Generation is a family name, not a frequency
2G is second-generation mobile technology, in Switzerland mainly GSM voice and text messaging. 3G, also called UMTS, brought practical mobile data. 4G, usually LTE, made packet data the primary service. 5G, or NR (New Radio), adds new radio technology, more flexible spectrum use and lower latency. The generations are technology families: the same frequency can carry different generations in different countries or at different times, and a tower can run several generations at once.
A common set of assignments in Europe looks like this: 2G on 900 and 1800 MHz, 3G on 2100 MHz (and 900 for coverage), 4G on 800, 900, 1800, 2100 and 2600 MHz, and 5G on 700 MHz, 1.4 GHz and 3.5 GHz. Treat it as typical rather than fixed — 900 MHz has carried 2G, 3G and 4G in turn, and 3.5 GHz is now the main European 5G mid-band.
How to read names such as LTE, NR, n78 and 800 MHz
LTE is the technical name for 4G radio access, NR the one for 5G. A number such as 800 MHz is a frequency: lower frequencies generally travel farther and penetrate obstacles better, while higher frequencies offer wider channels and more capacity. A label such as n78 is a 5G band designation, not a signal-strength score.
Band, carrier and frequency
A band is a defined range of frequencies. An operator may use several bands at one site. A carrier is an actual configured channel within a band. Frequency alone does not determine exposure: power, antenna pattern, distance, height, terrain, buildings and network activity all matter, which is exactly why this map models the geometry instead of colouring by band.
Site, sector, cell and antenna panel
A site is a physical location — a mast, a rooftop, a church tower. A site normally has several sectors pointing in different directions. A cell is the coverage area of a sector with a particular radio configuration, and one sector can serve several technologies, bands or carriers. An antenna panel is the physical radiating equipment. That is why a site count is much smaller than a sector or cell count: the 22,482 sites in the register behind this map correspond to far more individual radio cells.
Azimuth, beamwidth and tilt
Azimuth is the horizontal direction of the antenna, measured clockwise from north: 0° north, 90° east, 180° south, 270° west. Horizontal beamwidth is the angular width of the main lobe, quoted between the half-power points. For the outdoor macro panels used in Switzerland the usual figure is 65° — the value in the standard 3GPP sector model — with 90° for some wider panels and 33–45° for the narrow high-capacity ones. That half-power figure is often mistaken for the width of the whole footprint. A sector keeps radiating well past its half-power points, and a site is planned with three sectors to a mast precisely because each one covers about a third of the circle: the 120° that gets quoted is that arc, not the panel's width at half power. This map therefore models every fan over the whole of that arc: the field falls from full strength on the boresight, through a half-power point about 30° either side of it, to the panel's side-lobe floor at 60° — a twentieth of the peak gain, which is the standard 3GPP figure and what a real panel has in the direction of the arc's cut. What is drawn is the contour of that field, so a fan's base is the whole 120° wherever the field still reaches the threshold at the cut, and closes inside it only when a flank's own peak falls below the threshold first — which is what a raised Signal threshold does. What it never does is end on a cut edge: it closes on the contour, as a drop rather than a wedge. What a real panel also radiates faintly behind itself is left out of both the drawing and the model here, because a small blob drawn behind every mast reads as part of the fan. No free source publishes the real panel figure, so 65° is assumed, and the reference map draws every beam at a flat 60°. Down-tilt angles the beam below the horizon so it illuminates the ground rather than the distance, which is why standing directly under a mast is usually a weak position. A fan on a map is a diagram of that intended direction, not a photograph of the field, and energy does not stop exactly at its edges.
A note on how the fans are drawn, because it is easy to read too much into an outline. Each fan's amber is the model's own estimate at each point, so the shade thins with distance; the one-pixel line on its edge follows that same curve. Where two edges cross, the crossing is drawn at a quarter strength rather than piling up into black, so a mesh of overlapping fans can still be read one edge at a time, and the lines are drawn under the mast dots so a dot standing on a contour is never cut in half by it. An edge is still a contour of a model, not a boundary of anything physical.
Power, ERP, EIRP and MIMO
ERP and EIRP are effective radiated power figures that already include antenna gain, but they use different reference conventions, so they are not interchangeable without checking the definition. A BAKOM class such as "up to 5 000 W" describes a permitted installation category, not a value at your location. MIMO means multiple-input, multiple-output: several antenna paths improve capacity and reliability. A label such as 16×16 describes radio paths, not sixteen times the exposure, and adaptive 5G systems change their beams and scheduling over time, which is why a snapshot model is an upper bound rather than a schedule.
Units used in the map
µW/m² is power density. V/m is electric-field strength; in the far-field plane-wave approximation S = E²/377 with S in W/m². dBµV/m is field strength on a logarithmic scale referenced to 1 µV/m. dBm is received power referenced to 1 mW, which cannot be inferred from ambient power density without receiver and antenna assumptions. A bare "dB" means nothing without a stated reference.
What the generations do not tell you
Generation labels do not equal field strength, speed, exposure or health risk. A nearby low-power small cell can produce a very different local field from a distant high-power macro site. The map therefore keeps the technology filter separate from the modelled magnitude, and keeps the threshold — the level at which a fan stops being drawn — as a display setting rather than a claim about safety.
Short history, without the nostalgia
Digital GSM services launched in Switzerland in the 1990s. UMTS/3G followed around the turn of the millennium and expanded mobile data. LTE/4G deployment began in the 2010s and became the main mobile broadband layer, and 3G was progressively switched off during the 2020s. Commercial 5G began in Switzerland in 2019, first on existing low and mid-band spectrum and later on additional allocations, alongside the introduction of the adaptive antenna systems that the 3GPP standards allow at 3.5 GHz.