 What is LNB Skew? LNB "skew" angle is the rotational position of an LNB on the dish arm. |
| All LNBs (except those used for receiving circular polarised signals) require their rotational angle (skew) to be set within certain limits in order to minimise errors in data received. Without proper measuring equipment, the simplest way to make the adjustment is by observing the default transponder "signal quality" and turning the LNB for maximum reading. (This can be done ONLY AFTER you are certain that the dish is aligned accurately on the correct satellite.) | 
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| A professional will use a spectrum analyser to set the "skew" so that the average signal levels of horizontally- and vertically-polarised transponders are equal. A good quality meter will provide an error number that will achieve the same object. As you won't have either, just look at the "signal quality" indication on your TV screen. The actual "skew angle" is dependent on the satellite and on your location and on the dish orientation with respect to vertical. Your dish must be mounted so that its pole or bracket is set accurately to the vertical, otherwise the angle will not be correct. |
| Sky LNBs come with a fixed setting "3" but it is correct only for dishes located in parts of England, southern Scotland and N.I. It is incorrect for most of Cornwall, Pembrokeshire, Scotland and Ireland. To adjust the skew, you will usually have to loosen a screw on the clamp bracket to allow the LNB to turn. Here's an old fashioned Sky LNB set to skew position "3". | 
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| More information about dish alignment. | |
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| Here's a later Sky LNB with the 1-2-3-4-5 markings. (Apply plenty of silicone grease to the spigot and adapter for ease of removal from the arm in the future.) Also be sure to fill the 'F' plug with silicone grease to prevent corrosion of the copper wires. 
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| If the LNB collar bracket (red arrow) allows any forward-backward movement, you can move the LNB to its optimum focal position, which will give the highest signal strength indication. (Most Sky LNBs have no adjustment but some other LNBs have.) |
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| Map indicating the optimum "skew" setting for a Sky LNB (or Freesat) that is marked with appropriate numbers. This map also applies to Freesat installations, since they use the same satellite position (Astra-2). Read more about LNB fitting. |
| How important is it to set the skew accurately? Where the signal is strong (e.g. London) it hardly matters at all if you are a few degrees out. However, in a weak signal area (e.g. Northern Scotland, southern Europe) it can matter a lot. The "signal quality" really needs to be better than 50% to ensure reliable reception in poor weather. Do you still have Signal Problems after setting the skew correctly?
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| Return to SatCure index page Copyright © 2012 Martin Pickering
Version 1.1 updated on August 13, 2012
This file may be downloaded for private and personal use but NO part of it may be published in any form without the prior permission of the author. Martin Pickering is a satellite TV expert who has been in the business since 1990. |
