If you’re into amateur radio and love to tinker, here’s something weirdly fun to experiment with: rpitx2 — a software-only RF transmitter for the Raspberry Pi.

No, it’s not a substitute for your HF rig. No, it’s not going to replace your IC-7300 or even your Baofeng. But if you’re looking for an experimental project that lets you transmit real RF signals using just a Raspberry Pi and a bit of wire, rpitx2 is surprisingly powerful — in a nerdy kind of way.

What Is rpitx2?

rpitx2 is the second generation of the original rpitx by F5OEO. It’s a general-purpose RF transmitter that works by abusing (intentionally!) the Raspberry Pi’s GPIO pin to generate radio signals between 5 kHz and 1500 MHz. That covers everything from VLF to UHF.

All you need is:

• A Raspberry Pi (several models supported, more on that below)
• A short wire connected to GPIO 4 (pin 7) as an antenna
• The rpitx2 software
• And a sense of curiosity, because this is very much a let’s-see-if-it-works kind of project

A Word of Warning

This is experimental software. It hasn’t been certified for compliance with RF transmission regulations. You are entirely responsible for how you use it. If you’re a licensed amateur operator, stay within legal bands and power limits. If you’re not licensed — don’t transmit at all. Just use it into a dummy load or observe via SDR.

Also, don’t expect miracles. This is not a high-quality transmitter. The Pi is doing all the work in software. There’s no filtering, no PA stage, no real impedance matching — just raw RF squeezed out of a pin that was never meant to do this.

It’s great for short-range testing and learning about modulation, not for talking to DXCC entities.

What Can You Actually Transmit?

rpitx2 comes with a bunch of built-in demos and modes:

• FM with RDS: Yes, you can set up a mini pirate radio station (don’t, unless legal) that sends out stereo FM with station text.
• SSB Voice: Transmit your voice using single-sideband — just keep it low power.
• SSTV (Slow Scan TV): Send an image over HF using Martin1 mode and receive it on QSSTV.
• FreeDV: Try your hand at digital voice communication over RF.
• Pocsag: Yep, you can simulate a pager transmission.
• Carrier, Chirp, Spectrum tests: Great for SDR visualization and modulation experiments.

There’s also a “replay” function — you can record a signal with an SDR and replay it via rpitx2, for fun or analysis.

Hardware Compatibility

Here’s a quick breakdown of which Pi models work:

Raspberry Pi	Status
Pi Zero	Works
Pi Zero W	Works
Pi 3B / 3B+	Works
Pi 4	Sometimes
Pi 400	Sometimes
Pi 5	Not yet

Some models, especially Pi 4 and 400, can be unstable. Pi 3A+ seems to work quite well. Also, remember: no filtering means your Pi is potentially throwing out a lot of unwanted signals (harmonics). Be a good neighbor. Use a low-pass filter, or better yet, a dummy load.

Range? Power? Don’t Expect Much

At best, the Pi can output around 50 mW, depending on the GPIO drive strength and settings. The signal is enough to get picked up across a room or even down the block with the right antenna — but it’s not going to break through noise floors or reach satellites.

It’s been reported that a ~79 cm wire can give you a few hundred meters of range on 95 MHz in ideal conditions, but that’s highly variable.

The real value here isn’t range or power — it’s the education. You’ll learn about modulation schemes, SDR waterfall displays, antenna resonance, and more, all for the cost of a Raspberry Pi and some wire.

Use Cases for Hams

So why would a licensed ham care about this?

• Modulation experiments: Visualize FM, AM, SSB, and digital modes.
• Test signal generation: Useful for SDR calibration or receiver alignment.
• Digital mode experiments: Try encoding and decoding FreeDV, SSTV, POCSAG, etc.
• Beacons: Set up a temporary WSPR/OPERA-style beacon on ISM bands.
• Educational demos: Perfect for club meetings, STEM events, or just showing friends how modulation works.

Final Thoughts

rpitx2 is not a serious transmitter — but it’s not supposed to be. Think of it more like a radio playground for hackers and hobbyists. You’ll learn a lot, break a few things, maybe even disturb your FM radio a little. Just be responsible and legal about it.

It’s a brilliant reminder that sometimes, the best tools for learning aren’t the most expensive — they’re the most hackable.

Visit and learn more at https://github.com/KubaPro010/rpitx2

The post Playing with RF: rpitx2 Turns Your Raspberry Pi into a Radio Transmitter appeared on Hamradio.my - Amateur Radio, Tech Insights and Product Reviews by 9M2PJU.

If you’ve ever wanted to dive into the world of digital electronics, whether as a student, educator, engineer, or hobbyist, you’re going to love this tool: Digital — a powerful, free, and open-source logic circuit simulator created by Helmut Neemann. Available on GitHub at hneemann/Digital, this Java-based application combines clarity, flexibility, and educational value in one sleek package.

What Is Digital?

Digital is a logic circuit simulator designed with a clear goal: to make the teaching, learning, and development of digital logic intuitive and visual. It lets you create, simulate, and analyze logic circuits ranging from basic gates to complex CPUs — all with a drag-and-drop interface and real-time simulation.

Unlike other bloated EDA software, Digital is refreshingly simple, elegant, and lightweight. But don’t let its simplicity fool you — it’s capable of simulating complex architectures with clocked components, finite state machines, memory modules, and even custom microprocessors.

Key Features

• Intuitive Interface
  Drag and drop components onto your canvas, connect wires, and see how your circuit behaves in real-time.
• Real-Time Simulation
  Changes are reflected immediately, with live logic levels and animations that bring your circuits to life.
• Modular Design
  Use subcircuits and hierarchical design to keep things organized, even in large-scale projects.
• Clocked Components
  Simulate registers, flip-flops, RAM, and sequential logic effortlessly.
• Built-in CPU & Assembler
  Digital includes a simple, yet powerful CPU with its own instruction set and assembler — ideal for teaching computer architecture.
• Made for Education
  Widely used in universities and schools. Perfect for explaining logic gates, truth tables, FSMs, and microprocessor fundamentals.
• Cross-platform (Java-based)
  Works on Windows, macOS, and Linux. Just download and run!
• Open Source (GPL-3.0 License)
  Actively maintained and completely free. Fork it, contribute, or adapt it to your own projects.

Who Is It For?

• Students: Learn digital logic step by step with instant feedback.
• Educators: Use it in the classroom to teach logic circuits and CPU architecture interactively.
• Makers & Hobbyists: Build and test your own logic-based inventions.
• Researchers & Developers: Prototype logic systems before implementing them in hardware.

Whether you’re building an ALU, a traffic light controller, or your own 8-bit CPU, Digital gives you the tools to simulate it with precision.

Get Started in Minutes

1. Head over to the Digital GitHub repository.
2. Download the latest release (JAR file).
3. Run it using Java (Java 8 or higher required).
4. Start building your first circuit with just a few clicks.

No complex installations. No licenses. No fees. Just pure learning and tinkering joy.

Final Thoughts

In a world of expensive and overly complex simulation tools, Digital shines as a free, open-source, and educator-friendly alternative. It’s ideal for classrooms, home labs, and anyone curious about what happens beneath the silicon.

So if you’re ready to master digital logic — from basic gates to building your own CPU — it’s time to download Digital and start creating.

Explore. Simulate. Learn. With Digital.

The post Digital – Design, Simulate, and Understand Logic Circuits Like Never Before appeared on Hamradio.my - Amateur Radio, Tech Insights and Product Reviews by 9M2PJU.

When people talk about reliable laptops, the Lenovo ThinkPad often comes up. And there’s a good reason for that. The ThinkPad isn’t just a regular business laptop — it’s a machine built with purpose: durability, practicality, and long-term usability. It’s not flashy, but it works. Day after day, year after year.

If you’ve ever wondered how ThinkPads work and why they’re trusted everywhere from office desks to research stations in Antarctica, this article is for you.

Built Like a Tank (But Smarter)

One of the defining features of a ThinkPad is how durable it is. Many models are tested against MIL-STD-810H standards — a U.S. military-grade set of environmental tests. This includes things like:

• Drops and shocks
• Dust and sand exposure
• Vibration and humidity
• Extreme high and low temperatures
• Altitude pressure

These aren’t just marketing terms. Lenovo actually sends ThinkPads through these environmental torture tests so they can survive tough real-world conditions. That’s why you’ll see ThinkPads used in the field by engineers, scientists, emergency responders, and even the military.

Long Life, Long After Others Quit

A major reason people love ThinkPads is their lifespan. Unlike many consumer laptops that slow down or fail after a couple of years, ThinkPads are built to last 5–10 years or more — especially if you stick to the X, T, or P series.

Key reasons why:

• Easy repairability: Most ThinkPads can be opened with just a screwdriver. RAM, SSD, batteries, and even keyboards are user-replaceable.
• Long driver support: BIOS and firmware updates often continue years after release.
• Sturdy materials: Magnesium, carbon fiber, and aluminum are common in premium models like the X1 Carbon.

Made for Linux (Almost Literally)

ThinkPads are among the most Linux-compatible laptops out there — and that’s not by accident.

Many Linux developers use ThinkPads for their own work, and Lenovo has even partnered with distributions like Ubuntu and Fedora on official support for certain models.

Why Linux users love ThinkPads:

• Excellent driver support: TrackPoint, touchpads, Wi-Fi, cameras — they mostly “just work” out of the box.
• Open firmware options: Some models support Coreboot or Heads, giving privacy-focused users more control.
• BIOS settings made for developers: You can toggle things like virtualization, secure boot, or UEFI easily — without vendor lock-in.
• Great community support: Forums like the ThinkPad subreddit, Arch Wiki, and GitHub have tons of Linux-specific tips.

If you’re running Arch, Debian, Pop!_OS, or any other distro, you’ll probably find a ThinkPad that works flawlessly.

It’s Not About Looks — It’s About Doing the Job

ThinkPads aren’t designed to turn heads — they’re made to get stuff done. The black, boxy design hasn’t changed much over the years, and that’s intentional. Everything is designed with functionality in mind:

• TrackPoint (the red dot) lets you move your cursor without lifting your hands off the keyboard.
• Spill-resistant keyboards help protect against accidents.
• Docking compatibility for serious desk setups.

This no-nonsense design makes them ideal for programmers, IT pros, writers, and business travelers alike.

ThinkPad Models to Know

If you’re thinking of buying one, here are the ThinkPads that typically pass military-grade tests:

• X1 Carbon – ultralight and strong, premium flagship
• T14/T16 – balanced, versatile business workhorses
• P1/P16 – mobile workstations with serious performance
• X13/X280 – ultra-portable but rugged
• L14/L13 – more affordable, still durable

Real-World Trust

ThinkPads have a reputation for a reason. NASA sent them to the International Space Station. Police departments use them in patrol cars. Scientists take them to the Arctic. They’re everywhere people need a machine that won’t fail.

Under the Hood: How It All Works

Technically, a ThinkPad runs like any other PC: CPU, RAM, storage, OS. But it’s how these components are put together that makes the difference:

• Vapor chamber cooling in higher-end models keeps temperatures stable under load.
• Battery management firmware extends cycle life by allowing charge caps.
• BIOS-level security features, such as ThinkShield, give IT departments peace of mind.
• Optional 4G/5G modems, fingerprint readers, and TPMs for secure, mobile work.

Final Thoughts

A ThinkPad doesn’t try to be cool. It just works — and keeps working.

If you want a laptop that feels more like a tool than a toy, one that can survive drops, spills, extreme weather, and still be going strong years later, the ThinkPad is one of the best decisions you can make. Not just for business, but for anyone who values durability, Linux compatibility, and long-term reliability.

Bonus: Why Tech Professionals Love ThinkPads

• Fast BIOS access with full control
• Coreboot and Linux support on many models
• Matte displays to reduce eye strain
• Hardware kill switches for webcam/mic in newer models
• Huge ecosystem of spare parts and upgrades

The post How Lenovo ThinkPad Works: The Durable Laptop Built to Last appeared on Hamradio.my - Amateur Radio, Tech Insights and Product Reviews by 9M2PJU.

When you dive into the world of open-source software, you’ll eventually come across different licenses—each one spelling out what you can and can’t do with someone else’s code. One of the most well-known and widely used is the GNU General Public License version 3, or simply GPLv3.

But legal documents are hard to read. So let’s break it down in plain language.

What Is GPLv3, Really?

At its heart, GPLv3 is a license that protects freedom—your freedom to use, modify, share, and improve software.

It was created by the Free Software Foundation (FSF), an organization that believes software should serve its users, not the other way around.

So GPLv3 isn’t about restricting you—it’s about making sure that everyone has equal rights to software.

What Can You Do with GPLv3 Software?

You’re allowed to do a lot, including:

1. Use it however you want
   • Personal, commercial, educational… anything goes.
2. Modify it
   • You can change the code to suit your needs.
3. Distribute it
   • You can share the software with others, either in its original form or after you’ve made changes.
4. Charge money for it
   • Yup. You can sell GPLv3 software if you want—but you have to follow the rules (more below).

But There Are Some Rules…

GPLv3 is often called a “copyleft” license, meaning that it flips traditional copyright on its head. Instead of restricting copying, it requires sharing, with the same freedoms.

If you modify and distribute GPLv3 software (especially to the public), you must:

1. Also, share the source code
   • If you give someone a binary (compiled version), you must also give them the source code, or offer it.
2. Keep the license intact
   • Your users must get the same rights you got. You can’t restrict them from modifying or sharing.
3. State your changes
   • Be clear about what you changed and who did it.
4. Do not lock the software down
   • No DRM tricks. You can’t stop users from modifying the software you distribute.

What About “Tivoization”?

Back in the day, companies like TiVo started using GPL software in their products, but added hardware restrictions that blocked users from running modified versions. That didn’t sit well with the FSF.

So GPLv3 fixed that loophole. If you distribute GPLv3 software in a product, you must give users everything they need to actually use modified versions—including keys or documentation to bypass any restrictions.

Can I Use GPLv3 in My Business?

Yes—but be careful.

• If you only use GPLv3 software internally (e.g., running it on your servers), you’re fine.
• But if you distribute it (e.g., ship devices, sell software), you must comply with all the sharing requirements.
• If you mix GPLv3 code with proprietary code, things get tricky. You may be forced to open-source your code if it’s tightly integrated.

So, GPLv3 is great for collaboration, but it’s not ideal if your business model depends on keeping your source code private.

Why Do People Choose GPLv3?

People and projects choose GPLv3 because they want to:

• Promote freedom and community-driven development
• Prevent their code from being locked down or taken private
• Ensure that everyone who benefits from their work can also contribute back

Think of it like a software version of “take a penny, leave a penny.”

Quick FAQ

Q: Can I make money with GPLv3 software?
Yes! You can sell it, offer services, or build products with it—just follow the rules.

Q: Do I have to share my code if I just use GPLv3 software privately?
No. The license only kicks in if you distribute the software or a modified version.

Q: Can I use GPLv3 code in my app and keep my code closed-source?
Usually no. If the GPL code and your code are deeply connected, your code must also be GPL.

What GPLv3 Means

If you’re using, modifying, or even building something, GPLv3 grants you:

The freedom to use the software however you want
The right to modify the code
The ability to distribute original or modified versions
The option to sell

But it also requires you to:

Share the source code of any modified version you distribute
Keep the software under the same license (GPLv3)
Allow users to modify the software themselves (no locking down with DRM or proprietary hardware)

Final Thoughts

The GPLv3 is not about control—it’s about freedom. It’s designed to ensure that no one can take a shared resource and turn it into a walled garden. It encourages innovation, collaboration, and fairness. If you’re okay with giving back to the community and playing by open rules, GPLv3 is a powerful tool for building great software together.

Using software licensed under GPLv3 gives you the freedom to study, modify, and distribute it, but it doesn’t give you ownership over the original work. While you’re free to add your features or improvements and even copyright those specific changes, the entire combined project must still follow the rules of the GPLv3 license. That means you cannot lock it down, claim it as entirely your own, or prevent others from using it under the same terms. GPLv3 is about sharing knowledge, not claiming exclusive rights over a community-driven effort.

The post Understanding the GPLv3 License appeared on Hamradio.my - Amateur Radio, Tech Insights and Product Reviews by 9M2PJU.

In today’s increasingly connected amateur radio landscape, digital linking is no longer a novelty—it’s a vital part of modern ham operations. The SHARI PiZero (SA818 Ham Allstar Radio Interface for PiZero) is a purpose-built solution designed for hams who want a compact, efficient, and reliable Allstar node that they can build themselves. Whether you’re an experienced builder or new to DIY radio kits, the SHARI PiZero offers an excellent balance of performance, flexibility, and value.

What is SHARI PiZero?

The SHARI PiZero is a custom-designed hardware kit that transforms a Raspberry Pi Zero 2W into a fully functioning Allstar Node. Designed for use in the amateur radio service, the kit incorporates a NiceRF SA818 embedded radio module, available in UHF (420–450 MHz) or VHF (144–148 MHz) versions. It provides 250–500 milliwatts of RF power—ideal for hotspot use or local repeater access.

The kit includes a dedicated USB audio interface (CM108B), a lowpass filter to meet FCC Part 97 spurious emissions requirements, and a three-port microUSB hub to support accessories like USB-to-Ethernet adapters or external keyboards. This makes setup and configuration via wired Ethernet not only possible but preferred, especially for first-time builders working with the HamVOIP Allstar image.

Key Features at a Glance

• Embedded NiceRF SA818S module in UHF or VHF band options
• CM108B USB audio chip for high-quality audio handling
• Lowpass LTCC filter to ensure spectral cleanliness
• Integrated 3-port USB hub for peripherals and Ethernet adapters
• Surface mount components pre-installed — minimal soldering required
• Compact and rugged Hammond aluminum enclosure
• Optional pre-soldering and full assembly services

Construction and Setup: Designed with Builders in Mind

SHARI PiZero is designed as a partially pre-assembled kit. The PCB arrives with all small surface-mount components factory-installed. As the builder, you’ll install only a few through-hole components: the SA818 radio module, SMA RF connector, and headers for the Raspberry Pi. All necessary cables are included, and detailed instructions are provided via request.

One of the advantages of the SHARI PiZero design is its thoughtful inclusion of hardware for a clean build—such as 3D-printed end caps and optional blank end plates for custom modifications.

The Raspberry Pi Zero 2W (not included in the base kit) plugs directly into the SHARI motherboard using the GPIO header and a custom USB cable. Since the PiZero doesn’t have an Ethernet port, the onboard USB hub lets you plug in a microUSB-to-Ethernet adapter, ensuring a stable connection for image configuration and updates.

Kit or Fully Assembled: Your Choice

SHARI PiZero is available in two models:

• PiZeroU (UHF 420–450 MHz)
• PiZeroV (VHF 144–148 MHz)

You can purchase the kit for just $100, which includes all components except the Raspberry Pi Zero 2W, power supply, and microSD card. If you prefer, for an additional $5, the SA818 module can be pre-soldered for you.

Don’t have the time or tools to assemble the kit yourself? A fully assembled and tested SHARI PiZero is available for $205, which includes the Raspberry Pi Zero 2W and a power supply. For wired networking, an optional microUSB-to-Ethernet adapter can be added for $10—tested and guaranteed to work with the HamVOIP Allstar distribution.

Shipping to U.S. addresses is a flat $9 via USPS Priority Mail.

Community and Support

Builders and users of SHARI can access community-based support through the SHARI Groups.io group, which serves as the primary hub for troubleshooting, build questions, and ideas. For software-related support (e.g., configuring HamVOIP or ASL), users are encouraged to consult the respective project sites.

Get Started

Whether you’re setting up a remote Allstar node at your vacation cabin, building an RF link for your club repeater, or just want a portable digital access point, SHARI PiZero is a reliable and customizable solution.

To order, download the SHARI PiZero Order Form and email it to kits4hams@gmail.com. You’ll be added to the waitlist and notified when your kit is ready. Payment is accepted via PayPal.

Visit https://kits4hams.com/shari-pizero

The post Build Your Own Compact Allstar Node with SHARI PiZero appeared on Hamradio.my - Amateur Radio, Tech Insights and Product Reviews by 9M2PJU.

In the digital age, accurate timekeeping is more critical than ever. From ensuring data consistency across global servers to enabling GPS navigation and military operations, the precision of our clocks underpins modern infrastructure. This post explores how Network Time Protocol (NTP), atomic clocks, and the Global Positioning System (GPS) work together to synchronize time around the world—and what stratum levels really mean in timekeeping hierarchy.

What Is Network Time Protocol (NTP)?

NTP (Network Time Protocol) is a protocol used to synchronize the clocks of computers and devices over a network. It allows systems to keep time within milliseconds of Coordinated Universal Time (UTC), which is the global time standard.

NTP works using a hierarchical structure of stratum levels, with each level representing the “distance” from the reference clock (usually an atomic clock or GPS-based source).

How NTP Works

Here’s a simplified overview of the process:

1. A client computer sends a request to an NTP server.
2. The NTP server responds with the current time along with information about when the request was received and replied to.
3. The client calculates the round-trip delay and clock offset.
4. The local clock is adjusted accordingly, either gradually or immediately.

This process often repeats at regular intervals to maintain synchronization.

Understanding NTP Stratum Levels

NTP servers are organized into strata based on how close they are to the original time source:

• Stratum 0: These are the reference clocks—usually atomic clocks, GPS receivers, or radio clocks. They don’t connect directly to the internet.
• Stratum 1: Servers directly connected to stratum 0 devices. These are often publicly available NTP servers and offer highly accurate time.
• Stratum 2: Servers that sync with stratum 1 servers. Most users rely on these.
• Stratum 3–15: Each additional level syncs from the level above, with increasing latency and reduced accuracy.
• Stratum 16: Designated for unsynchronized servers or devices.

Example:
If your Raspberry Pi is syncing from time.google.com (a stratum 1 server), your device becomes a stratum 2 client.

What Is an Atomic Clock?

An atomic clock is the most precise timekeeping device available. It uses the natural oscillations of atoms—commonly cesium-133 or rubidium—as a reference.

Key Characteristics:

• Accuracy: Can measure time with precision better than 1 second in millions of years.
• Stability: Remains extremely consistent over long periods.
• Use Cases: GPS satellites, NTP stratum 0 devices, scientific labs, telecom networks.

The international definition of one second is based on the radiation cycles of cesium-133:
9,192,631,770 transitions = 1 second

How GPS Provides Accurate Time

The Global Positioning System (GPS) is not just for navigation—it’s also a precise time distribution network. Each GPS satellite contains multiple atomic clocks. When your GPS receiver locks onto satellites, it can:

• Determine location using trilateration
• Calculate the exact time from satellite signals

GPS Time vs UTC:

• GPS time started in 1980 and does not account for leap seconds, unlike UTC.
• GPS receivers convert GPS time to UTC using data in the satellite’s almanac.

For time servers, GPS receivers act as Stratum 0 sources, making GPS-based NTP servers (Stratum 1) popular for time-critical systems.

Real-World Applications

When Accuracy Matters

A tiny time drift can cause:

• Log mismatch in security systems
• Transaction failures in banking
• Packet loss or desync in VoIP and online gaming
• Routing issues in network infrastructure

Thus, reliable NTP configuration, ideally syncing from multiple stratum 1 servers or running your own GPS-based server, is best practice for critical systems.

Summary

Together, atomic clocks, GPS, and NTP form a robust global timekeeping system that powers everything from Google’s servers to battlefield operations and your APRS messages.

Build Your Own Stratum 1 NTP Server (Raspberry Pi + GPS + Chrony)

Creating your own Stratum 1 NTP server is a rewarding project, especially for ham radio operators, makers, and sysadmins who want reliable, low-latency timekeeping without relying on the internet.

What You Need:

• Raspberry Pi (any model with GPIO, preferably Pi 3/4/5)
• GPS module with PPS (Pulse Per Second) output (e.g. u-blox NEO-6M or NEO-M8N)
• Serial connection to GPS (UART)
• Internet for installation (optional afterward)
• Linux with chrony, gpsd, and PPS support

Step 1: Hardware Setup

1. Connect the GPS module:
   • TX (GPS) to GPIO 15 (RXD) on the Pi
   • PPS pin to GPIO 18 (Pin 12)
   • VCC and GND appropriately
2. Enable UART and PPS on the Pi: sudo raspi-config
   • Interface Options → Enable Serial (disable console over serial, enable hardware UART)
   • Reboot when prompted.

Step 2: Install Required Packages

sudo apt update
sudo apt install gpsd gpsd-clients chrony pps-tools

Step 3: Enable and Test PPS

1. Add the PPS overlay:

Edit /boot/config.txt and add:

dtoverlay=pps-gpio,gpiopin=18

2. Reboot:

sudo reboot

3. Check if /dev/pps0 appears:

ls -l /dev/pps*

4. Test PPS signal:

sudo ppstest /dev/pps0

You should see output like:

source 0 - assert 1716165796.000000000, sequence: 1234 - clear 1716165796.000001234

Step 4: Configure GPSD

Edit /etc/default/gpsd:

START_DAEMON="true"
DEVICES="/dev/serial0"
GPSD_OPTIONS="-n"

Restart the service:

sudo systemctl restart gpsd

Verify:

cgps -s

You should see satellite data and GPS time.

Step 5: Configure Chrony for GPS + PPS

Edit /etc/chrony/chrony.conf and add these lines at the top:

refclock SHM 0 offset 0.5 delay 0.2 refid GPS
refclock PPS /dev/pps0 refid PPS lock GPS

Also, comment out any existing pool or server lines if you want it to be completely standalone.

Restart Chrony:

sudo systemctl restart chrony

Step 6: Verify Chrony Status

chronyc sources -v

You should see entries like:

#x  Name/IP address            Stratum  Poll Reach  LastRx Last sample
===============================================================================
#?  GPS                          0       4   377     10     -4ns[  +23ns] +/- 30us
#*  PPS                          0       4   377     9      -1ns[   -5ns] +/- 0.1us

The * next to PPS indicates it’s the preferred source.

🖧 Optional: Share NTP on Your Network

Edit /etc/chrony/chrony.conf to allow LAN clients:

allow 192.168.1.0/24

Replace with your local subnet. Restart Chrony to apply.

This allows you to sync your entire home lab or shack with millisecond precision without depending on the internet.

The post Understanding Network Time Protocol (NTP), Atomic Clocks, and GPS: How Precise Timekeeping Powers the Modern World appeared on Hamradio.my - Amateur Radio, Tech Insights and Product Reviews by 9M2PJU.

In today’s fast-paced world, where technology evolves quickly, it’s rare to find a device that’s built to stand the test of time while offering customization, repairability, and sustainability. Enter the MNT Reform Next, a revolutionary modular laptop that takes open-source hardware to an entirely new level. Whether you’re a tech enthusiast, a professional, or someone who simply values control over your devices, the MNT Reform Next promises to be your next daily driver.

What Makes MNT Reform Next Stand Out?

1. Open Source Hardware:
At the heart of the MNT Reform Next is its open-source design. This means that not only can you see how everything works under the hood, but you can also customize and upgrade components to suit your specific needs. From the motherboard to the screen, everything is designed to be transparent, giving you full ownership and control.

2. Modularity:
Gone are the days when your laptop becomes obsolete after a few years. The MNT Reform Next is entirely modular, allowing you to easily swap out components. Need more storage? Add a new SSD. Want to upgrade the CPU or RAM? You can do that too. This level of flexibility ensures your laptop can grow with your needs, making it a long-term investment rather than just another piece of technology to be replaced.

3. Customizability:
Whether you’re looking for a specific keyboard layout, a unique display size, or a custom color for your casing, the MNT Reform Next allows you to make the laptop your own. This customizability isn’t just about aesthetics – it’s about building a machine that works for you in every way.

4. Repairability:
The MNT Reform Next is designed with repair in mind. Instead of relying on expensive and environmentally damaging repairs, you can easily open up your laptop and replace or fix components yourself. This eco-friendly approach ensures your device will last longer and reduces e-waste, making the MNT Reform Next the ideal choice for those who care about the planet.

5. High Performance Meets Mobility:
Despite its modularity, the MNT Reform Next doesn’t compromise on performance. With high-performance processors, ample storage, and a lightweight, compact design, this laptop is perfect for anyone on the go. Whether you’re working on a project or enjoying entertainment, the MNT Reform Next ensures a seamless experience without sacrificing portability.

The MNT Reform Ecosystem

The MNT Reform Next is part of the MNT Reform product family, which includes the classic MNT Reform, the MNT Pocket Reform, and the MNT Reform Camera and Keyboard. All of these products share the same commitment to open hardware, modularity, and upgradability. Whether you’re looking for a powerful desktop replacement or a portable mini-laptop, there’s a MNT device for every use case.

Perfect for Retro Computing Enthusiasts

For those who are passionate about retro computing, MNT has something special for you too. The company has developed a range of Amiga upgrades, including graphics and audio cards, designed to enhance your retro computing experience. This attention to the past alongside a focus on the future is what makes MNT so unique in the world of open-source hardware.

Why Choose MNT Reform Next?

• Sustainability: Repairable and upgradable design means less waste and a longer lifespan.
• Customizable: Tailor your device to your specific needs, from hardware to design.
• High Performance: A perfect blend of power and portability for everyday use.
• Open Hardware: Full transparency and control over your device’s design and functionality.

If you’re ready to break free from the limitations of traditional, closed-source laptops, the MNT Reform Next is the future of computing. With its open-source philosophy, modular design, and commitment to sustainability, it’s more than just a laptop – it’s a new way to think about technology.

Ready to experience the MNT Reform Next for yourself?

Visit https://mntre.com/index.html

The post Discover the MNT Reform Next: The Ultimate Modular Laptop for the Future appeared on Hamradio.my - Amateur Radio, Tech Insights and Product Reviews by 9M2PJU.

The world of off-grid communication just got a stylish and functional upgrade. The SenseCAP Indicator for Meshtastic & LoRa is a sleek 4-inch capacitive touchscreen device designed specifically for low-power, decentralized communication. With dual microcontrollers, built-in wireless support, and open-source flexibility, this is more than just a screen — it’s a fully capable IoT companion built for the modern maker.

Built for Meshtastic® and Beyond

Meshtastic® users will feel right at home with the SenseCAP Indicator. Thanks to onboard LoRa® support via the Semtech SX1262 module, this device can seamlessly act as a visual interface for your mesh network. Whether you’re sending messages off-grid, monitoring environmental data, or managing nodes, this device makes interaction intuitive and portable.

Dual MCU Design

Under the hood, the Indicator is powered by two powerful chips:

• ESP32-S3 – A dual-core LX7 microcontroller with 2.4GHz Wi-Fi and Bluetooth 5.0, perfect for cloud connectivity, local dashboards, or Matter integration.
• RP2040 – Raspberry Pi’s beloved microcontroller, providing additional I/O and real-time handling capabilities.

This dual-MCU design ensures efficient multitasking and smart division of labor between communications and control.

Stunning Display

• 4” RGB capacitive touch panel
• 480×480 resolution
• Crystal-clear and responsive UI experience

Whether you’re navigating menus, displaying sensor readouts, or showing message threads, the high-res screen brings clarity to your fingertips.

Connectivity & Expansion

• Wi-Fi (2.4GHz)
• Bluetooth 5.0 Low Energy
• LoRa® (868/915MHz)
• USB Type-C for power and data
• Grove port for expansion with hundreds of Seeed modules

It’s a plug-and-play platform ready for rapid prototyping or full deployment.

What’s in the Box

• 1x SenseCAP Indicator for Meshtastic® & LoRa®
• 1x USB Type-C Cable (1m)

Optionally, you can bundle it with compatible Grove modules like the Grove GPS (Air530) for precise location tracking or long-distance communication enhancements.

Use Cases

• Meshtastic® message viewer and controller
• Off-grid messaging terminal
• Portable sensor data dashboard
• Digital assistant for environmental monitoring
• Custom LoRa® communication interface
• Smart control panel for Home Assistant and Matter devices

Open Source & Developer Friendly

With full support for the Arduino and CircuitPython ecosystems, open-source firmware, and transparent documentation, developers are free to shape the device however they want. Whether you’re building from scratch or adapting existing projects, the platform is as flexible as your imagination.

Pricing & Availability

• Retail Price: $60.90
• Discounted Price: $47.90 (Save 21%)
• Warehouse: Ships from China
• Availability: In stock now

Buy now via Seeed Studio or add it to your cart while the offer lasts!

Final Thoughts

The SenseCAP Indicator for Meshtastic & LoRa is a well-rounded device that blends powerful hardware with open-source accessibility — ideal for hobbyists, tinkerers, and professionals alike. Whether you’re a mesh network explorer, LoRa® enthusiast, or someone seeking a capable touchscreen platform, this tool brings performance, portability, and purpose to your projects.

The post SenseCAP Indicator – A Smart Touchscreen Built for Meshtastic appeared on Hamradio.my - Amateur Radio, Tech Insights and Product Reviews by 9M2PJU.

In the world of signal processing and measurement, precision and versatility are key. Whether you’re an engineer, researcher, or enthusiast working with RF applications, having a reliable and high-performance tool is essential. The Red Pitaya SIGNALlab 250-12 is a game-changer in this domain, offering cutting-edge features that cater to both professional and educational applications.

Why Choose the Red Pitaya SIGNALlab 250-12?

The SIGNALlab 250-12 is designed for high-performance signal acquisition and analysis, making it ideal for a variety of applications, from software-defined radio (SDR) to scientific research and industrial testing. With its powerful 250 MSps sampling rate and 12-bit resolution, this device ensures accurate and high-fidelity signal processing.

Key Features and Benefits

High-Speed Sampling – The 250 MSps sampling rate provides exceptional signal resolution, making it perfect for demanding RF applications.
12-Bit ADC & DAC – Achieve high dynamic range and precision in your signal analysis.
Versatile Connectivity – Equipped with Gigabit Ethernet, USB, and SD card support, ensuring seamless integration into your existing setup.
Multiple Analog and Digital Inputs/Outputs – Adapt to different project needs with flexible I/O configurations.
Linux-Based Open-Source Ecosystem – Run custom applications, expand functionality, and leverage a thriving community of developers.
Compact and Portable Design – A powerful lab tool that fits in the palm of your hand, making field applications more practical.

Applications of SIGNALlab 250-12

This powerful device is not just another signal acquisition tool—it’s a full-fledged measurement platform that can be used in:

Software-Defined Radio (SDR) – Implement and experiment with RF signal processing applications.
Wireless Communication Testing – Analyze and troubleshoot wireless signals with ease.
Scientific Research & Education – A cost-effective tool for universities and research labs.
Industrial and IoT Applications – Use in control systems, automation, and real-time monitoring.
Signal Generator & Oscilloscope – Functions as an arbitrary waveform generator and a high-precision oscilloscope.

Why Red Pitaya?

Red Pitaya has gained a solid reputation for providing high-quality, affordable, and open-source hardware solutions for signal processing enthusiasts and professionals alike. The SIGNALlab 250-12 continues this tradition, delivering top-tier performance at a competitive price while maintaining the flexibility that engineers and researchers demand.

Final Thoughts

If you’re looking for a powerful, compact, and versatile signal processing tool, the Red Pitaya SIGNALlab 250-12 is a must-have. Whether you’re diving into RF applications, educational experiments, or industrial testing, this device delivers the accuracy, flexibility, and performance you need.

Ready to take your signal processing to the next level? Explore the Red Pitaya SIGNALlab 250-12 today and visit https://redpitaya.com/

The post Unlock the Power of High-Performance Signal Processing with Red Pitaya SIGNALlab 250-12 appeared on Hamradio.my - Amateur Radio, Tech Insights and Product Reviews by 9M2PJU.