> 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.