Ubuntu16.04, GQRX through the RTL-SDR Q channel to listen to medium and short wave

Hardware Preparation

Antenna: A dangling long-distance antenna, if only temporary use, directly with the ordinary 0.75 square PVC multi-stranded soft wire can be.

Baron: 9:1 Barron

Receiver: Q Channel adds RTL-SDR receiver for low frequency input

and the corresponding connection cable.

Receiver

The front and back of the circuit board, the connecting head is SMA, the outer screw inner hole, one connects the original antenna port, is responsible for the signal input of more than 25MHz, the other connects the Q Channel after the LC Channel, responsible for 100KHz to 25MHz signal input

The finished product after welding, wherein the green plate is a crystal with warm compensation

The actual connection

Software Gqrx

The installation of the software can refer to the previous article. Here is how to use GQRX to sample directly from the Q channel. In the Configure I/O devices, the direct_samp=2 parameter is added to the Device string,

After Setup is complete, you need to restart Gqrx to take effect. Restart Gqrx, you will be prompted to configure a problem, enter the editing interface, directly confirm access to the software.

For a description of the parameters, refer to Http://osmocom.org/projects/sdr/wiki/GrOsmoSDR

Argument	Notes
rtl=<device-ind Ex>	0-based device identifier OR serial number
rtl_xtal=<frequency>	Frequency (Hz) used for the RTL chip, accepts scientific notation
tuner_xtal=<frequency>	frequency (Hz) used for the tuner chip, accepts scientific notation
buffers=<number-of-buffers>	Default is +
BUFLEN=&L T;length-of-buffer>	Default is 256kB, must be multiple of a.
direct_samp=0|1|2< /td>	Enable Direct sampling mode on the RTL chip 0:disable, 1:use I channel, 2:use Q channel
offset_tune=0|1	Enable offset tune mode for E4000 tuners

Note:use to program rtl_eeprom -s your own serial number to the device
Note:if you don ' t specify Rtl_xtal/tuner_xtal, the underlying driver would use 28.0MHz

Run

Hardware Cooling

Receiver operation, the RTL2832 temperature is not too high, but if the receiver work in high frequency bands (such as FM), then the r820t2 fever is more severe, the finger can feel hot after a few seconds, if it is only used at room temperature, not to the extent of the need for heat sink. When running in low frequency bands, the R820T2 heat is significantly smaller.

Ubuntu16.04, GQRX through the RTL-SDR Q channel to listen to medium and short wave