Ham Radio Digital Infrastructure

Banana Pi OpenWRT-One · 44Net · EchoLink

Connecting to the K0USA .94 NET via the Internet

Presenter: Matt N3PAY
Date: 2026
Duration: ~40 minutes

"The internet is just a big radio network — let's use it like one."

Agenda

1. Why this stack? — The big picture (3 min)
2. Banana Pi OpenWRT-One — The hardware (5 min)
3. 44Net / AMPRNet — Ham-licensed IP space (8 min)
4. EchoLink — Voice over IP for hams (5 min)
5. The K0USA .94 Repeater & NETs — Our target (3 min)
6. Step-by-step: EchoLink node on Linux — SVXLink (10 min)
7. Step-by-step: Windows 11 Pro alternative (3 min)
8. Putting it all on the Banana Pi (3 min)
9. Q&A & Resources (← check the last slide)

Why This Stack?

The problem worth solving

• You want to participate in a local NET on K0USA 147.940 MHz
• You're not near a radio — maybe at work, traveling, or portable
• EchoLink lets licensed hams connect via the internet
• But most EchoLink guides assume a Windows PC on your desk

Why This Stack?

Our solution

[Your radio / laptop / phone]
        │  EchoLink
        ▼
[SVXLink on Banana Pi + 44Net IP]
        │  audio + PTT
        ▼
[Radio linked to K0USA .94 repeater]
        │  RF
        ▼
[K0USA 147.940 MHz NET]

The Banana Pi OpenWRT-One

AP-24.XY — The official OpenWrt community board

Why the Banana Pi OpenWRT-One for Ham Radio?

It was designed to run OpenWrt — not hacked into it

• Official OpenWrt board — mainline kernel support, no patches needed
• Dual storage = unbrickable — 16 MiB NOR holds a rescue firmware
• mikroBUS expansion — add SPI/I²C/UART radios, GPS, or peripherals
• M.2 slot — add NVMe SSD for logging, audio recordings, databases
• USB 2.0 — USB audio interface for radio TX/RX audio
• Low power — runs on PoE, great for remote installs
• OpenWrt = full Linux — opkg install anything you need

Ham use cases on this board

• 44Net gateway (WireGuard or IPIP tunnel)
• SVXLink EchoLink node
• APRS iGate / digipeater
• Winlink gateway (with USB TNC)
• AREDN node controller

Getting the Banana Pi OpenWRT-One

Where to buy

• Amazon — search "Banana Pi OpenWRT-One" (~$40–55 USD)
• AliExpress — directly from manufacturer
• Banana Pi official store — banana-pi.org

Getting the Banana Pi OpenWRT-One

What you also need

• USB-C power supply (5V/3A minimum) or PoE injector
• microSD card (for initial flash, optional after)
• USB audio adapter (for radio audio) — e.g., CM108-based (~$8)
• USB-to-serial adapter (for PTT via RTS/DTR pin)
• Ethernet cable (for initial setup)
• Radio interface cable — audio in/out + PTT to your transceiver

44Net / AMPRNet

What is it?

AMPRNet = Amateur Packet Radio Network
44Net = the 44.0.0.0/8 IP block

• Allocated in 1981 — one of the earliest registered /8 blocks
• Managed by ARDC (Amateur Radio Digital Communications)
• Only licensed amateur radio operators may request addresses
• IPs are globally routable — reachable from the public internet
• Free to use — no cost for the address space

44Net / AMPRNet

The address space today

How 44Net Connectivity Works

Option 1: IPIP Tunnel Mesh (classic)

[Your 44.x.x.x host]
      │  IPIP encapsulation over your ISP connection
      ▼
[UCSD tunnel router — ampr.org]
      │  routes 44.x.x.x traffic globally
      ▼
[Other 44Net nodes worldwide]

• Your ISP sees encrypted-looking IP-in-IP packets
• The 44.x.x.x address is your inner routable address
• Requires a static or semi-static public IP on your gateway

How 44Net Connectivity Works

Option 2: 44Net Connect (new — 2025/2026)

[Your device]
      │  WireGuard VPN
      ▼
[connect.44net.cloud]
      │  hands you a 44.x.x.x address automatically

Easiest option for beginners — no BGP, no tunnel config

Registering for 44Net — Step by Step

Prerequisites

• Valid amateur radio license (any class, any country)
• An email address
• Know your callsign

Step 1 — Create your account

https://portal.ampr.org  →  click REGISTER

Fill in: name, email, callsign, password
Check your email → click the verification link

Step 2 — Verify your callsign

Log into the portal → go to My Profile
Enter your callsign → ARDC verifies against FCC / ITU databases
This may take 24–48 hours for manual review

Registering for 44Net — Step by Step (cont.)

Step 3 — Request address space

Portal → Request address space

• Choose your region/state
• Choose type: "End User" (for a single node or small subnet)
• Request a /29 (6 usable addresses) or /30 (2 usable) for starters
• Describe your use case: "EchoLink node + experimental networking"

Registering for 44Net — Step by Step (cont.)

Step 4 — Register your gateway

Once approved, portal → Gateways → Add Gateway

• Enter your gateway's public IP address
• Enter your 44.x.x.x subnet

Step 5 — Add DNS records

Portal → DNS → add an A record for each host

mynode.k0abc.ampr.org  →  44.x.x.x

The UCSD tunnel router will not route to you without a DNS entry.

44Net Connect — The Easy Path (2025/2026)

If you just want a 44Net IP with minimal setup

# Install WireGuard
sudo apt install wireguard

# Get your config from https://connect.44net.cloud/
# (requires portal.ampr.org account first)

# Save config as /etc/wireguard/44net.conf
# Then:
sudo wg-quick up 44net

# Verify your 44 address
ip addr show 44net

44Net Connect — The Easy Path (2025/2026)

What you get

• A 44.x.x.x address assigned automatically
• Full connectivity to other 44Net nodes
• No static public IP required on your end
• Works behind NAT / CGNAT

EchoLink — Voice Over IP for Licensed Hams

What is EchoLink?

• Created by Jonathan Taylor, K1RFD in 2002
• Connects licensed amateur radio operators via VoIP
• Over 250,000 validated users worldwide
• Three node types:

Key facts

• Free — no subscription
• Requires FCC license validation before use
• Uses GSM codec for audio compression
• Ports: UDP 5198, UDP 5199, TCP 5200

EchoLink Network Architecture

[EchoLink Client — your phone/laptop]
         │  UDP 5198/5199
         ▼
[EchoLink Directory Servers]
         │  validates callsign, routes connection
         ▼
[SVXLink Node on Banana Pi — K0ABC-L]
         │  USB audio + PTT
         ▼
[Your radio TX/RX]
         │  RF — 147.940 MHz
         ▼
[K0USA Repeater .94]
         │  RF rebroadcast
         ▼
[NET participants on 147.940 MHz]

The K0USA .94 Repeater

147.940 MHz — Denver / Front Range area

The K0USA .94 Repeater

The NET concept

A NET is a scheduled on-air meeting:

• Held at a regular time on a repeater frequency
• A Net Control Station (NCS) runs the check-in list
• Participants check in, pass traffic, or just say hello
• EchoLink lets remote operators check in from anywhere

Your goal: run an EchoLink-linked node so anyone connecting to your EchoLink node number can participate in the K0USA NET.

SVXLink — The Engine

Why SVXLink, not the Windows EchoLink app?

• Native Linux — runs headless, no GUI needed
• Full repeater controller — CTCSS, hang time, IDs, courtesy tones
• Modular — EchoLink is just one module
• Rock solid — runs for months unattended
• Open source — github.com/sm0svx/svxlink
• Packaged — available in Debian, Ubuntu, Raspberry Pi OS

SVXLink — The Engine

Hardware you need

[Transceiver]
    ├── Audio OUT  ──►  USB audio adapter LINE IN
    ├── Audio IN   ──◄  USB audio adapter LINE OUT  
    └── PTT        ──◄  USB-serial adapter (RTS or DTR pin)
                             │
                         [Banana Pi / Linux PC]
                             │  SVXLink process

Linux Step-by-Step: Install SVXLink

Tested on: Debian 12, Ubuntu 24.04, Raspberry Pi OS

Step 1 — Update and install

sudo apt update && sudo apt upgrade -y

sudo apt install -y svxlink-server qtel \
    alsa-utils libsox-fmt-all \
    tcpdump curl git

Step 2 — Identify your USB audio device

# List capture devices (radio audio IN to PC)
arecord -l

# List playback devices (PC audio OUT to radio)  
aplay -l

# Example output:
# card 1: Device [USB Audio Device], device 0: USB Audio [USB Audio]

Note the card number — you'll need it (e.g., plughw:1,0)

Linux Step-by-Step: Audio Level Setup

Step 3 — Set audio levels with alsamixer

# Open mixer for your USB audio card (replace 1 with your card number)
alsamixer -c 1

• Press F4 → Capture section → set mic/line input to ~70%
• Press F3 → Playback section → set speaker/line out to ~70%
• Press Esc to exit

Step 4 — Save ALSA settings

sudo alsactl store

Linux Step-by-Step: Audio Level Setup

Step 5 — Test audio loopback

# Record 5 seconds from radio, play it back
arecord -D plughw:1,0 -f cd -t wav -d 5 /tmp/test.wav
aplay -D plughw:1,0 /tmp/test.wav

You should hear your radio audio played back. Adjust levels until clear.

Linux Step-by-Step: PTT Interface

Step 6 — Identify your serial port

# Plug in your USB-serial adapter, then:
dmesg | tail -20 | grep tty

# Usually shows: /dev/ttyUSB0  or  /dev/ttyACM0

Step 7 — Add your user to the dialout group

sudo usermod -aG dialout $USER
# Log out and back in for this to take effect

Linux Step-by-Step: PTT Interface

Step 8 — Test PTT manually

# Key up the radio (assert RTS high)
python3 -c "
import serial, time
s = serial.Serial('/dev/ttyUSB0')
s.rts = True
print('PTT ON — radio should be transmitting')
time.sleep(3)
s.rts = False
print('PTT OFF')
s.close()
"

Watch your radio's TX indicator. If it keys up, PTT is working.

Linux Step-by-Step: SVXLink Main Config

Step 9 — Edit /etc/svxlink/svxlink.conf

[GLOBAL]
MODULE_PLUG_IN_PATH=/usr/lib/svxlink
CFG_DIR=/etc/svxlink/svxlink.d
TIMESTAMP_FORMAT=%c

Linux Step-by-Step: SVXLink Main Config

[LOGIC:SimplexLogic]
TYPE=Simplex
RX=Rx1
TX=Tx1
MODULES=ModuleEchoLink
CALLSIGN=K0ABC            # ← YOUR callsign
SHORT_IDENT_INTERVAL=15
LONG_IDENT_INTERVAL=60
IDENT_ONLY_AFTER_TX=1
IDLE_TIMEOUT=300

Replace K0ABC with your actual callsign throughout.

Linux Step-by-Step: RX and TX Config

Still in /etc/svxlink/svxlink.conf

[RX:Rx1]
TYPE=Local
AUDIO_DEV=alsa:plughw:1,0   # ← your USB audio card
AUDIO_CHANNEL=0
SQL_DET=CTCSS               # or VOX if no CTCSS from radio
CTCSS_FQ=100.0              # ← tone your radio decodes
CTCSS_THRESH=15
SERIAL_PORT=/dev/ttyUSB0
SERIAL_PIN=CTS              # COS input from radio (optional)

[TX:Tx1]
TYPE=Local
AUDIO_DEV=alsa:plughw:1,0   # ← same USB audio card
AUDIO_CHANNEL=0
PTT_TYPE=SERIAL
SERIAL_PORT=/dev/ttyUSB0
SERIAL_PIN=RTS              # PTT output to radio
PTT_DELAY=0
TX_DELAY=500
MAX_TONE_AMP=50

Linux Step-by-Step: EchoLink Module Config

Step 10 — Edit /etc/svxlink/svxlink.d/ModuleEchoLink.conf

[ModuleEchoLink]
ID=2
TIMEOUT=60

# Your EchoLink credentials
CALLSIGN=K0ABC-L            # append -L (Link) or -R (Repeater)
PASSWORD=YourEchoLinkPass   # set at echolink.org
SYSOPNAME=Your Name
LOCATION=Denver CO USA

# EchoLink server
SERVER=naeast.echolink.org

# Ports (must be forwarded on your router)
BIND_PORT=5198

# Who can connect
ACCEPT_INCOMING=1
# To restrict to specific calls:
# CALLSIGN_ACL=K0*,W0*,N0*

# Link to K0USA .94 — connect on startup (optional)
# LINK_INCOMING=*

Linux Step-by-Step: EchoLink Registration

Before SVXLink will connect, you must validate your callsign

Step 11 — Register at echolink.org

1. Go to:  https://www.echolink.org/validation/
2. Enter your callsign
3. Enter your name and email
4. EchoLink staff will verify against FCC/ITU database
   — takes 1-3 business days
5. You'll receive an email with your password

Step 12 — Set your password in the config

sudo nano /etc/svxlink/svxlink.d/ModuleEchoLink.conf
# Set PASSWORD= to the password emailed to you

Never share this password. It's tied to your callsign and license.

Linux Step-by-Step: Port Forwarding

Step 13 — Forward EchoLink ports on your router

On OpenWrt (your Banana Pi):

LuCI → Network → Firewall → Port Forwards
→ Add rule:
    Name: EchoLink-UDP-5198
    Protocol: UDP
    External port: 5198
    Internal IP: [IP of your SVXLink machine]
    Internal port: 5198
→ Repeat for 5199

Or via command line on OpenWrt:

uci add firewall redirect
uci set firewall.@redirect[-1].dest_port='5198'
uci set firewall.@redirect[-1].proto='udp'
uci set firewall.@redirect[-1].dest_ip='192.168.1.100'
uci commit firewall && /etc/init.d/firewall restart

Linux Step-by-Step: Start SVXLink

Step 14 — Start and enable SVXLink

# Start the service
sudo systemctl start svxlink

# Enable on boot
sudo systemctl enable svxlink

# Check status
sudo systemctl status svxlink

# Watch the log in real time
sudo journalctl -fu svxlink

What success looks like in the log

EchoLink: Logging in to server naeast.echolink.org...
EchoLink: Logged in as K0ABC-L (node #XXXXXX)
EchoLink: Ready to accept connections

Write down your node number — that's what other hams will dial.

Connecting to the K0USA .94 NET

How to connect your EchoLink node TO the K0USA repeater

Option A — They connect to you

• K0USA net control or a trustee keys your EchoLink node number
• Their repeater controller connects to K0ABC-L
• All audio bridges between EchoLink and K0USA .94

Option B — Your node connects to theirs

In ModuleEchoLink.conf, or live via DTMF:

# Auto-connect to K0USA EchoLink node on startup
# (get their node number from echolink.org/links)
AUTOCONNECT_ON_START=K0USA-R

Joining the NET via EchoLink client (as a user)

1. Open EchoLink app (iOS, Android, or desktop)
2. Search for:  K0ABC-L   (your link node)
3. Connect
4. You are now on the air on K0USA 147.940 MHz
5. Wait for net control, then key up and give your call

Participating in the NET — Operating Procedure

Before the NET starts

• Confirm the NET schedule — day/time/format (voice check-in, traffic, etc.)
• Confirm your audio levels — transmit a few seconds, listen back
• Announce your EchoLink node to the net control trustee in advance

During the NET

Net Control: "QRZ for check-ins..."

You (via EchoLink):
  → Key up (push-to-talk on your client)
  → "[Your callsign], checking in via EchoLink, 44Net node"
  → Unkey

Net Control: "K0ABC via EchoLink, copy 5/9, thank you"

Good EchoLink operating practice

• Add 0.5–1 second after keying before speaking (propagation delay)
• Keep transmissions short — others may have high latency
• Announce "EchoLink" when identifying so local ops know

Windows 11 Pro — Alternative Path

When you want a quick setup without configuring Linux

Step 1 — Download EchoLink for Windows

https://www.echolink.org/download.htm
→ Download EchoLink Setup (latest version)
→ Run the installer

Step 2 — First launch validation

1. Enter your callsign → Next
2. EchoLink checks the FCC database automatically
3. If not found, click "Request Validation" → email process
4. Enter the password from your validation email

Step 3 — Configure audio device

EchoLink → Tools → Setup → Audio tab
  Soundcard Input:  [Your USB audio adapter]
  Soundcard Output: [Your USB audio adapter]
  Test both with the built-in test tones

Windows 11 Pro — PTT and Radio Interface

Step 4 — Configure PTT

EchoLink → Tools → Setup → PTT tab
  PTT method: VOX  (easiest, no serial needed)
    OR
  PTT method: Serial Port
    Port: COM3  (check Device Manager for your USB-serial port)
    Signal: RTS

Step 5 — Sysop Mode (Link Node)

EchoLink → Tools → Sysop Setup
  Node type: Link (-L)
  Callsign: K0ABC-L
  Password: [your EchoLink password]
  Location: Denver CO
  Enable "Receive-only when not connected"

Step 6 — Port forwarding on your Windows router

Router admin page → Port Forwarding:
  UDP 5198 → [Windows PC IP]
  UDP 5199 → [Windows PC IP]
  TCP 5200 → outbound (usually open by default)

Windows 11 Pro — Running as a Service

Keep EchoLink running even when not logged in

Option A — Startup folder (simple)

# Press Win+R → shell:startup
# Copy EchoLink shortcut into that folder
# EchoLink starts on login but not before

Option B — Task Scheduler (better)

Task Scheduler → Create Task
  General: Run whether user is logged on or not
           Run with highest privileges
  Trigger: At system startup
  Action:  Start program → C:\Program Files\EchoLink\EchoLink.exe
  Settings: If already running, do not start new instance

Option C — NSSM (Non-Sucking Service Manager)

# Download nssm.cc
nssm install EchoLink "C:\Program Files\EchoLink\EchoLink.exe"
nssm start EchoLink
# Now it's a proper Windows service

Putting It All Together on the Banana Pi

Running SVXLink directly on the OpenWRT-One

Step 1 — Install required packages via opkg

# SSH into your Banana Pi (default: ssh root@192.168.1.1)
opkg update
opkg install svxlink kmod-usb-audio alsa-utils \
             kmod-usb-serial-cp210x kmod-usb-serial

SVXLink may need to be compiled from source if not in opkg.
Alternative: run a Docker container or LXC with Debian inside OpenWrt.

Putting It All Together on the Banana Pi

Step 2 — Verify USB audio on OpenWrt

aplay -l     # list audio devices
arecord -l   # list capture devices

Step 3 — Use the same config files

The svxlink.conf and ModuleEchoLink.conf from earlier work unchanged.
Copy them to /etc/svxlink/ on the Banana Pi.

Banana Pi — 44Net Gateway + EchoLink Together

The full architecture on one board

[Internet WAN — 2.5 GbE port]
         │
         │  WireGuard tunnel to 44net.connect.cloud
         │  Your 44.x.x.x IP lives here
         │
[Banana Pi OpenWRT-One]
         │
         ├── WiFi AP — local ham shack network
         │
         ├── USB audio adapter ──► Radio audio I/O
         │
         ├── USB-serial adapter ──► Radio PTT
         │
         └── SVXLink process
               │  EchoLink module active
               └──► connects to K0USA .94 via EchoLink

Why 44Net on the same box?

• Your SVXLink node gets a globally routable ham IP
• Other 44Net nodes can reach you directly (no NAT issues)
• Useful for future AMPR services: Winlink, APRS, D-STAR gateways

Banana Pi — OpenWrt Firewall for EchoLink

Allowing EchoLink traffic through OpenWrt's firewall

# SSH into Banana Pi
# Allow EchoLink UDP ports in from WAN
uci batch << 'EOF'
add firewall rule
set firewall.@rule[-1].name='EchoLink-5198'
set firewall.@rule[-1].src='wan'
set firewall.@rule[-1].dest='lan'
set firewall.@rule[-1].proto='udp'
set firewall.@rule[-1].dest_port='5198-5199'
set firewall.@rule[-1].target='ACCEPT'
EOF

uci commit firewall
/etc/init.d/firewall restart

If SVXLink runs ON the Banana Pi (not a separate machine):

# Allow traffic destined for the router itself
uci set firewall.@rule[-1].dest='*'
uci set firewall.@rule[-1].target='ACCEPT'
uci commit firewall && /etc/init.d/firewall restart

Troubleshooting — Common Issues

Useful diagnostic commands

# Test EchoLink port reachability from outside
curl -s https://echolink.org/looptest.htm

# Check which process owns port 5198
ss -ulnp | grep 5198

# SVXLink live log
journalctl -fu svxlink --since "5 min ago"

Security Considerations

Running a ham radio node on the internet

• EchoLink validates licenses — only hams can connect
• Use CALLSIGN_ACL in ModuleEchoLink.conf to restrict to known calls
• The 44.0.0.0/8 space is not encrypted by default — don't pass sensitive data
• Keep your Banana Pi updated: opkg update && opkg upgrade
• Use WPA3 on the Banana Pi's WiFi AP
• Consider fail2ban if running SSH on a public IP
• Never share your EchoLink password — it's your license identity

Regulatory reminders

• No encryption of voice content on amateur frequencies
• No third-party traffic for hire
• Identify every 10 minutes and at end of transmission (FCC Part 97)
• SVXLink handles automatic ID for you if configured correctly

Resources & Links

Hardware

• Banana Pi OpenWRT-One docs: https://docs.banana-pi.org/en/OpenWRT-One/BananaPi_OpenWRT-One
• OpenWrt on BPI-One: https://openwrt.org/toh/banana_pi/banana_pi_bpi-r2_mini

44Net / AMPRNet

• AMPR Portal (registration): https://portal.ampr.org
• 44Net Wiki Quickstart: https://wiki.ampr.org/wiki/Quickstart
• 44Net Connect (WireGuard): https://connect.44net.cloud
• ARDC 44Net page: https://www.ardc.net/44net/

EchoLink

• EchoLink official site: https://www.echolink.org
• Callsign validation: https://www.echolink.org/validation/
• SVXLink project: https://www.svxlink.org
• SVXLink GitHub: https://github.com/sm0svx/svxlink

Repeaters

• K0USA .94 info: https://www.repeaterbook.com (search K0USA, 147.940)
• Colorado EchoLink repeaters: https://www.repeaterbook.com/repeaters/feature_search.php?state_id=08

Q & A

Thank you!

Node information:

• EchoLink node: [Your callsign]-L
• 44Net IP: 44.x.x.x (after registration)
• Linked to: K0USA 147.940 MHz — Denver area

NET schedule:

• Ask K0USA trustees or check: https://www.repeaterbook.com

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73 de N3PAY