diff --git a/ComLib.h b/ComLib.h
index 5acfcb5..4a7fbc9 100644
--- a/ComLib.h
+++ b/ComLib.h
@@ -32,7 +32,10 @@
 #include <SHELLAPI.H>
 
 #define	VERID	"Ver1.70"       //K6TU 1.68A -> 1.70A AA6YQ 1.65D->1.66G,  JE3HHT 1.67
-#define	VERBETA	"A"
+#define	VERBETA	"D"             //JA7UDE 1.70A -> 1.70B G3WYW FT-991 CAT support
+								//AA6YQ 1.70C added COM16-32 to PTT/FSK port selector and Radio port selector, added 991 to Yaesu Maker selector entry
+								//AA6YQ 1.70D prevent shift > 4000 Hz so CSlideFFT::Create does not divide by zero
+
 #define	VERTTL2	"MMTTY "VERID VERBETA
 #define	VERTTL  VERTTL2" (C) JE3HHT 2000-2010."
 
diff --git a/Option.dfm b/Option.dfm
index 35ee220..8a80866 100644
Binary files a/Option.dfm and b/Option.dfm differ
diff --git a/Rtty.cpp b/Rtty.cpp
index 4e5ec65..3646e2f 100644
--- a/Rtty.cpp
+++ b/Rtty.cpp
@@ -740,22 +740,26 @@ void CFSKDEM::SetLPFFreq(double f)
 
 void CFSKDEM::SetMarkFreq(double d)
 {
-	m_SetMarkFreq = m_AFCMarkFreq = m_MarkFreq = d;
-	MakeFilter(HMark, m_Tap, ffBPF, DemSamp, m_MarkFreq-m_FilWidth, m_MarkFreq+m_FilWidth, 60, 1.0);
-	SetIIR(m_iirfw);
-    m_Phase.SetCarrierFreq(m_AFCMarkFreq);
-	if( m_AFCSpaceFreq > m_AFCMarkFreq ) m_Phase.SetShift(m_AFCSpaceFreq - m_AFCMarkFreq);
-    m_AA6YQ.SetMarkFreq(m_AFCMarkFreq);
+	if ((m_AFCSpaceFreq - d) < 4000) {    //1.70D prevent divide by zero in M_SlideFFT.Create
+		m_SetMarkFreq = m_AFCMarkFreq = m_MarkFreq = d;
+		MakeFilter(HMark, m_Tap, ffBPF, DemSamp, m_MarkFreq-m_FilWidth, m_MarkFreq+m_FilWidth, 60, 1.0);
+		SetIIR(m_iirfw);
+		m_Phase.SetCarrierFreq(m_AFCMarkFreq);
+		if( m_AFCSpaceFreq > m_AFCMarkFreq ) m_Phase.SetShift(m_AFCSpaceFreq - m_AFCMarkFreq);
+		m_AA6YQ.SetMarkFreq(m_AFCMarkFreq);
+	}
 }
 
 void CFSKDEM::SetSpaceFreq(double d)
 {
-	m_SetSpaceFreq = m_AFCSpaceFreq = m_SpaceFreq = d;
-	MakeFilter(HSpace, m_Tap, ffBPF, DemSamp, m_SpaceFreq-m_FilWidth, m_SpaceFreq+m_FilWidth, 60, 1.0);
-	SetIIR(m_iirfw);
-    m_Phase.SetCarrierFreq(m_AFCMarkFreq);
-	if( m_AFCSpaceFreq > m_AFCMarkFreq ) m_Phase.SetShift(m_AFCSpaceFreq - m_AFCMarkFreq);
-    m_AA6YQ.SetSpaceFreq(m_AFCSpaceFreq);
+	if ((d - m_AFCMarkFreq) < 4000) {    //1.70D prevent divide by zero in M_SlideFFT.Create
+		m_SetSpaceFreq = m_AFCSpaceFreq = m_SpaceFreq = d;
+		MakeFilter(HSpace, m_Tap, ffBPF, DemSamp, m_SpaceFreq-m_FilWidth, m_SpaceFreq+m_FilWidth, 60, 1.0);
+		SetIIR(m_iirfw);
+		m_Phase.SetCarrierFreq(m_AFCMarkFreq);
+		if( m_AFCSpaceFreq > m_AFCMarkFreq ) m_Phase.SetShift(m_AFCSpaceFreq - m_AFCMarkFreq);
+		m_AA6YQ.SetSpaceFreq(m_AFCSpaceFreq);
+	}
 }
 
 void CFSKDEM::AFCMarkFreq(double d)
diff --git a/Sound.cpp b/Sound.cpp
index 0ccffb8..53e7eb2 100644
--- a/Sound.cpp
+++ b/Sound.cpp
@@ -60,7 +60,7 @@ __fastcall TSound::TSound(bool CreateSuspended)
 
 	m_ReqFifoSize = 0;
     m_IDDevice = WAVE_MAPPER;
-    m_IDOutDevice = WAVE_MAPPER; //AA6YQ 1.6.6
+	m_IDOutDevice = WAVE_MAPPER; //AA6YQ 1.66
 	m_playmode = 0;
 	m_susp = 0;
 	m_suspack = 0;
@@ -1074,7 +1074,7 @@ int __fastcall TSound::DrawFFTWater(Graphics::TBitmap *pBitmap, int sw, int XRD)
 
 
 //---------------------------------------------------------------------------
-//AA6YQ 1.6.6
+//AA6YQ 1.66
 LPCSTR __fastcall TSound::GetInputSoundcard(unsigned int ID)
 {
 
diff --git a/Sound.h b/Sound.h
index 262a263..b1c7a7a 100644
--- a/Sound.h
+++ b/Sound.h
@@ -123,7 +123,7 @@ public:
 	void __fastcall InitWFX(void);
 
 	UINT	m_IDDevice;
-    UINT    m_IDOutDevice; //AA6YQ 1.6.6
+    UINT    m_IDOutDevice; //AA6YQ 1.66
 
 	int		m_playmode;
 	int		m_susp;
diff --git a/radioset.cpp b/radioset.cpp
index 2f39292..0bf6039 100644
--- a/radioset.cpp
+++ b/radioset.cpp
@@ -29,7 +29,7 @@
 //Define Maker groups; index is used by IsCompatible to select the correct Maker based on PollType (RADIO_POLLx)
 LPCSTR	__MK[]={
 	"Yaesu FT 1000D, 1000MP, 920",                  //AA6YQ 1.66 cosmetic, MakerIndex=0
-    "Yaesu  FT 9000, 2000, 950, 450",                //AA6YQ 1.66         , MakerIndex=1
+    "Yaesu  FT 9000, 2000, 991, 950, 450",                //AA6YQ 1.66         , MakerIndex=1
 	"Yaesu  FT 736, 817, 847, 857, 897",                            //AA6YQ 1.66 cosmetic, MakerIndex=2
 	"Icom  xx=addr 01-7F",                          //                   , MakerIndex=3
 	"Ten-Tec Omni VI  xx=addr 00-64",               //                   , MakerIndex=4
@@ -560,3 +560,4 @@ void __fastcall TRADIOSetDlg::SBHelpClick(TObject *Sender)
 }
 //---------------------------------------------------------------------------
 
+
diff --git a/radioset.dfm b/radioset.dfm
index b2fb8e9..7deed2b 100644
Binary files a/radioset.dfm and b/radioset.dfm differ
diff --git a/radioset.h b/radioset.h
index 10fc7da..398e0d0 100644
--- a/radioset.h
+++ b/radioset.h
@@ -108,7 +108,7 @@ private:
 	int				m_DisEvent;
 	int __fastcall IsXX(void);
 	int __fastcall IsSame(LPCSTR v, LPCSTR t);
-    int __fastcall IsCompatible(int PollType, int MakerIndex); //AA6YQ 1.6.6
+    int __fastcall IsCompatible(int PollType, int MakerIndex); //AA6YQ 1.66
 	void __fastcall SetMaker(void);
 	void __fastcall UpdateUI(void);
 	void __fastcall SetVFOList(void);