diff --git a/artiq/examples/kasli_sawgmaster/repository/sines_urukul_sayma.py b/artiq/examples/kasli_sawgmaster/repository/sines_urukul_sayma.py
index 755235905..af43db1c1 100644
--- a/artiq/examples/kasli_sawgmaster/repository/sines_urukul_sayma.py
+++ b/artiq/examples/kasli_sawgmaster/repository/sines_urukul_sayma.py
@@ -5,7 +5,20 @@ class SinesUrukulSayma(EnvExperiment):
     def build(self):
         self.setattr_device("core")
         self.setattr_device("urukul0_cpld")
-        self.urukul_chs = [self.get_device("urukul0_ch" + str(i)) for i in range(4)]
+
+        # Urukul clock output syntonized to the RTIO clock.
+        # Can be used as HMC830 reference on Sayma RTM.
+        # The clock output on Sayma AMC cannot be used, as it is derived from
+        # another Si5324 output than the GTH, and the two Si5324 output dividers
+        # are not synchronized with each other.
+        # When using this reference, Sayma must be recalibrated every time Urukul
+        # is rebooted, as Urukul is not synchronized to the Kasli.
+        self.urukul_hmc_ref = self.get_device("urukul0_ch3")
+
+        # Urukul measurement channels - compare with SAWG outputs.
+        # When testing sync, do not reboot Urukul, as it is not
+        # synchronized to the Kasli.
+        self.urukul_meas = [self.get_device("urukul0_ch" + str(i)) for i in range(3)]
         self.sawgs = [self.get_device("sawg"+str(i)) for i in range(8)]
 
     @kernel
@@ -18,17 +31,22 @@ class SinesUrukulSayma(EnvExperiment):
     @kernel
     def run(self):
         f = 9*MHz
-        dds_ftw = self.urukul_chs[0].frequency_to_ftw(f)
+        dds_ftw = self.urukul_meas[0].frequency_to_ftw(f)
         sawg_ftw = self.sawgs[0].frequency0.to_mu(f)
         if dds_ftw != sawg_ftw:
             print("DDS and SAWG FTWs do not match:", dds_ftw, sawg_ftw)
             return
 
-        # Note: when testing sync, do not reboot Urukul, as it is not
-        # synchronized to the FPGA (yet).
         self.core.reset()
         self.urukul0_cpld.init()
-        for urukul_ch in self.urukul_chs:
+
+        delay(1*ms)
+        self.urukul_hmc_ref.init()
+        self.urukul_hmc_ref.set_mu(0x40000000, asf=self.urukul_hmc_ref.amplitude_to_asf(0.6))
+        self.urukul_hmc_ref.set_att(6.)
+        self.urukul_hmc_ref.sw.on()
+
+        for urukul_ch in self.urukul_meas:
             delay(1*ms)
             urukul_ch.init()
             urukul_ch.set_mu(dds_ftw, asf=urukul_ch.amplitude_to_asf(0.5))