Why do radio amateurs not leave large enough gaps ("overs") between transmissions?

Does the title of the above article sound familiar? 

On numerous occasions the ZS Link Network experience the "to quick on the trigger (PTT)" habit. Yes it is a bad habit and the author is also guilty at times.  No pointing of fingers here let's find out why this happens.

I wrote the following this morning on the WhatsApp Group:

"Gaps, gaps etc. Stations cannot connect to the ZS Link Network Group's networks. Stations are left out in the cold. We must please leave gaps and not be so quick to press the PTT between overs. There are some of our regulars who want to connect to the DMR links and other systems, but cannot get in. Let's please leave long enough (5-8 seconds) gaps between rounds. We don't want to lose stations because they can't connect/disconnect or log in. No, I have nothing to do with the administration of the network anymore, but just felt like bringing it to everyone's attention again in the interest of the group. - ZS1I"

In amateur radio, failing to leave a gap between "overs" (transmissions) is known as "quick-keying" or "tailgating." Experienced operators strongly advise against this because it disrupts the flow of communication and violates standard Ham Radio Etiquette.

Now why do radio amateurs not leave large enough gaps ("overs") between transmissions?

Radio amateurs often fail to leave sufficient gaps ("overs") between transmissions due to a combination of ingrained habits from crowded operating environments, the desire to prevent others from "stealing" the frequency, and the rapid, conversational nature of "rag-chewing" (casual chatting). 

Common reasons for short breaks or overlapping transmissions include:

• Habit from Crowded Frequencies: Many radio amateurs are accustomed to operating on crowded bands or repeaters (particularly on 10-meter or 75-meter bands), where any significant pause is perceived as an opportunity for another station to "steal" the frequency or interrupt the conversation.
• Fear of "Stealing" the Conversation: There is a common belief that if an operator leaves too long a pause, another user will break into the conversation, leading to a "quick key" reflex.
• "Rag-Chewing" Mentality: In casual, relaxed conversations, operators often treat radio like a telephone call, aiming for a rapid exchange of information rather than the formal, slow pace of traditional radio procedure.
• Misunderstanding Repeater Operation: Some operators do not wait for the repeater's "courtesy tone"—a sound that signals the repeater has reset and is ready for the next transmission—leading to "doubling" (talking over someone) or premature transmission.
• Unfamiliarity with Proper Etiquette: Not all operators are fully trained in, or consistently follow, best practices regarding break times, which recommend a 5-second pause to allow for emergencies or other stations to join.
• Imitating CB Practices: Some amateur radio operators carry over habits from 11-meter (CB) radio, where fast-paced, high-interference communication is common.

Best Practices to Avoid Overlapping:

• Listen First: Always listen for a few seconds before transmitting.
• Wait for the network to reset: On repeaters, wait for the network to reset before keying up.
• Pause intentionally: Leave a 5–8 second gap between "overs" to allow for break-ins, especially for emergency calls.
• Release the PTT: Fully release the push-to-talk button to ensure the repeater resets properly.

As far as DMR communications over the internet is concerned,  here is some information as to why on should leave a large enough gap between overs:

Networked Digital Mobile Radio (DMR) communications over the internet introduce significant and noticeable latency (delay) due to a combination of digital voice encoding and Forward Error Correction (FEC), and internet traffic delays.

Key Aspects of DMR Internet Latency:

• Operational Courtesy: Because of this latency, operators should wait at least 5 seconds after hearing the end of a transmission before initiating a new one to avoid breaking traffic.
• Transmission Delay: It is recommended to wait approximately 2 second after keying the transmitter before speaking to ensure the connection is established.
• Causes: Latency is introduced by the digital encoding of voice at the transmitter, FEC processing at the receiver, and internet packet routing.
• Technical Performance: Specialized DMR over Internet Protocol (DoIP) gateways can achieve a conversion delay of 9.10 ms, with an average jitter of 1.90 ms and low packet loss.

Operational Considerations:
Unlike analog radios, DMR does not have a "repeater squelch tail." The inherent digital delays mean conversations can feel staggered, requiring disciplined, patient, and structured communication protocols to avoid talking over others and to accommodate the shared nature of networked resources.

 

Enough written.  We all know now what to do from here-on!!

BREAKING NEWS: The Ultimate SvxLink Client For Smartphones & POCs. 145.500 QSO.link MHz

 

Forget the old dial! We no longer say 145.500 MHz, but QSO.link MHz.

Whether you use a high-end flagship or a rugged POC handset (the kind that looks like a 90s brick and could probably survive a tank), QSOLink is your professional gateway to SvxLink networks.

It runs on almost anything. As long as it has Android 9 or higher, it's a radio! (We decided Android 8 was just too "vintage", even for us). 

Dear SvxLink Community,

I am pleased to announce the release of QSOLink, a new Android application designed to connect to SvxLink Reflectors and Hotspots.

Built upon the solid foundation of the "Latry" project by Silviu (YO6SAY), QSOLink pushes the concept further with a complete UI overhaul, enhanced audio processing, and features dedicated to active operators.

Key Features:

• Advanced Audio Processing: Includes a configurable Jitter Buffer (essential for mobile/4G connections), Microphone Gain control, and AGC (Automatic Gain Control) for both TX and RX to ensure consistent audio levels.

• Network Management: Save up to 10 different network configurations (Reflectors/Hotspots) with a quick-switch grid. You can also Export/Import your networks via JSON files to share configs easily.

• Hardware Integration: Full support for Bluetooth PTT buttons (pedals, handheld mics) with a built-in "Key Sniffer" tool to easily detect and map your device's key codes.

• Integrated Logbook: The app automatically logs your reception history. You can view QSO details and export your log in ADIF format directly from the app.

• Modern UI: Designed with a dark, high-contrast interface suitable for AMOLED screens and low-light environments.

Availability:
You can download QSOLink here: https://www.swisstransfer.com/d/7d28daf3-680b-420e-bad4-8ecea383770a

I would appreciate your feedback and testing reports. My goal is to provide the most reliable and complete mobile client for the SvxLink ecosystem. Please keep in mind that this is an initial release, so there might still be some bugs.

Special thanks to Silviu (YO6SAY) for his initial work which made this project possible.

73,

Cedric, F4JGI

 

QSO LINK features:

QSOLink

is a feature-rich Android client for SvxLink reflectors, designed for connecting to Reflectors and Hotspots. It features advanced TalkGroup management with "Auto-Switch" (jumping to active, higher-priority TGs) and visual radar for station activity.

Key Features of QSOLink:

• Audio & DSP: Features a DSP audio chain with Auto Gain Control (AGC) for TX/RX and adjustable jitter buffer.
• Radio Control: Includes a Digital Tuning Wheel, Dual VFO management (A/B), and support for modes like LSB, USB, AM, FM, and CW.
• Networking & Scanning: Features intelligent network scanning, auto-switching to active TalkGroups, and real-time DX spot importation.
• APRS Integration: Features full integration with the global APRS-IS network, allowing for tracking and text messaging, with position broadcasting to services like aprs.fi.
• Interface & Usability: Includes a dedicated "Ultimate Car Mode" HUD for safety, Bluetooth support for headsets and handmics, and a resource-efficient design for mobile devices.
• Logging: Includes an integrated QSO history with ADIF format export capabilities.
• Compatibility: Designed for Android 8.0 or higher, with optimization for ARMv8 64-bit processors.

The application is highly optimized for network radio (POC) devices and includes a "Lite Edition" for older smartphones to reduce RAM and CPU usage.

 

QSOLink is a dedicated Svxlink Client for Android. It is not a standalone radio network. Users are required to configure the app to connect to their preferred third-party reflectors.

For more information, images and videos about QSOLink click HERE

Here is a highly detailed User Manual for QSOLink V1.2.0.

---

QSOLink User Manual

Version 1.2.0

Welcome to QSOLink, a lightweight and efficient Reflector/Hotspot client. This guide covers every aspect of the interface, configuration, and advanced audio settings.

---

1. The Main Interface

The screen is divided into distinct zones for quick access to essential features.

A. The Top Bar (Controls)

From left to right:

1. Connect Button (Link Icon):

   • Blinking: Connecting.

   • Solid Link: Connected.

   • Broken Link: Disconnected.

   • Action: Tap to Connect/Disconnect. If you are disconnected, tapping this opens the connection popup for the selected network.

2. Network Name: Displays the name of the currently selected configuration.

3. Smart TG Button (The colored rounded box):

   • Displays current TalkGroup (e.g., "TG 208").

   • Displays Monitoring status (Scan, Pause, or Revert Timer).

   • Short Click: Opens the Change TalkGroup popup to manually enter a TG.

   • Long Press: Opens the Monitor/Scan Configuration menu.

4. Audio Device Icon (Phone/Headset):

   • Shows the current audio output (Speaker, Wired Headset, Bluetooth, Car).

   • IMPORTANT: If you plug in a headset or connect Bluetooth after the app started, tap this icon once. It triggers a "Force Audio Restart" to re-detect the best audio device immediately.

5. Mute Button (Speaker): Toggles incoming audio On/Off.

6. Menu Button (Gear): Opens the main Settings.

B. Network Grid

Located below the Top Bar.

• Contains 10 Memory Slots.

• Blue/Highlighted: Active configuration.

• Grey: Empty or inactive configuration.

• Short Click: Selects the network. If disconnected, it prompts to connect. If connected to another network, it disconnects and connects to the new one.

• Long Press: Opens the Network Editor to configure that specific slot.

C. Status Frame (The "Ticker")

A rounded rectangle that displays real-time info:

• Ready: System is idle.

• Transmitting (Red): You are on air (shows TX timer).

• Receiving (Green): Shows the callsign of the person talking and their TG.

• Scan Info (Orange): Shows scanning status.

D. Log & Dashboard (Middle Section)

This area has two tabs:

1. HISTORY: A list of recent calls received.

   • Click a line: View details (Callsign, Date, Duration) or look up the user on QRZ.com.

2. DASHBOARD: Shows currently active stations on monitored TGs.

   • Mute Icon: Mute a specific TG temporarily.

   • JOIN Button: Immediately QSY (switch) your TX TalkGroup to that station's TG.

E. VU Meter

A compact bar above the PTT.

• Left (RX): Green bar showing incoming audio level.

• Right (TX): Red bar showing your microphone level. Use this to check if your Mic Gain is too high or too low.

F. PTT Button (Push-To-Talk)

• Green: Ready to TX.

• Red: Transmitting.

• Lock Icon / "RX BUSY": The button is disabled because someone else is talking (unless "Duplex" behavior is allowed by the reflector).

---

2. Configuration (Network Setup)

To set up a hotspot or reflector:

1. Long Press an empty slot in the Network Grid.

2. Fill in the fields:

   • Name: A label (e.g., "Home Hotspot").

   • Host: IP Address or DNS (e.g., srv.reflector.com or 192.168.1.50).

   • Port: Usually 5300 or 5301.

   • Callsign: Your callsign.

   • TG: The default TalkGroup to connect to (e.g., 208).

   • Password: The hotspot/reflector password.

3. Import from Clipboard: If you have a JSON config string copied, paste it in the bottom field and click "IMPORT" to auto-fill.

4. Click SAVE.

---

3. Monitoring & Scanning (The "Smart TG" Button)

QSOLink includes a powerful TalkGroup monitor.

To Configure: Long-press the Smart TG Button (top center).

Settings:

• Enable Switch: Turns monitoring On/Off.

• Mode:

  • Info Only: Shows activity on screen but does not switch audio.

  • Auto-Switch (Favorites): Switches audio to the active TG if it is in your list.

  • LIVE SCAN (ALL): Listens to any traffic sent by the reflector (promiscuous mode).

• Revert Delay: If the app switches to a monitored TG, it will wait this many seconds of silence before returning to your "Home TG".

Adding TGs:

1. Priority:

   • Normal: Standard priority.

   • High (+): Interrupts Normal traffic.

   • Max (++): Interrupts everything (Red).

   • Low (-): Only listened to if channel is totally free.

2. TG ID: Enter the number (e.g., 91).

3. Click ADD.

---

4. Main Settings Menu (Gear Icon)

A. SYSTEM

• Network Quality (Jitter): Crucial for audio stability.

  • 40ms - 80ms: Only for perfect Wi-Fi.

  • 150ms - 250ms: Recommended for 4G/LTE.

  • 400ms - 500ms: Use in cars or areas with bad signal. Higher = more delay but fewer audio cuts.

• Time-Out Timer (TOT): Automatically stops transmission after 60/90/120/180 seconds to prevent overheating or blocking the channel.

B. DISPLAY

• Show Networks: Toggle between 10 slots (small) or 5 slots (large).

• Show Logo / Status Bar / Logbook: Hide elements to save screen space.

C. AUDIO (Advanced)

• Mic Gain: Hardware amplification.

  • Adjust while watching the TX VU Meter. The red bars should peak near the top but not hit the max constantly.

• AGC TX (Auto Level): Automatic Gain Control for your microphone.

  • Enabled: The app dynamically adjusts volume to hit the "TX Target" (e.g., -10dB). Recommended.

• AGC RX (Limiter): Automatic volume leveling for incoming audio. Prevents loud stations from hurting your ears.

D. OPTIONS (PTT Config)

• Screen PTT Mode:

  • PTT (Momentary): Press and Hold to talk. Release to listen.

  • Switch (Locked): Tap once to talk. Tap again to stop.

• External PTT Mode: Same logic but for Bluetooth buttons/Headsets.

• Bluetooth Button Setup:

  • Enable "Bluetooth Button".

  • Click SCAN.

  • A popup appears ("Bluetooth Sniffer").

  • Press the physical button on your Bluetooth Handmic/Headset/Pedal.

  • The code appears (e.g., "Code: 126" or "Code: 79").

  • Click SAVE.

E. DATA & STORAGE

• Backup Config (JSON): Saves all your networks and settings to a file in your Downloads folder. Use this to transfer settings to another phone.

• Restore Config: Loads a previously saved JSON file.

• Export Logbook (ADIF): Exports your received calls history to a standard ADIF file for logging software (QRZ, LOG4OM, etc.).

---

5. Troubleshooting / Pro Tips

Audio Routing Issues

If the audio is coming out of the wrong speaker (e.g., phone ear-piece instead of loudspeaker, or not going to Bluetooth):

1. Connect your Bluetooth device.

2. Tap the Audio Device Icon (top bar, next to Mute).

3. You will see a small animation. This forces the internal audio engine to restart and grab the correct device.

"RX BUSY" on PTT

If the PTT button shows a lock icon and says "RX BUSY":

• This means someone is currently talking.

• QSOLink blocks TX by default to prevent "doubling" (talking over someone).

• Wait for the person to finish.

Backing up before update

Always go to Menu > DATA & STORAGE > EXPORT > Backup Config before uninstalling or updating the app to ensure you don't lose your 10 memory slots.

Here is the Support & Information section, professionally translated into English, ready to be added to the end of your User Manual.

---

6. SUPPORT & INFORMATION

Need Help?

If you encounter configuration issues, bugs, or have feature requests, please contact the developer:

• Support Email: f4jgi.cedric@gmail.com

• QRZ.com Page: https://www.qrz.com/db/F4JGI

Support the Project

QSOLink is free software developed during spare time. If you enjoy using this application and wish to contribute to server costs or encourage future development, you can make a donation via PayPal:

• PayPal Donation: redgis01@free.fr

• Or simply click the "Donate" link at the bottom of the main screen in the app.

Credits & Acknowledgments

QSOLink is an evolution based on the open-source project Latry.

• Android Development & Adaptation: Cedric F4JGI.

• Original Core Code: Special thanks to Silviu YO6SAY for his formidable work on the original Latry engine.

Legal Information

QSOLink V1.2.0
Copyright © 2025 Cedric F4JGI.

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License.

Disclaimer: This software is provided "as is", without warranty of any kind, express or implied. The author cannot be held liable for any direct or indirect damages resulting from the use of this application. Please use it responsibly and in accordance with the amateur radio regulations in your country.

---

End of Document - QSOLink User Manual - Rev 1.0

 

Rulhof ZS4RM - AllStar Portable / Mobile Node Project

Awhile ago Rulhof ZS4RM informed me that he is busy building an AllStar Portable / Mobile Node which he will be using whenever the need arises.

Now what on earth is a Portable / Mobile AllStar Node?

A

DIY mobile AllStar node is a custom-built, portable device that uses a low-power computer, a radio interface, and amateur radio equipment to connect to the global AllStarLink network via the internet  (often a mobile hotspot). This setup allows amateur radio operators to communicate with thousands of other nodes and repeaters worldwide using their handheld or mobile radios, essentially acting as a personal gateway or "hotspot". 

The "DIY" aspect means the operator assembles the components themselves, which is a common and cost-effective approach within the ham radio community, as opposed to buying a pre-built commercial unit. 

 

Key Components:

 

A typical DIY mobile AllStar node requires the following main components: 

• A Computing Device: A small, low-power computer, most commonly a Raspberry Pi (Pi 3 or Pi 4 are popular choices). It runs a Linux-based operating system with the AllStarLink software, often a pre-configured image like HamVoIP.
• A Radio/Audio Interface: A small circuit board or device that connects the computer's USB port (via a C-Media CM108/CM119 sound IC) to the radio's audio input/output and Push-to-Talk (PTT) lines. Pre-made interfaces like the DMK URIx or Masters Communications DRA boards are available, or advanced users can build their own from scratch.
• A Node Radio: A simple, often inexpensive, UHF or VHF radio (e.g., a Baofeng UV-5R or similar) dedicated to the node. This radio receives signals from your personal handheld radio and transmits audio back from the network.
• Power Source: For a mobile setup, a portable battery bank or a buck converter for a vehicle's power system is used.
• Internet Connection: The node needs internet access, which can be provided by Wi-Fi or by tethering to a mobile phone hotspot.

Functionality:

 

The setup works by:

1. Receiving an FM signal from your handheld radio on a specific frequency.
2. Converting the audio to digital data via the sound interface and the Raspberry Pi.
3. Transmitting that digital data over the internet to other AllStar nodes.
4. Receiving internet audio from other nodes.
5. Converting the digital audio back to an FM signal for transmission to your handheld radio.

This allows for seamless communication over vast distances, bridging the gap between local RF (Radio Frequency) coverage and the global internet network. 

 

Building Your Own:

 

To build a DIY node, you would typically follow these general steps:

1. Register for an AllStar node number on the AllStarLink website.
2. Gather the necessary hardware components.
3. Install the AllStar software (like HamVoIP) onto the Raspberry Pi's SD card.
4. Wire the radio to the interface board (if necessary).
5. Configure the software settings, including audio levels and network parameters, often using a program like PuTTY for remote access.
6. Test the node using the "Parrot mode" feature.

There are many online guides and YouTube tutorials available to walk users through the process.

 

Information regarding the ZS4RM AllStar Portable / Mobile Node:

 

Call Sign:  ZS4RM

Frequency:  433.4125 Mhz

CTCSS:  100 Hz

Node Number:  647031

Location:  Bloemfontein

Site:  Bayswater

Affiliation:  Hammies Free State (ZS4ZU)

 

The "inauguration"   of the node took place during the recent holiday season when Rulhof visited  Shelly Beach in Kwazulu Natal.  He use the node regularly while mobile and even portable when he visited the beach.  The node is functioning well and is definitely a great asset when going mobile or portable.  Congratulations on constructing a useful and effective node, Rulhof.  It is clear from the videos that you enjoy the node to the full.

Images:  Click on images for larger view.

 

Videos:

Opgedateerde Vloei Diagram: ZS1I ZS-Link Netwerk - Besoekende Radio Amateurs aan Mosselbaai, Hartenbos en Danabaai

Images: Click on image for larger view or download below

Ek is by verskeie geleethede gevra om meer inligting te verstrek rondom die ZS1I HUB Netwerk in Mosselbaai. Die vloei diagram is slegs gebasseer op nodes, herhalers en netwerke wat tans aan die ZS1I HUB gekoppel is.  Ek het 'n nuwe vloei diagram saamgestel wat die nodige inligting bevat  rondom die HUB en hoe radio amateurs kan inskakel by die HUB.  Weereens is dit baie moeilik om al die inligting op een velletjie papier beskikbaar te stel.  Ek beoog om later 'n volledige "handleiding" van die algehele ZS-Link Netwerk in die Suid Kaap en ander dele van Suid Afrika saam te stel soos wat die tyd my dit toelaat.  Ek vertrou dat die vloei diagram van hulp sal wees vir diegene wat dalk nie verstaan hoe die network funksioneer nie.  Vrae op die lug asook op "Die 625 - 6 Uur  Half 5 Span" WhatsApp groep rakende die ZS Link Netwerk is meer as welkom.

Aflaai / Download: Vloei Diagram / Flow Diagram

Updated Flow Diagram: ZS1I ZS-Link Network - Visiting Radio Amateurs to Mossel Bay, Hartenbos and Dana Bay

I have been asked on several occasions to provide more information about the ZS1I HUB Network in Mossel Bay. The flow diagram is only based on nodes, repeaters and networks that are currently connected to the ZS1I HUB. I have compiled a new flow diagram that contains the necessary information about the HUB and how radio amateurs can connect to the HUB.  Again, it is very difficult to make all the information available on one sheet of paper. I intend to later compile a complete "manual" of the complete ZS-Link Network in the Southern Cape and other parts of South Africa as time permits. I trust that the flow diagram will be of assistance to those who may not understand how the network functions. Questions on the air and "Die 625 - 6 Uur  Half 5 Span" WhatsApp Group about the ZS Link Network is more than welcome.

Bloemfontein ZS4RM AllStarLink Node now active!

 

Yet again another AllStar Node has been activated. This time it is the node of  Roelhof ZS4RM from Bloemfontein.

Bloemfontein is located in the central region of South Africa, within the Free State province. It is the capital of the Free State and serves as the judicial capital of South Africa.  

Key details about its location:

    Country: South Africa.
    Province: Free State.
    Geographic Position: Situated in the center of the country.
    Nickname: Known as "The City of Roses" due to its abundant rose bushes.
    Sesotho Name: Its Sesotho name is Mangaung, meaning "place of cheetahs".

Now lets look at the ZS4RM AllStar Node 

Images:  (Click on images for larger view.)

Herewith information and connection details:

Node Number: 647030

Node hardware = Raspberry Pi

Link Radio = Motorola Radius

Frequency = 145.550 Mhz

AllStar Software = ASL3

Location:  Bloemfontein, South Africa

Finally:  Next time you visit Bloemfontein you most welcome to use the node to talk to the World.  A big thank you to Rulhof ZS4RM who undertook this project and made it a reality.  Well done Rulhof!!  

Images:  (Click on images for larger view.)