Hi Andrey Sviyazov
 
I confirm that  both UmTRX's runs with the same FPGA images (and firmware). I have updated them to the latest version.
I will try some other programs to check the problem.
 
Best Regards,
 
jiangwy
 
From: Andrey Sviyazov
Date: 2013-08-03 00:54
To: wyjiang
CC: UmTRX; Alexander Chemeris
Subject: Re: Re: The Difference of Signal Strength From Two Channels on The Same Board is Big
Hi Jiang Wenyi.

Please double check that both UmTRX's runs with the same FPGA images (and firmware).
If absolutely the same then seems one board is broken.
Please double check it also by some other tests to be sure before send to us for repair.

Best regards,
Andrey Sviyazov.


2013/8/2 jiangwy <wyjiang@ljshuoda.com>
I try another UmTRX board, and it's OK. The difference from the channel 0 and 1 is very small.
 
jiangwy
 
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@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:
>
> On Fri, Aug 2, 2013 at 12:09 PM, jiangwy <wyjiang@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 / ïïï õÍòÁÄÉÏ
>
 
 
 
-- 
Regards,
Alexander Chemeris.
CEO, Fairwaves LLC / ïïï õÍòÁÄÉÏ