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TV / Video RF aerial connection problem - very strange

Discussion in 'Electrics UK' started by garrymum, 1 Jan 2006.

  1. garrymum

    garrymum

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    Hi
    My father has bought a new tv. Panasonic LCD one (TX-26LXD52). I went to help him set it all up and have come across a strange problem.
    I plugged the aerial into the video, then another co-ax from the video to the tv. When the video is plugged into the power and the tv does the auto tune for both analogue and freeview stations (has a built in freeview tuner) it only finds 4-5 digital channels and the picture quality for all is terrible. However, when I disconnect the power from the video and re-do the auto tune the tv finds everything with perfect quality!

    I thought it was the video so tried there second video and the same thing happened.

    It is as of whenever the video has power the feed from the RF out is reduced to a point where the quality is rubbish.

    Any help would be greatly appreciated.

    Thanks
     
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  3. 2scoops0406

    2scoops0406

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    Could it be the cable from the video into the TV is rubbish?
     
  4. JohnD

    JohnD

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    I believe most videos actually amplify the signal a bit, to overcome losses with all the extra cables and plug connections in the co-ax. I wonder if the signal could be too strong and need attenuating?

    Does it make any diff if you remove the freeview?

    As it only happens if you have power on to the video it probably isn't the co-ax cables.

    Maybe you could bypass the video coax out, and just use the scart , with a siamese aerial connection to the vid?

    Something that might possibly be relevant - the RF output from the video should be adjustable, it might be in contention with a frequency used by the Freeview or something else (in my area I had probs with RN Radar around Portsmouth Harbour). Look for a tiny tuning screw on the back of the vid near the co-ax, or read the instructions. The TV will then just re-tune itself to the new Video ouput channel.
     
  5. garrymum

    garrymum

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    The cable must be fine as it is perfect when the video it not plugged in.

    I cannot remove the freeview as it integrated into the tv. With the video plugged in both the digital and the analogue picture is really bad.

    What do you mean by this?

    Thanks
     
  6. JohnD

    JohnD

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    I meant:

    Put a Y-shaped coax aerial splitter on the incoming from the aerial. Connect one of the legs to the TV aerial input, and one to the video aerial input.

    Connect the output scart from the video to the input scart on the TV.

    That way, the TV will receive its aerial input untroubled by any incompatibility from the video.

    The video will receive its own aerial input

    The video, on playback, will send the sound and pictures to the TV through the Scart without needing to pass an RF signal.
     
  7. big-all

    big-all

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    because you loosing signal in a specific area i also think as said above its probably the output frequenct of the video interfering with the signal off the freeveiw

    my setup is ariel in to freeveiw then in turn video 1 then video 2 then all round the house out to tvs

    and when i re tune for a new freeveiw channel i have to remove the vidioes from the loop even though they are in the loop "after" the freeveiw it still tunes into them causing interfearence[a back feed through the scart from the tv i assume]

    so could you not try retuning the video to a different output frequency and see what happens
    just disconect every thing have a scart between video and tv play a video so you know its the video and alter the output frequency away from the known freeveiw frequences


    good luck
     
  8. garrymum

    garrymum

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    I presume you mean alter the RF channel frequency. The video was set to RF OFF. I have just talked my dad over the phone to change the frequency to No 28 and try and re-tune. This time he got the stations but the quality was bad. I will try change the RF frequency and repeat the auto tune procedure. What frequencies are best not to use to avoid interference with the freeview?
     
  9. JohnD

    JohnD

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    I think you just change it a few up and try again. Keep a note of which channels are bad.
     
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  11. 1974stephen

    1974stephen

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    The channels not to use will vary depending which transmitter you are using, as each transmitter in the country uses different RF channels to transmit the same TV stations. That's why if you take a working TV from Scotland, and try using it in the Midlands, it won't work, unless you re-tune it. When selecting VCR channels etc, you must avoid the actual TV channel number, each one either side, and preferably not have them 5 or 9 apart. If you look on the web you should be able to work out which transmitter you are using, and what channels they are transmitting on.
     
  12. Chris.J

    Chris.J

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    I agree with JohnD that this is the best approach.
    However, if you don't have a splitter to hand, just feed the Ae. direct to the TV & see if it finds all the chan's it should (about 85 freeview IIRC for a full house).
    But note if you have an Ae. thats been up a few years, it's almost certainly not wideband, so, unless you are v. close to the transmitter, you will probably only get some of the MUX's, so you won't get a full house of Freeview chan's.
    The amp in the video was boosting the signal to the TV as you had it initially, and so you could have too strong a signal and/or the mixed in video o/p sig. (used to be about ch. 36, but usually menu variable thesedays) interferring with one of the MUX's the Freeview tuner is trying to resolve.
    I rigged up a new wideband Ae. on a place last year, with good dist. amp. to feed several rooms, reckoned I had done a really good job, but the signal was too strong for the TV to sort out the tuning, & I had to attenuate the sig. This RF stuff can be a bit tricky!
     
  13. JohnD

    JohnD

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    Good point, this will also show you what channels are in use, so you know you have to retune the video RF output to one of the others.
     
  14. garrymum

    garrymum

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    I did putting the aerial direct into the tv and bypassing the video but it only found a few channels. To get all freeview and good quality I have to put through the VCR but keep the VCR un-plugged. My mum and dad live in Filey which is not the best area for a good reception on the best of days and I am in Leeds. I am going back across on Tuesday to change the RF frequency to try and get a better picture. IS the RF freq between 21 and 68?
     
  15. Chris.J

    Chris.J

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  16. garrymum

    garrymum

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    Thanks to everyone that replied. Going off on a tangent slightly how would one record from the freeview using a tv with an integrated tuner. If an external freeview tuner was installed the tuner would be connected directly into the tv and the VCR. Given that the tv has an integrated tuner the output from the vcr is connected to one of the scart sockets of the tv. Do I need to connect another scart from one of the tv scarts and put this into the scart in of the VCR or is the one cable sufficient?

    Which input/programme would the vcr be on to tape a freeview prgramme?

    Does the tv have to be on to record something?
     
  17. tockworth

    tockworth

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    firstly looking at your postings the root of your problem may simply be solely signal strength to your home you do need a certain level of terrestial signal and if this is not adequate your digi tuner will not tune most digi channels and the ones it does will probably lock up when viewing ie go blocky and freeze. the way to check this is to connect your aerial direct to the tv and tune in the terrestial channels (on auto tune it will automatically tune digi channels first then tune terrestial.) when that is complete select one or more of your terrestial channels (refer to the tv manual to see what channels allocate to your 4 or 5 terrestial channels) and if they look snowy then that indicates your signal strength is low or inadequate to carry digi signals. If the signal is really weak looping it through your video would just exasperate the problem. secondly to record digi from your tv the signal can only be taken from your tv out of the scart socket. the there may be up to three scart sockets at the back of your tv. It is important to select one of them that does indicate that the particular socket does output. This is indicated by a right facing arrow on the socket. It is likely that one of the sockets has a left facing arrow and a right facing arrow on the same socket this indicates it is suitable for outputting the signal from the tv while also imputing signal on the same socket. This makes it suitable to connect to your vcr which outputs the signal to the tv on playback and will need to input the signal to record from the tv. Problem then is you can only record on digi channel and it will be the channel selected on your tv at the time, but you should have the facility to record a digi channel, while that is recording switch to a terrestial channel but to do this on most digi tv,s you will have to refer to the manual as a process will have to done. Hope this is of some help to you
     
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