Freeview reception has changed?
From time to time people find that their Freeview box, integrated set (idTV) or Personal Video Recorder (PVR) has lost many channels without any apparent changes.
There are a number of factors to consider
Freeview is broadcast on digital multiplexes. This means that, once broken down into a stream of bits, each television channel is combined into a single transmission of 1s and 0s. This means that reception is of the multiplex first if this is lost it affects all the channels in the multiplex in the same way.The signal strength received by the box or TV for a particular multiplex from a given transmitter determines if the data can be received or not. So, a poor signal results in no data, an adequate signal in perfect data and a low signal in either none or all.
Poor digital signal levels do not result, as they do with old-fashioned analogue television, in a sub-standard picture or sound. Poor signals often result in a perfect data-stream, but are prone to periods of no reception. Sometimes this will be for hours, but can also be several times a minute when caused by induction from fridges, freezers, central heating systems, two-stroke scooters, baby monitors and so on.
If you have lost ALL your Freeview channels
First disconnect the aerial lead from the Freeview box or TV set and reconnect it and then follow this reset procedure to scan for channels again. If this does not result in services being restored, check the Freeview transmitters page to see if there are any engineering problems with your local transmitter.How to check all cables, connectors and aerials
The RF connectors need to be in very good condition to work. There are two general types:Factory-fitted connectors are very reliable as they cannot easily be taken apart, but they can be damaged by wear and tear. On the female-type the central section is often composed of two parts which can often be forced apart, resulting in a poor connection you can push them back together if this has happened with a pair of tweezers. On male connectors if the central pin is damaged, you will need a new cable. If there are any loose partials in the connector, remove them.
Another problem with these cables is that quite easy to sprain the connector at the back which causes little obvious external damage, but disconnects the internal connection. This happens often when a set-top box is pushed backwards into a cabinet.
Hand made cables can also suffer from similar problems to factory made ones and they are also prone to accidental damage from a cable being pulled. If such a connector is not firmly attached to the cable, the connector may need refitting.
Cables
Make a visual check of the cables. There are a few basic checks:If the cable has been slashed or cut, it will not be very effective or reliable. If such a cable is fitted externally, this can allow rainwater to enter the cable and this will reduce the signal levels.
You can easily damage an RF cable by crushing it, for example in a door. If the outside of the cable has a permanent kink in the cable or has been very tightly looped, this could be the site of damage.
Aerial
For reliable and effective Freeview reception, a rooftop aerial is required. It is hard to make a visual check of such an aerial without putting yourself in potential danger.You can make a visual check of the route between the aerial and the transmitter. Any form of obstruction will damage the digital signals. In particular trees coming into leaf, as these will leech the signal before it reaches your aerial. This applies to both trees adjacent to the aerial and at a distance.
Another common problem in cities is building work. A large crane will often change position many times during the day, and if this is between your aerial and the transmitter this can reduce the signal levels in an unpredictable way.
If your system uses a booster, the power may have failed. Check the fuse to the power to the booster.
Weather problems
There are two main weather problems that effect Freeview reception.The Inversion Effect: please see What is the Inversion Effect and why does it effect my Freeview TV reception?
Wind: high winds sometime can dislodge the aerial this results in a poor signal.
Rain: poor or old cables can fill with water and this results in a poor signal. If this happens, the cables will require replacement.
Help with Freeview, aerials?
Tuesday, 21 May 2024
C
Chris.SE5:00 AM
John Dennis:
Really (LCN17) is carried on the ArqA/COM5 multiplex and Great!TV (LCN50) is on the ArqB/COM6 multiplex. If you are missing those then you should also be missing others on each multiplex if this is totally due to reception problems.
Eg. also 11, 19, 31, 26, 40, 43 and others on ArqA plus 12, 25, 27, 34, 39 and others on ArqB.
Are those ones also missing?
As noted on the Darvel transmitter page, the transmitter is yet again subject to Planned Engineering. It has been so for many weeks this year apart from most of February. However this wouldn't be the explanation for those low Quality figures, but 75% signal strength shouldn't be a problem.
Your location has clear line of sight to Darvel unless you have any very local obstructions, such as are there any nearby trees directly on the line of sight - the direction the aerial is pointing? Or other things recently such as scaffolding or other new building?
Where is the aerial? Is it on the roof or in a loft? If the latter have you changed anything in the loft, or added things like solar panels?
During the Planned Engineering, transmission can be interrupted for periods of time, although usually short. I hope that you didn't try retuning when you had no signal or badly pixellated pictures!
You cannot tune to signals that are not there or cannot be decoded.
The usual result is to clear the correct tuning or possibly tune to another transmitter where reception may be poor and unreliable. In your location Black Hill is virtually on the same line-of-sight!
Check in your TV Tuning section, that you are correctly tuned to Darvel's UHF channels -
They are C22, C25, C28, C32, C34, C35 and possibly C31 that's in the multiplex order BBCA/PSB1, D3&4/PSB2, BBCB HD/PSB3, SDN/COM4, ArqA/COM5, ArqB/COM6 and possibly the Local Multiplex.
If you are correctly tuned, post back with some more detail, such as aerial location, do you have any amp/splitter to feed more than one TV, whether you've changes any electrical equipment in the house (possible sources of interference etc).
Are the Quality figures low on the BBC channels for example or is it just ArqA and ArqB?
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Steve Donaldson7:16 PM
John Dennis: This full list of Freeview programme channels is here:
Channel listings for Industry Professionals | Freeview
This indicates which multiplex (mux) each is carried on. The six main multiplexes are:
PSB1 = BBC A (BBC standard definition TV and BBC radio)
PSB2 = D3&4 (ITV1, Channel 4, Channel 5 and others)
PSB3 = BBC B (all HD channels)
COM4 = SDN
COM5 = Arq A
COM6 = Arq B
How is COM4 reception? Is the quality down on this channel? What about the three PSB channels?
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Wednesday, 25 September 2024
A
AJ Southam2:12 PM
I have a Panasonic HDD Recorder and LG TV both nearly 10 years old to receive my Freeview Signal via an external Aerial using the Rowridge Transmitter. The reception has been perfect and on Friday the Panasonic recorded a BBC1 HD programme , but come Saturday 21st September the HD channels BBcB had disappeared from both EPGs . I have not altered the wiring and have rescanned twice now . Any help please.
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StevensOnln13:08 PM
AJ Southam: There is currently planned engineering work taking place at Rowridge. Rescanning causes most TVs to delete their existing channel list before scanning again and listing the channels that are found at the time of the scan (some TVs do this automatically overnight), so any channels which aren't found won't be listed. Check for any loose cables or connections then rescan again periodically and the missing channels aren't being affected by engineering work.
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Thursday, 26 September 2024
C
Chris.SE2:02 AM
AJ Southam:
If you continue to have problems, post back with the details of the Signal Strength and Quality % figures for each multiplex's UHF channel as found in your LG TV's Tuning Section under Signal Test.
A full postcode would also help as we can then check predicted reception and check for possible interference from new/upgraded mobile phone masts.
Are the aerial rods (or squashed Xs) horizontal or vertical?
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