The F/D is the ratio of the dish focal length to the dish diameter. The horn of the LNB is designed to correctly receive signals bouncing off the dish, but not receive noise spilling over from outside the dish. Imagine you are shining a torch at a dish. If you stand too close to the dish, there will be a circle of light in the centre, but if you stand too far away, you will be illuminating the dish and the wall behind the dish.

When the LNB is situated at the focal point of the dish, a correct feed horn is designed to only illuminate the dish and no more or less. This angle of illumination is described by the F/D, and Invacom LNBs with integrated feed horns are designed for dishes with an F/D of 0.55 - 0.65.

The signal level meter only gives an indication of the signal level, not the signal quality. The important parameter is the C/N or BER, which is not indicated on the level meter. Many cheaper LNBs have a gain which is above the level specified by Astra. This can cause some receivers to give a poor picture, although they give a high reading on the signal level meter

Everyone knows that noise figure is important for an LNB, but in your instance, the isolation of the LNB will be just as important. This is because the very strong signals on the satellite can interfere with the very weak signals that you are wanting to see. The strong signals act as noise, so reducing the C/N.

Most people are finding that the Invacom QDF-031, used with a good quality feed horn matched to the dish, is the best performing combination for these areas, and outperforms other people's LNBs with much larger dishes.

This scale is for the skew adjustment of the LNB. LNB rotation allows for the affects of where you are situated on the planet.

Vertical and horizontal signals from, for instance the Astra satellites are nominally in the zero position in say Germany yet in the UK they are offset by 7.5°. This is called the “skew angle” and it is achieved by rotating the LNB clockwise when looking at the dish. This angle varies with longitude not latitude and you should be able to obtain the skew settings for your location from the satellite operator or maybe even from their website.

Please note that this skew may well vary from satellite to satellite and if you have a motorised dish it may well have a “motorised skew adjust” as well as a dish position adjust.

This is the same for all LNBs, and satellite reception generally where you want to line up the LNB with the actual orientation of the vertical and horizontal polarisation’s coming from the satellite.

If the unit is not in the optimum skew position then performance can be effected, although you may still be able to receive pictures - this will depend on the signal you are trying to receive (i.e. skew is more important for weaker signals).

Yes it can be. The step will have little affect on the loss, however it can degrade the cross polar performance of the dish/LNB combination. If you are trying to receive weak signals from a satellite that also has strong signals, the cross polar isolation is important.

The DSS channels from DirecTV or Dish networks are circular polarised signals. They cannot be received with our LNBs. However, many Free To Air (FTA) channels are linear polarised, and our LNBs are ideal for these.