Home digital TV retuning advice
If your Sky box distribution system is suffering from a poor picture or patterning interference then your Sky box RF modulator will need retuning.
This guide also provides help to fix missing Freeview channels or wrong channel numbers caused by the addition of new terrestrial digital TV channels in the UK or changes to digital multiplexes (UHF channel allocations).
Many regional TV transmitters have undergone changes to digital TV channels as a result of Digital Switchover and in many cases this means a Sky box retune is needed to avoid interference.
The default UHF channel for a Sky box UHF modulator is Channel 68. Ch68 was chosen as it is least used across the UK for terrestrial digital or analogue TV services, but it does have disadvantages - since it's the highest UHF channel in the Ch21-Ch68 TV band allocation, it also suffers the highest coaxial cable signal losses.
This often leads to a poor Sky picture particularly where long cable runs are needed from the Sky box to the distribution amplifier. It is recommended that all Sky box distribution cabling utilises PF100 Digital TV/Satellite Coaxial Cable which is double screened coaxial cable to minimise losses. This type of coaxial cable has much lower signal loss and much better intereference immunity, leading to a much improved Sky picture on TV's fed by your Sky distribution amp (loft box).
Please refer to the retuning procedure for adjusting the Sky UHF modulator channel used by a Sky Digibox or Freeview Set Top Box to prevent patterning interference or a noisy (snowy) Sky picture. This will help to solve picture interference problems caused by Digital Switchover changes where your Sky box's assigned UHF modulator channel suffers interference from a re-assigned digital multiplex or weak analogue signal. Symptoms which indicate a Sky digibox retune is required include picture patterning or noise (causing a snowy Sky picture).
To adjust the UHF modulator channel of a Sky Digibox requires access to the hidden Sky Installer Menu. To enter installer mode, turn on the Sky box and press "Services" on the handset. Then press the following keys on the handset one after the other in quick succession:
"4" to enter "System Setup" then "0" then "1" then "Select". This will enter the "Installer Setup".
Then press "4" for RF Outlets to access the menu to adjust the UHF modulator RF channel number. The default channel number at Sky Digibox installation is 68 (the highest channel number). This can be rather problematic as higher channels have the most coaxial cable signal loss.
To get the best picture, try to choose a free UHF channel number which is as low as possible and away from any analogue or digital TV channels transmitted in your region. Enter a new UHF channel number with the Sky handset and save the changes by pressing "Select" before quitting the menu.
Refer to our Digital TV re-tuning procedure for help in finding the best UHF modulator channel for your Sky Digibox modulator.
On a new Sky+ HD box with the new EPG the key sequence is different to access the hidden Installer Setup menu: For Sky HD press 'Services' then '0' then '0' again then '1' then "Select". Then scroll right with the Sky handset and select the "RF Out" menu and configure the UHF modulator channel and RF Outlet Power Supply as required.
The RF Outlet Power Supply Option (when set 'On') applies DC power to the RF Out 2 socket on your Sky box for a loft distribution amplifier.
When selecting an RF Channel Number always pick a UHF channel number free from any digital or analogue TV services in your area. Enter the required UHF channel number with the Sky handset, then move down to "Save Settings" and press "Select" before quitting the menu.
I use Channel 52 or 56 in Newbury, but another UHF channel may be needed in your area! Read our Digital TV re-tuning procedure for help in finding a clear UHF TV channel suitable for your Sky Digibox modulator.
When in the Installer Setup menu, do not turn on the RF Outlet Power Supply unless you are using a Sky TV distribution amplifier or TV Link and Remote Eye connected to RF Outlet No. 2 which requires 12 volt power from the coaxial cable.
In mid January 2011 Freeview retuning is recommended in all areas of the UK in order to add new freeview channel ITV1+1 on Channel 33 and to correct the amended ITV2+1 channel number (now Freeview channel 27).
To carry out a digibox re-tune it is best to delete all channels in the 'Channel List' of your TV or Freeview box and then carry out a full 'Auto-tune' of 'Manual re-tune' to reinstall all available channels. On most equipment, retuning to add new Freeview channels can be done by using the handset to access the 'Edit Channel List' menu. Then selecting all channels in the Channel list using 'Select all' before deleting them with the 'Delete' option.
If you receive signals from more than one transmitter it may then be sensible to re-install your Freeview channels manually by entering the UHF channel numbers of each digital multiplex followed by a 'Manual Tune' or 'Manual Re-installation'. Refer to the instruction manual that came with your specific Freeview box or IDTV for details of how to do this or download retuning instructions for your specific equipment manufacturer from www.tvretune.co.uk.
To find your local digital TV transmitter and details of the Freeview lineup available in your area visit http://www.digitaluk.co.uk. The UHF multiplex channel numbers specific to your transmitter will be needed for manual set top box retuning. To find these enter your postcode and house number into Digital UK postcode checker then on on the results page, click on 'Find out more' (under 'Reception and channels' in the 'Aerial' row under 'Method of reception'), then click on the pink 'How do I re-tune' menu to reveal the UHF channels needed to re-tune the Freeview service from your local transmitter).
Common problems which arise when new Freeview channels like ITV1+1 are added by the broadcaster or the EPG channel numbers change include missing channels or wrong channel numbers affecting your set top box / TV or Freeview PVR. These often only come to light when the published channel numbers don't match the ones displayed on your TV or you no longer have access to one or more channels. These problems can be solved quickly using the above retuning advice.
Should you fail to receive all available Freeview channels you may need an TV aerial upgrade. Visit our Freeview reception page for help and advice to improve Freeview reception in weak signal areas or read our loft aerial installation guide if you are experiencing problems with an indoor aerial.
Before you can re-tune the UHF modulators used by your TV equipment to eliminate interference, it is necessary to identify free UHF TV channels which are not used by analogue or digital TV services in your area. You can then adjust the UHF modulator of your Sky Digibox, Freeview Box or VCR, to use these channels thus avoiding interference.
In the UK, TV frequencies are split into separate UHF TV channels the lowest UHF frequency being designated channel 21 and the highest channel 68. Nowadays, with many additional TV channels being used for Freeview DVB-T digital multiplexes, finding a clear UHF channel for your Sky Digibox or Freeview receiver UHF modulator can be a real challenge.
To assist, you first need to identify which UHF TV channels are used in your area for both digital and analogue TV services. You must then avoid these channels when adjusting the UHF modulator channel of any Sky Digibox, Freeview Set Top Box, PVR or Video Recorder. Start by obtaining all of the digital (DVB-T) and analogue TV channels used in your area by clicking here.
Then adjust the UHF channel modulator of your Freeview box, Sky Digibox, PVR and VCR to be at least two channels away from any analogue TV channel in your area and at least one channel away from any DVB-T digital TV multiplex. When adjustment is complete, check all analogue TV pictures and your VCR channel (often Channel 0 on your TV) are free from patterning interference with all set top boxes and peripherals powered on.
If TV patterning interference is still present on any TV channel after re-tuning, we recommend adjusting the UHF modulator to alternative, unused UHF channel number/s for your Sky Digibox, Freeview Set Top Box and Video.
Here in Newbury, Berkshire, our local TV transmitter is Hannington with reception also possible in favourable locations from Crystal Palace and Oxford. Therefore, the UHF modulator channel used for Freeview or Sky Digiboxinstallations around Newbury should be adjusted to avoid all of the UHF channel numbers listed below for the Hannington TV transmitter and depending on received signal levels the Crystal Palace and Oxford UHF channels may have to be avoided too.
If your get TV reception from the Oxford or Crystal Palace transmitter (London) you'll also need to avoid the analogue andDVB-T digital multiplex UHF channels used by whichever of these transmitters serves you, when retuning the UHF modulator channel for any Freeview box or Sky Digibox.
A complete list of all current UHF TV channels used for Freeview digital TV and analogue TV channels in Berkshire is givenbelow. A "D" suffix against a channel number indicates that it is used to transmit digital TV:-
Hannington TV Transmitter
35 (CH5 Analogue), 39 (BBC1 South Analogue), 40D, 41D, 42 (ITV1 Meridian-N Analogue), 43D, 44D, 45 (BBC2 South Analogue), 46D, 50D, 66 (CH4 South Analogue).
Crystal Palace TV Transmitter
22D, 23 (ITV1 Analogue), 25D, 26 (BBC1 London Analogue), 28D, 29D, 30 (CH4 London Analogue), 32D, 33 (BBC2 London Analogue), 34D, 37 (CH5 London Analogue).
Oxford TV Transmitter
29D, 34D, 47 (Six TV Oxford Analogue), 48D, 49 (CH5 Oxford Analogue), 51D, 52D, 53 (CH4 Oxford Analogue), 57 (BBC1 Oxford Analogue), 60 (ITV1 Oxford Analogue), 63 (BBC2 Oxford Analogue), 68D.
Older Video Recorders (VCR's)
It is imperative that the UHF modulator channel of a video recorder is adjusted to an unoccupied TV frequency, so as not to cause interference to your own analogue and digital TV reception. Some older video recorders have a screw adjustment to adjust the UHF modulator frequency. These older video recorders (VCR's) usually have a restriction on the range of UHF channels (frequencies) that can be tuned. Modulator adjustment is normally possible between about UHF CH31 and 40). Click here for an example UHF frequency adjustment on the back of a Sony video recorder. Similar adjustments are present on most old video recorders.
Set your TV to an unused TV channel in your area and then adjust the video recorder's UHF channel adjustment screw carefully with a small screwdriver to get an interference-free picture from the video recorder for tape playback. When the re-tuning is completed, check each of your analogue TV channels (BBC1, BBC2, ITV1, Channel 4 and Channel 5) for signs of patterning interference with the video recorder playing a pre-recorded tape. If interference is present on any analogue TV channel, slightly re-tune the video modulator adjustment screw to minimise it. Use the UHF channel adjustment screw to re-tune the video recorder UHF signal away from the frequencies used by analogue TV channels and digital TV multiplexes.
Recent Model Video Recorders (VCR's)
The UHF modulator channel adjustment on later video recorders is carried out with the video recorder handset using the on-screen installation menus with adjustment possible between Ch21 to Ch68. (see your particular video recorder manual for adjustment details). Again, pick a clear UHF channel for the modulator.
The information contained in this digital TV retuning guide is provided in good faith and is accurate to the best of our ability. No guarantees are offered concerning accuracy of information provided. Use this information entirely at your own risk. We cannot be held responsible for any personal injury or equipment damage arising directly or indirectly from using knowledge gained or advice given in this website.
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