diff --git a/gprMax/fields_output.py b/gprMax/fields_output.py
index e2b50c27..a34e21f3 100644
--- a/gprMax/fields_output.py
+++ b/gprMax/fields_output.py
@@ -38,7 +38,7 @@ def prepare_output_file(outputfile, G):
     f.attrs['Iterations'] = G.iterations
     f.attrs['dx, dy, dz'] = (G.dx, G.dy, G.dz)
     f.attrs['dt'] = G.dt
-    f.attrs['txsteps'] = (G.txstepx, G.txstepy, G.txstepz)
+    f.attrs['srcsteps'] = (G.srcstepx, G.srcstepy, G.srcstepz)
     f.attrs['rxsteps'] = (G.rxstepx, G.rxstepy, G.rxstepz)
     f.attrs['ntx'] = len(G.voltagesources) + len(G.hertziandipoles) + len(G.magneticdipoles)
     f.attrs['nrx'] = len(G.rxs)
diff --git a/gprMax/gprMax.py b/gprMax/gprMax.py
index 88b53313..0b4a6903 100644
--- a/gprMax/gprMax.py
+++ b/gprMax/gprMax.py
@@ -287,11 +287,11 @@ def run_model(args, modelrun, numbermodelruns, inputfile, inputdirectory):
         f = prepare_output_file(outputfile, G)
 
         # Adjust position of sources and receivers if required
-        if G.txstepx > 0 or G.txstepy > 0 or G.txstepz > 0:
+        if G.srcstepx > 0 or G.srcstepy > 0 or G.srcstepz > 0:
             for source in itertools.chain(G.hertziandipoles, G.magneticdipoles, G.voltagesources):
-                source.positionx += (modelrun - 1) * G.txstepx
-                source.positiony += (modelrun - 1) * G.txstepy
-                source.positionz += (modelrun - 1) * G.txstepz
+                source.positionx += (modelrun - 1) * G.srcstepx
+                source.positiony += (modelrun - 1) * G.srcstepy
+                source.positionz += (modelrun - 1) * G.srcstepz
         if G.rxstepx > 0 or G.rxstepy > 0 or G.rxstepz > 0:
             for receiver in G.rxs:
                 receiver.positionx += (modelrun - 1) * G.rxstepx
diff --git a/gprMax/grid.py b/gprMax/grid.py
index 385b848f..c2a44b48 100644
--- a/gprMax/grid.py
+++ b/gprMax/grid.py
@@ -52,9 +52,9 @@ class FDTDGrid():
         self.hertziandipoles = []
         self.magneticdipoles = []
         self.txs = [] # Only used for converting old output files to HDF5 format
-        self.txstepx = 0
-        self.txstepy = 0
-        self.txstepz = 0
+        self.srcstepx = 0
+        self.srcstepy = 0
+        self.srcstepz = 0
         self.rxstepx = 0
         self.rxstepy = 0
         self.rxstepz = 0
diff --git a/gprMax/input_cmds_singleuse.py b/gprMax/input_cmds_singleuse.py
index 7d7793f4..c3e3c457 100644
--- a/gprMax/input_cmds_singleuse.py
+++ b/gprMax/input_cmds_singleuse.py
@@ -205,11 +205,11 @@ def process_singlecmds(singlecmds, multicmds, G):
         tmp = singlecmds[cmd].split()
         if len(tmp) != 3:
             raise CmdInputError(cmd + ' requires exactly three parameters')
-        G.txstepx = rvalue(float(tmp[0])/G.dx)
-        G.txstepy = rvalue(float(tmp[1])/G.dy)
-        G.txstepz = rvalue(float(tmp[2])/G.dz)
+        G.srcstepx = rvalue(float(tmp[0])/G.dx)
+        G.srcstepy = rvalue(float(tmp[1])/G.dy)
+        G.srcstepz = rvalue(float(tmp[2])/G.dz)
         if G.messages:
-            print('All sources will step {:.3f}m, {:.3f}m, {:.3f}m for each model run.'.format(G.txstepx * G.dx, G.txstepy * G.dy, G.txstepz * G.dz))
+            print('All sources will step {:.3f}m, {:.3f}m, {:.3f}m for each model run.'.format(G.srcstepx * G.dx, G.srcstepy * G.dy, G.srcstepz * G.dz))
 
 
     # rx_steps
diff --git a/tools/outputfile_old2new.py b/tools/outputfile_old2new.py
index ab266c19..fb762274 100644
--- a/tools/outputfile_old2new.py
+++ b/tools/outputfile_old2new.py
@@ -56,9 +56,9 @@ with open(outputfile, 'rb') as f:
     G.dz, = struct.unpack('f', f.read(4))
     G.dt, = struct.unpack('f', f.read(4))
     nsteps, = struct.unpack('h', f.read(2))
-    G.txstepx, = struct.unpack('h', f.read(2))
-    G.txstepy, = struct.unpack('h', f.read(2))
-    G.txstepz, = struct.unpack('h', f.read(2))
+    G.srcstepx, = struct.unpack('h', f.read(2))
+    G.srcstepy, = struct.unpack('h', f.read(2))
+    G.srcstepz, = struct.unpack('h', f.read(2))
     G.rxstepx, = struct.unpack('h', f.read(2))
     G.rxstepy, = struct.unpack('h', f.read(2))
     G.rxstepz, = struct.unpack('h', f.read(2))