The New LiNK500MP Mk2 for the Lab599 TX-500MP

Portable operators have wanted a radio that can survive real field conditions for years. Not park activations. Not picnic-table deployments. Real field work. Rain, snow, cold fingers, long-duration power constraints, and setups that must work when, where, and how you operate.

At the moment, the Lab599 TX-500MP is the closest radio we have delivering on these requirements.

The Lab599 TX-500MP is one of the most energy-efficient, rugged HF and 6 meter man-portable radios available. Wide voltage input. Direct solar compatibility. BP-550 18650 lithium-ion battery pack support. Internal antenna tuner. Extremely low RX current draw. I understand it is not easy to get. Most niche radios aren’t. Still, from an RF and power discipline perspective, the TX-500MP is built for grid-down operations.

The Hard Truth

If your mission includes structured messaging, position reporting, or long-distance keyboard-to-keyboard chat, the TX-500MP definitely needs some help. If we are looking at the TX-500MP as the core of a modular radio, you would be forgiven for thinking it is missing some important features from a data Operator perspective.

• There is no internal audio interface.
• There is no integrated GNSS receiver like the Icom IC-705.
• There is no wireless CAT control like the Icom IC-705.
• There is no integrated data interface.

These are not flaws! It simply means the radio was designed as a rugged but modular HF/6M platform first.

Many Operators waited on manufacturers like Yaesu to come out with the successor to the FT-817/FT818. I wasn’t going to hold my breath, especially since the Icom IC-705 set the bar so high. So, we can either wait for a manufacturer to add features in a future revision, or we can solve the problem now without compromising what already works.

That is where the LiNK500MP Mk2 fits.

Introducing the LiNK500MP Mk2

The LiNK500MP Mk2 is a multi-standard TNC with an integrated APRS tracker, GNSS receiver, audio interface for AFSK data modes, and purpose-built for the TX-500MP.

The Link500MP Mk2 doesn’t feel like an accessory. It feels like something the manufacturer should have included with the radio.

Its job is simple.

It turns the TX-500MP into a fully wireless data station, covering the capability gaps you would otherwise have to solve with external hardware. Then we try to do that while preserving everything that makes the TX-500MP strong.

Why Wireless Matters in the Field

On a bench at home, cables are fine.

In the field, cables fail.

For decades, ham radio operators have connected makeshift audio cables between their rigs and computers. We already know what happens. Cables get tangled. Cables get broken. Cables get lost. How many times has that CAT control cable come loose from the back of your FT-817 or FT-818?

We plug in USB GPS dongles for position and time, and on a laptop we quickly run out of USB ports between audio, CAT control, and GNSS. Now try managing all of that in cold weather while wearing gloves. Try troubleshooting a loose connection with your mitts on.

We waste time fiddling instead of turning on the radio and getting our signals down range.

Every connector is a potential failure point.
– Julian OH8STN

The LiNK500MP Mk2 mounts directly to the TX-500MP and provides:

• Wireless audio over Bluetooth
• Wireless CAT control over Bluetooth
• Integrated multi-standard TNC
• Standalone APRS tracker
• Integrated GNSS receiver
• USB audio and CAT fallback when required

Pair your laptop, tablet, or phone once, and your audio and CAT control are handled wirelessly.

No external sound card.
No USB serial adapter.
No external GNSS puck.

It does not add problems you did not already have. It removes several.

Wireless Multi-Platform Data Without Workarounds

After installing the LiNK500MP Mk2 onto the TX-500MP and pairing it to my iPad, one thing became immediately clear: this is not a niche feature. It works the way modern operating systems expect wireless devices to work.

The LiNK500MP Mk2 uses Bluetooth for audio and CAT control. It presents itself to the operating system like a standard Bluetooth audio device, similar to AirPods, with radio control layered on top.

There is no third-party bridging software required. The operating system manages the Bluetooth audio and serial interfaces directly.

This works cleanly with:

• iOS
• iPadOS
• Android
• Windows
• macOS

Linux works perfectly over USB, and Bluetooth testing is ongoing. Over USB, the device presents standard audio and serial interfaces handled natively by the operating system, with no proprietary bridging software required.

So far, most of my testing has been done on an Apple iPad M4 Pro. I will continue testing on Windows, Android, and eventually macOS and Linux. For now, on iPadOS, my practical examples are APRS.fi and the Winlink client called RadioMail, which can now operate completely wirelessly over Bluetooth audio with the LiNK500MP Mk2.

Apple has long enforced sandboxing on iOS and iPadOS, limiting direct hardware connections. Instead, Apple generally prefers wireless interfaces for external device integration.

Supporting direct USB communication on iOS or iPadOS has traditionally required participation in Apple’s hardware programs, certification processes, and compliance with specific accessory frameworks. For smaller hardware developers, that path can be complex, restrictive, and often expensive.

As a result, direct radio-to-device USB integrations on iPhones and iPads have historically been more complicated than on other platforms.

With the LiNK500MP Mk2 presenting standard Bluetooth audio and CAT control, that barrier is effectively removed. Developers now have access to both audio and control channels in a way that aligns with Apple’s preferred interface model. For ham radio development on iPads and iPhones, this opens the door to cleaner, native solutions without awkward hardware workarounds.

It is important to be clear here. The Icom IC-705 is one of the best portable radios available for data mode communications. It uses Wi-Fi to provide wireless connectivity, and that approach works well. However, it relies on intermediary software to create virtual ports for audio and CAT control, and it depends on the Wi-Fi network remaining stable.

With Wi-Fi, you are operating over a network layer. If that network drops, you lose your radio connection. You troubleshoot networking instead of RF.

With the LiNK500MP Mk2 over Bluetooth, there is no intermediary network. The radio pairs directly to your mobile device, tablet, or laptop. It behaves like a wireless cable. Radio to device. That’s it.

One less layer. One less failure point.

Integrated GNSS Without Extra Hardware

The LiNK500MP Mk2 includes an internal multi-GNSS receiver supporting GPS, GLONASS, and GALILEO with NMEA output and integrated antenna.

For operators running APRS, Winlink with position reporting, JS8Call location sharing, or other position-aware workflows, the location data is available directly from the LiNK500MP Mk2.

This gives you IC-705-style GNSS without swapping radios or breaking the TX-500MP’s design.

No separate GNSS module.
No reliance on a phone’s location services.
No extra battery to maintain.

In a grid-down scenario, fewer devices means fewer things to manage.

Data Mode Flexibility Without Lock-In

The strength of the LiNK500MP Mk2 is not limited to Robust Packet or APRS. Those are useful capabilities, but they are not the only feature.

The insane feature we’re really talking about here is flexibility.

Any AFSK-based data mode can be used with this device. If your software can use a standard audio input and output and CAT control, the LiNK500MP Mk2 can work with it.

What “AFSK Data” Actually Means

When we talk about data modes in amateur radio, we are not talking about digital voice like DMR or D-STAR. We are talking about sending real information over the air. Text messages, position reports, email, files.

AFSK stands for Audio Frequency-Shift Keying. It is one of the simplest ways to send data through a normal voice radio.

Your computer creates digital data. That data is converted into two audio tones. One tone represents a “1.” The other represents a “0.” Those tones go into the radio like microphone audio. The radio simply transmits them.

On the other end, another computer hears the tones and turns them back into data.

The information is digital. What travels through the radio is analog audio.

That is why AFSK works with almost any radio that can pass clean audio.

That includes tools like:

• Winlink
• JS8Call
• VARA
• FT8 or FT4

And whatever else you choose to run.

Robust Packet and APRS are built into the integrated TNC, and they are there if you want them. But they are not mandatory. The wireless audio and CAT layer alone already solves most of the TX-500MP’s data limitations. Think of them as another tool in our toolbox.

You are not locked into one protocol.

Propagation changes. Power budgets change. Mission requirements change. The LiNK500MP Mk2 gives you options instead of constraints.

If you tried to assemble the same feature set separately, you would typically need:

• A standalone TNC capable of AX.25 and Robust Packet
• An external GNSS receiver
• An audio interface for AFSK data modes
• CAT control interface
• Power distribution for each device
• Multiple interconnecting cables

Each device needs mounting space. Each device needs power. Each connection is another potential failure point.

Now compare that to the LiNK500MP Mk2.

It integrates:

• Multi-standard TNC with AX.25 support
• Robust Packet capability
• Integrated GNSS receiver
• Audio interface for AFSK-based data modes
• CAT control
• Bluetooth wireless audio and control
• USB fallback for wired operation

All in a single compact unit designed to mount directly to the Lab599 TX-500MP.

From a field perspective, this matters.

No separate TNC box bouncing around in your pack.

No USB GPS dongle sticking out of your laptop.

No external sound card.

No extra power leads.

No cable nest between radio and computer.

You mount the unit. Pair your device. Operate.

Power is handled through the radio. The additional draw is modest. You are not building a secondary power system just to run accessories.

Bluetooth removes the network layer that Wi-Fi introduces. There is no router. No hotspot. No dependency on a local network remaining stable. The radio pairs directly to your device. It behaves like a wireless cable.

If you prefer wired operation, USB provides standard audio and serial interfaces handled natively by the operating system. No proprietary middleware.

Platform flexibility is built in. iOS, iPadOS, Android, Windows, macOS all handle Bluetooth audio and serial interfaces natively. Linux works cleanly over USB, and Bluetooth testing continues. The device does not lock you into a single ecosystem.

Integrated GNSS means position data is always available for APRS, Winlink position reporting, JS8Call location sharing, or time reference without adding another device to manage.

In practical terms, the LiNK500MP Mk2 reduces:

• Physical size
• Weight
• Cable complexity
• Power distribution complexity
• Setup time
• Troubleshooting in adverse conditions

In cold weather, in rain, in low light, fewer components mean fewer mistakes.

Instead of assembling a stack of boxes and cables, you have a compact HF/6 meter platform with wireless and wired data capability built in.

Turn on the radio. Pair the device. Get on the air.

Multi-Standard TNC as a Built-In Layer

Internally, the LiNK500MP Mk2 integrates:

• Teensy-based DSP processing
• AFSK Packet modem
• Robust Packet (OFDM/DPSK)
• AX.25 support
• KISS mode support
• Standalone APRS tracker

If you need traditional packet, it is there.
If you want Robust Packet on HF, it is there.
If you want standalone APRS tracking, it is there.

But you are not required to use any of those. The wireless audio and CAT layer alone already solves most of the TX-500MP’s data limitations.

The device presents standard interfaces usable across modern operating systems. Your choice of software determines how you use it.

So far, this all looks good on the bench.

So far, this all looks good on the bench. But bench testing is not field testing.

The integration is clean. Pairing is straightforward. Audio and CAT control behave exactly as expected. GNSS locks quickly. On iPadOS and Android, APRS and Winlink are already working wirelessly.

Over the coming weeks, this setup will be evaluated where it actually matters. Cold weather. Battery discipline. Gloves on. Limited daylight. Real deployments, not a controlled environment.

Android and Windows are next in line for deep dive testing over Bluetooth, alongside continued validation on iPadOS. macOS and Linux are important, but I’m initially focused on man-portable operations. The Microsoft Surface, the Android tablets and Smartphones, and the iPad.

My objectives are simple: confirm that the integration holds in less than ideal conditions, where equipment is less forgiving.

If it performs in the field the way it does on the bench, then we are no longer talking about an interesting accessory. We are talking about a genuinely capable off-grid HF and 6 meter platform with practical wireless data capability.

Final Thoughts

This is not a sponsored review. Oliver sent the LiNK500MP Mk2 to me for testing. I did not promise a positive review, only that I would share my findings publicly. This post reflects exactly that.

I am not comparing the LiNK500MP Mk2 to a dozen competing devices because, at the moment, there are no direct 1:1 competitors offering this specific combination of features in a purpose-built form factor for the Lab599 TX-500MP. A clean mechanical mount, integrated multi-standard TNC, built-in GNSS, Bluetooth audio and CAT control without a network layer, AFSK flexibility for Winlink, JS8Call, VARA, FT8, and others, all in a compact, low-power package designed to reduce failure points. That combination is genuinely unique in this niche.

The Lab599 TX-500MP itself remains one of the few truly rugged, energy-disciplined HF radios available. Weather resistant, extremely low receive current, wide voltage input, and solar friendly. Most other portable radios prioritize feature density and convenience for casual activations. The TX-500MP prioritizes resilience. The LiNK500MP Mk2 extends that resilience into the data domain without turning the station into a cable nest.

Yes, I am enthusiastic. I operate in this niche, and I care about reducing complexity in harsh conditions. Fewer cables. Fewer boxes. Fewer failure points in rain, cold, darkness, or stress. That is not hype, but sometimes, it is the mission.

At the same time, this is still early. The device arrived only days ago, and bench testing in a warm room is not the same as operating at minus twenty-eight degrees in northern Finland. The coming field sessions will determine whether this integration holds up under real-world conditions, battery discipline, and man-portable use.

If it performs in the field the way it does on the bench, then we are not talking about “marketing.” We will be talking about the genuine off-grid capability of an HF and 6 meter platform with practical wireless data support.

The Field will decide.

If you want more information about the LiNK500MP Mk2, check out Olivers website at https://diy599.net

73
Julian OH8STN

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