[USRP-users] Transmitting with the N210

Dave NotTelling dmp250net at gmail.com
Mon Mar 14 18:56:11 EDT 2016


Marcus,

     I will have to give the bench power supply a try.  I think I have
access to one that will work.


Ian,

     Thanks for the input.  I'll try to feed in from the front panel using
the connector off of an old power supply.



-David

On Mon, Mar 14, 2016 at 2:30 PM, Ian Buckley via USRP-users <
usrp-users at lists.ettus.com> wrote:

> 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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