diff --git a/Conf.cpp b/Conf.cpp
index eaf7263..0f62639 100644
--- a/Conf.cpp
+++ b/Conf.cpp
@@ -187,6 +187,7 @@ m_fmRFAck("K"),
 m_fmNetAck("N"),
 m_fmAckSpeed(20U),
 m_fmAckFrequency(1750U),
+m_fmAckMinTime(5U),
 m_fmAckDelay(1000U),
 m_fmAckLevel(80.0F),
 m_fmTimeoutLevel(80.0F),
@@ -727,6 +728,8 @@ bool CConf::read()
 			m_fmAckSpeed = (unsigned int)::atoi(value);
 		else if (::strcmp(key, "AckFrequency") == 0)
 			m_fmAckFrequency = (unsigned int)::atoi(value);
+		else if (::strcmp(key, "AckMinTime") == 0)
+			m_fmAckMinTime = (unsigned int)::atoi(value);
 		else if (::strcmp(key, "AckDelay") == 0)
 			m_fmAckDelay = (unsigned int)::atoi(value);
 		else if (::strcmp(key, "AckLevel") == 0)
@@ -1555,6 +1558,11 @@ unsigned int CConf::getFMAckFrequency() const
 	return m_fmAckFrequency;
 }
 
+unsigned int CConf::getFMAckMinTime() const
+{
+	return m_fmAckMinTime;
+}
+
 unsigned int CConf::getFMAckDelay() const
 {
 	return m_fmAckDelay;
diff --git a/Conf.h b/Conf.h
index 2460cb9..84127a4 100644
--- a/Conf.h
+++ b/Conf.h
@@ -185,6 +185,7 @@ public:
   std::string  getFMNetAck() const;
   unsigned int getFMAckSpeed() const;
   unsigned int getFMAckFrequency() const;
+  unsigned int getFMAckMinTime() const;
   unsigned int getFMAckDelay() const;
   float        getFMAckLevel() const;
   float        getFMTimeoutLevel() const;
@@ -445,6 +446,7 @@ private:
   std::string  m_fmNetAck;
   unsigned int m_fmAckSpeed;
   unsigned int m_fmAckFrequency;
+  unsigned int m_fmAckMinTime;
   unsigned int m_fmAckDelay;
   float        m_fmAckLevel;
   float        m_fmTimeoutLevel;
diff --git a/MMDVM.ini b/MMDVM.ini
index f7c73bc..c7b70a4 100644
--- a/MMDVM.ini
+++ b/MMDVM.ini
@@ -155,6 +155,7 @@ RFAck=K
 NetAck=N
 AckSpeed=20
 AckFrequency=1750
+AckMinTime=4
 AckDelay=1000
 AckLevel=80
 TimeoutLevel=80
diff --git a/MMDVMHost.cpp b/MMDVMHost.cpp
index 9693309..e1c34ad 100644
--- a/MMDVMHost.cpp
+++ b/MMDVMHost.cpp
@@ -620,6 +620,7 @@ int CMMDVMHost::run()
 		std::string  netAck            = m_conf.getFMNetAck();
 		unsigned int ackSpeed          = m_conf.getFMAckSpeed();
 		unsigned int ackFrequency      = m_conf.getFMAckFrequency();
+		unsigned int ackMinTime        = m_conf.getFMAckMinTime();
 		unsigned int ackDelay          = m_conf.getFMAckDelay();
 		float        ackLevel          = m_conf.getFMAckLevel();
 		unsigned int timeout           = m_conf.getTimeout();
@@ -644,6 +645,7 @@ int CMMDVMHost::run()
 		LogInfo("    Net Ack: %s", netAck.c_str());
 		LogInfo("    Ack Speed: %uWPM", ackSpeed);
 		LogInfo("    Ack Frequency: %uHz", ackFrequency);
+		LogInfo("    Ack Min Time: %us", ackMinTime);
 		LogInfo("    Ack Delay: %ums", ackDelay);
 		LogInfo("    Ack Level: %.1f%%", ackLevel);
 		LogInfo("    Timeout: %us", timeout);
@@ -655,7 +657,7 @@ int CMMDVMHost::run()
 		LogInfo("    Hang Time: %us", hangTime);
 
 		m_modem->setFMCallsignParams(callsign, callsignSpeed, callsignFrequency, callsignTime, callsignHoldoff, callsignHighLevel, callsignLowLevel, callsignAtStart, callsignAtEnd);
-		m_modem->setFMAckParams(rfAck, ackSpeed, ackFrequency, ackDelay, ackLevel);
+		m_modem->setFMAckParams(rfAck, ackSpeed, ackFrequency, ackMinTime, ackDelay, ackLevel);
 		m_modem->setFMMiscParams(timeout, timeoutLevel, ctcssFrequency, ctcssThreshold, ctcssLevel, kerchunkTime, hangTime);
 	}
 
diff --git a/Modem.cpp b/Modem.cpp
index a3fa859..3b9e51a 100644
--- a/Modem.cpp
+++ b/Modem.cpp
@@ -1893,12 +1893,12 @@ bool CModem::setFMCallsignParams(const std::string& callsign, unsigned int calls
 	return true;
 }
 
-bool CModem::setFMAckParams(const std::string& ack, unsigned int ackSpeed, unsigned int ackFrequency, unsigned int ackDelay, float ackLevel)
+bool CModem::setFMAckParams(const std::string& ack, unsigned int ackSpeed, unsigned int ackFrequency, unsigned int ackMinTime, unsigned int ackDelay, float ackLevel)
 {
 	assert(m_serial != NULL);
 
 	unsigned char buffer[80U];
-	unsigned char len = 7U + ack.size();
+	unsigned char len = 8U + ack.size();
 
 	buffer[0U] = MMDVM_FRAME_START;
 	buffer[1U] = len;
@@ -1906,12 +1906,13 @@ bool CModem::setFMAckParams(const std::string& ack, unsigned int ackSpeed, unsig
 
 	buffer[3U] = ackSpeed;
 	buffer[4U] = ackFrequency / 10U;
-	buffer[5U] = ackDelay / 10U;
+	buffer[5U] = ackMinTime;
+	buffer[6U] = ackDelay / 10U;
 
-	buffer[6U] = (unsigned char)(ackLevel * 2.55F + 0.5F);
+	buffer[7U] = (unsigned char)(ackLevel * 2.55F + 0.5F);
 
 	for (unsigned int i = 0U; i < ack.size(); i++)
-		buffer[7U + i] = ack.at(i);
+		buffer[8U + i] = ack.at(i);
 
 	// CUtils::dump(1U, "Written", buffer, len);
 
diff --git a/Modem.h b/Modem.h
index 6b0fbe3..82ba207 100644
--- a/Modem.h
+++ b/Modem.h
@@ -46,7 +46,7 @@ public:
 	virtual void setTransparentDataParams(unsigned int sendFrameType);
 
 	virtual bool setFMCallsignParams(const std::string& callsign, unsigned int callsignSpeed, unsigned int callsignFrequency, unsigned int callsignTime, unsigned int callsignHoldoff, float callsignHighLevel, float callsignLowLevel, bool callsignAtStart, bool callsignAtEnd);
-	virtual bool setFMAckParams(const std::string& ack, unsigned int ackSpeed, unsigned int ackFrequency, unsigned int ackDelay, float ackLevel);
+	virtual bool setFMAckParams(const std::string& ack, unsigned int ackSpeed, unsigned int ackFrequency, unsigned int minTime, unsigned int ackDelay, float ackLevel);
 	virtual bool setFMMiscParams(unsigned int timeout, float timeoutLevel, float ctcssFrequency, float ctcssThreshold, float ctcssLevel, unsigned int kerchunkTime, unsigned int hangTime);
 
 	virtual bool open();