10 Mar
2013
10 Mar
'13
10:28 p.m.
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(a)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(a)gmail.com> wrote:
Hi Joel.
On Fri, Feb 22, 2013 at 6:28 PM, joel yabut <joel(a)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.