Strange new behavior-Multiple SDRs 1 PC

[CKnobb]

Until yesterday, I have been running multiple (up to 5) SDRs on one PC (2 Airspy min and 3 Nooelec), using a combination of SDR# and SDRtrunk. No problems, no conflicts, just a smooth operation. Yesterday my new Airspy R2 arrived. I shut down all the programs and SDRs, plugged in the R2 and fired up SDRtrunk. All seemed well until I started an SDR# session with a Nooelec (also tried with a Mini). SDR# worked as expected, but the SDRtrunk with the R2 suddenly couldn't lock on the control channel. I made sure to disable any other but the R2 in the Tuners tab of SDRtrunk. Just can't get it to work unless I shut down all other instances of SDR# and other SDRs. No scan, no nothin. Basically, the R2 will only work if it is the only SDR in use. Does this make sense to anyone? I'm flummoxed and back to just monitoring a large P25 system on SDRtrunk with my new R2 until I can figure this out. Thanks for any insight.
Jim

 

[DSheirer]

The R2 may be using more than half of the total USB bus bandwidth and now SDR# and sdrtrunk are competing. You may find that there are errors in the sdrtrunk log or that sdrtrunk is getting dropped samples causing the poor/incomplete decodes.

 

[CKnobb]

Good to know and I will check it out. Thanks Denny.
Jim

 

[CKnobb]

Turns out that's exactly the issue. My mini PC has plenty of firepower, memory, CPU etc., but apparently I don't have the USB bandwidth to handle an R2 with all the USB devices I have installed. I'm showing 2 controllers.


Most of my devices are on a multiport hub. I plugged the R2 directly into a 2.0 port directly on the PC (1st controller) and unpliugged the other device on port 2, but still didn't have enough bandwidth as SDRtrunk would not lock on until other SDRs were closed. I tried a spare USB-C port on the front, but then my USB-C video port for my 3rd monitor wouldn't fire up. The R2 requires a lot more USB bandwidth than I'd imagined. Lesson learned! (and my new R2 just sits on the shelf).)