diff --git a/software/firmware/source/SoftRF/src/platform/CC13XX.h b/software/firmware/source/SoftRF/src/platform/CC13XX.h
index d0d82b41d..e8f9c1849 100644
--- a/software/firmware/source/SoftRF/src/platform/CC13XX.h
+++ b/software/firmware/source/SoftRF/src/platform/CC13XX.h
@@ -268,7 +268,7 @@ extern SCSerial                 scSerial;
 
 #define USE_OGN_ENCRYPTION
 
-//#define ENABLE_ADSL
+#define ENABLE_ADSL
 
 //#define EXCLUDE_GNSS_UBLOX
 #define EXCLUDE_GNSS_SONY
diff --git a/software/firmware/source/SoftRF/src/platform/ESP32.h b/software/firmware/source/SoftRF/src/platform/ESP32.h
index 94b077b42..6ca8bf1fb 100644
--- a/software/firmware/source/SoftRF/src/platform/ESP32.h
+++ b/software/firmware/source/SoftRF/src/platform/ESP32.h
@@ -343,7 +343,7 @@ struct rst_info {
 //#define USE_GDL90_MSL
 #define USE_OGN_ENCRYPTION
 #define ENABLE_PROL
-//#define ENABLE_ADSL
+#define ENABLE_ADSL
 
 //#define EXCLUDE_GNSS_UBLOX    /* Neo-6/7/8, M10 */
 #define ENABLE_UBLOX_RFS        /* revert factory settings (when necessary)  */
diff --git a/software/firmware/source/SoftRF/src/platform/ESP8266.h b/software/firmware/source/SoftRF/src/platform/ESP8266.h
index 340c779b7..519fe0aec 100644
--- a/software/firmware/source/SoftRF/src/platform/ESP8266.h
+++ b/software/firmware/source/SoftRF/src/platform/ESP8266.h
@@ -119,7 +119,7 @@ extern Adafruit_NeoPixel strip;
 #define EXCLUDE_BME680
 
 /* Experimental */
-//#define ENABLE_ADSL
+#define ENABLE_ADSL
 #define ENABLE_PROL
 
 #if defined(pgm_read_float_aligned)
diff --git a/software/firmware/source/SoftRF/src/platform/RP2040.h b/software/firmware/source/SoftRF/src/platform/RP2040.h
index 818a339a0..23532ae36 100644
--- a/software/firmware/source/SoftRF/src/platform/RP2040.h
+++ b/software/firmware/source/SoftRF/src/platform/RP2040.h
@@ -287,7 +287,7 @@ struct rst_info {
 //#define EXCLUDE_OLED_BARO_PAGE
 
 /* Experimental */
-//#define ENABLE_ADSL
+#define ENABLE_ADSL
 #define ENABLE_PROL
 #if defined(USE_TINYUSB)
 //#define USE_USB_HOST
diff --git a/software/firmware/source/SoftRF/src/platform/RPi.h b/software/firmware/source/SoftRF/src/platform/RPi.h
index 2073409e0..d2b4bf453 100644
--- a/software/firmware/source/SoftRF/src/platform/RPi.h
+++ b/software/firmware/source/SoftRF/src/platform/RPi.h
@@ -135,7 +135,7 @@ extern const char *Hardware_Rev[];
 //#define ENABLE_D1090_INPUT
 
 /* Experimental */
-//#define ENABLE_ADSL
+#define ENABLE_ADSL
 //#define ENABLE_PROL
 
 //#define USE_OGN_RF_DRIVER
diff --git a/software/firmware/source/SoftRF/src/platform/STM32.h b/software/firmware/source/SoftRF/src/platform/STM32.h
index 329689b31..d6815be2d 100644
--- a/software/firmware/source/SoftRF/src/platform/STM32.h
+++ b/software/firmware/source/SoftRF/src/platform/STM32.h
@@ -176,7 +176,7 @@ typedef struct stm32_backup_struct {
 #define USE_TIME_SLOTS
 
 /* Experimental */
-//#define ENABLE_ADSL            //  +  2 kb
+#define ENABLE_ADSL              //  +  2 kb
 #define ENABLE_PROL              //  + 18 kb
 
 /* Secondary target ("Blue pill") */
@@ -286,7 +286,7 @@ typedef struct stm32_backup_struct {
 #define USE_OGN_ENCRYPTION
 
 /* Experimental */
-//#define ENABLE_ADSL
+#define ENABLE_ADSL
 #define ENABLE_PROL
 
 #elif defined(ARDUINO_WisDuo_RAK3172_Evaluation_Board)
diff --git a/software/firmware/source/SoftRF/src/platform/nRF52.h b/software/firmware/source/SoftRF/src/platform/nRF52.h
index 69109db5a..4730fc53a 100644
--- a/software/firmware/source/SoftRF/src/platform/nRF52.h
+++ b/software/firmware/source/SoftRF/src/platform/nRF52.h
@@ -315,7 +315,7 @@ struct rst_info {
 //#define EXCLUDE_NUS
 //#define EXCLUDE_IMU
 #define USE_OGN_ENCRYPTION
-//#define ENABLE_ADSL
+#define ENABLE_ADSL
 #define ENABLE_PROL
 #if !defined(ARDUINO_ARCH_MBED)
 #define USE_BLE_MIDI
diff --git a/software/firmware/source/SoftRF/src/protocol/radio/Legacy.cpp b/software/firmware/source/SoftRF/src/protocol/radio/Legacy.cpp
index c38e81ac8..eb1443a48 100644
--- a/software/firmware/source/SoftRF/src/protocol/radio/Legacy.cpp
+++ b/software/firmware/source/SoftRF/src/protocol/radio/Legacy.cpp
@@ -363,7 +363,6 @@ size_t legacy_encode(void *legacy_pkt, ufo_t *this_aircraft) {
 
 #else
 /*
- * Volunteer contributors are welcome:
  * https://pastebin.com/YB1ppAbt
  */
 
@@ -426,6 +425,42 @@ static unsigned int enscale_unsigned(unsigned int value,
     return (value);
 }
 
+static unsigned int enscale_signed(  signed int value,
+                                   unsigned int mbits,
+                                   unsigned int ebits)
+{
+    unsigned int offset  = (1 << mbits);
+    unsigned int signbit = (offset << ebits);
+    unsigned int max_val = signbit - 1;
+    unsigned int sign    = 0;
+
+    if (value < 0) {
+      value = -value;
+      sign  = signbit;
+    }
+
+    unsigned int rval;
+    if (value >= offset) {
+      unsigned int e      = 0;
+      unsigned int m      = offset + (unsigned int) value;
+      unsigned int mlimit = offset + offset - 1;
+
+      while (m > mlimit) {
+        m >>= 1;
+        e += offset;
+        if (e > max_val) {
+          return (sign | max_val);
+        }
+      }
+      m -= offset;
+      rval = (sign | e | m);
+    } else {
+      rval = (sign | (unsigned int) value);
+    }
+
+    return (rval);
+}
+
 bool legacy_decode(void *legacy_pkt, ufo_t *this_aircraft, ufo_t *fop) {
     const uint32_t xxtea_key[4] = LEGACY_KEY5;
     uint32_t key_v7[4];
@@ -574,18 +609,16 @@ size_t legacy_encode(void *legacy_pkt, ufo_t *this_aircraft) {
     pkt->hs            = enscale_unsigned(speed10, 8, 2); /* 0 ... 3832 */
 
     int16_t vs10       = (int16_t) roundf(vsf * 10.0f);
-    if (vs10 >  952) { vs10 =  952; }
-    if (vs10 < -952) { vs10 = -952; }
-    if (vs10 < 64 && vs10 > -64) {
-      pkt->vs          = vs10;
-    } else {
-      pkt->vs          = (vs10 < 0) ? -63 : 63; /* TODO */
-    }
+    pkt->vs = this_aircraft->stealth ? 0 : enscale_signed(vs10, 6, 2); /* 0 ... 952 */
 
     pkt->course        = (int) (course * 2);
     pkt->airborne      = ((int) speedf) >= legacy_GS_threshold[acft_type] ? 2 : 1;
 
-    /* TODO */
+/*
+ * TODO
+ * Volunteer contributors are welcome:
+ * https://pastebin.com/YB1ppAbt
+ */
     pkt->_unk1         = 0;
     pkt->_unk2         = 0;
     pkt->_unk3         = 3;
diff --git a/software/firmware/source/SoftRF/src/protocol/radio/Legacy.h b/software/firmware/source/SoftRF/src/protocol/radio/Legacy.h
index afa2d48f5..08e819cff 100644
--- a/software/firmware/source/SoftRF/src/protocol/radio/Legacy.h
+++ b/software/firmware/source/SoftRF/src/protocol/radio/Legacy.h
@@ -187,7 +187,6 @@ typedef struct {
     /********************/
 } __attribute__((packed)) legacy_v7_packet_t;
 
-
 bool   legacy_decode(void *, ufo_t *, ufo_t *);
 size_t legacy_encode(void *, ufo_t *);