SVXSpot: An SVXLink Analog Hotspot/Transceiver for the Raspberry Pi Zero

Quick Start

1. Flash the image to an SD card (https://etcher.balena.io/#download-etcher): (The device already includes a freshly flashed SD card — you can skip this step and go straight to step 2.)

   https://storage.googleapis.com/rf-guru/rpi-images/hotspot-2025-12-09.img.gz

2. Insert the SD card into the Raspberry Pi Zero 2W and power it with a stable 5V supply (usb port on the far right of the device).

3. Wait for it to boot up. While waiting for boot you can subscribe to our RF Guru's Analog Hotspot mailinglist. https://listmonk.rf.guru/subscription/form

4. Connect to the Wi-Fi AccessPoint of the Hotspot SSID:
   AccessPopup
   Password: 1234567890

5. Open the dashboard:
   http://192.168.50.5/ (or http://hotspot.local)

6. Open Shell → log in:

   • Username: hotspot
   • Password: hotspot

   

7. Configure Wi-Fi (add as many networks you want, but do not remove AccessPopup):

    sudo nmtui
   

   (YouTube how-to) https://youtu.be/EJn0JkStWuY

   Note: When you save a new Wi-Fi network, the hotspot may immediately connect to it and disable the AccessPopup access point. Your PC will then lose the AccessPopup Wi-Fi connection (this is normal). Just connect your PC to your own Wi-Fi network, then reopen the portal via: http://hotspot.local (or use the announced IP address if mDNS is not available) login hotspot/hotspot and go to step 12.

8. Reboot:

   sudo reboot
   

9. After reboot, connect via:

• http://hotspot.local
  or
• the spoken IP address announced over RF (434.925 MHz — FM Narrow | 145.925 MHz — FM Narrow)
• If this does not work, check whether the AccessPopup network is still being broadcast over Wi-Fi. If it is, something went wrong while entering your network details. Go back to point 6 and repeat the setup.

13. Start configuration:

Use your own email adress ! And use real coordinates, some reflectors do not like hotspots info to be hidden ! Look at the local AUP!

sudo hotspot-config

(video demo https://youtu.be/bKF9JRo0ORM?t=125)

14. For Belgian users, set the domain:

    be.svx.link is the domain, the portal of this domain is https://portal.be.svx.link

15. After initial configuration, your SVXReflector sysop must sign your certificate.
    Once signed, your hotspot is fully operational.

16. Continue setup:

We encourage everyone to leave Temperature tuning on !

Some people find the callsigns announcements in QSO's ennoying, you can turn this on or off here!

sudo hotspot-options

17. Belgian users can update talkgroups + button presets:

sudo hotspot-on-webportal

18. You are now ready to rumble 🎙️📡

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Optional

for the 4G version install the module via: (it's default configured for the https://alwaysconnected.eu/ provider)

sudo install-4gmodule

Configure another provider

sudo hotspot-4g-config

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Available Products

• RF.Guru Analog Hotspot/Transceiver
  https://shop.rf.guru/collections/hotspot
  300–500 mW Output Power

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SVXLink Bookworm Image

Supports UHF and VHF on Raspberry Pi Zero 2W.

Default Configuration

UHF

• 434.925 MHz — FM Narrow
• CTCSS Input: 88.5 Hz
• CTCSS Output: 250.3 Hz

VHF

• 145.925 MHz — FM Narrow
• CTCSS Input: 88.5 Hz
• CTCSS Output: 250.3 Hz

Download

https://storage.googleapis.com/rf-guru/rpi-images/hotspot-2025-12-09.img.gz

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Mailinglist for software updates

https://listmonk.rf.guru/subscription/form

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Wi-Fi Setup (AccessPopup)

1. Connect to:

   • SSID: AccessPopup
   • Password: 1234567890

2. Open:
   http://192.168.50.5/

3. Choose Shell.

Login

• Username: hotspot
• Password: hotspot

Configure Wi-Fi

    sudo nmtui

Reboot:

    sudo reboot

After reboot

If your router supports mDNS:

http://hotspot.local/

If not:
The hotspot announces its IP address over RF on the default frequency. (434.925 MHz — FM Narrow | 145.925 MHz — FM Narrow)

Tutorial video:
https://www.youtube.com/watch?v=bKF9JRo0ORM

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Built-In Tools

• D911# — Speaks IP address over RF
• hotspot-frequency — Quick frequency setup
• hotspot-options — Thermal + announcements
• hotspot-talkgroups — Talkgroup/CTCSS mapping
• hotspot-volume — Audio control

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Supported PI's

• Raspberry PI4
• Raspberry PI5
• Raspberry PiZero 2W
• Raspberry Compute Module 4
• Raspberry Compute Module 5

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GPIO Pin Usage

• Pin 3 → GPIO2
• Pin 6 → GPIO3
• Pin 35 → GPIO19
• Pin 8 → TX
• Pin 10 → RX
• Pin 12 → CLK
• Pin 32 → GPIO12 (COS input)
• Pin 36 → GPIO16 (PTT)
• Pin 38 → GPIO20
• Pin 40 → GPIO21
• Pin 31 → GPIO6
• Pin 33 → GPIO13
• Pin 25 → GPIO7
• Pin 29 → GPIO5

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iPhone Hotspot Notes

iOS does not broadcast the hotspot SSID continuously.
Open Settings → Personal Hotspot to force visibility.

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Logs

sudo tail -f /var/log/svxlink

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Activating a Talkgroup

To activate a talkgroup, send the corresponding CTCSS tone from the mapping while in TG0.

You’ll hear a bleep tone 15 seconds after a QSO. This will instantly open the talkgroup – no need for double presses like before. You can start speaking immediately!

Alternatively you can use:

DTMF 91<TALKGROUP>#

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Retrieving the Current IP Address

To get the current IP address of the hotspot, send:

DTMF D911#

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Monitoring Multiple Talkgroups

To set up multiple talkgroups for monitoring, configure them in hotspot-config using this format:

8++, 23+, 50, 51, 52, 53, 54, 55

The TX CTCSS tone remains the same across all talkgroups. The plus signs (+) indicate priority levels.

Temporarily monitor (for one hour) another talkgroup:

DTMF 94#

Example for TG23:

9423#

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CTCSS Talkgroup Mapping

You can map talkgroups via CTCSS tones using the following format:

tone:talkgroup, tone:talkgroup, …

Example default mapping:

67.0:8400, 69.3:8, 71.9:23, 74.4:9000, 77.0:50, 79.7:51, 82.5:52, 85.4:53, 88.5:54, 91.5:55

Mapping a single default talkgroup:

88.5:8

This maps CTCSS tone 88.5 to talkgroup 8.

To switch wait until hotspot is on talkgroup 0 or send DTMF 910#

Accessing the Local Portal

You can access the local dashboard:

• Via hostname (if your network supports mDNS)
• Or via the hotspot’s IP address

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Choosing a Frequency and CTCSS Tone

We advise selecting a frequency not used by nearby repeaters. Do not use the ISM frequency 433.000 MHz.

Recommended defaults we use:

• 70 cm: 439.100 MHz
• 2 m: 145.250 MHz
• CTCSS: 88.5 Hz

Use a tone/frequency not locally used.

For the CTCSS TX tone best to pick on between 67 and 85.4 (best audio quality)

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Installing Bluetooth for the HotSpot companion app

Enables a BLE GATT service so a phone or laptop can drive the hotspot (send DTMF, restart SVXLink, toggle 4G, watch live state) without SSH.

Install on the hotspot:

    sudo /usr/sbin/install-bluetooth

After install, the device advertises over BLE as its hostname. Pair from the companion app — no PIN, the hotspot auto-accepts on first connect.

Belgian users — SvxPortalApp

If you're on the Belgian reflector, use SvxPortalApp:

https://github.com/Guru-RF/SvxPortalApp/releases

Currently available for macOS / Windows / Linux; iOS and Android will follow.

For everybody else: the portal app integrates deeply with the reflector and needs extra software running on the reflector side. If there's interest in deploying it on your own reflector, please get in touch.

Standalone companion app — everyone

There is also a standalone companion app that talks to any hotspot over BLE without any reflector-side dependency:

https://github.com/Guru-RF/Analog-HotSPOT-App/releases

Available for macOS / Windows / Linux; iOS and Android will follow. It has no map and you need to define the talkgroups manually.

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Modify Talkgroups on the Dashboard

Edit base talkgroups:

    sudo vi /var/www/html/include/tgdb.php

Edit talkgroup buttons:

    sudo vi /var/www/html/include/config.inc.php

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Remove certificates (and request a new one)

    sudo rm -f /var/lib/svxlink/pki/*
    sudo systemctl restart svxlink

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Raspberry Pi Connect

Connect remotely to your hotspot.

https://connect.raspberrypi.com

Update the system:

    sudo apt -y update
    sudo apt -y upgrade
    sudo reboot

Install rpi-connect

    sudo apt -y install rpi-connect-lite
    loginctl enable-linger
    rpi-connect on
    rpi-connect signin

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2nd USB port

The second USB port can be used for ethernet, or to attach an AMBE dongle for Bridging to DMR !

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Repeater Mode

Extras useful when you're running the box as an actual repeater rather than a personal hotspot.

svxlink-watchdog

Watches GPIO16 (PTT) once per second. If the PTT line stays asserted (LOW) for more than 150 seconds, it assumes SVXLink is stuck in a keyed state and runs systemctl restart svxlink. While the pin is LOW, the script logs a countdown every 5 seconds.

Follow it live with:

sudo journalctl -t svxlink-watchdog -f

Install (no clone, no hotspot-config needed):

wget -qO- https://raw.githubusercontent.com/Guru-RF/Analog-HotSPOT-SVXLink/master/install-svxlink-watchdog.sh | sudo bash

The installer pulls the script + systemd unit, enables svxlink-watchdog.service, and starts it.

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SVXLink Hotspot in Action

Svxlink.Hotspot.rPiZero.mp4