Day: May 10, 2018

Let’s see if my new SDR works fine with FT8.

The operating system is macOS High Sierra (10.13.4).

I use Soundflower to send the audio stream from Gqrx to WSJT-X.

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Now the settings for Gqrx. Remember that the Mode must be USB.

The Audio output should be either “Multi-Output Device” or “Soundflower (2ch)”.

Do not forget to enable Remote control (Tools -> Remote control).

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Finally, the settings for WSJT-X.

“Hamlib NET rigctl” is selected as rig control.

Select “Soundflower (2ch)” for Soundcard Input.

You can control Gqrx using telnet.

import numpy as numpy
import matplotlib.pyplot as plt
import telnetlib
HOST = "127.0.0.1"
EXPECTED =b"dummy"
TOUT = 0.1

tn = telnetlib.Telnet(HOST, 7356)
xvalue = []
yvalue = []

tn.write(b"M CW 1000\n")
print(tn.read_until(EXPECTED, timeout=TOUT).decode('ascii'), end="")

for freq_hz in range(79000000, 81000000, 1000):
	freq=b"F "+str(freq_hz).encode('ascii')+b"\n"
	tn.write(freq)
	tn.read_until(EXPECTED, timeout=TOUT)

	tn.write(b"f\n")
	f = int(tn.read_until(EXPECTED, timeout=TOUT).decode('ascii'))
	xvalue.append(f)
	print(f)

	tn.write(b"l\n")
	l = float(tn.read_until(EXPECTED, timeout=TOUT).decode('ascii'))
	yvalue.append(l)
	print(l)

plt.figure(1, figsize=(8,8))
plt.subplot(111)
plt.title('Airspy HF+')
plt.xlabel('Freq [Hz]')
plt.ylabel('Signal Strength [dBm]')
plt.grid(True)
plt.plot(xvalue, yvalue, color='blue', linewidth=1)
plt.show()

The program scan the FM band, and plot the signal strength.