UmTRX performance questions

Joel Yabut joel.yabut at gmail.com
Mon Mar 11 02:28:44 UTC 2013


Yes i need to attenuate the tx output and Also take into consideration the 1 db compression. I just have to 
 min attenuation to 8.

Sent from my Ipad

On Mar 11, 2013, at 3:20 AM, Andrey Sviyazov <andreysviyaz at gmail.com> wrote:

> Hi Joel.
> 
> > 2. What is the power output in dbm of your umtrx?
> After fixing this issue I measured + 20 dBm for 900 MHz band and +17 dBm for 1800.
>  
> I will be testing this UMTRX with a DCS amp with 10 dBM input. Just to be sure, I just need to adjust attenuation to at least 7 dBM and 8 probably to avoid clipping the RF amp as below:
> 
> GSM.Radio.PowerManager.MaxAttenDB 8 
> GSM.Radio.PowerManager.MinAttenDB 0 
> 
> Please explain more what att do you try to use and what clipping do you mean (may be 1dB gain compression) ?
> Anyhow, you can easy adjust output signal of UmTRX by using --gain in case of UHD TX control.
> Also can be used TXVGA2 gain in case of direct LMS registers control via Python scripts.
> 
> 
> Is using an LNA with BPF advisable with your UMTRX? 
> Yes of course.
> External LNA and duplexer or band pass filter should be used for better NF performance.
>    
> 
> What is the operating temperature of your UMTRX as I want to make sure the HD case I am using for testing is good enough. I installed a small fan and so far temperature is around 40 deg C.
> 
> You can find on the board FUN2 control IC (U35)  MAX6665ASA45.
> So, at the PCB temperature +45'C FUN2 must start to cooling.
> And if you do not use FAN2 (or broken) then this IC will switch off UmTRX at temperature 45+30=75'C.
> Low temperature limit is minus 40'C due to industrial components (is not tested 100% in production).
> 
> 
> The LEDs are on the board and I may want to solder some LEDs to monitor status, where on the board can I terminate the power for LEDs?
> 
> You can use any DC-DC output higher 2V through current limiting resistor.
> Pleas refer to datasheet of your LED's type to find proper resistor value.
> 
> 
> 
> On Tue, Mar 5, 2013 at 10:16 AM, Andrey Sviyazov <andreysviyaz at gmail.com> wrote:
> Hi Joel.
> 
> On Fri, Feb 22, 2013 at 6:28 PM, joel yabut <joel at jointventure.com> wrote:
> > May i know the following specs
> > 1. What is the tx and rx isolation of umtrx?
> Not yet measured and unfortunately there are no info from Lime Micro.
> 
> > 2. What is the power output in dbm of your umtrx?
> After fixing this issue I measured + 20 dBm for 900 MHz band and +17 dBm for 1800.
>  
> 
> > 3. How is the lna on the rx input and is an external lna and bpf
> > recommended?
> 
> For Fairwaves 10W base stations we're developing UmSEL, which has
> channel filter and an additional LNA. For the use without amplifier
> you don't need any additional filters or LNAs.
> 
> > 4. What is the main advantage of umtrx compared to usrp by ettus?
> 
> If you want to use it for GSM, then it's cheaper and gives you
> dual-channel support.
> 
> --
> Regards,
> Alexander Chemeris.
> CEO, Fairwaves LLC / ООО УмРадио
> http://fairwaves.ru
> 
> Best regards,
> Andrey Sviyazov.
> 
> 
> 
> -- 
> Mother Ignacia Avenue corner Scout Rallos St.
> Quezon City, Metro Manila, Philippines
> 
> 
> Best regards,
> Andrey Sviyazov.
> 
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osmocom.org/pipermail/umtrx/attachments/20130311/07b56f0d/attachment.html>


More information about the UmTRX mailing list