Prototype Radio V - CAT Control with Omni-Rig

I continue to experiment with the CAT control of the Si5351 with the simple DC receiver. I wanted to document the use of Omni-rig that I mentioned in the last post. After Omni-Rig is installed, HDSDR will be able to access the Omni-Rig setup screen below. You just select the rig type, the COM port the Arduino is on, and the baud rate (e.g. we are using 4800, but it can be changed in the code).

The best way to run it is to Sync the LO frequency and then check the sync to/from Omni-Rig as seen below. The you just click on the frequency and type in the frequency you want and press enter. Then you will see the span of frequencies based on your bandwidth setting. To tune around at this point, change the LO not the TUNE frequency. Your offsite will remain fixed based on the setting below. This works well for me at this point. I am able to use 192K sample rate which gives me more than 80 Khz (this is half of the 192 since this is not a true SDR which would center you and give you 80 below and 80 above)

There is a setting that positions the SDR cursor when you tune it. The default is 10000 hz or 10Khz, but you may want to adjust it to the best part of the pass-band. I find that 40khz is the lowest noise part of my pass-band for my setup. I have also been investigating noise issues that are caused by the PC's USB port. I will need to devise some filtering next. In the mean time I have found that placing an "un-powered" USB power block across the DC buss cuts most of the noise. I just use a USB cable that has the power pins broken out to pins plugged into the breadboard and plugged into the power block.

Here is the offsite screen with the default 10khz setting.