fading_dir = strdup(optarg);
             break;
+        case 'j':
+            impulse_en = 1;
+            impulse_period = atof(optarg);
+            break;
         case 'h':
         case '?':
             goto helpmsg;
@@ -215,7 +224,8 @@ int main(int argc, char *argv[])
     // units more sensible, and fix all the tests that depend on this scaling
     No = pow(10.0, NodB/10.0)*1000*1000;
     variance = Fs*No;
-
+    impulse_clock = 0; impulse_wait_samples = 0;
+    
     tx_pwr = tx_pwr_fade = noise_pwr = 0.0;
     noutclipped = 0; nclipped = 0;
     peak = 0.0;
@@ -408,6 +418,39 @@ int main(int argc, char *argv[])
             noise_pwr += pow(scaled_noise.real, 2.0) + pow(scaled_noise.imag, 2.0);
         }
 
+        /* Impulse noise --------------------------------------*/
+
+        /* we simulate front end overload (e.g. static crash) by
+           dropping out the channel for 10ms */
+        
+        if (impulse_en) {
+            for(i=0; i<BUF_N; i++) {
+                impulse_clock++;
+                int next_state = impulse_state;
+                switch(impulse_state) {
+                case 0:
+                    if (impulse_clock >= impulse_wait_samples) {
+                        impulse_clock = 0;
+                        impulse_wait_samples = 0.01*Fs;
+                        next_state = 1;
+                    }
+                    break;
+                case 1:
+                    ch_fdm[i].real = 32767; ch_fdm[i].imag = 32767;
+                    if (impulse_clock >= impulse_wait_samples) {
+                        impulse_clock = 0;
+                        // std dev of time to next impulse is mean period/2  
+                        float impulse_wait_s = impulse_period/1000.0 + (impulse_period/2000.0)*gaussian();
+                        if (impulse_wait_s < 0) impulse_wait_s = 0;
+                        impulse_wait_samples = impulse_wait_s*Fs;
+                        next_state = 0;
+                    }
+                    break;
+                }
+                impulse_state = next_state;
+            }
+        }
+
         /* FIR filter to simulate (a rather flat) SSB filter. We
            filter the complex signal by shifting it down to DC and
            using real coefficients. */