2 Aug
2013
2 Aug
'13
4:09 a.m.
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
2 Aug
2 Aug
4:20 a.m.
New subject: 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(a)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
4:55 a.m.
New subject: The Difference of Signal Strength From Two Channels on The Same Board is Big
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(a)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
5:30 a.m.
New subject: 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(a)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(a)ljshuoda.com> wrote:
--
Regards,
Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио
http://fairwaves.ru
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
7:09 a.m.
New subject: The Difference of Signal Strength From Two Channels on The Same Board is Big
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(a)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(a)ljshuoda.com> wrote:
--
Regards,
Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио
http://fairwaves.ru
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
7:53 a.m.
New subject: The Difference of Signal Strength From Two Channels on The Same Board is Big
I try another UmTRX board, and it's OK. The difference from the channel 0 and 1 is
very small.
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(a)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(a)ljshuoda.com> wrote:
--
Regards,
Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио
http://fairwaves.ru
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
12:54 p.m.
New subject: 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(a)ljshuoda.com>
**
I try another UmTRX board, and it's OK. The difference from the channel 0
and 1 is very small.
------------------------------
jiangwy
*From:* Alexander Chemeris <alexander.chemeris(a)gmail.com>
*Date:* 2013-08-02 17:30
*To:* wyjiang <wyjiang(a)ljshuoda.com>
*CC:* UmTRX <umtrx(a)lists.osmocom.org>
*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(a)ljshuoda.com> wrote:
--
Regards,
Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио
http://fairwaves.ru
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(a)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
10:19 p.m.
New subject: The Difference of Signal Strength From Two Channels on The Same Board is Big
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(a)ljshuoda.com>
I try another UmTRX board, and it's OK. The difference from the channel 0 and 1 is
very small.
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(a)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(a)ljshuoda.com> wrote:
--
Regards,
Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио
http://fairwaves.ru
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
10:48 p.m.
New subject: The Difference of Signal Strength From Two Channels on The Same Board is Big
Hi Andrey Sviyazov.
I have tried the kal program on both boards, the output are:
The following commands are executed on the normal board
./kal -s GSM900 -v -R A:0
kal: Scanning for GSM-900 base stations.
channel detect threshold: 19506.878626
chan: 11 (937.2MHz - 13.389kHz) power: 53673.23
chan: 14 (937.8MHz + 4Hz) power: 64031.10
chan: 16 (938.2MHz + 30Hz) power: 37823.70
chan: 43 (943.6MHz + 2Hz) power: 77249.29
chan: 50 (945.0MHz - 24Hz) power: 29420.52
./kal -s GSM900 -v -R B:0
kal: Scanning for GSM-900 base stations.
channel detect threshold: 28406.616263
chan: 11 (937.2MHz - 6.120kHz) power: 53776.77
chan: 14 (937.8MHz - 59Hz) power: 76683.83
chan: 16 (938.2MHz + 28.945kHz) power: 46724.84
chan: 43 (943.6MHz + 38.130kHz) power: 65350.20
chan: 50 (945.0MHz - 21Hz) power: 29930.09
The following commands are executed on another board seeming to be abnormal
./kal -s GSM900 -v -R A:0
kal: Scanning for GSM-900 base stations.
channel detect threshold: 4486.504362
chan: 5 (936.0MHz - 15Hz) power: 6734.70
chan: 12 (937.4MHz + 50Hz) power: 9339.20
chan: 83 (951.6MHz - 13Hz) power: 6462.91
./kal -s GSM900 -v -R B:0
kal: Scanning for GSM-900 base stations.
channel detect threshold: 27671.315417
chan: 5 (936.0MHz + 24Hz) power: 29673.93
chan: 12 (937.4MHz + 40Hz) power: 69096.60
chan: 83 (951.6MHz - 4Hz) power: 46394.73
./kal -c 1004 -R A:0
kal: Calculating clock frequency offset.
Using E-GSM-900 channel 1004 (931.0MHz)
average [min, max] (range, stddev)
+ 2Hz [-80, 79] (159, 44.543312)
overruns: 0
not found: 34
./kal -c 1004 -R B:0
kal: Calculating clock frequency offset.
Using E-GSM-900 channel 1004 (931.0MHz)
average [min, max] (range, stddev)
+ 1Hz [-13, 19] (32, 8.658517)
overruns: 0
not found: 0
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(a)ljshuoda.com>
I try another UmTRX board, and it's OK. The difference from the channel 0 and 1 is
very small.
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(a)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(a)ljshuoda.com> wrote:
--
Regards,
Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио
http://fairwaves.ru
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
5 Aug
5 Aug
6:30 a.m.
New subject: The Difference of Signal Strength From Two Channels on The Same Board is Big
Андрей, напиши ему свой адрес?
Меня в копию поставь.
On Sat, Aug 3, 2013 at 6:48 AM, jiangwy <wyjiang(a)ljshuoda.com> wrote:
**
Hi Andrey Sviyazov.
I have tried the kal program on both boards, the output are:
The following commands are executed on the normal board
./kal -s GSM900 -v -R A:0
kal: Scanning for GSM-900 base stations.
channel detect threshold: 19506.878626
chan: 11 (937.2MHz - 13.389kHz) power: 53673.23
chan: 14 (937.8MHz + 4Hz) power: 64031.10
chan: 16 (938.2MHz + 30Hz) power: 37823.70
chan: 43 (943.6MHz + 2Hz) power: 77249.29
chan: 50 (945.0MHz - 24Hz) power: 29420.52
./kal -s GSM900 -v -R B:0
kal: Scanning for GSM-900 base stations.
channel detect threshold: 28406.616263
chan: 11 (937.2MHz - 6.120kHz) power: 53776.77
chan: 14 (937.8MHz - 59Hz) power: 76683.83
chan: 16 (938.2MHz + 28.945kHz) power: 46724.84
chan: 43 (943.6MHz + 38.130kHz) power: 65350.20
chan: 50 (945.0MHz - 21Hz) power: 29930.09
The following commands are executed on another board seeming to be abnormal
./kal -s GSM900 -v -R A:0
kal: Scanning for GSM-900 base stations.
channel detect threshold: 4486.504362
chan: 5 (936.0MHz - 15Hz) power: 6734.70
chan: 12 (937.4MHz + 50Hz) power: 9339.20
chan: 83 (951.6MHz - 13Hz) power: 6462.91
./kal -s GSM900 -v -R B:0
kal: Scanning for GSM-900 base stations.
channel detect threshold: 27671.315417
chan: 5 (936.0MHz + 24Hz) power: 29673.93
chan: 12 (937.4MHz + 40Hz) power: 69096.60
chan: 83 (951.6MHz - 4Hz) power: 46394.73
./kal -c 1004 -R A:0
kal: Calculating clock frequency offset.
Using E-GSM-900 channel 1004 (931.0MHz)
average [min, max] (range, stddev)
+ 2Hz [-80, 79] (159, 44.543312)
overruns: 0
not found: 34
./kal -c 1004 -R B:0
kal: Calculating clock frequency offset.
Using E-GSM-900 channel 1004 (931.0MHz)
average [min, max] (range, stddev)
+ 1Hz [-13, 19] (32, 8.658517)
overruns: 0
not found: 0
Best Regards.
------------------------------
jiangwy
*From:* Andrey Sviyazov <andreysviyaz(a)gmail.com>
*Date:* 2013-08-03 00:54
*To:* wyjiang <wyjiang(a)ljshuoda.com>
*CC:* UmTRX <umtrx(a)lists.osmocom.org>rg>; Alexander
Chemeris<alexander.chemeris(a)gmail.com>
*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(a)ljshuoda.com>
--
Regards,
Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио
http://fairwaves.ru
**
I try another UmTRX board, and it's OK. The difference from the channel 0
and 1 is very small.
------------------------------
jiangwy
*From:* Alexander Chemeris <alexander.chemeris(a)gmail.com>
*Date:* 2013-08-02 17:30
*To:* wyjiang <wyjiang(a)ljshuoda.com>
*CC:* UmTRX <umtrx(a)lists.osmocom.org>
*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(a)ljshuoda.com> wrote:
--
Regards,
Alexander Chemeris.
CEO, Fairwaves LLC / ООО УмРадио
http://fairwaves.ru
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(a)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
4373
days inactive
4376
days old
9 comments
3 participants
participants (3)
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Alexander Chemeris -
Andrey Sviyazov -
jiangwy