diff --git a/ogn/aprs_parser.py b/ogn/aprs_parser.py
index 2e353c6..8789c87 100644
--- a/ogn/aprs_parser.py
+++ b/ogn/aprs_parser.py
@@ -4,7 +4,10 @@ from .model import Beacon, AircraftBeacon, ReceiverBeacon
 from ogn.exceptions import AprsParseError
 
 
-def parse_aprs(packet, reference_date=datetime.utcnow()):
+def parse_aprs(packet, reference_date=None):
+    if reference_date is None:
+        reference_date = datetime.utcnow()
+    print(reference_date)
     if not isinstance(packet, str):
         raise TypeError("Expected packet to be str, got %s" % type(packet))
     elif packet == "":
diff --git a/ogn/model/beacon.py b/ogn/model/beacon.py
index 4614bfe..fd00df5 100644
--- a/ogn/model/beacon.py
+++ b/ogn/model/beacon.py
@@ -30,7 +30,9 @@ class Beacon(AbstractConcreteBase, Base):
     altitude = Column(Integer)
     comment = None
 
-    def parse(self, text, reference_date=datetime.utcnow()):
+    def parse(self, text, reference_date=None):
+        if reference_date is None:
+            reference_date = datetime.utcnow()
         result = re_pattern_aprs.match(text)
         if result is None:
             raise AprsParseError(text)