From 62623aab18447e0b8bff602a9daf5873b424d88d Mon Sep 17 00:00:00 2001
From: Mark Jessop <vk5qi@rfhead.net>
Date: Fri, 5 Feb 2021 20:00:44 +1030
Subject: [PATCH] Added dual 4FSK script.

---
 start_dual_4fsk.sh                          | 108 ++++++++++++++++++++
 start_dual_rx.sh => start_dual_rtty_4fsk.sh |   0
 2 files changed, 108 insertions(+)
 create mode 100755 start_dual_4fsk.sh
 rename start_dual_rx.sh => start_dual_rtty_4fsk.sh (100%)

diff --git a/start_dual_4fsk.sh b/start_dual_4fsk.sh
new file mode 100755
index 0000000..7531d77
--- /dev/null
+++ b/start_dual_4fsk.sh
@@ -0,0 +1,108 @@
+#!/usr/bin/env bash
+#
+#	Dual Horus Binary Decoder Script
+#	Intended for use with Dual Launches, where both launches have 4FSK payloads closely spaced (~10 kHz)
+#
+#	The SDR is tuned 5 kHz below the Lower 4FSK frequency, and the frequency estimators are set across the two frequencies.
+# 	Modem statistics are sent out via a new 'MODEM_STATS' UDP broadcast message every second.
+#
+
+# Receive requency, in Hz. This is the frequency the SDR is tuned to.
+RXFREQ=434195000
+
+# Where in the passband we expect to find the Lower Horus Binary (MFSK) signal, in Hz.
+# For this example, this is on 434.290 MHz, so with a SDR frequency of 434.195 MHz,
+# we expect to find the signal at approx +5 kHz.
+# Note that the signal must be located ABOVE the centre frequency of the receiver.
+MFSK1_SIGNAL=5000
+
+# Where in the receiver passband we expect to find the higher Horus Binary (MFSK) signal, in Hz.
+# In this example, our second frequency is at 434.210 MHz, so with a SDR frequency of 434.195 MHz,
+# we expect to find the signal at approx +15 kHz.
+MFSK2_SIGNAL=15000
+
+# Frequency estimator bandwidth. The wider the bandwidth, the more drift and frequency error the modem can tolerate,
+# but the higher the chance that the modem will lock on to a strong spurious signal.
+RXBANDWIDTH=5000
+
+# Receiver Gain. Set this to 0 to use automatic gain control, otherwise if running a
+# preamplifier, you may want to experiment with different gain settings to optimize
+# your receiver setup.
+# You can find what gain range is valid for your RTLSDR by running: rtl_test
+GAIN=0
+
+# Bias Tee Enable (1) or Disable (0)
+# NOTE: This uses the -T bias-tee option which is only available on recent versions
+# of rtl-sdr. Check if your version has this option by running rtl_fm --help and looking
+# for it in the option list.
+# If not, you may need to uninstall that version, and then compile from source: https://github.com/osmocom/rtl-sdr
+BIAS=0
+
+# Receiver PPM offset
+PPM=0
+
+
+
+
+# Check that the horus_demod decoder has been compiled.
+DECODER=./build/src/horus_demod
+if [ -f "$DECODER" ]; then
+    echo "Found horus_demod."
+else 
+    echo "ERROR - $DECODER does not exist - have you compiled it yet?"
+	exit 1
+fi
+
+# Check that bc is available on the system path.
+if echo "1+1" | bc > /dev/null; then
+    echo "Found bc."
+else 
+    echo "ERROR - Cannot find bc - Did you install it?"
+	exit 1
+fi
+
+# Use a local venv if it exists
+VENV_DIR=venv
+if [ -d "$VENV_DIR" ]; then
+    echo "Entering venv."
+    source $VENV_DIR/bin/activate
+fi
+
+
+# Calculate the frequency estimator limits
+# Note - these are somewhat hard-coded for this dual-RX application.
+MFSK1_LOWER=$(echo "$MFSK1_SIGNAL - $RXBANDWIDTH/2" | bc)
+MFSK1_UPPER=$(echo "$MFSK1_SIGNAL + $RXBANDWIDTH/2" | bc)
+
+MFSK2_LOWER=$(echo "$MFSK2_SIGNAL - $RXBANDWIDTH/2" | bc)
+MFSK2_UPPER=$(echo "$MFSK2_SIGNAL + $RXBANDWIDTH/2" | bc)
+
+echo "Using SDR Centre Frequency: $RXFREQ Hz."
+echo "Using MFSK1 estimation range: $MFSK1_LOWER - $MFSK1_UPPER Hz"
+echo "Using MFSK2 estimation range: $MFSK2_LOWER - $MFSK2_UPPER Hz"
+
+BIAS_SETTING=""
+
+if [ "$BIAS" = "1" ]; then
+	echo "Enabling Bias Tee."
+	BIAS_SETTING=" -T"
+fi
+
+GAIN_SETTING=""
+if [ "$GAIN" = "0" ]; then
+	echo "Using AGC."
+	GAIN_SETTING=""
+else
+	echo "Using Manual Gain"
+	GAIN_SETTING=" -g $GAIN"
+fi
+
+STATS_SETTING=""
+
+if [ "$STATS_OUTPUT" = "1" ]; then
+	echo "Enabling Modem Statistics."
+	STATS_SETTING=" --stats=100"
+fi
+
+# Start the receive chain.
+rtl_fm -M raw -F9 -s 48000 -p $PPM $GAIN_SETTING$BIAS_SETTING -f $RXFREQ | tee >($DECODER -q --stats=5 -g -m binary --fsk_lower=$MFSK1_LOWER --fsk_upper=$MFSK1_UPPER - - | python -m horusdemodlib.uploader) >($DECODER -q --stats=5 -g -m binary --fsk_lower=$MFSK2_LOWER --fsk_upper=$MFSK2_UPPER - - | python -m horusdemodlib.uploader) > /dev/null
diff --git a/start_dual_rx.sh b/start_dual_rtty_4fsk.sh
similarity index 100%
rename from start_dual_rx.sh
rename to start_dual_rtty_4fsk.sh