[USRP-users] Transmitting with the N210

Marcus Müller marcus.mueller at ettus.com
Mon Mar 14 13:36:39 EDT 2016


Hi Dave,

ok, 5.65V does seem a bit low, in fact. Might still work with that voltage.
Is it possible to test the USRP incl. UBX with e.g. a bench power supply
at a stable 6V? (please take care not to reverse voltage, but you could
use J102 to connect the supply).

Best regards,
Marcus

On 03/13/2016 09:21 PM, Dave NotTelling via USRP-users wrote:
> Nate,
>
>      The board does power up without the UBX installed.  The power
> supply did squeal even without the daughterboard.  I did find that the
> power supply had to warm up before it started squealing.  For the
> first 30 minutes of testing things it didn't make a sound.  Once it
> had warmed up it always made noise.  The pitch of the squeal would
> directly correlate to changes to the RX and TX parameters.  For
> instance, increasing the RX bandwidth from 5 MHz to 25 MHz would cause
> a noticeable change in the pitch of the squeal.  Modifying the TX
> amplitude / gain would also case changes in pitch.
>
>      While testing the voltage on J102, I could see that the voltage
> would dip as low as 5.65 volts while transmitting at full power.
>  5.88-5.98 Volts was about the norm when idle just after startup.
>
>
>      LEDs:
>           RXing: C D E F
>           TXing: A D E F
>           Idle: D E F
>
>      J105: 2.42 - 2.52 Volts
>      J104: 3.32 - 3.36 Volts
>      J103: 1.16 - 1.24 Volts
>
>      D203 comes on when I plug the board in.  It goes off about two
> seconds later, then comes on after another 1-2 seconds, and finally
> goes off about 3 seconds after that.  It does not appear to come back
> on at any point including RX/TXing.
>
>
>      
> Thank you!
>
> -David
>
> On Sat, Mar 12, 2016 at 8:49 PM, Dave NotTelling <dmp250net at gmail.com
> <mailto:dmp250net at gmail.com>> wrote:
>
>     Nate,
>
>          I'll make sure to try the N210 without the UBX.
>
>          This is the UBX-40 and it is only a week or two old at this
>     point.
>
>     Thank you!
>
>     -David
>
>     On Sat, Mar 12, 2016 at 8:47 PM, Nate Temple
>     <nate.temple at ettus.com <mailto:nate.temple at ettus.com>> wrote:
>
>         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 <mailto: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 <mailto: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
>         <mailto: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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>         > >
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>         >
>         >
>
>
>
>
>
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