diff --git a/src/include/jalocha/pj_mfsk.h b/src/include/jalocha/pj_mfsk.h
index e19e9cad..c475a69a 100755
--- a/src/include/jalocha/pj_mfsk.h
+++ b/src/include/jalocha/pj_mfsk.h
@@ -413,13 +413,21 @@ public:
 
 // the symbol shape described in frequency domain
 static const double MFSK_SymbolFreqShape[] =
-// { 1.0, 1.0 } ;
- {  +1.0000000000, 
-    +1.1913785723, 
-    -0.0793018558, 
-    -0.2171442026, 
-    -0.0014526076 
-};
+ { 1.0, 1.0 } ; // use raised cosine shape - experimental
+// from gMFSK
+// {  +1.0000000000, 
+//    +1.1913785723, 
+//    -0.0793018558, 
+//    -0.2171442026, 
+//    -0.0014526076 
+//};
+// from DM780
+//{
+//	+1.0000000000,
+//	+2.1373197349,
+//	+1.1207588117,
+//	-0.0165609232 
+//};
 
 static const size_t MFSK_SymbolFreqShapeLen = 
     sizeof(MFSK_SymbolFreqShape) / sizeof(double);
@@ -595,8 +603,12 @@ private:
     void AddSymbol(int Freq, int Phase) {
         size_t Time;
         for (Time = 0; Time < SymbolLen; Time++) {
-            // Type Shape=1.0-CosineTable[Time];
-            OutTap[TapPtr] += CosineTable[Phase] * SymbolShape[Time];
+// experimental use with {1.0, 1.0};
+            Type Shape=1.0-CosineTable[Time];
+            OutTap[TapPtr] += CosineTable[Phase] * Shape;
+            
+//            OutTap[TapPtr] += CosineTable[Phase] * SymbolShape[Time];
+
             Phase += Freq;
             Phase &= WrapMask;
             TapPtr += 1;
diff --git a/src/olivia/olivia.cxx b/src/olivia/olivia.cxx
index 8de6cb29..b405a2c1 100755
--- a/src/olivia/olivia.cxx
+++ b/src/olivia/olivia.cxx
@@ -86,8 +86,13 @@ void olivia::tx_init(SoundBase *sc)
 void olivia::send_preamble()
 {
 	double freqa, freqb;
-    int i, sr4 = samplerate / 4;
-
+    int i, j, sr4 = samplerate / 4;
+    double ampshape[sr4];
+    
+    for (int i = 0; i < sr4; i++) ampshape[i] = 1.0;
+    for (int i = 0; i < sr4 / 4; i++)
+        ampshape[i] = ampshape[sr4 - 1 - i] = 0.5 * (1.0 - cos(M_PI * i / (sr4/4)));
+        
 	if (reverse) { 
 		freqa = txbasefreq + (bandwidth / 2.0); 
 		freqb = txbasefreq - (bandwidth / 2.0); 
@@ -96,22 +101,27 @@ void olivia::send_preamble()
 		freqb = txbasefreq + (bandwidth / 2.0); 
 	}
 
-	for (i = 0; i < sr4; i++)
-		outbuf[i] = nco(freqa);
-	for (i = sr4; i < 2*sr4; i++)
-		outbuf[i] = nco(freqb);
-	for (i = 2*sr4; i < 3*sr4; i++)
-		outbuf[i] = nco(freqa);
-	for (i = 3*sr4; i < samplerate; i++)
-		outbuf[i] = nco(freqb);
+	for (i = 0, j = 0; i < sr4; i++, j++)
+		outbuf[i] = nco(freqa) * ampshape[j];
+	for (i = sr4, j = 0; i < 2*sr4; i++, j++)
+		outbuf[i] = nco(freqb) * ampshape[j];
+	for (i = 2*sr4, j = 0; i < 3*sr4; i++, j++)
+		outbuf[i] = nco(freqa) * ampshape[j];
+	for (i = 3*sr4, j = 0; i < samplerate; i++, j++)
+		outbuf[i] = nco(freqb) * ampshape[j];
 	ModulateXmtr(outbuf, samplerate);
 }
 
 void olivia::send_postamble()
 {
 	double freqa, freqb;
-	int i, sr4 = samplerate / 4;
-
+	int i, j, sr4 = samplerate / 4;
+    double ampshape[sr4];
+    
+    for (int i = 0; i < sr4; i++) ampshape[i] = 1.0;
+    for (int i = 0; i < sr4 / 8; i++)
+        ampshape[i] = ampshape[sr4 - 1 - i] = 0.5 * (1.0 - cos(M_PI * i / (sr4/8)));
+        
 	if (reverse) { 
 		freqa = txbasefreq + (bandwidth / 2.0); 
 		freqb = txbasefreq - (bandwidth / 2.0); 
@@ -120,14 +130,14 @@ void olivia::send_postamble()
 		freqb = txbasefreq + (bandwidth / 2.0); 
 	}
 
-	for (i = 0; i < sr4; i++)
-		outbuf[i] = nco(freqa);
-	for (i = sr4; i < 2*sr4; i++)
-		outbuf[i] = nco(freqb);
-	for (i = 2*sr4; i < 3*sr4; i++)
-		outbuf[i] = nco(freqa);
-	for (i = 3*sr4; i < samplerate; i++)
-		outbuf[i] = nco(freqb);
+	for (i = 0, j = 0; i < sr4; i++, j++)
+		outbuf[i] = nco(freqa) * ampshape[j];
+	for (i = sr4, j = 0; i < 2*sr4; i++, j++)
+		outbuf[i] = nco(freqb) * ampshape[j];
+	for (i = 2*sr4, j = 0; i < 3*sr4; i++, j++)
+		outbuf[i] = nco(freqa) * ampshape[j];
+	for (i = 3*sr4, j = 0; i < samplerate; i++, j++)
+		outbuf[i] = nco(freqb) * ampshape[j];
 	ModulateXmtr(outbuf, samplerate);
 }