Full Freeview on the Rowridge (Isle Of Wight, England) transmitter
 | Google Streetview |  | Google map |  | Bing map |  | Google Earth |  | 50.676,-1.369 or 50°40'35"N 1°22'7"W |  | PO30 4HT |
The symbol shows the location of the Rowridge (Isle Of Wight, England) transmitter which serves 620,000 homes. The bright green areas shown where the signal from this transmitter is strong, dark green areas are poorer signals. Those parts shown in yellow may have interference on the same frequency from other masts.
This transmitter has no current reported problems
The BBC and Digital UK report there are no faults or engineering work on the Rowridge (Isle Of Wight, England) transmitter._______
Digital television services are broadcast on a multiplexes (or Mux) where many stations occupy a single broadcast frequency, as shown below.
64QAM 8K 3/4 27.1Mb/s DVB-T MPEG2
DTG-12 QSPK 8K 3/4 8.0Mb/s DVB-T MPEG2
H/V: aerial position (horizontal or vertical)
Which Freeview channels does the Rowridge transmitter broadcast?
If you have any kind of Freeview fault, follow this Freeview reset procedure first.Digital television services are broadcast on a multiplexes (or Mux) where many stations occupy a single broadcast frequency, as shown below.
64QAM 8K 3/4 27.1Mb/s DVB-T MPEG2
DTG-12 QSPK 8K 3/4 8.0Mb/s DVB-T MPEG2
H/V: aerial position (horizontal or vertical)
Which BBC and ITV regional news can I watch from the Rowridge transmitter?
BBC South Today 1.3m homes 4.9%
from Southampton SO14 7PU, 26km north (354°)
to BBC South region - 39 masts.
ITV Meridian News 0.9m homes 3.6%
from Whiteley PO15 7AD, 24km north-northeast (20°)
to ITV Meridian (South Coast) region - 39 masts.
All of lunch, weekend and 50% evening news is shared with all of Meridian plus Oxford
Are there any self-help relays?
| Portsmouth Docks | Transposer | 2 km N city centre | 50 homes Estimate. Group of houses' |
How will the Rowridge (Isle Of Wight, England) transmission frequencies change over time?
| 1950s-80s | 1984-97 | 1997-98 | 1998-2012 | 2012-13 | 2 May 2018 | ||||
| VHF | A K T | A K T | A K T | A K T | W T | ||||
| C3 | BBCtvwaves | ||||||||
| C21 | C4waves | C4waves | C4waves | +BBCB | BBCB | ||||
| C22 | +ArqA | ArqA | |||||||
| C24 | BBC2waves | BBC2waves | BBC2waves | BBCA | BBCA | ||||
| C25 | SDN | SDN | |||||||
| C27 | ITVwaves | ITVwaves | ITVwaves | D3+4 | D3+4 | ||||
| C28 | ArqB | ArqB | |||||||
| C29 | LSO | ||||||||
| C31 | BBC1waves | BBC1waves | BBC1waves | com7 | |||||
| C37 | com8 | ||||||||
| C55tv_off | com7tv_off | ||||||||
| C56tv_off | COM8tv_off |
tv_off Being removed from Freeview (for 5G use) after November 2020 / June 2022 - more
Table shows multiplexes names see this article;
green background for transmission frequencies
Notes: + and - denote 166kHz offset; aerial group are shown as A B C/D E K W T
waves denotes analogue; digital switchover was 7 Mar 12 and 21 Mar 12.
How do the old analogue and currrent digital signal levels compare?
| Analogue 1-4 | 500kW | |
| PSB1||, PSB1≡, PSB2||, PSB2≡, PSB3||, PSB3≡ | (-4dB) 200kW | |
| COM4≡, COM4||, COM5≡, COM5||, COM6≡, COM6|| | (-10dB) 50kW | |
| com7≡ | (-13.1dB) 24.4kW | |
| Mux 1*, Mux 2*, Mux A*, Mux B*, Mux C*, Mux D* | (-14dB) 20kW | |
| com8≡ | (-14.3dB) 18.4kW | |
| LSO≡ | (-17dB) 10kW |
Local transmitter maps
Rowridge Freeview Rowridge DAB Rowridge TV region BBC South Meridian (South Coast micro region)Which companies have run the Channel 3 services in the Rowridge transmitter area
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Sunday, 24 February 2013
R
Roy Barton9:33 AM
Wimborne
Interesting comment by JB38. In the hypothetical case where two signals were combined from two aerials through a (perfect) diplexer, the output signal power would be the two added together. This would be dependent upon the two signals being perfectly in phase. It is likely that they would be in phase in the case put forward.
The above is a non-practical arrangement to illustrate adding signals together in a cable. However adding electromagnetic signals together in space is somewhat different. In space it is possible to have phase differences and also polarisation differences. If we assume that there are no phase differences in signals from an H aerial and V aerial we are left with polarisation angle differences. This is where vector summing comes in. Two equal signals at 90 degrees add together should give a single signal at 45 degrees. Presumably the power in the resulting signal would be the sum of the two added together.
I dont think the above comments have anything to with my problem (hopefully now gone away because I wiggled the connectors a bit). However there is a chance that I have misunderstood the H & V polarisation issue and anybody reading this might put me right.
One thing about polarisation if we were talking about visible light, polarisation would effect reflections from surfaces. I expect polarisation of TV signals might effect differences in reflection off pylons, clouds etc.
As I finish this email I see that the signal strength/quality meter on the Sharp TV is still steady at 98%/99% and has been that for three days. Channel 28 now shows the same result as all the other transmission channels. (The screen presentation for signal quality on this TV is excellent but I do accept that it probably not very linear but it serves a purpose very well.)
Initially I was very confused. There are Transmission Channel numbers and Entertainment Channel numbers. (Not many people differentiate.)
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Roy's: mapR's Freeview map terrainR's terrain plot wavesR's frequency data R's Freeview Detailed Coverage
Roy Barton: You might be interested in MIMO - Will MIMO bring HD to Freeview? | High definition | ukfree.tv - 10 years of independent, free digital TV advice ...
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R
Roy Barton11:33 AM
Wimborne
Thanks Briantist. That MIMO link explains all. I did not realise that the signals on H and V were different. I now understand, different signals on H and V keeps them separate. (Therefore effectively doubling the bandwidth.)
With the V & H co-frequency concept it is easy to see how you can can obtain 100% signal strength and 0% quality. (IE the two polarisations interfere perfectly with each other.)
I can see the problem, if the receiving aerial is not perfectly H or V then there is potential for the different signals operating on the same wavelength to interfere. Worse still any reflectors such as pylons might change the polarisation (?) and that would result in cross channel interference.
I am surprised that mixing H & V on the same transmitter works as well as it does on the fringes.
I wonder if the H & V divide explains why my BBC HD channel changed from 51 to 101 when I retuned? Before and after I got perfect signal quality and pictures on BBC HD (and all the other entertainment channels other than those on transmission channel 28) Is BBC HD on channel 51 in H and 101 in V ???
The subject gets clearer every post. (But there is still lots to mystify.
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R
Roy Barton11:40 AM
Wimborne
Given what I wrote above, I can see it would not be a good idea to use a diplexer to combine signals from an H aerial with that from a V aerial. A switch would be the thing to use. (Nobody ever suggested that this would be a good thing to do.)
The more I think about it it seems that my H aerial may also pick up V signals as well. If that is the case I wonder what has happenned in the last few days to stop this happening. Perhaps the H and V signals have been made identical???
I could get paranoid over this !!!
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ROY BARTON-
There is no reason to combine a HP and VP signal, although they are received differently they are outputting reception on exactly the same UHF settings.
Thus all you will be actually doing is combining 2 identical signals.
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jamie's: mapJ's Freeview map terrainJ's terrain plot wavesJ's frequency data J's Freeview Detailed Coverage
J
jb387:51 PM
Roy Barton: With regards to the latter part of my reply and where I gave an example of a reverse situation to transmission involving the reception of H & V polarised signals from two aerials being combined in a diplexer and with reference to this in relation to the first paragraph of your latest posting, I did actually say >> a viewer receiving from "two" stations radiating on different polarities << and not two aerials of differing polarities being diplexed when receiving from the same bi-polarity station, something which I feel would be a pointless exercise anyway.
It has to be appreciated that when dealing with RF signals in any frequency band under that of microwave that "nothing" is exact once the signals have travelled via airspace, and so have to be looked at in a somewhat different way to that as though they were still contained "within" a transmitter station and being carried via trunking or cabling, as once an RF signal has left the mast this is where theory and practice generally starts to part company and elements of educated guesswork is the order of the day in attempting to solve any reception problem, but of course based on knowledge of the range of variables that is likely to apply, as the problem with remote diagnosing of reception difficulties is that the only way of assessing the situation is by feedback supplied by the viewer and so the more info supplied the better!
That said though, nothing can really beat an on site visit armed with a quality signal meter and a test aerial of the medium sized log periodic type so that the levels indicated are not being biased by the characteristics of the aerial, as well as it being beneficial for other bits and pieces to be at hand to either boost or reduce the signal level dependant on the location in relation to that of the transmitter, as a number of physical checks can be carried out on an installation in the first stages of an on site visit that cannot really be done without exceptionally lengthy two way "questions and answers" postings being involved.
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J
jb387:57 PM
Roy Barton: Just noticed that Jamie has made a posting earlier on regarding the subject of polarity, me having likewise composed a reply earlier on elsewhere then copied and pasted it into the sites reply box "without" having checked first.
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R
Roy Barton8:33 PM
Wimborne
Roy Barton:
If as Jamie says the V and H signals are identical then they add up to a signal at 45 degress polarisation. Is that right?
If that is the case then I can't really see the point... unless it just a convenient way of getting a large signal that has V and H components.
Possibly a higher power from an transmitter antenna at 45 degrees migh be impractical.
I wonder what an omnidirectional H antenna looks like?
Probably the complexity of a omnidirectional aerial at 45 degrees makes it easier to have separate V and H ???
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R
Roy Barton10:28 PM
Wimborne
To JB38. I too missed your posts when I replied to Jamie. Actually I did understand that you were being hypothetical in regard to combining signals. Your diplexing hypothesis triggered the thoughts I had on how H and V transmissions might interfere with each other if an aerial picked up both polarisations. With every post I get a better understanding.
We have just had another day of perfect reception on all channels. At this rate I won't have to dig out the satellite kit that purchased more than year ago and have not unpacked yet.
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Monday, 25 February 2013
J
jb389:18 PM
Roy Barton: I don't think that Jamie was referring to anything connected to signal strength but more the case of the technical characteristics of the actual signals themselves being identical from both aerials, which of course they are, although problems can still be experienced as referred to in the next paragraph.
Although I am not privy to the details of the aerial set up at Rowridge, the reason for the high power radiating on vertical polarity is to avoid the possibility it causing interference to distant stations and not connected in anyway to the station providing some form of slant polarisation, because as far as using an H and V polarised aerial diplexed together to receive signals from the Rowridge mast is concerned this type of thing is really a non starter, because rather than provide the best of both worlds its liable to be the opposite by it creating the potential for possible phase clash problems to occur in locations where the horizontal signal is received at a reasonably high level, viewers at distances being somewhat better off because of the horizontal component being low.
The only type of situation where a pair of identical aerials facing the same transmitter is capable of giving great results is when they are arranged as a phased pair, the setting up of same really being outwith the domain of most (excl engineers) except the most dedicated enthusiast armed with a high quality signal meter, as it takes the utmost precision (as well as a good deal of patience!) to set up this type of system otherwise no advantage whatsoever is gained, plus even when perfectly set up the advantage can be lost if the signals being received are corrupted by ground reflections etc which unbalances the system.
Of course this type of set up is used more for killing off a signal that's not wanted in favour of the one that is.
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