The Difference of Signal Strength From Two Channels on The Same Board is Big

jiangwy wyjiang at ljshuoda.com
Fri Aug 2 08:55:55 UTC 2013


I use the following command

./umtrx_lms.py --lms {1,2} --lms-get-rx-vga2-gain 

the outputs are all the same ( 15 ).




jiangwy

From: Alexander Chemeris
Date: 2013-08-02 16:20
To: wyjiang
CC: UmTRX
Subject: Re: The Difference of Signal Strength From Two Channels on The Same Board is Big
Hi Jiang,

Are you sure you're setting Rx gain properly for both channels?
I recommend you to use umtrx_lms.py script from this repository to
check Rx LNA and Rx VGA settings for both LMS chips:
https://github.com/fairwaves/umtrx_scripts

On Fri, Aug 2, 2013 at 12:09 PM, jiangwy <wyjiang at ljshuoda.com> wrote:
> Hi Alexander Chemeris,
>
> According to rx_multi_samples , I write a program to receive samples from
> two channels on the same board.
> The program receive samples from 2 channels and calculate the signal
> strength respectively. The signal is from a BTS arround.
> I find the difference of signal strength is very big, about 20dB, and
> channel 1 is bigger than channel 0.
> I  exchange the antenna and feeder of the them, but the result is same.
> I think there is some problem, but I cann't find it.
> Would you please give me some sugguestion?
>
> Best Regards.
>
> ________________________________
> Jiang Wenyi



-- 
Regards,
Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио
http://fairwaves.ru
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