DiSEqC Motor Positioning: USALS vs DiSEqC 1.2
If you have a motorised dish, you choose between two ways to tell it where to point: USALS and DiSEqC 1.2. They do the same job differently.
USALS: Automatic
USALS (Universal Satellite Automatic Location System) calculates the motor position for any satellite once you enter your own latitude and longitude. Select a satellite in the list and the motor drives there by itself.
DiSEqC 1.2: Manual
DiSEqC 1.2 requires you to move the motor to each satellite manually, peak the signal, and store that position. You build a position library yourself.
Which Is Better?
- USALS: faster, automatic, great once calibrated.
- DiSEqC 1.2: more hands-on, useful if USALS is unavailable or you want exact manual control.
Setting Up USALS
- Enter your latitude and longitude accurately.
- Pick a reference satellite due south.
- Peak the reference satellite.
- Test east and west satellites.
When to Use DiSEqC 1.2
If your receiver does not support USALS, or if you want to fine-tune each stored position, use 1.2. It is also useful if USALS has drifted after the mount was knocked.
Calibration Matters
USALS is only as good as your mount. If the pole is not vertical or the mount is not due south, USALS will command the motor to the mathematically correct but physically wrong spot.
Mixing Both
Many receivers let you use USALS as the default, then fine-store a position with DiSEqC 1.2 when a satellite is slightly off.
USALS is the modern, automatic choice; DiSEqC 1.2 is the manual fallback. Get the mount right and USALS just works.
