Hum on 2 meter signal through transverter

Wayne W5GIE

I recently bought and connected a Ukraine 2 meter transverter to my 6600M.  The setup was quite easy once I discovered that the 2 meter repeater offset should be 0.600 MHz instead of 600 KHz.  
The only problem is that there is a hum on received repeater signals when using SmartSDR.  The hum is not noticed directly at the 6600M.
I don't think PL tones are transmitted by the repeater, and I haven't managed to conjure up a way that a hum would be added with SmartSDR.
Any thoughts?

Thanks
Wayne  W5GIE

John - AI4FR

I think it's normal and you are hearing the PL.

Paul - GI4FZD

yes, i drop the 63 and 125 hz sliders to -10db on the rx equaliser to minimise it.

Wayne W5GIE

Thanks John and Paul.   I am not aware of any local repeaters that pass through the CTSS tones that accessed the repeater.  On the 6600M itself, which supplies the audio to my desktop computer running SmartSDR via wifi, there is no hum on the received signal.  The desktop computer when running an external SDR has no hum on the received signal.  I'm stumped.  However, it is most likely an operator error.
Wayne W5GIE

John - AI4FR

Hmmm, maybe we are thinking/hearing different things here. There's not a lot of repeaters with-in reach of my antenna's where I am located and of those most are very quiet. If you have time and if possible create an audio file and post it. Hopefully someone will be along with a solution or if nothing else we'll be able to say "yup, sounds the same here". Either way, good luck with it.

Wayne W5GIE

John....an update.  I just had time to access the 6600M via SmartSDR wifi on a laptop, and there is no hum on the signals.  So the condition seems to be confined to my desktop. 
Thus, the Ukariane tranverter and 6600M combination operated via SmartSDR appears to have no problem at all.
In recap, the setup was quite simple one I realized that the offset field is for MHz in the FLEX transverter settings.  The LO in the transverter I received was right on frequency.  Just a bit of jiggling of the transmit audio level and all was good.
The 6600M tranverter output level set at 5 dbm gives about 5 watts of transverter output.  I'm about 10 miles line of sight from my local repeater in the mountains, so 5 watts is plenty for me.
Thanks
Wayne W5GIE

John - AI4FR

Thanks for the follow up Wayne and I am glad you have narrowed it down to the PC without a doubt. The setup here consists of running all wifi so I have no wires from the flex 6700 to the PC. If you do, you know what to do, jiggle the wires, be sure they are in the correct socket, are in all the way, and that windows is directed to them(default, found by windows, etc.). You'll get it.