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9 posts

Wannabe Geek


# 104208 17-Jun-2012 00:57
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Hi All

Currently we have what I think must be a UHF aerial (See photo #1), the wire you see attached in photo #2 runs to my lounge. It is a flat cable with what appears to be two lots of copper wiring on each side, positive and negative for instance. How this is connected to the aerial I could not see, in the lounge where it is connected to a plug, each twist of copper (1 & 2) is connected to a terminal by a small screw (2 terminals) and from here this plugs in to my TV. We have a Samsung UA46D6600, and can pick up freeview easily using this method and works perfect.

However I'm doing some renovations in the lounge and figured I should upgrade this cable to coax RG6 as have been reading this is a good thing to do as I am unsure of the limitations of my existing flat cabling.
I got a 15m length, enough to run from the lounge to the aerial and the guys at the shop used a compression tool and fitted a screw on F connector, which I can then screw on to the back of a tv wall faceplate and from here I can plug my tc cable in to this faceplate.

However..how do I connect the other end of the cable to the aerial? Photo 2 shows what appears to be the 2 wires joined to the aerial in the same way as how they are joined inside, a positive and negative type connection. My only problem with that is on the coax cable it appears to only have 1 wire, the centre copper wire, what would one use as the 2nd wire?

want to get all this sorted tomorrow so I can gib it back up, never to be able to touch anything behind again.

Help appreciated.


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727 posts

Ultimate Geek
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  # 641989 17-Jun-2012 01:11
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There may be more to it than this, but to answer your question, the second "wire" is the braided wire shield just under the insulation.

I don't see any photos, by the way.

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  # 641993 17-Jun-2012 06:39
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No photos, but if it's a flat cable, then it seems like it's an old 300ohm ribbon cable....that is old, and most likely not an UHF aerial as that was never used with UHF in NZ

http://en.wikipedia.org/wiki/File:Twinlead.gif

If it is then you need to ditch it, as it is very prone to interference, run some RG6,


 
 
 
 


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  # 642004 17-Jun-2012 09:18
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At the antenna, you probably need a balun (balanced - unbalanced converter) that will convert the 75ohm RG6 cable to the correct 300ohm impedance for the antenna.

In your current setup, you moist likely have 300ohm ribbon cable (rarely seen these days) running from the antenna, with an indoor balun converting it to coaxial 75ohm as it enters the TV (it will just look like a plug).

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  # 642007 17-Jun-2012 09:32
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It sounds very unlikely that your antenna is UHF. 300 ohm ribbon is really old and goes back to the days of black & white TVs (VHF only).
Buy a new UHF antenna, fit another F plug at the antenna end of the coax and connect it to the F socket which will be on the new antenna.



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Wannabe Geek


  # 642042 17-Jun-2012 11:32
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I have investigated and can not see any Balun on the current chord, straight wire from the aerial to the TV it appears.

If it is a VHF aerial, my TV has freeview built in and I can receive 1080i signal, what would be the benefit in buying a UHF aerial?

That balun thing looks like exactly what I need.

Photos attached.




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  # 642045 17-Jun-2012 11:58
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Yes this is a VHF aerial and 300ohm ribbon cable, I'm surprised that you get a picture at all and it must be just plain dumb luck you are getting enough UHF signal for the TV to process a digital signal.

Best advise, ditch the aerial and cable, install a brand spanking new UHF aerial and cable to your TV

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  # 642046 17-Jun-2012 11:59
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Hi, that antenna is not a UHF antenna, it also is buggered and it has an old 300ohm ribbon feeder to it, this is not suitable for UHF, the entire antenna and cable needs replacing with a UHF antenna and new RG6 coaxial cable.

Cyril

 
 
 
 


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  # 642055 17-Jun-2012 12:12
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You could stick that antenna in a museum ;-)

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Ultimate Geek
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  # 642056 17-Jun-2012 12:14
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Hi there!  Looking at the photos the posts above have guessed right:

1 - That IS a VHF aerial (You must be in a very good reception area for freeview to be getting the UHF signal on it!)
2 - The aerial cable is 300 Ohm.

The advantages of RG6, (especially at UHF frequencies), are less interference/longer run length and the ability to split the singal to multiple TVs if you want. (OK, someone will probably say you can split a 300 Ohm signal as well but it reallly is just an obsolete technology!).  To attach the RG6 cable you have, at the aerial end you need somthing like this:

http://www.dicksmith.co.nz/product/L4465/tv-balun-indoor-outdoor

Do you need a UHF aerial?  Probably not, as what you have now seems to work OK. You may if you connect more TVs but even then maybe not.  My guess is you live in a very high signal area ;)

That said, UHF aerials are pretty cheap and if you replace it you'll be all set for now and the future.  If you get the balun you may end up having to get an new aerial in future anyway ;) 



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Wannabe Geek


  # 642065 17-Jun-2012 12:35
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Thanks heaps for your replies.

I will run the coax cable, get the balun and connect it up, see if I can still receive freeview, if so, all good will keep the VHF for now, but ditch the ribbon cable, if this somehow interferes with the precise balancing act that seems to be my vhf aerial and ribbon cable receiving freeview I will replace aerial with a new UHF one, connected to my now coax cable.



Either way, by having the coax cable there will give me some future proofing.

Sounds good? Thanks everyone.

Just discovered I have a 2nd aerial on the other side of the house which also has a ribbon cable.. but is not used so will leave it for now.



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Wannabe Geek


  # 642206 17-Jun-2012 20:09
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Got the balun this afternoon, hooked up the coax to the vhf aerial and works good! Disconnected the old ribbon and pulled it out of the wall..plugged the coax in at the TV...freeview working, 1080i signal.

Good ol' VHF freeview



Cheers for all your help everyone.

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