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

jiangwy wyjiang at ljshuoda.com
Fri Aug 2 11:09:26 UTC 2013


umtrx_lms.py --lms-get-rx-lna --lms 1 
umtrx_lms.py --lms-get-rx-lna --lms 2

then output nothing




jiangwy

From: Alexander Chemeris
Date: 2013-08-02 17:30
To: wyjiang
CC: UmTRX
Subject: Re: Re: The Difference of Signal Strength From Two Channels on The Same Board is Big
Ok.

Also check that a correct input is selected on both chips
(--lms-get-rx-lna option).

Then, could you check whether this is consistent among both UmTRX you have?

On Fri, Aug 2, 2013 at 12:55 PM, jiangwy <wyjiang at ljshuoda.com> wrote:
> 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
>



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