New subject: UmTRX preselector

8 Aug 2012

2012/8/8 Jean-Samuel Najnudel - BJT PARTNERS SARL &lt;jsn(a)bjtpartners.com&gt;

...
  Hi Andrey,

 Thank you very much for your reply.

 I understand your point of view regarding the ADF4350. I agree with you,
 the ADF4350 still have quite good performances. I also agree that easier
 software support is also important. It would just be a great news if we
 could pass the GSM spec, at least as micro BTS.

 Regarding the GSM 1800 version of the selectivity board, it will not be a
 problem to change the mixer and the filters. However, are you sure we will
 be able to get the correct matching if we only change the passives ? Are
 you sure we would not need to modify the PCB traces to get a good matching
 for a 1800 MHz version of the board ? What do you think ?
 Most of cooper would be 50 Ohm, so only FR-4 losses a bit higher.
Also RF cables losses and so on, therefore 1800 parameters will be a bit
worse, but it typical.
About components, I've checked again and found that RF SAW filter for 1800
UL require coil at input (added).

Best regards,
Andrey Sviyazov.

...

 Best regards.

 Jean-Samuel.
 :-)

 On Tue, Aug 7, 2012 at 7:27 PM, Andrey Sviyazov &lt;andreysviyaz(a)gmail.com&gt;wrote;wrote:

  Hi Jean-Samuel.

 1/ A few weeks ago, we discussed together about phase noise issues to be
  able to pass the GSM spec. You explained
HMC830LP6GE has much better
 performances than the ADF4350. I know the HMC830LP6GE is a bit more
 expensive but, as discussed together before, I really believe this worth
 the extra cost. This would allow us to pass the macro or at least micro BTS
 specs without the need for designing another slectivity board. This would
 save a lot of work. Moreover, we espcially need this preselectivity board
 for a micro or even macro BTS. In this use case, I really believe price
 difference (like 40 or 50 USD) will be very low, especially compared to all
 other costs of a mid-long range micro/macro BTS installation. Unless you
 really disagree, I would really suggest to use the best performance
 components as we reasonably can.

 First of all, Robin said that ADF4350 already supported by UHD therefore
 it could save time to implement it for UmTRX.
 2nd, I think that parameters differences isn't really as significant (few
 dB) as price and soft changing time cost.
 3rd, it isn't last design and I am sure that we will change it for more
 functions, performances and for housing adaptations.
 Also I'm planing to buy HP4352 to design and measure PLL's, so of course
 I'll test HMC830 too, but now we just have to be sure that it will work
 properly and without risks.

  2/ In my deployment in Mayotte, I will also
deploy GSM 1800 band base
 stations because most of the spectrum I have is in this frequency band. To
 avoid making another PCB for GSM 1800, could you design the board to allow
 to populate either GSM 900 or GSM 1800 filters and matching passives with
 the same PCB copper ? A single PCB would be easier to test and to maintain.
 Moreover, this would save some costs as we will be able to order lager PCB
 volumes. This could make a quite significant saving. Please let me know
 what you think about this.
  As I mentioned before, there are band specific components with same
 footprint.
 So, there are no changes required in PCB design for 1800 band, only BOM.
 For example, HMC485 instead of HMC483 and FAR-F6KA-1G7475 instead of
 FAR-F5KA-897.

 Best regards,
 Andrey Sviyazov.

 Anyway, thank you very much for this design. With UmTRX, this would
 really make a cost effective and great performances base station. Thanks a
 lot.

 By the way, as I am abroad, I may take a bit more time than usual to
 reply to your e-mails. I really appologize for this and I will do my best
 to reply as soon as I can.

 Best regards.

 Jean-Samuel.
 :-)

 On Mon, Aug 6, 2012 at 5:07 PM, Andrey Sviyazov &lt;andreysviyaz(a)gmail.com&gt;wrote;wrote:

  I've found first error:
 Missed AC block required for Vref pin of ADF4350.
 Also translated some components descriptions to English to avoid
 misunderstanding of Russian.
 All newest files here in zip.

 Best regards,
 Andrey Sviyazov.

 2012/8/6 Andrey Sviyazov &lt;andreysviyaz(a)gmail.com&gt;

> Sorry.
> Zip file here :)
>
> Best regards,
> Andrey Sviyazov.
>
>
>
> 2012/8/6 Andrey Sviyazov &lt;andreysviyaz(a)gmail.com&gt;
>
>> Hi all.
>>
>> Here first release of preselector project, schema and BOM.
>> Any questions and suggestions welcomed.
>>
>> Best regards,
>> Andrey Sviyazov.
>>
>>
>

Re: UmTRX preselector