You have made the investment. Your portable ADS-B receiver is mounted, your EFB is running, and your traffic overlay is live. You feel covered.
Here is the question that rarely gets asked: how much of the traffic sharing your airspace are you actually seeing?
For a radio-only device, the answer, particularly in uncontrolled airspace at low altitude, is considerably less than most pilots assume. Understanding non-ADS-B traffic visibility starts with being honest about what the technology can and cannot do, and then looking at what the best devices do to close the gap.
How ADS-B In Works, and Where It Stops
Understanding the limits of your portable ADS-B receiver for traffic awareness begins with the fundamentals.
ADS-B is a broadcast system. An aircraft equipped with ADS-B Out transmits its GPS-derived position, altitude, and velocity on 1090 MHz or 978 MHz, continuously and automatically. A receiver on another aircraft picks up that broadcast and plots the target. The system is accurate, low-latency, and requires no interrogation from the ground. It is also entirely dependent on the other aircraft having ADS-B Out switched on and transmitting.
The FAA's 2020 mandate made ADS-B Out compulsory for operations in Class A, B, C, and most Class E airspace. As of mid-2024, over 105,000 fixed-wing GA aircraft carried rule-compliant ADS-B Out. Significant progress, but the mandate contains carve-outs that leave large portions of the active flying population transmitting nothing. Aircraft without certificated electrical systems, aircraft flying exclusively below the mandated airspace floor, and the entire European light GA fleet operating without an equivalent mandate all fall outside the picture your radio can build.
Traffic Information Service-Broadcast (TIS-B) partially addresses this by rebroadcasting radar-derived positions for some transponder-equipped aircraft. But TIS-B is ground-station-dependent, deteriorates in mountainous or remote terrain, and does nothing for non-transponder traffic. Radio reception alone is a starting point, not a complete solution.
The Aircraft Your Radio Cannot Hear
The gap between what a radio-only device receives and what is actually flying near you is where the risk accumulates. Here is the traffic that simply does not appear on a standard receiver's display:
Gliders and motorgliders are among the most significant blind-spot categories in busy training and cross-country airspace. European gliders overwhelmingly use FLARM, operating on 868 MHz, as their standard anti-collision system. A radio-only ADS-B receiver is entirely deaf to FLARM, meaning a glider 800 feet above your level and two miles ahead may show nothing on your display.
Paragliders and paramotors increasingly carry FANET devices, a peer-to-peer networking system designed for non-motorised and lightly motorised aircraft. FANET data is only accessible through internet-sourced aggregation. It is invisible to radio-only hardware regardless of the receiver's quality.
Microlights and ultralights operating in Class G carry no transponder or ADS-B obligation in most jurisdictions. They are legally airborne and electronically invisible to standard receivers.
Military and government aircraft flying under ADS-B exemptions highlight a specific and recently high-profile version of this problem. The January 2025 collision near Washington DC saw an Army helicopter flying with ADS-B Out switched off under a national-security exemption, invisible to every standard receiver in the area.
The common thread across all of these categories is that the aircraft are present, airborne, and sharing your airspace. The problem is not with the aircraft. The problem is with relying on a single radio protocol to build a complete traffic picture in airspace where many aircraft use different systems or none at all.
How SafeSky Inside Solves the Non-ADS-B Traffic Problem
This is exactly the gap that SafeSky Inside, the multi-source fusion engine inside SkyRecon, is built to close. Rather than relying solely on what its radio can receive, SkyRecon connects to a cloud-based network that aggregates traffic from over 30 sources simultaneously.
These sources include FLARM ground station networks across Europe, FANET aggregation for paragliders and paramotors, OGN (Open Glider Network), Mode-S MLAT, PilotAware, and live position data from over 75,000 active pilots sharing their location through SafeSky in real time. The result is that your portable ADS-B receiver for traffic awareness shows you aircraft that a radio-only device would never detect: the glider in the thermal ahead, the paramotor joining the circuit at your destination, the military helicopter with its transmitter off.
To access this internet-sourced data layer, SkyRecon uses either your smartphone's hotspot or, in the Data+ variant, a SIM card tray for your own data SIM, providing always-on connectivity independent of your handset. In areas without internet access, SkyRecon continues displaying locally received ADS-B traffic on its round 3.4-inch LCD screen as a standalone device.
SkyRecon is also a proud member of the ADS-L Coalition, supporting EASA's ongoing push for wider electronic conspicuity adoption. As that standard grows, it will further shrink the invisible traffic population for every GA pilot flying in European airspace.
Stop Flying with Half the Picture
The SafeSky Inside traffic layer (FLARM, FANET, OGN, community data, and more) flows directly into your existing EFB via GDL90 output. ForeFlight users see it on their ForeFlight chart. SkyDemon users see it on their SkyDemon map. The traffic is richer, but the interface is unchanged.
A portable ADS-B receiver for traffic awareness should show you everything that is airborne and electronically visible, not just the aircraft that share your radio standard. SafeSky Inside moves SkyRecon's picture from partial to genuinely comprehensive without adding complexity to your cockpit workflow.
For the full overview of SkyRecon's capabilities, including CO monitoring, EFB integration, and hardware specification, return to our guide on the best portable ADS-B receiver for general aviation.
Secure your SkyRecon today -- preorders open now with a EUR100 deposit.