The reference condition: line of sight
Every range figure on this site is a line-of-sight (LOS) reference value. That means unobstructed visual path, a substantially clear first Fresnel zone, and reasonable antenna installations on both ends. The number exists so models can be compared on equal footing — it is a ceiling under good conditions, not a promise for yours.
A useful sanity check: at 100 km, radio horizon alone puts real constraints on how high both ends must be. When a mission plan assumes the datasheet number at low altitude, the plan is wrong before the radio is even powered.
Altitude and the geometry of 'air-to-ground'
Air-to-ground range grows with altitude because a higher aircraft clears terrain and shortens the obstructed part of the path. This is why the catalog separates air-to-ground from ground-to-ground rows: the same radio does very different distances in the two geometries.
Ground-to-ground at long range needs mast height on at least one end. Budget for it explicitly, or re-scope the distance.
Antennas: the highest-leverage hardware
Antenna choice and placement usually move real-world range more than any settings change. On the aircraft: keep the antenna clear of carbon structures, batteries, and payload metal, with the radiation pattern matching the flight attitude. On the ground: gain and height pay directly.
Coax runs cost you twice — in loss and in weight. Keep them short and matched.
Power, band, and data rate
Transmit power helps, but it is regulated per band and market, and it is the least efficient lever: doubling range by power alone means quadrupling it. The long-range models in the catalog reach their class with legal power levels by combining band choice (sub-GHz to 1.7 GHz propagates better than 2.4 GHz), modulation, and antenna gain.
Data rate is part of the same budget: links step down modulation to hold the connection as margin shrinks, so effective throughput at the far end of the quoted range is well below the peak figure.
Interference, hopping, and the environment
In crowded spectrum, the margin you planned can disappear into someone else's transmission. The FrequencyHopping series exists for this: it hops across the band to keep the link alive where a fixed-frequency link would degrade.
Foliage, rain, and urban clutter each take their share. Short-range waterproof models quoting 1–5 km are honest about being short-range — their figures carry the same LOS condition as the 100 km units.
Turning this into a test plan
Validate range where you will operate: same altitude profile, same ground installation, same band. Measure at decreasing distance and record where modulation steps down — that number, not the datasheet, is your mission range.
The RFQ sample path exists for exactly this: order a sample pair, test on your platform, then scale.
