The first step was to connect the Elecraft KX3 RX I/Q interface to a sound card in the computer. A quick visit to Radio Shack was required as I did not have a 2.5 mm to 3.5 mm stereo Y-adapter (part 274-945). Using a normal male-to-male 3.5 stereo audio cord I connected KX3 to my home brew computer Line Interface (Light Blue connector in ASUS P8Z68-V PRO/GEN3 motherboard as shown in the ASUS P8Z68 Manual ). See fig 1. below - don't use the pink microphone input jack.
|Fig 1. ASUS P8Z68-V audio connectors|
Next step was to configure PowerSDR properly. When you start PowerSDR without turning Flex3000 on first it will pop up a window - note the button "Add Legacy Radios" below.
|Fig 2. PowerSDR Radio Interfaces|
You can add SoftRock 40 legacy radio - no need to add anything on Serial Number field.
|Fig 3. Adding Legacy Radios|
You will get back to Fig 2. window and select "Use" button on the right. Main window of PowerSDR software should come up.
Next step is to select Setup menu from the top and General / Hardware Config. You can setup the Center Frequency here - see Fig 4. below.
|Fig 4. Set Center Frequency|
Next you configure the Audio / Primary settings. In my case I am using the built-in sound card of the ASUS motherboard which is not on the supported sound cards list. There I selected "Unsupported Card" as shown in Fig 5. below. Also, I configured Sample Rate to 192,000 to get maximum frequency coverage from KX3 RX I/Q signals. I also used "MME" Driver of Windows 7 and selected Input and Mixer to "Line In High Definition Audio" and selected Output to my video monitor "EQ276W DP-1 (NVIDIA...)".
|Fig 5. Audio Hardware Configuration|
Time to press the "Start" button on PowerSDR. You should see some signals on panadapter if evrrything is configured correctly.
|Fig 6. PowerSDR showing 96 Khz of signal coming from Elecraft KX3|
Note that PowerSDR expects the center frequency be at 14.200 MHz (see Fig 4. above) and
to get the frequency display correct you need to tune KX3 at that frequency. You can also see that PowerSDR covers approximately 96 kHz bandwidth centered around 14.2 MHz. Of course you can change that by just going to Setup menu.
|Fig 7. Elecraft KX3 tuned at 14.200 Mhz|
I was running Flex3000 and KX3 in parallel listening some stations while switching the antenna between KX3 and Flex3000. I did not do any scientific A/B comparison study but just by using two instances of the same PowerSDR version connected to different radios I could not really tell much difference between these two radios. Both picked up the faint DX stations equally well. The only difference was really the few kHz noise band around the KX3 center frequency - outside of that the sensitivity and sound quality was very similar in both of these radios.
I was also playing with the CAT interface of PowerSDR - however, it does not recognize Elecraft as an option so I did not spend much time on that. In comparison HDSDR uses Omnirig CAT interface which has more choices, including Elecraft K3 that works well with KX3. If you can figure out a way to get KX3 CAT interface working also with PowerSDR please let me know.
In conclusion I wanted to test if I can make PowerSDR software to use Elecraft KX3 as a receiver. As you can see above this was a quick and painless configuration effort.