Add Layer400 without breaking your ADS-B feeder.

Layer400 can share a capable Raspberry Pi computer, but it cannot share the same radio. Your ADS-B feeder normally uses an SDR around 1090 MHz. Layer400's pilot uses a dedicated Wi-Fi adapter in monitor mode for compatible broadcast Remote ID.

Take screenshots of the current feeder status in its own account, then record service and network state. These commands do not stop or restart anything.

systemctl --no-pager --full status fr24feed.service 2>/dev/null || true
systemctl --no-pager --full status piaware.service 2>/dev/null || true
systemctl --no-pager --full status dump1090-fa.service 2>/dev/null || true
systemctl --no-pager --full status readsb.service 2>/dev/null || true
ip route show default
lsusb

• Write down the service names that are active on this Pi.
• Confirm the existing feeder is sending data before Layer400 changes begin.
• Identify the Internet interface and the ADS-B USB device.
• Keep the existing provider's configuration backup and recovery notes.

free -h
df -h /
uptime
vcgencmd get_throttled 2>/dev/null || true
sudo dmesg --level=err,warn | tail -n 40

A clean result is not a capacity guarantee. Observe the Pi before and after a controlled Layer400 start. Watch for undervoltage, thermal throttling, out-of-memory events, USB resets and new gaps in ADS-B sharing.

The Layer400 capture adapter enters monitor mode and cannot be relied upon for ordinary Internet traffic. Ethernet is the clearest coexistence path.

1. 01
   Identify the uplink

   The interface shown by ip route show default must remain under the existing network manager.

2. 02
   Attach the separate ALFA adapter

   Do not move the ADS-B SDR or change its USB assignment.

3. 03
   Run the Layer400 radio inventory

   The assistant must select only the dedicated Wi-Fi adapter and refuse the default route.

Complete the account and fixed-station steps in the main Pi guide. The public package is not released, so do not run an installer copied from a forum, chat or search result. During managed access, compare the archive's full SHA-256 digest with the value supplied through Layer400's separate authenticated handoff.

sha256sum layer400-receiver-<release>.tar.gz

Continue at the radio, enrolment and controlled-test sections of the new Pi guide.

• The original ADS-B services remain active with no new restart loop.
• The original provider still receives data and feed gaps have not increased.
• The Pi remains free of undervoltage and thermal-throttling warnings.
• The default route is unchanged.
• Layer400's radio inventory identifies only the separate Wi-Fi adapter.
• Layer400 reports a healthy clock, signed heartbeat and bounded queue.

Observe the combined station for at least one normal operating period before moving it outdoors. If either network becomes less reliable, disable Layer400 and move it to a separate computer.

sudo systemctl disable --now layer400-feeder.service layer400-radio.service

1. 01
   Pause Layer400

   Disable only layer400-feeder and layer400-radio.

2. 02
   Confirm ADS-B recovery

   Check the original services and the provider's account before changing anything else.

3. 03
   Preserve diagnostics

   Create the privacy-scrubbed Layer400 support bundle. Do not delete the spool or device identity during fault finding.

4. 04
   Move to separate hardware

   When coexistence is uncertain, a dedicated Pi is the clean fix.