ksdr - port 1 - no sensitivity

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derbot
Posts: 2
Joined: Fri Jan 29, 2021 6:01 pm

ksdr - port 1 - no sensitivity

Post by derbot » Fri Jan 29, 2021 6:30 pm

Hi,

My ksdr doesn't seems to have any sensitivity on the first sdr/antenna port.
Received the device about 1 month ago and I did just some basic tests then and I cannot say if it was like this when it arrived or something happened after (but I remember ending using port 4 for most of the tests).

Tried:
a) at first I thought the pigtail which connects the antenna port is broken, asked somebody to resolder it
b) swaped port1 pigtail with port2 pigtail (should have done this first)
c) tried differed gains (read somewhere it might help)

I don't know if I voided the warranty by opening the case and messing with the pigtails but anyway I would prefer to solve it locally instead of shipping it back overseas.

Below the tests I did using rtl_power. Connected the same antenna on each port and collected rtl_power samples from FM band. For good measure did also a test on each port without an antenna connected.

My hypotheses are:
a) the port1 was broken when it arrived
b) ESD damage
c) damage from the soldering iron

I'm no radio or electronics expert but I've used SDRs for 5+ years.
Can you help me with some advice ?

Thanks.

Code: Select all

#
# connected antenna to 1st port
#
[email protected]:/usr/src/rtl-sdr-blog/build/src# ./rtl_power -g 45  -f 106.5M:106.9M:25k -e 1000s -d 0
Found 4 device(s):
  0:  RTL-SDR, KerberosSDR, SN: 001
  1:  RTL-SDR, KerberosSDR, SN: 002
  2:  RTL-SDR, KerberosSDR, SN: 003
  3:  RTL-SDR, KerberosSDR, SN: 004

Using device 0: Generic RTL2832U OEM
Number of frequency hops: 1
Dongle bandwidth: 2800000Hz
Downsampling by: 7x
Cropping by: 0.00%
Total FFT bins: 16
Logged FFT bins: 16
FFT bin size: 25000.00Hz
Buffer size: 16384 bytes (2.93ms)
Reporting every 10 seconds
Found Rafael Micro R820T tuner
Tuner gain set to 44.50 dB.
Exact sample rate is: 2800000.037087 Hz
[R82XX] PLL not locked!
2021-01-29, 19:48:42, 106500000, 106900000, 25000.00, 1651902, -31.27, -30.85, -28.32, -25.17, -21.89, -26.80, -28.04, -27.29, -26.02, -26.02, -27.17, -30.64, -31.25, -31.96, -31.99, -31.76, -31.76
2021-01-29, 19:48:52, 106500000, 106900000, 25000.00, 1763790, -31.21, -30.68, -28.12, -25.15, -22.14, -26.88, -28.35, -27.19, -25.86, -25.86, -27.75, -30.91, -31.30, -31.95, -31.99, -31.76, -31.76
2021-01-29, 19:49:02, 106500000, 106900000, 25000.00, 1765344, -31.25, -30.73, -28.30, -25.35, -22.00, -26.99, -28.42, -27.38, -26.10, -26.10, -27.77, -30.99, -31.32, -31.94, -32.02, -31.76, -31.76
2021-01-29, 19:49:12, 106500000, 106900000, 25000.00, 1764826, -31.27, -30.88, -28.42, -25.26, -21.66, -26.98, -28.61, -27.57, -26.30, -26.30, -27.90, -31.03, -31.33, -31.97, -32.00, -31.77, -31.77
^CSignal caught, finishing scan pass.

#
# moved antenna from 1st to 2nd port
#
User cancel, exiting...
[email protected]:/usr/src/rtl-sdr-blog/build/src# ./rtl_power -g 45  -f 106.5M:106.9M:25k -e 1000s -d 1
Found 4 device(s):
  0:  RTL-SDR, KerberosSDR, SN: 001
  1:  RTL-SDR, KerberosSDR, SN: 002
  2:  RTL-SDR, KerberosSDR, SN: 003
  3:  RTL-SDR, KerberosSDR, SN: 004

Using device 1: Generic RTL2832U OEM
Number of frequency hops: 1
Dongle bandwidth: 2800000Hz
Downsampling by: 7x
Cropping by: 0.00%
Total FFT bins: 16
Logged FFT bins: 16
FFT bin size: 25000.00Hz
Buffer size: 16384 bytes (2.93ms)
Reporting every 10 seconds
Found Rafael Micro R820T tuner
Tuner gain set to 44.50 dB.
Exact sample rate is: 2800000.037087 Hz
[R82XX] PLL not locked!
2021-01-29, 19:50:02, 106500000, 106900000, 25000.00, 1649830, -1.10, -0.83, 0.91, 3.48, 6.98, 2.25, 0.80, 1.24, 1.69, 1.69, 0.38, -1.82, -2.33, -2.28, -1.99, -1.52, -1.52
2021-01-29, 19:50:12, 106500000, 106900000, 25000.00, 1765344, -0.10, -0.06, 1.21, 3.31, 6.73, 2.23, 1.02, 1.85, 2.23, 2.23, 0.71, -0.92, -1.24, -1.14, -0.80, -0.40, -0.40
2021-01-29, 19:50:22, 106500000, 106900000, 25000.00, 1765344, -0.02, -0.01, 1.25, 3.49, 6.89, 2.35, 1.04, 1.66, 1.96, 1.96, 0.79, -0.92, -1.26, -1.13, -0.80, -0.38, -0.38
2021-01-29, 19:50:32, 106500000, 106900000, 25000.00, 1765862, 1.01, 0.93, 1.71, 3.96, 6.56, 3.03, 1.70, 2.19, 2.37, 2.37, 1.31, 0.08, -0.14, -0.02, 0.38, 0.74, 0.74
^CSignal caught, finishing scan pass.

User cancel, exiting...

#
# moved antenna from 2nd to 3rd port
#

[email protected]:/usr/src/rtl-sdr-blog/build/src# ./rtl_power -g 45  -f 106.5M:106.9M:25k -e 1000s -d 2
Found 4 device(s):
  0:  RTL-SDR, KerberosSDR, SN: 001
  1:  RTL-SDR, KerberosSDR, SN: 002
  2:  RTL-SDR, KerberosSDR, SN: 003
  3:  RTL-SDR, KerberosSDR, SN: 004

Using device 2: Generic RTL2832U OEM
Number of frequency hops: 1
Dongle bandwidth: 2800000Hz
Downsampling by: 7x
Cropping by: 0.00%
Total FFT bins: 16
Logged FFT bins: 16
FFT bin size: 25000.00Hz
Buffer size: 16384 bytes (2.93ms)
Reporting every 10 seconds
Found Rafael Micro R820T tuner
Tuner gain set to 44.50 dB.
Exact sample rate is: 2800000.037087 Hz
[R82XX] PLL not locked!
2021-01-29, 19:51:30, 106500000, 106900000, 25000.00, 1588706, 1.83, 1.79, 2.39, 3.86, 6.05, 3.33, 2.24, 2.34, 2.40, 2.40, 1.77, 0.95, 0.79, 0.94, 1.24, 1.57, 1.57
2021-01-29, 19:51:40, 106500000, 106900000, 25000.00, 1765344, 1.44, 1.46, 2.28, 3.87, 6.34, 3.20, 2.10, 2.27, 2.26, 2.26, 1.49, 0.56, 0.36, 0.49, 0.81, 1.12, 1.12
2021-01-29, 19:51:50, 106500000, 106900000, 25000.00, 1764308, 1.23, 1.25, 2.10, 3.70, 6.57, 2.88, 1.98, 2.22, 2.18, 2.18, 1.46, 0.36, 0.14, 0.26, 0.58, 0.93, 0.93
2021-01-29, 19:52:00, 106500000, 106900000, 25000.00, 1765862, 0.80, 0.80, 1.70, 3.40, 7.28, 2.56, 1.61, 1.91, 1.98, 1.98, 1.15, -0.16, -0.42, -0.32, 0.02, 0.43, 0.43
^CSignal caught, finishing scan pass.

User cancel, exiting...

#
# moved antenna from 3rd to 4th port
#

[email protected]:/usr/src/rtl-sdr-blog/build/src# ./rtl_power -g 45  -f 106.5M:106.9M:25k -e 1000s -d 3
Found 4 device(s):
  0:  RTL-SDR, KerberosSDR, SN: 001
  1:  RTL-SDR, KerberosSDR, SN: 002
  2:  RTL-SDR, KerberosSDR, SN: 003
  3:  RTL-SDR, KerberosSDR, SN: 004

Using device 3: Generic RTL2832U OEM
Number of frequency hops: 1
Dongle bandwidth: 2800000Hz
Downsampling by: 7x
Cropping by: 0.00%
Total FFT bins: 16
Logged FFT bins: 16
FFT bin size: 25000.00Hz
Buffer size: 16384 bytes (2.93ms)
Reporting every 10 seconds
Found Rafael Micro R820T tuner
Tuner gain set to 44.50 dB.
Exact sample rate is: 2800000.037087 Hz
[R82XX] PLL not locked!
2021-01-29, 19:52:59, 106500000, 106900000, 25000.00, 1716134, 2.35, 2.20, 2.29, 3.57, 6.74, 3.11, 2.07, 2.40, 2.44, 2.44, 1.97, 1.22, 1.06, 1.29, 1.86, 2.22, 2.22
2021-01-29, 19:53:09, 106500000, 106900000, 25000.00, 1765862, 3.38, 3.31, 3.45, 3.99, 4.93, 3.72, 3.04, 2.86, 2.81, 2.81, 2.66, 2.46, 2.47, 2.65, 2.98, 3.23, 3.23
2021-01-29, 19:53:19, 106500000, 106900000, 25000.00, 1765344, 3.21, 3.16, 3.30, 4.03, 5.16, 3.69, 2.94, 2.78, 2.72, 2.72, 2.52, 2.28, 2.26, 2.45, 2.77, 3.08, 3.08
2021-01-29, 19:53:29, 106500000, 106900000, 25000.00, 1764826, 3.36, 3.27, 3.32, 3.85, 5.00, 3.53, 2.94, 2.87, 2.87, 2.87, 2.66, 2.46, 2.44, 2.61, 2.93, 3.22, 3.22
^CSignal caught, finishing scan pass.

User cancel, exiting...
[email protected]:/usr/src/rtl-sdr-blog/build/src# ./rtl_power -g 45  -f 106.5M:106.9M:25k -e 1000s -d 1^C
[email protected]:/usr/src/rtl-sdr-blog/build/src# echo disconnect antenna
disconnect antenna

#
# disconnected antenna, also no terminators connected
#
[email protected]:/usr/src/rtl-sdr-blog/build/src# ./rtl_power -g 45  -f 106.5M:106.9M:25k -e 1000s -d 0
Found 4 device(s):
  0:  RTL-SDR, KerberosSDR, SN: 001
  1:  RTL-SDR, KerberosSDR, SN: 002
  2:  RTL-SDR, KerberosSDR, SN: 003
  3:  RTL-SDR, KerberosSDR, SN: 004

Using device 0: Generic RTL2832U OEM
Number of frequency hops: 1
Dongle bandwidth: 2800000Hz
Downsampling by: 7x
Cropping by: 0.00%
Total FFT bins: 16
Logged FFT bins: 16
FFT bin size: 25000.00Hz
Buffer size: 16384 bytes (2.93ms)
Reporting every 10 seconds
Found Rafael Micro R820T tuner
Tuner gain set to 44.50 dB.
Exact sample rate is: 2800000.037087 Hz
[R82XX] PLL not locked!
2021-01-29, 19:54:48, 106500000, 106900000, 25000.00, 1616160, -31.18, -31.16, -31.12, -31.10, -31.03, -30.96, -30.90, -30.85, -30.89, -30.89, -30.92, -30.97, -30.93, -31.11, -31.13, -31.16, -31.16
2021-01-29, 19:54:58, 106500000, 106900000, 25000.00, 1764826, -31.17, -31.16, -31.12, -31.09, -31.04, -30.96, -30.91, -30.86, -30.88, -30.88, -30.91, -30.97, -30.93, -31.09, -31.14, -31.17, -31.17
2021-01-29, 19:55:08, 106500000, 106900000, 25000.00, 1764826, -31.17, -31.15, -31.14, -31.08, -31.03, -30.96, -30.91, -30.86, -30.89, -30.89, -30.90, -30.99, -30.93, -31.09, -31.15, -31.15, -31.15
2021-01-29, 19:55:18, 106500000, 106900000, 25000.00, 1763790, -31.18, -31.16, -31.13, -31.08, -31.02, -30.98, -30.91, -30.87, -30.89, -30.89, -30.92, -30.98, -30.92, -31.08, -31.14, -31.15, -31.15
^CSignal caught, finishing scan pass.

User cancel, exiting...
[email protected]:/usr/src/rtl-sdr-blog/build/src# ./rtl_power -g 45  -f 106.5M:106.9M:25k -e 1000s -d 1
Found 4 device(s):
  0:  RTL-SDR, KerberosSDR, SN: 001
  1:  RTL-SDR, KerberosSDR, SN: 002
  2:  RTL-SDR, KerberosSDR, SN: 003
  3:  RTL-SDR, KerberosSDR, SN: 004

Using device 1: Generic RTL2832U OEM
Number of frequency hops: 1
Dongle bandwidth: 2800000Hz
Downsampling by: 7x
Cropping by: 0.00%
Total FFT bins: 16
Logged FFT bins: 16
FFT bin size: 25000.00Hz
Buffer size: 16384 bytes (2.93ms)
Reporting every 10 seconds
Found Rafael Micro R820T tuner
Tuner gain set to 44.50 dB.
Exact sample rate is: 2800000.037087 Hz
[R82XX] PLL not locked!
2021-01-29, 19:55:32, 106500000, 106900000, 25000.00, 1607354, -28.32, -28.18, -28.30, -28.26, -28.18, -28.12, -28.07, -27.99, -28.04, -28.04, -28.08, -28.14, -27.81, -28.26, -28.32, -28.34, -28.34
2021-01-29, 19:55:42, 106500000, 106900000, 25000.00, 1764826, -28.35, -28.19, -28.31, -28.27, -28.22, -28.14, -28.10, -27.99, -28.06, -28.06, -28.10, -28.17, -27.86, -28.29, -28.35, -28.38, -28.38
2021-01-29, 19:55:52, 106500000, 106900000, 25000.00, 1765344, -28.36, -28.21, -28.34, -28.27, -28.23, -28.16, -28.08, -28.00, -28.08, -28.08, -28.11, -28.17, -27.85, -28.31, -28.36, -28.38, -28.38
2021-01-29, 19:56:02, 106500000, 106900000, 25000.00, 1764826, -28.38, -28.20, -28.34, -28.31, -28.24, -28.17, -28.10, -28.03, -28.09, -28.09, -28.13, -28.18, -27.86, -28.31, -28.36, -28.40, -28.40
^CSignal caught, finishing scan pass.

User cancel, exiting...
[email protected]:/usr/src/rtl-sdr-blog/build/src# ./rtl_power -g 45  -f 106.5M:106.9M:25k -e 1000s -d 2
Found 4 device(s):
  0:  RTL-SDR, KerberosSDR, SN: 001
  1:  RTL-SDR, KerberosSDR, SN: 002
  2:  RTL-SDR, KerberosSDR, SN: 003
  3:  RTL-SDR, KerberosSDR, SN: 004

Using device 2: Generic RTL2832U OEM
Number of frequency hops: 1
Dongle bandwidth: 2800000Hz
Downsampling by: 7x
Cropping by: 0.00%
Total FFT bins: 16
Logged FFT bins: 16
FFT bin size: 25000.00Hz
Buffer size: 16384 bytes (2.93ms)
Reporting every 10 seconds
Found Rafael Micro R820T tuner
Tuner gain set to 44.50 dB.
Exact sample rate is: 2800000.037087 Hz
[R82XX] PLL not locked!
2021-01-29, 19:56:16, 106500000, 106900000, 25000.00, 1589224, -28.11, -28.10, -28.09, -28.02, -27.93, -27.89, -27.80, -27.67, -27.78, -27.78, -27.83, -27.90, -27.33, -28.04, -28.07, -28.11, -28.11
2021-01-29, 19:56:26, 106500000, 106900000, 25000.00, 1765344, -28.14, -28.11, -28.10, -28.05, -27.95, -27.91, -27.82, -27.69, -27.80, -27.80, -27.87, -27.93, -27.36, -28.07, -28.11, -28.13, -28.13
2021-01-29, 19:56:36, 106500000, 106900000, 25000.00, 1764826, -28.17, -28.13, -28.09, -28.04, -27.97, -27.89, -27.82, -27.71, -27.81, -27.81, -27.87, -27.93, -27.37, -28.06, -28.11, -28.14, -28.14
2021-01-29, 19:56:46, 106500000, 106900000, 25000.00, 1765344, -28.18, -28.13, -28.12, -28.07, -27.97, -27.91, -27.84, -27.71, -27.81, -27.81, -27.88, -27.95, -27.38, -28.08, -28.12, -28.16, -28.16
^CSignal caught, finishing scan pass.

User cancel, exiting...
[email protected]:/usr/src/rtl-sdr-blog/build/src# ./rtl_power -g 45  -f 106.5M:106.9M:25k -e 1000s -d 3
Found 4 device(s):
  0:  RTL-SDR, KerberosSDR, SN: 001
  1:  RTL-SDR, KerberosSDR, SN: 002
  2:  RTL-SDR, KerberosSDR, SN: 003
  3:  RTL-SDR, KerberosSDR, SN: 004

Using device 3: Generic RTL2832U OEM
Number of frequency hops: 1
Dongle bandwidth: 2800000Hz
Downsampling by: 7x
Cropping by: 0.00%
Total FFT bins: 16
Logged FFT bins: 16
FFT bin size: 25000.00Hz
Buffer size: 16384 bytes (2.93ms)
Reporting every 10 seconds
Found Rafael Micro R820T tuner
Tuner gain set to 44.50 dB.
Exact sample rate is: 2800000.037087 Hz
[R82XX] PLL not locked!
2021-01-29, 19:57:02, 106500000, 106900000, 25000.00, 1740998, -30.14, -30.12, -30.08, -30.03, -29.98, -29.91, -29.84, -29.76, -29.81, -29.81, -29.87, -29.92, -29.78, -30.04, -30.11, -30.12, -30.12
2021-01-29, 19:57:12, 106500000, 106900000, 25000.00, 1764308, -30.14, -30.12, -30.09, -30.04, -29.98, -29.91, -29.85, -29.79, -29.84, -29.84, -29.86, -29.94, -29.78, -30.06, -30.09, -30.11, -30.11
2021-01-29, 19:57:22, 106500000, 106900000, 25000.00, 1764308, -30.15, -30.11, -30.08, -30.05, -29.98, -29.91, -29.86, -29.77, -29.81, -29.81, -29.87, -29.95, -29.76, -30.05, -30.10, -30.14, -30.14
2021-01-29, 19:57:32, 106500000, 106900000, 25000.00, 1763272, -30.15, -30.14, -30.09, -30.05, -29.97, -29.91, -29.85, -29.78, -29.83, -29.83, -29.89, -29.95, -29.77, -30.07, -30.11, -30.14, -30.14
^CSignal caught, finishing scan pass.




rtlsdrblog
Site Admin
Posts: 2892
Joined: Mon Nov 19, 2012 11:54 pm

Re: ksdr - port 1 - no sensitivity

Post by rtlsdrblog » Wed Feb 10, 2021 2:25 am

Best to contact us at [email protected] and [email protected] as it might be a bad uFL connector. Might also just be a blown R820T2 chip. Either way we would warranty a fault.

derbot
Posts: 2
Joined: Fri Jan 29, 2021 6:01 pm

Re: ksdr - port 1 - no sensitivity

Post by derbot » Thu Feb 25, 2021 2:24 pm

Hi,

Meantime:
- I asked a friend to take a look. He measured things inside and said that the gain control part is the problem.
- Also port4 failed similary since then

I have no other idea other than the box is very sensitive to ESD (but I have handled it the same as all the other sdrs and electronics I have) or just a bad batch.

The ksdr is purchased from here:
https://www.hamradio.co.uk/sdr-othernet ... -11276.php

I assume I should contact them directly or should I follow up with you by email ?

Thanks.

rtlsdrblog
Site Admin
Posts: 2892
Joined: Mon Nov 19, 2012 11:54 pm

Re: ksdr - port 1 - no sensitivity

Post by rtlsdrblog » Fri Mar 05, 2021 4:31 am

You can follow up with them and us. It shouldn't be more sensitive to ESD that any other SDR and there is good ESD protection on it.

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