Question Advice on best indoor aerial for COM7 HD.

Discussion in 'Freeview & YouView' started by Lord Childe, Jul 20, 2015.

  1. Lord Childe

    Lord Childe
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    I’ve tried four indoor aerials (including Avantek’s amplified effort) – all either can’t get COM7 HD/ch33, or the signal is very poor. Every other channel signal is strong (London). So instead of wasting my money on a crap aerial based on Amazon reviews, I’d like advice on what to look out for – high gain, wideband…etc.
     
    Last edited: Jul 20, 2015
  2. grahamlthompson

    grahamlthompson
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    Com7 and 8 are much lower power. Can't you mount a small outdoor aerial like a small log periodic aerial ?

    Aerials, TV Aerial and Digital Aerial

    Crystal Palace Transmitter
     
  3. Lord Childe

    Lord Childe
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  4. grahamlthompson

    grahamlthompson
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    In all honesty a small outdoor aerial used indoors is likely to be much better. You could try the DM log, but it depends on where you can put it. A room on the same side of the building as the transmitter and ideally through a single glazed window. Modern double glazing uses low energy glass whicxh stops rf dead or a loft with roof tiles on the transmitter side.
     
  5. Rodders53

    Rodders53
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    Where in London?

    We tend to not recommend set top aka room aerials on this forum. Avoid amplified room aerials like the plague... as you've found they don't do anything useful. Room aerials often need careful placement and moving to different positions for different UHF TV frequencies as you get reflections inside a room from objects and people that may reinforce or cancel out signals.

    Aerials, TV Aerial and Digital Aerial and Best aerial for indoor outdoor motorhome or caravan log periodic are both word reading.

    Why can't you use a loft aerial or a split feed off the main aerial for the house/flat?

    A proper outside log periodic aerial can be placed on top of a wardrobe or shelf (if you are able to get it pointing at Crystal Palace) and would probably work better than any small room aerial (but they are a bit bigger, of course). However, as COM7/8 are some 7dB down on the main muxes the signal level inside a room may never be enough in your area of London (and the other muxes are going to be pretty close to the digital cliff borderline as well).
     
  6. Lord Childe

    Lord Childe
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    Right, it never crossed my mind to use an outdoor aerial indoors. I'll certainly consider it.

    I get COM8/ch35 alright - the signal is 'very good'. But the channels offered are a waste of space. Typical.
     
  7. Lord Childe

    Lord Childe
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    I'm in SE4

    Thanks for the info. Yes, my cheap little 'August' aerial is as good (or bad) as the amplified Avantek. Currently I've got two aerials hooked up pointing in different directions - one for BBC, the other for all the rest.
     
  8. MartinPickering

    MartinPickering
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    That's rather vague but you probably have an EXTREMELY strong signal from Crystal Palace so try sticking a bit of wire in the aerial socket. A paperclip might do.

    If that's no good, I'd recommend a "Group A" log-periodic aerial such as the V11-20A2.
     
  9. TJT1

    TJT1
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    This one from screwfix is really titchy. It fits into a 14.5" square box. I have one and am well pleased with it. It's wideband though if that's seen as a problem but my local transmitter is all band A at the moment.
     
  10. MartinPickering

    MartinPickering
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    Crystal palace requires a "Group A" aerial. Since the OP already has problems, there's no point in asking for trouble by using a "wideband" aerial.
     
  11. TJT1

    TJT1
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    What are the bandpass characteristics of "a bit of wire in the aerial socket." or "A paperclip might do"?
     
  12. grahamlthompson

    grahamlthompson
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    Pretty well all available log-periodics now have the 80Mhz+ channels filtered out. They therefore remain the best choice for strong to medium strength reception areas. Very few will need 4G filters anyway, as the effects have been massively overblown. The excellent off axis reception of a log periodic as always is the best design to ignore off axis signals. For example the log40 now replaced by the log36 is now the best choice for all but the weakest reception areas for any transmitter. Log periodics have the flattest gain curves (now rolled of above 700MHz), as result if you need a degree of amplification you are unlikely to over amplify any Mux at the peak of a group A yagi. Paired with the excellent impulse noise rejection they are truly the best aerial you can buy for the majority of people. Lost count of the number of posters with group A aerials installed pre-dso that now require a attenuator.

    There is no guarantee that future Freeview content from CP or anywhere else will be in group A.

    I have a log36 in my loft over 30mls from a relay (Lark Stoke), it delivers perfect signals although it does need a source amplifier due entirely to the number of tuners it feeds entirely based on passive spliitters.
     
    Last edited: Jul 22, 2015
  13. mints

    mints
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    Reading about the reception problems listed in the above post has reminded me that my rule was whenever I have looked at a new gaff I always checked out the tv reception.

    If it was not up to the mark I did not buy and as a result have always had a contented tv watching life over the last 50+ yrs.
     
  14. grahamlthompson

    grahamlthompson
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    That may well be the issue, you cannot simply connect two aerials using a simple combiner, you need to split the two transmitter frequencies with a properly designed diplexer that avoids one interfering with the other. Depending on the two transmitters you will need a different diplexer,

    As always the best source of info is here.

    If you identify which transmitter other than Crystal Palace a suitable channel split would be easier to identify (see the options for CP at the link below)

    Television Aerial Boosters / Amplifiers, Splitters, Diplexers & Triplexers
     
  15. Lord Childe

    Lord Childe
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    Cheers, I'll plumb for this. Relatively inexpensive.
     
  16. MartinPickering

    MartinPickering
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    There are no guarantees in life. All you can do is install the best system for now. In the case of Crystal Palace, Rowridge, Stockland Hill, Caldbeck and Divis that means a "Group A" log-periodic such as the V11-20A2.

    If you want a vision of the future: it has already been leaked that the government wants to do away with Freeview altogether and sell off ALL the spectrum for mobile use. So for future-proofing, simply throw away your aerials.
     
    Last edited: Mar 8, 2017
  17. Rodders53

    Rodders53
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    SE4: Brockley, Honor Oak, parts of Crofton Park and Ladyell in the Borough of Lewisham... So fairly close to CP , so likely much of the signal flying above the rooftops due to the 'lighthouse beam' transmitted from the tower.

    That ch33 is poor and higher power (albeit only slightly) than ch35 implies that you have a 'standing wave' issue due to reflections in the room making that one weaker by cancellation. Two aerials pointing different ways for different muxes suggests the same. You probably will never achieve good reception on all muxes inside your room no matter what aerial is used, without continual re-adjustment of position: higher/lower; crabbing left/right and moving fore/aft. You are likely throwing more good money after bad, that could be spent more wisely, by buying yet another aerial.

    I repeat my earlier question: Why can't you use a loft aerial or a split feed off the main aerial for the house/flat? Such an aerial will almost certainly not be subject to reflections in the same way.
     
    Last edited: Jul 21, 2015
  18. winston2010

    winston2010
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    Once again you have the facts wrong. The 700MHz band is still in use for TV and will be for a number of years. Some logs are cut off above 800MHz but none above 700MHz.
     
  19. grahamlthompson

    grahamlthompson
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    It was a simple typo as I am sure you know as do most anyone else reading thread. Unlike some of the long threads you have posted in the past with totally out of date and inaccurate info with reference to modern surround sound formats, (8 is very close to 7 in the dark ).

    A polite post pointing out the error would have been the sensible thing to do, instead of your personal vendetta with someone who doesn't believe your somewhat minority opinions (I don't think I am alone in this opinion). Offending post will be edited.
     
  20. winston2010

    winston2010
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    Well you don't seem to have edited it very well. 80Mhz cut off and still 700Mhz roll off?

    Perhaps you should invest in a light if 8 is so close to 7.

    I don't recall myself making any of my posts about surround sound formats. Perhaps you are thinking of someone else.
     
  21. gimboid

    gimboid
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    Sorry for resurrecting an old thread, but I'm having a similar problem to the OP. I'm in a basement flat and I can't receive any COM7 channels whatsoever with an indoor aerial, despite being within range of Crystal Palace. I've looked up the recommended V11-20A2 aerial and while there's lots of info about it I can't seem to find anywhere that's actually selling it. Anywhere know where I can find one? If not, should I just go with another Group A log periodic like this one?

    Vision V20a2 Aerial Log Periodic Group A: Amazon.co.uk: Electronics
     
  22. TJT1

    TJT1
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    Try Satcure here . First hit when I Googled it. But read the notes as to what the R means.
     
  23. Rodders53

    Rodders53
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    Location? Leighton Buzzard is 'within range' of CP, so is Dulwich... they both need very different aerials.

    Unless you are going to fit the aerial outside on the building or on a pole in the garden (on the side towards CP) you are probably wasting your time and money. Getting an aerial higher is likely to result in a significant signal level increase - i.e. many dB extra.

    Flats should share a communal aerial system on the roof, not rely on room aerials. There are planning rules that are designed to inhibit the placing of a plethora of separate antennas (TV 'aerials' and dishes) on one building to encourage such systems to be installed.
     
  24. gimboid

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    Oops, found that site when looking up info on log periodics, but never noticed they were a shop.

    I'm in Epsom, Surrey, living in a large old house that has been converted into studio flats with no roof aerial system. I've been happily using a 45dB amplified indoor aerial for several months, and didn't realise it was lacking until I got a Now TV box and could get some HD only freeview channels but not others. Turns out the missing ones are all on the COM7 multiplex, along with several standard freeview channels I'm also not getting, despite freeview post code checker saying I should be getting all of them.

    Will getting a better aerial not do anything if it's still at a low elevation?
     
  25. TJT1

    TJT1
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    No, it won't not do anything.(well, don't ask negative questions:rotfl:). But a log can be a little unsightly in your living room unless you can hide it on top of a cupboard or similar.

    The best way of finding out is to get one and try it, Buy it on line and you can send it back if it doesn't improve things for you. Have you tried moving your areal around the room?

    The Freeview postcode check assumes a sensibly sited outdoor or loft mounted aerial. And it's about the worst coverage checker there is. It says I can only get the local limited Bexhill transmitter and Heathfield is my my nearest main transmitter, and completely omits to mention that there is a transmitter at Hastings that covers most of Bexhill.

    What other 'standard Freeview' channels do you not get?
     
  26. Rodders53

    Rodders53
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    Random Epsom High Street postcode gives 17km from CP. Same distance I am from Sandy Heath. Wolfbane predicts 72dBuV at 1 metre agl... although that assumes no buildings or trees in the way ;) The proverbial wet string should work... as that is a very high level of signal (the two Com7/8 muxes would be 65dBuV).

    Try an UNamplified aerial the amplifier may be distorting the otherwise clean signal?

    Try moving the aerial: higher/lower, crab left/right, move forward/back : within a cube of space with sides up to about 1 metre (3 feet). Signals within lofts, rooms and even sometimes outside have reinforcement and cancellation on the different frequencies. You are trying to find a spot where this Com7 frequency is better without losing any of the others. The TVs signal meter may help with this? Of course, having found the sweet spot you'll need to devise a way of keeping the room aerial there!
    (Cube of space is all needed as the patterns of peaks and troughs in signal repeat.)

    You could even try making a simple dipole aerial with a scrap of coax and a TV aerial plug. Pull about 10cm of the centre core with its insulation through a hole made in the braid and form the core and braid into a T shape. Top of T horizontal and broadside on to the NorthEast (Crystal Palace is 51 degrees from Epsom).
     

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