Re: [Discuss-gnuradio] S printouts and then either U printouts (and fails/stops transmitting) or seg fault with 4 USRPs

[Pavan Yedavalli]

Hi Marcus,

Thanks for getting back to me. The following is the setup:

I have a Lenovo X1 Carbon with 7.6 GB of memory, Intel Core i7-4600U CPU @ 2.10 GHz x 4, with a 32-bit OS and I believe 200 GB HD. I am using 4 USRP N210s. 

This laptop does NOT have an ethernet port built in - instead, I need to use this adapter, which I then connect to this TP-Link 8-Port Gigabit Ethernet switch.

From here, I connect all 4 USRPs to the switch. To be more specific though, I connect one USRP (master) directly to the switch, with another connected via MIMO cable to that master USRP. Then, I connect two more directly to the switch. I could change this configuration so that all 4, instead of 3, are connected directly to the switch, but I had a MIMO cable, so I decided to use it. All of the USRP N210s are connected to the same computer via this switch and adapter.

I tried with just a simple flow graph sending a single tone with all 4 USRPs, as mentioned, and S appears almost immediately then too, but it seems to stop after a bit and continues to transmit, with Us not appearing. Once I use my block though, Ss and Us appear almost immediately and everything halts.

Attached is probably a not so helpful image of the connection, but just to get an idea.

--

Pavan

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