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Joel Yabut joel.yabut at gmail.comYes 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.htm>