Vertical Aerial for Rowridge?

Paul_CurtisPaul_Curtis Posts: 9
Forum Member
I had assumed that aerials to receive from the Rowridge transmitter would be the conventional type with the dipoles(?) horizontal.

Someone told me that that was true until recently, but now the aerials should be mounted vertically, as the vertical transmission was ten times stronger. (I assume by 'vertically' they mean that the length of the aerial remains horizontal, but is rotated 90 degrees).

I cannot make head nor tail of the Rowridge data. I don't understand MUxs, channels, or Groups. All the aerials I see around here point to Rowridge and are mounted conventionally.

I am wondering if someone who understands these things can shed some light on it for me please, and confirm this?

Thanks.

Comments

  • kevkev Posts: 21,070
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    I had assumed that aerials to receive from the Rowridge transmitter would be the conventional type with the dipoles(?) horizontal.

    Someone told me that that was true until recently, but now the aerials should be mounted vertically, as the vertical transmission was ten times stronger. (I assume by 'vertically' they mean that the length of the aerial remains horizontal, but is rotated 90 degrees).

    The beams that are normally sticking out horizontal from the aerial get rotated 90' - the main boom still stays horizontal and points towards the transmitter.
    I cannot make head nor tail of the Rowridge data. I don't understand MUxs, channels, or Groups. All the aerials I see around here point to Rowridge and are mounted conventionally. .

    The Vertical polarization is for people suffering co-channel interference from Crystal Palace and France.

    Basically
    PSB1-3 (the main channels from BBC, ITV, Channel 4) - all transmitted in both polarisations at the same power.

    COM4-5 (the remaining Freeview channels available on a HD box) - Transmitted at 200kW vertical, 50kW horizontal

    COM7-8 (some more channels available on Freeview HD equipment) are transmitted at 24kW and 18kW HORIZONTAL only.

    Basically if you are in a strong signal area try Horizontal first and you should get all services. If you are in an area prone to losing the signal due to co-channel interference you might have to switch to vertical.

    http://www.aerialsandtv.com/rowridgetx.html has more info
  • Nigel GoodwinNigel Goodwin Posts: 58,328
    Forum Member
    I had assumed that aerials to receive from the Rowridge transmitter would be the conventional type with the dipoles(?) horizontal.

    'Conventional' aerials are mounted either horizontal (most main stations), or vertical (most relay stations) - both are just as 'conventional' depending what station you're on.

    Someone told me that that was true until recently, but now the aerials should be mounted vertically, as the vertical transmission was ten times stronger. (I assume by 'vertically' they mean that the length of the aerial remains horizontal, but is rotated 90 degrees).

    I cannot make head nor tail of the Rowridge data. I don't understand MUxs, channels, or Groups. All the aerials I see around here point to Rowridge and are mounted conventionally.

    I am wondering if someone who understands these things can shed some light on it for me please, and confirm this?

    As far as I'm aware, Rowridge is a special case, as due to potential interference from the continent it uses BOTH polarities, so you can pick whichever you like. According to the link below, the vertical com multiplexes are four times the power, but the main multiplexes are the same power.

    https://en.wikipedia.org/wiki/Rowridge_transmitting_station
  • Mark CMark C Posts: 20,724
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    kev wrote: »

    The Vertical polarization is for people suffering co-channel interference from Crystal Palace and France.

    ....and Stockland Hill
    kev wrote: »
    Basically
    PSB1-3 (the main channels from BBC, ITV, Channel 4) - all transmitted in both polarisations at the same power.

    COM4-5 (the remaining Freeview channels available on a HD box) - Transmitted at 200kW vertical, 50kW horizontal

    COM7-8 (some more channels available on Freeview HD equipment) are transmitted at 24kW and 18kW HORIZONTAL only.

    Hang on, not quite. PSB 1 and 2 are DVB-T1, as are COM 4,5 and 6, (and the local muxes)

    PSB 3, COM 7 and COM 8 are DVB-T2 and if you like to describe such as 'Freeview HD (I don't because those muxes also carry SD channels
  • Paul_CurtisPaul_Curtis Posts: 9
    Forum Member
    Wow, thanks for the fast replies. Sorry Mark, the end of your reply didn't mean anything to me, can you make it simpler please?

    From what I gather then, if I am not prone to interference (and I am not aware I am) then H will give me more channels than V, but V will give better reception if there is a weak signal or interference, albeit less channels.

    Is that about the size of it?
  • robbie2robbie2 Posts: 166
    Forum Member
    Wow, thanks for the fast replies. Sorry Mark, the end of your reply didn't mean anything to me, can you make it simpler please?

    From what I gather then, if I am not prone to interference (and I am not aware I am) then H will give me more channels than V, but V will give better reception if there is a weak signal or interference, albeit less channels.

    Is that about the size of it?

    Yes. The extra channels include the local TV station 'That's Solent'
  • Paul_CurtisPaul_Curtis Posts: 9
    Forum Member
    Thanks Robbie.
  • Mickey_TMickey_T Posts: 4,962
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    It's annoying that the COM muxes on H are only a quarter of the power that they are on V.

    Why is this?
  • Mark CMark C Posts: 20,724
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    Mickey_T wrote: »
    It's annoying that the COM muxes on H are only a quarter of the power that they are on V.

    Why is this?

    To protect the COM 4,5,6 muxes on CP and Stockland Hill, they are all co-channel (UHF Ch 22, 25, 28),

    It's a circular argument really, Rowridge is VP to protect against the HP COMs from CP and SH, plus whatever in France is co-channel with PSB 1,2,3
  • Mark CMark C Posts: 20,724
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    Wow, thanks for the fast replies. Sorry Mark, the end of your reply didn't mean anything to me, can you make it simpler please?

    In the UK the HD channels use an updated version of the system that carries the main SD channels. It's called DVB-T2, (the original system used since 1998 and OnDigital is called DVB-T (or T1).

    It's a more efficient system than T1, which means more data can be carried in the same amount of radio spectrum. However it was developed about 10 years ago, and came into use in about 2009 so obviously any older receivers will not be able to decode T2 signals.

    We opted to use it to carry HD channels on Freeview, so that's why you will see mention of 'HD Freeview Tuners'. T2 can (and does) carry SD and radio too, but
    you still need what many call an 'HD Tuner' to receive them.

    I prefer, (and it's more technically accurate) to refer to these receivers as DVB-T2 capable
  • Paul_CurtisPaul_Curtis Posts: 9
    Forum Member
    Thanks for the explanation Mark, I understand.
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