Full Freeview on the Rowridge (Isle Of Wight, England) transmitter

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1:07 AM

Colin: Obviously try the "existing" vertically. Indeed, whilst there is perhaps nothing lost to try it horizontally, be mindful that vertically is expected to be better.

Could you receive before ?

Did you have to wait until 18th April to receive the Commercial ?

I'm not a professional aerial installer, but I use a aerial. It was sufficient to get solid on all channels before switchover.

However, after switchover I found that my Sony RDR-HXD870 froze for a few seconds every 15 or 30 minutes on the worst affected channels. With two other receivers connected to the same aerial as well, all tuned to the same channel, the others were solid and the Sony continued with occasional freezing.

I moved the aerial down the loft and replaced it and the problem continued. It was mounted on the L shaped bracket on one of the rafters.

The solution was to use a straight pole and mount it on the top of one of the joists so as to allow 2 or 3 feet between the back of the aerial and the sloping . Previously it was more like a foot with the L pole.

There is another loft aerial, which appears to be a shorter Philex SLx model to the one you have. This works solid even though it is also mounted with its rear within a foot of the rafters and felt. It has a massive reflector on the rear so I can only conclude that it screens against whatever the roof does to affect the signal.

Obviously different roof types affect the signal in different ways. Also the direction to the probably plays a part.

You might try sloping it upwards a bit, with the thinking that the signal is "sort of" coming from above.

I would be looking to whether it may be too much signal. I tried this with my own problem and it didn't make a scrap of difference, although I'm 25 miles from the transmitter so it's not likely to be the cause.

Try connecting the lead to the TV with only the centre conductor connected. So strip back the screening and put the centre core into the centre of the TV's aerial socket. Then see what you get on . It's crude but it should hopefully "loose" some signal if this is your problem.

Colin
9:02 AM

Dave:
many thanks for the. We have only moved here recently and the previously there looks like an ancient uhf...surprisingly this worked ok but didn't get , hence the attempt with the new one.
I will have another go at the weekend with your suggestions.

Colin's 4 posts GB flag

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3:31 PM

Colin: Let us know how it goes.

I can see the contours on the map and from the images they have trees on them which could be a problem. They may be a problem all the time or just at some times, such as when they're wet, blowing about or when they have leaves on. Or, having sorted the problem with , you may be lucky and never encounter poor .

Try to get C28 tuned in, even if this means taking the and moving it, perhaps on the first floor or even outside in the garden. Each time, do a manual tune on C28. Logically, it would seem a good assumption that the further away from the bottom of the decline you are the more chance you are of picking it up. Try moving in that direction (going into the garden if necessary). Whilst moving it, try and view the strength and of the other multiplexes to get an idea of where the best and worst spots are.

The COMs (25, 22 and 28) use a less robust of signal, so a poorer signal makes them more susceptible to break-up than the PSBs (24 and 27). I have no idea to what degree that might affect things, but maybe being mindful of this might identify "not-so-good-spots".

Different receivers have differing levels of functionality and usefulness for the DIY aerial installer. Some give little away, maybe having a single scale for both strength and quality. So look at the receivers you have and find the one or ones that give the most information and use it/them for your testing.

Once you have C28 tuned in and it has added the on it (Yesterday etc), then don't retune as the tuning is correct.

Try to logically discount things. So if the runs down from the to the lounge and you keep going down to the lounge to look at the set, then disconnect the cable from the aerial and attach a short piece to which you connect a TV to see what you get.

If you then get something on C28, keep it connected like that whilst you site your aerial to best effect. Then turn your attention to the seemingly faulty downlead. Maybe try the old aerial as well and see which works best.

I should point out that if you have a distribution amp for feeding multiple rooms, then disconnect this whilst you're trying to get your aerial to work. It could be a problem caused by the amp.

If you have a -head amp, then trying with and without and with varying levels of amplification (if there is such a setting) might be worth a try.

Always be mindful that you could have too much signal and be looking to the theory.

An aerial's in one direction comes about at the expense of sensitivity in other directions. So to have more gain, there is more loss of sensitivity in other directions. So a higher gain aerial tends to have a narrower angle of acceptance.

If you live within line of sight of the , but a long way away such that when the signal gets to you it is weak, then obviously gain on the narrow beam from the transmitter is what you want.

But the lower you live down a drop, the more you are trying to pick up a less focused signal. If the brow and the slope have trees on, then they will be moving about changing the signal. Thus an aerial with narrow acceptance angle may be what you don't want in such circumstances.

As I say, I'm not a professional but I've seen this explained and it makes sense.

I cannot say whether this is or is not of importance in your case. Clearly the fact that you are close to the transmitter helps more than if you had been further away.

Friday, 15 June 2012

JAMIE

_{sentiment_satisfied}Silver

5:08 PM
Portsmouth

COLIN -

Hi, I am a PROFESSIONAL INSTALLER RDI APPROVED

sometimes there has been ocassions when some locations will have a complete mux missing even though all others are OK.

RARE but possible.

You could be just one of the unlucky ones.

As I said before, try the in different locations as simply moving the aerial a few feet left or right, or even up and down can make a difference in how your is received.

This may be difficult if you are not using a meter which can show you the readings of the MUXS seperately.

GOOD LUCK

regards

Jamie Stevens
Jays Cabling

JAMIE's 207 posts GB flag

JAMIE's: J's Freeview map J's terrain plot J's frequency data J's Freeview Detailed Coverage

Saturday, 16 June 2012

John
12:09 PM
Southampton

Why are the strong placed on vertical transmissions when 90% odd of all aerials are horizontal?

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John's: J's Freeview map J's terrain plot J's frequency data J's Freeview Detailed Coverage

_{sentiment_very_satisfied}Platinum

1:53 PM

John: The short answer is shortage of (frequencies). And the fact that the Commercial ' coverage isn't as extensive as the Public Service ones.

To understand the long answer, it is necessary to explain that there are two types of services:

- Public Service Broadcaster (PSB) | These being BBC, Channel 3 (the various ITV1 regions in England), and Channel 5. The PSB multiplexes (signals) also carry ITV1+1, ITV2, Channel 4+1, E4, More 4 and the four HD services.

- Commercial (COM) | These carry other services like ITV3, Pick TV, Yesterday, Film 4 and Dave.

For a full list of what's carried on what, see DMOL Post-DSO Multiplex Channel Allocations
This page shows that there are three PSB multiplexes and three COMs. Each is carried on a single UHF channel; each single service used one UHF channel.

The design of the of transmitters means that PSBs are given the same coverage as the former four-channel analogue. The plan was for aerials that worked with analogue before to work for the PSBs.

There are 81 main and larger transmitters that carry all six multiplexes. The 1,000 or so other small relays are PSB-only. The COMs achieve about 90% coverage of the population, whereas the PSBs cover 98.5%.

The COMs don't have a "Public Service" obligation which is why they don't have the extensive coverage that the PSBs do. So no one who can receive the PSBs is "guaranteed" to receive the COMs.

In some cases, aerials may need to be replaced to receive COMs. Or in the case of viewers, they may need to adjust their aerials to vertical.

The horizontal signals from Rowridge are therefore primarily to ensure compatibility with horizontal aerials.

Due to the shortage of channels (frequencies) available, Rowridge's COMs use channels that are also used by other transmitters, including and (PSBs are not co-channel). These two transmitters are exclusively horizontal. Stockland's COMs are co-channel with those of Rowridge, but lower to its PSBs. So you can see that they have had to restrict the coverage of Stockland's COMs so as to prevent . Or to look at it another way, channels are reused by transmitters in much closer proximity that they would have been previously.

So fringe viewers on Stockland, for example, will only COMs intermittantly, or may have to spend money on a more sensitive , or may only be able to receive PSBs.

For the reason of these other horizontally polarised transmitters using the same channels, Rowridge's COMs have restricted power horizontally. That is, to protect against interference where Stockland and Crystal Palace overlap Rowridge.

The PSBs get the better channel allocations whereas COMs may get ones where they are restricted in coverage and in places where other transmitters prevent because they are co-channel.

Previously with analogue, each transmitter had four channels. With digital, the 81 most powerful transmitter require six. Plus there is the fact that the number of channels available is reduced due to the plan to sell of some for 4G mobile operators and some more being ringfenced for selling to three more COM licencees. If the channels set aside for future COMs had been used, then there would have been less clashes and less people who have to replace or adjust their aerials.

Sunday, 17 June 2012

Colin
9:39 AM

Dave and Jamie: thanks for the replies. I have tried a small length of wire in the tv, this gave good pics but with slightly reduced strength and . Having had time to investigate, I only receive channels 24 and 27, the psbs, in both hp and vp. Would this be due to my location to the south of , out of transmitting direction for the coms?, aside from my position behind a hill and trees? My next attempt will be to run a wire to the top of the hill for a direct view of Rowridge. I will let you know how I get on. Thanks again for the informative replies.

Colin's 4 posts GB flag

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10:19 PM

Colin: How did you get on with your wire to the top of the hill?

It is possible that the COMs don't broadcast to the south. Maybe they couldn't get international clearance for them to do so.

The of the transmitters is secret, unfortunately.

See here for a list of multiplexes (those with a bullet in the "E"/England column apply): DMOL Post-DSO Multiplex Channel Allocations

What I suggest you do is focus on one service from each. I usually look for the first in each:

PSB1 (BBC One) =
PSB2 (ITV1) =
PSB3 (BBC One HD) =
COM4 (ITV3) =
COM5 (Pick TV) =
COM6 (Yesterday) =

So for COM4, look at ITV3 if it is tuned in on your , or manually tune to C25 until you pick it up.

They installed a taller at for , so you could always go and ask if you can have a few sections of the old one to mount your aerial on.

Wednesday, 20 June 2012

charles hayter
9:25 AM
Verwood

bh31 7df we are getting beakup on only bbc chanels through the day but seems to clear up in the evening but not always, never had any trouble before the switch over.still have old ariel no trouble on any other perfect .we also have a in the .charles, verwood dorset

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charles's: ...

Mark Fletcher

_{sentiment_satisfied}Gold

6:04 PM
Barnsley

Charles Hayter,Verwood.
I would look up the posting below yours by on Wednesday 20 June 2012 at 2.27pm.That could be one possibility.
The other possibility you mentioned is the in the .Try bypassing this.