UmTRXv2 final project

Jean-Samuel Najnudel - BJT PARTNERS SARL jsn at
Tue Jul 3 18:59:28 UTC 2012

Hi Alexander,

Thank you very much for your e-mail.

1/ They did not started the PCB manufacturing yet. They are still
waiting for my feedback on the questions I asked to Andrey.

Actually, if we need to replace the SRAM and/or the flash to use
cheaper equivalent components, we may need to reroute the PCB. This is
why I ask them to wait for the feedback from Andrey before starting
the PCB production. They can start as soon as we let them know what we
do about the SRAM and the flash (with or without PCB files update).

Anyway, I was not very worried about the delay. As discussed together
last time in Paris, before deploying the UmTRX on the field, we would
need OpenBTS to support handover. Even for tests, if I open the
network without handover, because of the terrain in Mayotte, there
will be so much call drops nobody in Mayotte will accept to use our
network anymore in the future. Really, handover is very important in

As I understand OpenBTS is under development but it is quite hard
work. It will probably not be ready before the end of this summer.
This is why I did not feel very worried about the PCB production

Anyway, I will do my best to get the UmTRX prototypes ready as soon as
possible. I just need a feedback from Andrey because, if it does not
lower the UmTRX board performances, we should really try to find an
alternative solution to use cheaper SRAM and flash chips. This could
improve a lot the cost structure of the UmTRX.

2/ I did not contacted Lime yet but I will do this as soon as
possible. I will do my best to get the LMS chips on time.

By the way, for both PCB assembly and LMS order, how many UmTRX board
would you like the fab makes ? We discussed together about 5 or 10
units but we did not took the final decision yet. It can be any
reasonable number between 5 and 10. Please let me know the quantity
you would need. I will ask the fab and order the component quantities
we need.

By the way, the meeting with the fab this morning was fine and they
are ready to start the production asap.

Andrey, please let me know your feedback about my last e-mail and I
will push this to the fab asap.

Thanks a lot for your help.

Best regards.


On 7/3/12, Alexander Chemeris <alexander.chemeris at> wrote:
> Hi Jean-Samuel,
> Thank you for the update! Andrey and I have just arrived back to Moscow,
> hopefully he will be able to answer tomorrow.
> Few questions from me:
> 1. Have they started PCB manufacturing already? With 3w of manufacturing
> time it would be better to start manufacturing asap.
> 2. Have you contacted Lime to get more LMS chips?
> Sent from my Android device.
> --
> Regards,
> Alexander Chemeris
> CEO, Fairwaves LLC
> 02.07.2012 22:16 пользователь "Jean-Samuel Najnudel - BJT PARTNERS SARL" <
> jsn at> написал:
>> Hi Andrey,
>> I have some news from the fab today and I have a meeting with them
>> tomorrow morning.
>> They sent me the BOM with components price list. This bring me a few
>> questions.
>> 1/ Would you know a distributor for the Murata chokes ? The fab them to
>> have some issue to source these.
>> 2/ Would you suggest a distributor for the GPS chip ?
>> 3/ The CY7C1460AV33-167AXI costs more than 50 Euros on the list ! I know
>> SRAM is expensive but would you know where we could purchase this
>> component
>> at a lower price ? If not, do you think we could use a cheaper but
>> equivalent SRAM chip ?
>> 4/ The M25P64-VMF6 costs more than 20 Euros on the list ! This is huge
>> for
>> a 64M flash. Would you know where we could purchase this component at a
>> lower price ? If not, do you think we could use a cheaper but equivalent
>> flash chip ?
>> Please let me know about this. This would help me a lot to move forward
>> to
>> the next sample production step.
>> Thanks a lot for your help.
>> Best regards.
>> Jean-Samuel.
>> :-)
>> On Mon, Jun 18, 2012 at 11:19 AM, Jean-Samuel Najnudel - BJT PARTNERS
>> <jsn at> wrote:
>>> Hi Andrey,
>>> I sent the files last week. The fab needs a few days to update its
>>> pricing and launch the production process.
>>> Anyway, I just called them today. Work is in progress. They will provide
>>> me with some updates later this week. They confirm this should not take
>>> too
>>> much time for production and they will anyway contact me if they need
>>> anything.
>>> I will let you know asap.
>>> Best regards.
>>> Jean-Samuel.
>>> :-)
>>> On Mon, Jun 18, 2012 at 9:49 AM, Andrey Sviyazov
>>> <andreysviyaz at>wrote:
>>>> Hi Jean-Samuel.
>>>> Took another week, but still no news from you.
>>>> Could you please inform us about the progress in the production of
>>>> prototypes.
>>>> Best regards,
>>>> Andrey Sviyazov.
>>>> 2012/6/13 Andrey Sviyazov <andreysviyaz at>
>>>>> Hi Jean-Samuel.
>>>>> Please inform us about fabrication progress even there are no issues.
>>>>> Best regards,
>>>>> Andrey Sviyazov.
>>>>> (Sent from my mobile client)
>>>>> 12.06.2012 4:48 пользователь "Andrey Sviyazov"
>>>>> <andreysviyaz at>
>>>>> написал:
>>>>>  Here PcbDoc file @ 12/06/2012 .
>>>>>> So, it all done :)
>>>>>> Best regards,
>>>>>> Andrey Sviyazov.
>>>>>> 2012/6/12 Andrey Sviyazov <andreysviyaz at>
>>>>>>> Hi all!
>>>>>>> Here final project UmTRXv2 @ 12/06/2012 (PcbDoc file will be
>>>>>>> attached
>>>>>>> to the next e-mail).
>>>>>>> I found an mistake with non-SMD LED's positions in compare to Ettus
>>>>>>> where A-B in left-to-right orientation (see picture).
>>>>>>> Andrew Karpenkov suggested me to change it because of it is not yet
>>>>>>> standard but people accustomed to this.
>>>>>>> It is done.
>>>>>>> Also he suggest me to make four test points for RXOUT legs of LMS
>>>>>>> because he work with this now and found it helpfull.
>>>>>>> It is done.
>>>>>>> Also test points which without connector now referenced as TST and
>>>>>>> therefore RefDes of some connectors changed.
>>>>>>> Jean-Samuel, please find Gerber files, NC drill and layer stack
>>>>>>> desription files which usually required to produce PCB.
>>>>>>> Best regards,
>>>>>>> Andrey Sviyazov.
>>>>>>> 2012/6/10 Andrey Sviyazov <andreysviyaz at>
>>>>>>>> Hi all!
>>>>>>>> Here final project UmTRXv2 @ 10/06/2012 (PcbDoc file will be
>>>>>>>> attached to the next e-mail).
>>>>>>>> Jean-Samuel, please check SMD LED's placed at the front edge of the
>>>>>>>> PCB.
>>>>>>>> If you agree with this variant then I'll generate Gerber files vs
>>>>>>>> required layers and description to produce PCB.
>>>>>>>> If anybody find any mistake, please inform me immediatelly.
>>>>>>>> Best regards,
>>>>>>>> Andrey Sviyazov.

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