Selection guide
Two axes or three: what actually changes on deck
The difference is not "better vs worse" — it is which axis carries the vessel's heel. A 2-axis mount covers elevation and azimuth and lets automatic skew handle polarization; a 3-axis mount adds a cross-level axis so the dish stays square to the satellite while the ship leans. Below is what that costs in weight, in elevation range and in the footprint you can hold.
What each axis does
A satellite appears to move across the sky as the vessel turns and travels. Elevation and azimuth are the two coordinates that point at it, and every stabilized TVRO drives both. A 2-axis platform therefore covers the geometry of pointing — but as the hull rolls, the dish does not only need to point at the satellite, it needs to stay rotated correctly around its own boresight. That is the third degree of freedom, and it is handled in two different ways.
The V Series solves it with automatic skew: polarization is rotated electrically or mechanically so the feed stays aligned with the satellite's polarization plane, while the platform keeps two axes of mechanical stabilization. The X Series adds a third mechanical axis — cross-level — so the antenna assembly stays level relative to the satellite even at large heel angles, and skew is automatic on top of that.
The numbers, side by side
Both families are specified for the same ship-motion envelope and the same tracking rate. What separates them is the geometry they can hold, the aperture they come in, and the weight that follows from it.
| Parameter | V Series (2-axis) | X Series (3-axis) |
|---|---|---|
| Stabilization | 2-axis + automatic skew | 3-axis + automatic skew |
| Elevation range | 0° to 90° | −5° to 115° |
| Cross-level range | not applicable (2-axis) | ±35° |
| Azimuth range | 0°–690° | 0°–690° |
| Ship motion | Roll ±25°, pitch ±15°, yaw ±8° @ 6 s period | same |
| Tracking rate | > 90°/s | > 90°/s |
| Aperture options | 33 / 45 / 60 / 75 cm | 64 / 85 / 105 cm |
| Weight | 5 / 12 / 20 / 32 kg | 37 / 80 / 125 kg |
| Minimum EIRP | 50 / 48 / 46–47 / 44 dBW | 46 / 43 / 41 dBW |
| Frequency | Ku 10.7–12.75 GHz; Ka dual band listed | Ku 10.7–12.75 GHz |
TVROVSAT catalogue, page 1 (V Series) and page 2 (X Series). Ranges are listed smallest to largest model.
Why the negative elevation matters
The X Series elevation range starts at −5°, the V Series at 0°. On a large ship the antenna sits high and the satellite is always above the horizon plane, so 0° is enough. On a small vessel — a fishing boat, a tender, a low-profile workboat — the radome can sit below the level of the deck edge or on a low mast, and at high latitudes a geostationary satellite can appear very close to the horizon. The ability to look slightly below the horizontal is what keeps the link alive in those positions.
The same logic applies to cross-level ±35°: a sailing or expedition vessel that heels continuously needs the dish to stay square while the hull is over, which is what the third axis provides. A displacement hull that rolls but comes back upright does not put the same demand on it.
What the third axis costs you
Weight is the honest trade. The largest 2-axis model (V7, 75 cm) weighs 32 kg; the smallest 3-axis model (X6, 64 cm) weighs 37 kg, and the X10 at 105 cm reaches 125 kg. That is a different mounting problem: a mast or hardtop that carries a 32 kg radome is not the same structure that carries 125 kg with the lever arm of a 105 cm dish.
Aperture buys margin, not magic. Minimum EIRP falls from 50 dBW on the smallest V model to 41 dBW on the X10 — that is the number that decides whether the antenna can hold a lock on a weak footprint. If your target satellite delivers 44 dBW over your route, a V7 (44 dBW) is at the edge and an X8 (43 dBW) sits comfortably inside it. The axis count is a geometry decision; the aperture is a link-budget decision. Both are in the same table for a reason.
A 2-axis V Series is the right call when
- The vessel is a displacement hull that rolls and returns — workboat, fishing vessel, tug, coastal ferry, small yacht
- Deck space and mast loading are tight, and the radome has to stay under roughly 75 cm
- The satellite is well above the horizon on your route, so 0° elevation is enough
- The footprint delivers 44 dBW or better, which the V7 covers
A 3-axis X Series is the right call when
- The vessel heels continuously or works at high latitude where the satellite sits low — sailing, expedition, long ocean passages
- You need 85 or 105 cm of aperture to hold a satellite at 41–43 dBW
- The antenna is mounted low relative to the deck edge, so −5° elevation is useful
- The structure can take 37–125 kg with the lever arm of a larger dish
Sources: TVROVSAT catalogue pages 1–3 (V Series, X Series, ACU table).
Buyer questions
2-axis vs 3-axis
Can a 2-axis antenna work on a sailing yacht?+−
It will track azimuth and elevation, but with no cross-level axis the dish geometry is tied to the hull's heel while automatic skew only corrects polarization. On a boat that spends long periods heeled, that is where a 3-axis platform earns its weight.
Is more aperture always better?+−
It lowers the minimum EIRP the antenna needs, which is real margin — but it also adds weight, wind load and mounting structure. The right size is the smallest aperture that holds your weakest satellite footprint with margin, not the largest that fits.
Do both families use the same ACU?+−
The catalogue documents one ACU family, Basic and Advanced, used across the antenna range. The Advanced unit adds webpage configuration, cloud data monitoring and vessel route tracking on top of manual setup.
What does "automatic skew" correct that the axes do not?+−
The axes point the dish; skew rotates the feed so its polarization plane matches the satellite. Without it, a linearly polarized signal loses part of its level as the vessel changes heading — which shows up as a slow fade rather than a lost lock.