Full Freeview on the Rowridge (Isle Of Wight, England) transmitter
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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.
Are there any planned engineering works or unexpected transmitter faults on the Rowridge (Isle Of Wight, England) mast?
Rowridge transmitter - Rowridge transmitter: Possible effect on TV reception week commencing 29/05/2023 Pixelation or flickering on some or all channels 
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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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Thursday, 21 February 2013
I live in Brighton but use Rowridge, I have lost Chs 25 and 28 for some weeks now. Are they are on reduced power I wonder ?
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Saturday, 23 February 2013
R
Roy Barton4:37 PM
Wimborne
For the last 48 hours the signal strength and signal quality as registered by or TV has been pretty steady at strength 98% to 99%. tiny fluctuations of a 1% or 2% occurs extremely rarely. The pictre reception is perfect. So keeping my fingers crossed the problem that has seemed to get worse slowly over a couple of months may have cleared. Possbily somebody at Freeview may have sorted something out.
If the problem has cleared on a permanent basis I am faced with the embarrassing possibility that the problem occured at the connectors on the aerial splitter/amp situated right close to the TV.
If it was a connector fault then it was a very weird one as the signal fluctuated on a very random basis between perfcet and zero with much of the time giving readings between the extremes. All this without any physical disturbance of the cabling.
One possibility is that the connector had some minor corrosion. Copper oxide can act as a semiconductor and possibly the non-linear effect of this coupled to the non-linear performance of the TV signal meter (hinted at by Mazbar)may have interacted with minor variations in the signal strength resulting in extreme results.
Who knows perhaps the problem will return and make the speculation above in this eamil turn out to be rubbish.
However whatever the facts are the observations I have made (and reception dropping out) are very weird and defy understanding.
One positive thing from this is that given the help of the postings above I have gained some understanding of what digital TV transmission is all about.
I don't understand how a channel can transmit simultaneously both horizonatlly and vertically. Vector analysis would suggest that the result would be something like 45 degrees polarisation. (But what would I know? )
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J
jb385:31 PM
Roy Barton: With regards to you having doubts about the problem having possibly been caused by your own installation, which of course has not been proven as yet, but this is the type of situation where its sometimes advisable to make some local enquiries for purposes of determining if the problem is being experienced elsewhere, as its by far the quickest way to confirm (or otherwise) if your installation is at fault or not.
As far as Vertical as well as Horizontal transmissions are concerned, its just simply the case that the transmitter output (via a matching unit) is connected to the radiating elements used for the two polarities involved, this just the reverse situation of a viewer receiving from two stations that radiate of different polarities, both the aerials being combined in a diplexer and fed to the receiver via one coax.
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K
KMJ,Derby6:35 PM
Roy Barton: The mention of 45 degrees polarisation reminded me that some local radio FM transmitters used to use slant polarisation in order to offer reception on both horizontal and vertical aerials. This was before FM transmissions were standardised to have horizontal and vertical components, now refered to as mixed polarisation.
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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 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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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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