All posts by Dave Lindsay
Below are all of Dave Lindsay's postings, with the most recent are at the bottom of the page.
G England: Unless your TV was tuned incorrectly in the first place (i.e. to the wrong transmitter) retuning is only ever going yield negative or neutral results. What you are probably doing is wiping everything that's stored in the hope of picking it up again!
I suggest that you contact at800 which is the company set up by the mobile operators and charged with alleviating reception issues caused by 4G services operating in the 800MHz band. Midhurst uses channels which are just below 800MHz which could perhaps make it more susceptible than Rowridge (Isle of Wight) which uses channels at the lower end of the band. at800 will be able to confirm whether you may be suffering from 4G interference or not.
You may need a filter fitting to the aerial system, assuming that the installer didn't filter it as a matter of course. Also, you might consider switching back to Rowridge which got a taller mast for switchover. I guess if you're anything but Rowridge in the Portsmouth area then you must be unlucky.
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G England: at800's phone number is here:
Contact us | Advice or general enquiries | at800
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G England: I would add that if you can receive from Rowridge then you may be able to get the new quasi-national HD services, these not broadcast by Midhurst. These are multiplexes COM7 and COM8 and carry BBC Four HD, BBC News HD, Channel 4+1 HD and others. A full list of Freeview services by multiplex is here:
Digital UK Industry - Channel listings
On that page you can click "Mux" to order by multiplex, so as to see which services are on COM7 and COM8. These services will only be available with Freeview HD (DVB-T2) receivers, even those which are standard definition. You may also be able to receive That's Solent, although it's signal is more restricted than the rest, and therefore not as strong.
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Linda Mann: No engineering work is indicated by Digital UK as taking place at the Angus transmitter.
If you reside in a block with a shared aerial system and the neighbours you refer to also use this system then the problem could be a fault with the system. Therefore you will need to notify the party responsible for it.
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DAVID: I don't know whether you're aware, but you could potentially require a different aerial for good reception of COM7 and COM8. This is because they are out-of-group as far as Group C/D aerials go. They are on UHF channels 31 and 37 respectively.
Further explanation:
Aerials, TV Aerial and Digital Aerial
They are also, according to Digital UK, on around a quarter of the power of the others, although at your location this would be unlikely to be an issue.
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DAVID: Digital UK publishes engineering works here:
www.digitaluk.co.uk/help_and_advice/engineering_works
Winter Hill is "Possible weak signal" so this could be the cause of your difficulty.
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David Monk: Having confirmed that you are indeed tuned to Bromsgrove for BBC One by checking that the tuned UHF channel number on the signal strength screen is 26, then too high a signal level could be the cause. Fit some attenuation and/or reduce amplification level:
Freeview signals: too much of a good thing is bad for you
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David Monk: If the signal level varies as the cable is moved then this could be because of an issue with the cable or plug or socket, this sort of problem being much easier to observe with analogue.
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Wednesday 27 May 2015 11:22AM
A Peapell: If interference from 4G signals is suspected then the course of action should be to call at800 as this will ascertain whether it could be the case or not. They will do a look-up based on postcode and give an immediate answer.
As the issue occurs during the warmer part of the year and it affects a number of properties then I would suggest it's likely to be caused by vegetation, for which there is nothing you can do, other than perhaps raising the height of your aerial.
Looking at Streetview, Folly Fields is on a slope and I can see trees in the way in the direction of Stockland Hill.
Now to look further afield. Here is a terrain plot from your location to the Stockland Hill transmitter:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
You may have clear line-of-sight at 23 miles. However, there are two peaks around 10 to 11 miles out which, although they don't obstruct line-of-sight, they are within the first Fresnel zone. The first Fresnel zone is shown on the plot and is between the straight yellow line and the purple one.
Anything which changes in the zone could potentially change the reception. Clicking a point on the plot takes one to a map indicating the point. These points are Warren Hill and St Rayn Hill, adjacent to the A30 as it runs between Crewkerne and Chard. There are trees on the former.
Signals travel in straight lines. When a signal passes through an object it gets diffracted, like how water diffracts light. Therefore if the object that is diffracting changes, the degree of diffraction may change. This could the cause of your difficulty.
Different frequencies travel differently as they are affected in different ways and to different degrees. The only way they would all travel exactly the same and therefore arrive at the receiving location exactly the same (all good or all iffy) is if there were absolutely nothing around, no objects, no ground and no air (a vacuum). As soon as you introduce these things you bring in variables whose effect varies by frequency.