diff --git a/Makefile b/Makefile
index edf9694..5e57735 100644
--- a/Makefile
+++ b/Makefile
@@ -1,3 +1,8 @@
+AUTO_RX_VERSION := $(shell PYTHONPATH=./auto_rx python -m autorx.version)
+
+CFLAGS = -O3 -Wall -Wno-unused-variable -DVER_JSN_STR=\"$(AUTO_RX_VERSION)\"
+export CFLAGS
+
 SUBDIRS := \
 	demod/mod \
 	imet \
diff --git a/demod/mod/Makefile b/demod/mod/Makefile
index afbdb2b..743f87a 100644
--- a/demod/mod/Makefile
+++ b/demod/mod/Makefile
@@ -1,11 +1,3 @@
-# Makefile for demod programs
-
-# Auto_RX version number - needs to match the contents of autorx/__init__.py
-# This can probably be done automatically.
-#AUTO_RX_VERSION="\"1.4.1-beta8\""
-AUTO_RX_VERSION := $(shell PYTHONPATH=../../auto_rx python -m autorx.version)
-
-CFLAGS = -O3 -Wall -Wno-unused-variable -DVER_JSN_STR=\"$(AUTO_RX_VERSION)\"
 LDLIBS = -lm
 
 PROGRAMS := rs41mod dfm09mod rs92mod lms6mod lms6Xmod meisei100mod m10mod m20mod imet54mod mp3h1mod
diff --git a/imet/Makefile b/imet/Makefile
index e6262ef..4d9b0bb 100644
--- a/imet/Makefile
+++ b/imet/Makefile
@@ -1,11 +1,4 @@
-# Makefile for imet programs
-
-# Auto_RX version number - needs to match the contents of autorx/__init__.py
-# This can probably be done automatically.
-#AUTO_RX_VERSION="\"1.4.1-beta8\""
-AUTO_RX_VERSION := $(shell PYTHONPATH=../auto_rx python -m autorx.version)
-
-CFLAGS = -Ofast -Wall -Wno-unused-variable -DVER_JSN_STR=\"$(AUTO_RX_VERSION)\"
+CFLAGS += -Ofast
 LDLIBS = -lm
 
 PROGRAMS := imet1rs_dft imet4iq
diff --git a/mk2a/Makefile b/mk2a/Makefile
index 6d06f8b..6bb7252 100644
--- a/mk2a/Makefile
+++ b/mk2a/Makefile
@@ -1,11 +1,5 @@
 # Makefile for scan programs
 
-# Auto_RX version number - needs to match the contents of autorx/__init__.py
-# This can probably be done automatically.
-#AUTO_RX_VERSION="\"1.4.1-beta8\""
-AUTO_RX_VERSION := $(shell PYTHONPATH=../auto_rx python -m autorx.version)
-
-CFLAGS = -O3 -Wall -Wno-unused-variable -DVER_JSN_STR=\"$(AUTO_RX_VERSION)\"
 LDLIBS = -lm
 
 PROGRAMS := mk2a_lms1680 mk2a1680mod
diff --git a/scan/Makefile b/scan/Makefile
index 19b1932..dd8338b 100644
--- a/scan/Makefile
+++ b/scan/Makefile
@@ -1,10 +1,3 @@
-# Makefile for scan programs
-
-# Auto_RX version number - needs to match the contents of autorx/__init__.py
-# This can probably be done automatically.
-#AUTO_RX_VERSION="\"1.4.1-beta8\""
-AUTO_RX_VERSION := $(shell PYTHONPATH=../auto_rx python -m autorx.version)
-
 CFLAGS = -O3 -Wall -Wno-unused-variable -DVER_JSN_STR=\"$(AUTO_RX_VERSION)\" -DNOC34C50
 LDLIBS = -lm
 
diff --git a/utils/Makefile b/utils/Makefile
index 6e03c22..f5411d6 100644
--- a/utils/Makefile
+++ b/utils/Makefile
@@ -1,11 +1,3 @@
-# Makefile for util programs
-
-# Auto_RX version number - needs to match the contents of autorx/__init__.py
-# This can probably be done automatically.
-#AUTO_RX_VERSION="\"1.4.1-beta8\""
-AUTO_RX_VERSION := $(shell PYTHONPATH=../auto_rx python -m autorx.version)
-
-CFLAGS = -O3 -Wall -Wno-unused-variable -DVER_JSN_STR=\"$(AUTO_RX_VERSION)\"
 LDLIBS = -lm
 
 PROGRAMS := fsk_demod