Full Freeview on the Rowridge (Isle Of Wight, England) transmitter
Brian Butterworth first published this on - UK Free TV
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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Wednesday, 16 January 2013
Christopher Martin James: The existing aerial should be fine (assuming it's not damaged of course).
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Friday, 15 February 2013
Idris Martin
10:08 PM
10:08 PM
Hi
I live in Weymouth & have fitted a high gain vertically polorised ariel with mast head booster set up by compass bearing then fine tuned with the signal strength meter in the tv's menu.
However,the ststions on multiplex channel 22 keep breaking up, signal strength ok, but quality poor except on a sunny day when it is ok.
Can somebody explain why the other multiplex channels ore ok but not channel 22.
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Idris Martin: Because different frequencies are affected by objects in the path to differing degrees. Different frequencies radiate slightly differently from the transmitter.
You have a quality issue. The fact that it is OK on a sunny day suggests that there is vegetation somewhere in the path.
The terrain plot shows that the Purbeck Hills are in the way and so you have no where near line of sight. For that reason I think that a high-gain aerial is likely not to be the best device.
The higher the gain, the narrower the acceptance "beam". As you aren't anywhere near line of sight, you don't have anything to aim at. Rather, your objective is to pick up what you can.
As digital reception requires good quality (digits intact) a wider acceptance angle could perhaps give better results. It stands to reason that if the quality of the signal across a wider angle is better than across a narrower one then reception is better, even though a lower gain aerial has been used. You can increase the signal strength with an amplifier, but you can't repair its quality.
If it is a wideband high-gain aerial then it isn't "high" gain on the channels you are trying to receive as the gain of wideband yagi aerials drops off on lower channels.
As you have no where near line of sight then it might be worth trying turning the aerial a bit to see if it improves it.
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Saturday, 16 February 2013
R
Roy Barton3:08 PM
Wimborne
For years we had perfect reception at BH21 7BT. Over the last few months it has degraded. I recently rescanned all the channels and it was puzzling why BBC1HD should have moved from ch 50 to ch101. But tht is trivial compared to our real problem. As a qualified electronics engineer I can't understand why signal strength and quality for BBC on Channel 24 is 99% but signal strength of Film4 on channel 28 is almost non existent on a good day as measured by our sharp TV signal strnegth is high but n a bad day quality is down to 1% or no signal at all. I have advice that we should rotate our aerial so that is is Vertical polarisation. We have not tried it yet. WE are confused as the UKfree.tv website indicates that Rowridge is H. But there are clues that it might be also V. Any info on this is very confusing, probably because some info on your website is out of date.
Please clarify. Should we continue pointing at rowridge and rotate our aerial through 90 degrees so the dipoles are vertical? I guess we should be using a type A aerial. Would you confirm that a wideband aerial is not to be recommended for our location.
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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: The short answer is yes, rotate your aerial for vertical polarisation with Rowridge; there isn't, generally, a requirement to replace the aerial. The information at the top of this page is correct and says that each multiplex is broadcast horizontally and vertically.
The gain (sensitivity) of yagi aerials drops on lower channels. A wideband yagi is a greater compromise than a Group one as by the time you get down to Group A channels the gain is low. Manufacturers will quote the gain on the highest channel which is likely to be not what you're using it for. Rowridge is all Group A, so for that reason if you use a yagi then use a Group A one. For example gain curves that illustrate the point, see:
Gain (curves), Again
Above it does say "To receive Freeview from the Rowridge transmitter you will require an aerial of group A positioned horizontally." I will alert the site administrator to see if it can be changed.
The longer explanation: There are the PSB (Public Service) channels and there are the COM (Commercial) channels. The COMs don't have as extensive a coverage as the PSBs. This is due mainly to the fact that small relays don't carry them, but there will also be a few who won't get them reliably even though they use a transmitter that broadcasts them.
Basically, the PSB-network is designed to serve all areas that the former four-channel analogue network did and without requirement for existing aerials to be adjusted or replaced. The COM transmitters fit in where they can and in some cases require a replacement aerial, or in the case of Rowridge, vertical polarisation may be beneficial.
Rowridge broadcasts horizontally so as to be backward-compatible with existing aerials.
Because the COM channels fit in where they can, the channels that are used for them are reused by other transmitters in closer proximity than those of the PSB channels. Rowridge's COMs are co-channel with those of Stockland Hill's in the west and Crystal Palace's in the east. This is the reason that Rowridge's COMs are effectively restricted power horizontally; it's so they don't spread as far. Turning your aerial for vertical polarisation will increase the "rejection" of the unwanted Stockland signals (which are only horizontal).
Vertical polarisation may also reduce co-channel interference during lift conditions. Like the UK, France uses horizontal polarisation for high-power transmitters. (Rowridge being the one exception.)
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R
Roy Barton11:24 PM
Wimborne
John Lindsay. Thank you for your answer. Can I assume that a wide band aerial would be a definite bad choice?. (I bought one just today **** )
I also purchased a Labgear aerial amplifier. In the blurb it states it is for terrestial digital TV DTT and radio T-DAB and no mention of DVB-T. Is it safe to assume that a MSA111 would not degrade the signal in any way. (Other than when it might be overloaded) ?
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Roy's: mapR's Freeview map terrainR's terrain plot wavesR's frequency data R's Freeview Detailed Coverage
Sunday, 17 February 2013
Roy Barton: A yagi wideband is not a good idea for a Group A transmitter.
Log periodic aerials have very flat gain curves and therefore the same issue does not apply; they are fine. See:
Rowridge Transmitter
Using the aerial amplifier is fine. It needs to be as close to the aerial as possible because it will be amplifying the noise picked up in the aerial lead, which is what you don't want (poorer snr). See:
Television Aerial Boosters / Amplifiers, Splitters, Diplexers & Triplexers
If you have a Group A aerial, then you should re-orientate it for vertical polarisation. A wideband aerial isn't necessary (over that of a Group A one) because all of Rowridge's channels are within Group A.
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Roy Barton: Here is a plot of the terrain between you and the transmitter:
Terrain between ( m a.g.l.) and (antenna m a.g.l.) - Optimising UK DTT Freeview and Radio aerial location
You will note that one mile away, the ground obscures line-of-sight. This corresponds to Holt Heath.
Therefore, your task is to receive what is "coming over" the brow. (Imagine if it were a light.) As far as the COMs go, you may have to contend with interference from Stockland Hill's COMs, which are co-channel.
You are only 28 miles away; that said, we don't know how the COMs might have restriction WRT the PSBs, in your direction. The Digital UK Coverage Checker suggests that they may be a bit inferior to the PSBs. The predicted figures are that one third of Rowridge viewers won't get the COMs, so they must be inferior in some way.
Obviously, with Stockland being in the opposite direction, the reflector is important WRT blocking interference.
As I say, I would start by changing the existing aerial to vertical polarisation and take it from there. Only then will you know whether it is sufficient to pull in the COMs or not.
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Tuesday, 19 February 2013
R
Roy Barton12:59 PM
Roy Barton:
John Lindsay. I really do appreciate the detail in your answers. I have checked with the manufacturers of my wideband aerial (not yet fitted). It is a labgear LAB450/WS
Labgear
They say it is not a Yagi, but when pressed they said it was based upon a Yagi but having 3 booms they say it was strictly not a Yagi. They went on to say as regards a log periodic it would perform as well as a group A on channel 28 where we have the problem. Some local stockists only stock wideband, but one distributor offers just one item in Group A, and it less than 25% of the cheapest wideband. Labgear only manufacture wideband.
You have made it clear what I should do. I will try to get a refund on the wideband and fit the cheap group A on vertical polarisation. To me this seems to be an aerial jungle. I would appreciate your comment. LAB450/WS is it worth messing with? (BH217DX)
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