[USRP-users] Transmitting with the N210

Nate Temple nate.temple at ettus.com
Sat Mar 12 20:47:28 EST 2016


Hi David,

Ideally, yes you should test the power supply when it is running. 

Before you test the power supply with an oscilloscope, can you try running the N210 without the UBX in it? When running the N210 by itself, does the power supply continue to squeal? Does the N210 by itself respond normally with uhd_usrp_probe ?

Is this a UBX-40? and how old is it?

- Nate



> On Mar 12, 2016, at 4:39 PM, Dave NotTelling <dmp250net at gmail.com> wrote:
> 
> Nate,
> 
>      Thank you for the speedy reply!!  
> 
>      Unfortunately I do not have eyes on the device right now.  Here is what I can answer in the short term:
> 
> 	• I have not tested the power supply yet.  I thought about hooking it up to an oscilloscope to see if it was noisy or under/over voltage.  My concern was that I would not be able to get an accurate measurement unless the power supply were loaded down.  That would mean hooking my scope up to a running board.  Under normal circumstances that would be no problem.  Unfortunately I didn't have the probes on hand a the time and thought it wise not to poke random alligator clips into the running device.  Does the measurement need to happen with the N210 running (actively RX/TXing)?
> 	• I did re-seat the UBX
> 	• They are nice and tight.  Double checked.
> 	• RX does appear to be working fine.  The only think I noticed was that if I went from something high like 5 GHz and then tuned to something lower than 500 MHz, then I would see a small signal (~500 KHz across) slowly sweep across the spectrum (~ 25 MSPS).  I could not recreate it after power cycling the N210.
>      I have tried this on the maint branch of UHD as well as the master branch.  I think the versions were 3.10 and 3.9.2 respectively.  I cloned fresh copies of the UHD repo for both on Friday.
> 
>      As for your second set of ideas:
> 
> 	• The fan definitely does spin
> 	• I'll have to check the LEDs when I have eyes on it next
> 	• The Ethernet lights to flash and I am hooked directly into the 1 Gbps LAN connection on my motherboard.  I can verify with bwm-ng that I am getting samples at just under 1 Gbps when RXing 25 MSPS.
> 	• I'll check those voltages when I have eyes on it next
> 	• No idea about the D203 light.  I'll have to look
> 
>      I can also say that the RX and TX lights on the UBX do come on when they are supposed to.
> 
>      I am not using the GPSDO.  The power supply I have is what came with the N210.  6 Volts at 3 Amps.
> 
>      Thank you very much for the assistance!!
> 
> -David
> 
> On Sat, Mar 12, 2016 at 7:05 PM, Nate Temple <nate.temple at ettus.com> wrote:
> Hi David,
> 
> Just a quick follow up question. Are you using a GPSDO along with the UBX on the N210? If so, it is required to use a 6V/4A power supply.
> 
> - Nate
> 
> 
> > On Mar 12, 2016, at 6:58 AM, Dave NotTelling via USRP-users <usrp-users at lists.ettus.com> wrote:
> >
> > I am having issues transmitting with my N210 using the UBX daughterboard.  The signal is so weak that I have to put another radio directly next to it to even see the transmitted signal at all.  The transmit test was done using osmocom_siggen and uhd_siggen_gui.  I tried cranking the gain and amplitude up all the way in both interfaces and it's barely 1-2 dB above the noise floor.  Additionally, the heatsink gets too hot to touch and the power supply emits a high pitch squalling noise when the radio is actually being used.  The power supply itself gets pretty warm too.  Is there something that I am not doing right that could be causing this?  Maybe some argument that I'm not passing in that I should be?
> >
> > Thank you!
> >
> > -David
> > _______________________________________________
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> > USRP-users at lists.ettus.com
> > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
> 
> 





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