diff --git a/artiq/frontend/artiq_sinara_tester.py b/artiq/frontend/artiq_sinara_tester.py
index 809fcb521..dd16a5934 100755
--- a/artiq/frontend/artiq_sinara_tester.py
+++ b/artiq/frontend/artiq_sinara_tester.py
@@ -408,7 +408,7 @@ class SinaraTester(EnvExperiment):
             print("Testing attenuators. Frequencies:")
             for card_n, channels in enumerate(chunker(self.mirnies, 4)):
                 for channel_n, (channel_name, channel_dev) in enumerate(channels):
-                    frequency = 2000 + card_n * 250 + channel_n * 50
+                    frequency = 2000. + card_n * 250 + channel_n * 50
                     print("{}\t{}MHz".format(channel_name, frequency*2))
                     self.setup_mirny(channel_dev, frequency)
                     print("{} info: {}".format(channel_name, channel_dev.info()))
@@ -450,7 +450,7 @@ class SinaraTester(EnvExperiment):
         print("Frequencies:")
         for card_n, channels in enumerate(chunker(self.mirnies, 4)):
             for channel_n, (channel_name, channel_dev) in enumerate(channels):
-                frequency = 1000*(card_n + 1) + channel_n * 100
+                frequency = 1000.*(card_n + 1) + channel_n * 100
                 print("{}\t{}MHz".format(channel_name, frequency))
                 self.setup_mirny(channel_dev, frequency)
                 print("{} info: {}".format(channel_name, channel_dev.info()))