Switching between RX1 and RX2 with the LimeSuite

[Krombopulus]

I have a rather simple question, quite similar to the following topic:

Selecting RF port on LimeSDR

I’m currently trying to run gr-ieee80211 with my LimeSDR. All the software seems to be working, but I’m seeing no signal (ie the constellation diagram has all points at [0,0]). It looks like the USB Quick Test receive test is working at 800 MHz on port RX1_L using the example.ini file they provide. With the USRP, there’s an option in gnuradio-companion to set the RF input/output port used, but I haven’t been able to find anything like that for LimeSDR. Does it automatically choose the input port…

except I want to change the RX ports with the LimeSuite and not with any other 3rd party software or python application.

After hooking up a LimeSDR-USB on my computer and loading in the example.ini, I was trying to switch between the RX1 and RX2 ports with the GUI controls. Switching between LNAL, LNAH and LNAW is possible with no problems but how can I switch to the corresponding ports of RX2?

I tried to change the RX channel in [Modules] → [FFT viewer] via the drop down menu from Channel A to Channel B without any usefull results: the FFT plot does not even move or update as it does on RX1.
I assume Channel A and B refer to RX1 and RX2? Even after manually adjusting every parameter of the A Channel to B Channel there is no change in the FFT viewer.

Best regards,
Krombopulus

[Dynamix_yang]

Hi Krombopulus,
Try to select MIMO and select channel B on the top of the LimeSuite. Then you can change RF route in RFE/TRF page.

[Krombopulus]

Hey Dynamix_yang, thank you for your reply and sorry for my delayed response! Unfortunately I was not able to switch to RX2 with your suggestions. After enabling channel B and MIMO I tried everything in the RFE tab to get a correct FFT spectrum out of RX2 with no luck. Isn’t there a simple way to switch between RX1 and RX2 ports or am I missing something way too obvious here?

[Zack]

Hi @Krombopulus,

First of all, there are 6 Rx RF inputs on LimeSDR-USB board.
These belongs to MIMO channel A: RX1_H, RX1_W, RX1_L.
These belongs to MIMO channel B: RX2_H, RX2_W, RX2_L.

To switch between channels, perform these steps:

1. Connect to the LimeSDR-USB board in LimeSuiteGUI;
2. Push “Default” button as shown by 4th red box in the picture bellow;
3. Check “Enable MIMO” check box as shown by 2nd red box in the picture bellow;
4. Select “A CHANNEL” radio button as shown by 2nd red box in the picture bellow if you want to switch between Rx RF inputs of MIMO channel A (RX1_X ports will be affected); select “B CHANNEL” radio button as shown by 3rd red box in the picture bellow if you want to switch between Rx RF inputs of MIMO channel B (RX2_X ports will be affected).
   4.1 To activate RXN_H (where N is 1 or 2, depending on selction in step 4): “LNAH” as shown by 3rd red box in the picture bellow; Check “input of LNAL” check box and “input of LNAW” check box as shown by 1st red box in the picture bellow;
   4.2 To activate RXN_L (where N is 1 or 2, depending on selction in step 4): “LNAL” as shown by 3rd red box in the picture bellow; Un-Check “input of LNAL” check box; Check “input of LNAW” check box as shown by 1st red box in the picture bellow;
   4.3 To activate RXN_W (where N is 1 or 2, depending on selction in step 4): “LNAW” as shown by 3rd red box in the picture bellow; Check “input of LNAL” check box; Un-Check “input of LNAW” check box as shown by 1st red box in the picture bellow.

In FFTVIewer:

Select “Display channel” as shown in red box in picture bellow you want to see. “A” will be for RX1_x, B will be for RX2_x. Then push “START” button. Then you will see signal from RF input, selected in procedure above.

Let us assume, you want to see RX1_W channel in FFTViewer. Select “A CHANNEL” in step 4 in procedure above, then perform step 4.3. In FFTViewer select “A” in "Display channel and press “START” button. That’s it, you wil see RX1_W channel data in FFTViewer.

Let us assume, you want to see RX2_H channel in FFTViewer. Select “B CHANNEL” in step 4 in procedure above, then perform step 4.1. In FFTViewer select “B” in "Display channel and press “START” button. That’s it, you wil see RX2_H channel data in FFTViewer.