Airspy HF+の仕様は;
+10 dBm Maximum RF input.
となっています。
IC-7410の最大出力は100Wなので、40dB以上の減衰量がアンテナスイッチには求められます。
非常に雑な実験をしてみると、送信RFパワーが7MHzで35dBmの場合、受信機ポートには-6dBm (=S9+67dB)程度の漏れがあるので、41dBの減衰があることになります。
Ham Radio Blog
WSJT-Xを2つ同時に起動します:
% wsjtx --rig-name=IC7410 & % wsjtx --rig-name=AirspyHF &
pi@raspberrypi:~ $ aplay -l **** List of PLAYBACK Hardware Devices **** card 0: ALSA [bcm2835 ALSA], device 0: bcm2835 ALSA [bcm2835 ALSA] Subdevices: 7/7 Subdevice #0: subdevice #0 Subdevice #1: subdevice #1 Subdevice #2: subdevice #2 Subdevice #3: subdevice #3 Subdevice #4: subdevice #4 Subdevice #5: subdevice #5 Subdevice #6: subdevice #6 card 0: ALSA [bcm2835 ALSA], device 1: bcm2835 ALSA [bcm2835 IEC958/HDMI] Subdevices: 1/1 Subdevice #0: subdevice #0 card 1: Loopback [Loopback], device 0: Loopback PCM [Loopback PCM] Subdevices: 8/8 Subdevice #0: subdevice #0 Subdevice #1: subdevice #1 Subdevice #2: subdevice #2 Subdevice #3: subdevice #3 Subdevice #4: subdevice #4 Subdevice #5: subdevice #5 Subdevice #6: subdevice #6 Subdevice #7: subdevice #7 card 1: Loopback [Loopback], device 1: Loopback PCM [Loopback PCM] Subdevices: 8/8 Subdevice #0: subdevice #0 Subdevice #1: subdevice #1 Subdevice #2: subdevice #2 Subdevice #3: subdevice #3 Subdevice #4: subdevice #4 Subdevice #5: subdevice #5 Subdevice #6: subdevice #6 Subdevice #7: subdevice #7 card 2: CODEC [USB Audio CODEC], device 0: USB Audio [USB Audio] Subdevices: 1/1 Subdevice #0: subdevice #0 pi@raspberrypi:~ $ arecord -l **** List of CAPTURE Hardware Devices **** card 1: Loopback [Loopback], device 0: Loopback PCM [Loopback PCM] Subdevices: 8/8 Subdevice #0: subdevice #0 Subdevice #1: subdevice #1 Subdevice #2: subdevice #2 Subdevice #3: subdevice #3 Subdevice #4: subdevice #4 Subdevice #5: subdevice #5 Subdevice #6: subdevice #6 Subdevice #7: subdevice #7 card 1: Loopback [Loopback], device 1: Loopback PCM [Loopback PCM] Subdevices: 8/8 Subdevice #0: subdevice #0 Subdevice #1: subdevice #1 Subdevice #2: subdevice #2 Subdevice #3: subdevice #3 Subdevice #4: subdevice #4 Subdevice #5: subdevice #5 Subdevice #6: subdevice #6 Subdevice #7: subdevice #7 card 2: CODEC [USB Audio CODEC], device 0: USB Audio [USB Audio] Subdevices: 0/1 Subdevice #0: subdevice #0
pi@raspberrypi:~ $ lsb_release -a No LSB modules are available. Distributor ID: Raspbian Description: Raspbian GNU/Linux 9.4 (stretch) Release: 9.4 Codename: stretch pi@raspberrypi:~ $ uname -a Linux raspberrypi 4.14.34-v7+ #1110 SMP Mon Apr 16 15:18:51 BST 2018 armv7l GNU/Linux pi@raspberrypi:~ $ ps aux | grep time systemd+ 276 0.0 0.4 17276 4012 ? Ssl Jun18 0:00 /lib/systemd/systemd-timesyncd pi@raspberrypi:~ $ timedatectl status Local time: Tue 2018-06-19 01:55:55 UTC Universal time: Tue 2018-06-19 01:55:55 UTC RTC time: n/a Time zone: Etc/UTC (UTC, +0000) Network time on: yes NTP synchronized: yes RTC in local TZ: no pi@raspberrypi:~ $ cat /etc/systemd/timesyncd.conf # Entries in this file show the compile time defaults. # You can change settings by editing this file. # Defaults can be restored by simply deleting this file. # # See timesyncd.conf(5) for details. [Time] #NTP= #FallbackNTP=0.debian.pool.ntp.org 1.debian.pool.ntp.org 2.debian.pool.ntp.org 3.debian.pool.ntp.org pi@raspberrypi:~ $ ls -l /var/lib/systemd/clock -rw-r--r-- 1 systemd-timesync systemd-timesync 0 Jun 19 01:59 /var/lib/systemd/clock
FT8信号をデコードする非常に小さなシステムです。
pi@raspberrypi:~ $ uname -a Linux raspberrypi 4.14.34-v7+ #1110 SMP Mon Apr 16 15:18:51 BST 2018 armv7l GNU/Linux pi@raspberrypi:~ $ aplay -l **** List of PLAYBACK Hardware Devices **** card 0: ALSA [bcm2835 ALSA], device 0: bcm2835 ALSA [bcm2835 ALSA] Subdevices: 7/7 Subdevice #0: subdevice #0 Subdevice #1: subdevice #1 Subdevice #2: subdevice #2 Subdevice #3: subdevice #3 Subdevice #4: subdevice #4 Subdevice #5: subdevice #5 Subdevice #6: subdevice #6 card 0: ALSA [bcm2835 ALSA], device 1: bcm2835 ALSA [bcm2835 IEC958/HDMI] Subdevices: 1/1 Subdevice #0: subdevice #0 card 1: Loopback [Loopback], device 0: Loopback PCM [Loopback PCM] Subdevices: 8/8 Subdevice #0: subdevice #0 Subdevice #1: subdevice #1 Subdevice #2: subdevice #2 Subdevice #3: subdevice #3 Subdevice #4: subdevice #4 Subdevice #5: subdevice #5 Subdevice #6: subdevice #6 Subdevice #7: subdevice #7 card 1: Loopback [Loopback], device 1: Loopback PCM [Loopback PCM] Subdevices: 7/8 Subdevice #0: subdevice #0 Subdevice #1: subdevice #1 Subdevice #2: subdevice #2 Subdevice #3: subdevice #3 Subdevice #4: subdevice #4 Subdevice #5: subdevice #5 Subdevice #6: subdevice #6 Subdevice #7: subdevice #7 pi@raspberrypi:~ $ arecord -l **** List of CAPTURE Hardware Devices **** card 1: Loopback [Loopback], device 0: Loopback PCM [Loopback PCM] Subdevices: 7/8 Subdevice #0: subdevice #0 Subdevice #1: subdevice #1 Subdevice #2: subdevice #2 Subdevice #3: subdevice #3 Subdevice #4: subdevice #4 Subdevice #5: subdevice #5 Subdevice #6: subdevice #6 Subdevice #7: subdevice #7 card 1: Loopback [Loopback], device 1: Loopback PCM [Loopback PCM] Subdevices: 8/8 Subdevice #0: subdevice #0 Subdevice #1: subdevice #1 Subdevice #2: subdevice #2 Subdevice #3: subdevice #3 Subdevice #4: subdevice #4 Subdevice #5: subdevice #5 Subdevice #6: subdevice #6 Subdevice #7: subdevice #7 pi@raspberrypi:~ $ cat /etc/modules snd-aloop pi@raspberrypi:~ $ sudo modprobe snd_aloop pi@raspberrypi:~ $ lsmod Module Size Used by snd_aloop 24576 4
注意: 以下の全ての場合で、USB MOD Level(IC-7410のメニュー39)は、100%に、そして、RF出力レベルは最小(約1W)に設定されています。
Linuxサウンドシステムの出力ボリュームは、最大よりははるか下です。
WSJT-X Transmitter Audio Leve: -30dB.
WSJT-X Transmitter Audio Leve: -20dB.
WSJT-X Transmitter Audio Leve: -10dB.
WSJT-X Transmitter Audio Leve: -6dB.
WSJT-X Transmitter Audio Leve: -3dB.
WSJT-X Transmitter Audio Leve: -1dB.
WSJT-X Transmitter Audio Leve: 0dB.
Transmitter Audio Levelが0dBだと、若干クリップしているようです。
上からTransmitter Audio Levelは; 0dB, -1dB, -3dB, -6dB, -10dB, -20dB, -30dB, -40dB, and -45dBです。