diff --git a/DMRDMOTX.cpp b/DMRDMOTX.cpp
index c30f50e..b0175c8 100644
--- a/DMRDMOTX.cpp
+++ b/DMRDMOTX.cpp
@@ -166,7 +166,10 @@ uint8_t CDMRDMOTX::getSpace() const
 
 void CDMRDMOTX::setTXDelay(uint8_t delay)
 {
-  m_txDelay = 240U + uint16_t(delay) * 12U;        // 200ms + tx delay
+  m_txDelay = 600U + uint16_t(delay) * 12U;        // 500ms + tx delay
+
+  if (m_txDelay > 1200U)
+    m_txDelay = 1200U;
 }
 
 void CDMRDMOTX::createCACH(uint8_t* buffer, uint8_t slotIndex)
diff --git a/DMRDMOTX.h b/DMRDMOTX.h
index 022ecd0..98ffdb0 100644
--- a/DMRDMOTX.h
+++ b/DMRDMOTX.h
@@ -42,7 +42,7 @@ private:
   CSerialRB                        m_fifo;
   arm_fir_interpolate_instance_q15 m_modFilter;
   q15_t                            m_modState[16U];    // blockSize + phaseLength - 1, 4 + 9 - 1 plus some spare
-  uint8_t                          m_poBuffer[800U];
+  uint8_t                          m_poBuffer[1200U];
   uint16_t                         m_poLen;
   uint16_t                         m_poPtr;
   uint32_t                         m_txDelay;
diff --git a/DStarTX.cpp b/DStarTX.cpp
index 4f81574..92fb6d5 100644
--- a/DStarTX.cpp
+++ b/DStarTX.cpp
@@ -434,6 +434,9 @@ void CDStarTX::writeByte(uint8_t c)
 void CDStarTX::setTXDelay(uint8_t delay)
 {
   m_txDelay = 300U + uint16_t(delay) * 6U;        // 250ms + tx delay
+
+  if (m_txDelay > 600U)
+    m_txDelay = 600U;
 }
 
 uint8_t CDStarTX::getSpace() const
diff --git a/P25TX.cpp b/P25TX.cpp
index 0b7f279..bf0f8e9 100644
--- a/P25TX.cpp
+++ b/P25TX.cpp
@@ -166,6 +166,9 @@ void CP25TX::writeByte(uint8_t c)
 void CP25TX::setTXDelay(uint8_t delay)
 {
   m_txDelay = 600U + uint16_t(delay) * 12U;        // 500ms + tx delay
+
+  if (m_txDelay > 1200U)
+    m_txDelay = 1200U;
 }
 
 uint8_t CP25TX::getSpace() const
diff --git a/YSFTX.cpp b/YSFTX.cpp
index e7fb862..a5a8b92 100644
--- a/YSFTX.cpp
+++ b/YSFTX.cpp
@@ -152,6 +152,9 @@ void CYSFTX::writeByte(uint8_t c)
 void CYSFTX::setTXDelay(uint8_t delay)
 {
   m_txDelay = 600U + uint16_t(delay) * 12U;        // 500ms + tx delay
+
+  if (m_txDelay > 1200U)
+    m_txDelay = 1200U;
 }
 
 uint8_t CYSFTX::getSpace() const