Hi John, so, the R820T tuner IC is very well-supported in my experience, as you can see from the fact that librtlsdr *tries* to talk to it. I've seen similarly catastrophic behaviour on a USB port that simply couldn't supply enough power to keep the RTL Dongle operational. Maybe it's also a different tuner chip that has compatible ID register (compare: librtlsdr.c, current git master, l. 1553); but I've personally not encountered such before. You might want to look inside your device and identify the tuner IC (there will be only two or three "large" ICs on that PCB; one with a crab, that's the RTL2838, and one very close to the antenna connector, that's the tuner IC). Other than that, your stick might also be damaged. There might be other reasons for this behaviour, too, but "power problems" sounds like it's the most likely explanation; can you try on a different USB port? Best regards, Marcus On 21.10.2017 18:08, John wrote:

Hello,

I am new to this list and to SDR radio. I have purchased an SDR dongle but am having trougble getting it to work. The dongle was described as an RTL8232U/R820T2 device. I am running on Linux MINT version 18.2 and lsusb detects the device as follows:

Bus 002 Device 051: ID 0bda:2838 Realtek Semiconductor Corp. RTL2838 DVB-T

Is it an RTL2832U or an RTL2838? I'm not really sure.

From research it seems that It seems like the fist order of business is to blacklist the kernel driver? So I have done this by adding a backlist-rtl.conf file to /etc/modprobe.d and rebooted the computer. I have also added a rules file to /etc/udev/rules.d with the following content:

# Realtek Semiconductor Corp. RTL2838 DVB-T SUBSYSTEMS=="usb", ATTRS{idVendor}=="0bda", ATTRS{idProduct}=="2838", MODE:="0666", GROUP="adm", SYMLINK+="rtl_sdr"

I can now access the device in user mode without permission errors so I assume that this is working OK.

So my next step was to run rtl_test -t. The output I got contained errors.If I then try to run any sdr software such as rtl_fm or gqrx, the device is reset and the application fails to run. Subsequentlly running 'rtl_test -t' gives:

No supported devices found.

Even running rtl_test-t sometimes does the same so i'm not sure whether the device is 'dropping out' of its own accord.

I am wondering whether the current crop of devices are supported? Or is this a configuration problem?

The output from rtl_test:

rtl_test -t Found 1 device(s): 0: Realtek, RTL2838UHIDIR, SN: 00000001

Using device 0: Generic RTL2832U OEM Found Rafael Micro R820T tuner r82xx_write: i2c wr failed=-1 reg=13 len=7 r82xx_write: i2c wr failed=-1 reg=0c len=1 r82xx_init: failed=-1 rtlsdr_demod_write_reg failed with -1 rtlsdr_demod_read_reg failed with -1 Supported gain values (29): 0.0 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28.0 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5 48.0 49.6 rtlsdr_demod_write_reg failed with -1 rtlsdr_demod_read_reg failed with -1 r82xx_write: i2c wr failed=-1 reg=0a len=1 rtlsdr_demod_write_reg failed with -1 rtlsdr_demod_read_reg failed with -1 rtlsdr_demod_write_reg failed with -1 rtlsdr_demod_read_reg failed with -1 rtlsdr_demod_write_reg failed with -1 rtlsdr_demod_read_reg failed with -1 rtlsdr_demod_write_reg failed with -1 rtlsdr_demod_read_reg failed with -1 rtlsdr_demod_write_reg failed with -1 rtlsdr_demod_read_reg failed with -1 rtlsdr_demod_write_reg failed with -1 rtlsdr_demod_read_reg failed with -1 rtlsdr_demod_write_reg failed with -1 rtlsdr_demod_read_reg failed with -1 WARNING: Failed to set sample rate. No E4000 tuner found, aborting. rtlsdr_demod_write_reg failed with -1 rtlsdr_demod_read_reg failed with -1 rtlsdr_demod_write_reg failed with -1 rtlsdr_demod_read_reg failed with -1 rtlsdr_write_reg failed with -1