[USRP-users] Transmitting with the N210

Ian Buckley ianb at ionconcepts.com
Mon Mar 14 14:30:53 EDT 2016


I have a (vague) recollection that I ran into issues powering N210 via J102
due to narrow PCB traces causing excessive voltage drop.
FWIW

-Ian


On Mon, Mar 14, 2016 at 10:36 AM, Marcus Müller <usrp-users at lists.ettus.com>
wrote:

> 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>
> 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>
>> 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>
>>> 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>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
>>> > > _______________________________________________
>>> > > USRP-users mailing list
>>> > > USRP-users at lists.ettus.com
>>> > > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>>> >
>>> >
>>>
>>>
>>
>
>
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