I think my aerial might be knackered - thoughts?

[Andy112285]

I have recently moved into a new house.

None of the rooms had aerial sockets in but they where cleary in there at some point but it was a bit of a bodge job, you can see little bits of coaxial cable running through the corners of some of the windows. There is also an aerial on the top of the roof with about 5 meters of coaxial cable running from the aerial to the the fascia.

Over the weekend I ran coaxial cable through into the loft then joint it to the existing coaxial cable from the aerial and into a six way splitter and then down into the bedrooms and the lounge so we could watch TV other than just the Sky.

Now I thought it was almost impossible to break an aerial and coaxial cable is pretty simple stuff, obviously I was wrong as none of the TV's where picking up any signal. So I did the obvious thing and took the plug out of the six way amplifier/splitter thing and put it back in again, didn't change a thing so I went up on the roof and checked all the connections to the aerial and everything seemed fine with the aerial and the existing coaxial cable.

This is the point where I'm at now, I thought this would be an easy job but it seems to be really dragging so I thought I'd ask a few questions here.

Could it be possible that the amplifier/splitter thing I've bought is broken?

Could the aerial just be broken? (can't see it myself it looks fine and well it's only an earial)

I think I will now go and buy a signal tester meter and plug that in and see what it says, I can't see how I've made any mistake doing the wiring as it's all very simple.

Starting to get annoying as I can't really see anything that could really be wrong.

Sorry for the essay.... hope someone can help and I'll report back with my findings from the strength meter tomorrow.

 

[big-all]

first thing to do is look and see if the arials on the other houses are the same or simmilar looking pointing in the same direction and the same orientation[rotated 90 % on the long axis]

 

[Andy112285]

Ok will have a look in the morning, hadn't thought about that just assumed even if it was in a totally wrong position it would at least pick up something.

 

[Mickymoody]

I suspect the cable from the aerial being faulty.

 

[Diyisfun]

Try it without using the splitter/amp, ie Aerial straight to tv.

 

[Andy112285]

Try it without using the splitter/amp, ie Aerial straight to tv.

I have borrowed a little adapter to join two coaxial plugs so i'll be able to test that tomorrow, just the aerial straight down to the tv in my bedroom.

I suspect the cable from the aerial being faulty.

I think it's probably that as well (maybe a dud amplifier), however when I looked at the wire it looked fine and the connections where fine onto the aerial. All a bit strange really, should hopefully have the answer tomorrow when I crack on with my strength reader.

 

[ericmark]

Most aerials have no electronic parts and are just bits of metal in the sky. The only thing that seems to fail is the box where the coax connects to the aerial.

Without transmitting it is hard to test an aerial and cable and it could be simply moved by wind or birds and be OK once re-aimed.

All diagnoses can fall into two basic methods.
1) Guess what might be wrong and test that.
2) Start at one end and work along the route.

With the avant of digital TV the old method of tuning to bad signal and moving aerial for best reception no longer works. Either you have to use built in signal strength meter of TV or buy a separate signal strength meter.

The meter build into TV will likely show if there is any signal even if weak and worth looking at. Freeview boxes don't always have a built in meter.

I would start with visual. Does aerial look OK? And pointing is approx right direction. The aerial normally causes a DC short on coax disconnecting and reconnecting coax and testing with normal meter does give some pointers. But water in coax with alter it's frequency and although it tests OK with DC it may still be US.

Cable seems most likely to fail and I change the cable first then look at rest. Petroleum jelly I find really helps to stop water entering at the aerial end. Of course were the aerial has tuning capacitors one has to be careful.

 

[Mickymoody]

Cable seems most likely to fail and I change the cable first then look at rest. Petroleum jelly I find really helps to stop water entering at the aerial end. Of course were the aerial has tuning capacitors one has to be careful.

I think every aerial fault I've ever seen is due to bad cable, I've had tuners on videos full of water and corroded because the water gets inside the cable and runs downhill. Satellite is 50/50 cable/LNB.

Places that the cable fails are at the aerial itself, or where it folds near the gutter, or where it goes into the property.

I've even had aerials with no reflector plate picking up a good signal, but a massive hi-gain aerial, with a bad cable picking nothing up.

We are lucky in this area, as the transmitter is line of sight, with no trees or anything blocking the view, or the need for a pole to raise the height, or double transmitters close to one another, so no overload of signal, and no cross interferrence.

 

[Andy112285]

I've bought a signal strength meter and it seems to be picking up some sort of signal, annoyingly though the coaxial points i've used don't fit into the meter so I just had to take them off and poke the cable into the reader which seemed to work ok.

I then ran the cable straight from the aerial into a tv and ignorred the 6 way splitter I thought, hoping it would work but again it doesn't pick up any channels at all.

Starting to annoy me now, as I'd expected it to be such a simple job.

I think my next course of action will be to replace the 5 meters of coaxial cable that was already existing, would dodgy cable still be able to pick up a signal through my strength meter?

Any ideas would be appreciated, if the new cable doesn't sort it then I'm stumped, all I can assume is that I've done my connections incorrectly or haven't put the plug things on properly.

 

[Colin Brenton]

Just a thought, while you are installing cables, be sure to use decent quality, double screened stuff. The cable sold as satelite cable should be the stuff to use. Don't buy normal "TV" coax. See here for why...

http://www.wrightsaerials.tv/topics/coaxial-cable-screening.shtml

This is a good site to skim though if you are having aerial related problems.

Cable quality makes a huge difference. In my place, with standard TV cable I couldn't get any digital TV signals at all, and snowy analouge. With good cable, I can get near-prefect digital.

Once all the cables are in good order the signal strength meter can be used to point the aerial in the right direction, and then check with a TV.

Just a thought, what does this site say to your postcode - if it's a new house, is terrestrial TV definately available?

http://www.freeview.co.uk/availability

Hope this helps, post back and let us know how you get on.

Cheers,

Colin

 

[Andy112285]

Hi Colin thanks for the reply.

I have already done all the cabling and just used the stanard co-axial cable, I think it was £30 for 100m from Wickes.

I've had a look at that site thanks, I think tomorrow I'll redo the joint from existing cable to the new and make sure it's perfect then try again, if that doesn't work I'll have to get my roof ladder out and run new cable from the aerial and hope that works.

I really don't fancy having to upgrade to satelite cable just to get a signal =/

Is the direction of the aerial really that important? I would have thought even if it was a little bit out it would still be able to pick up something.

 

[Colin Brenton]

Hi Andy,

It's odd, as Wickes list 100m of "TV" coax for £29.99, but 100m of satelite cable for £22.49 (!)

To be honest, in some locations you would get away with a bit of wet string rather than a cable, but if you are having problems, this is one good place to start looking.

It's easy to tell what type you have. Cheap cable has the plastic outside sheath, then copper braid, then plasic insualtion and a single copper core. The better stuff has a metal foil between the braid and the inner plastic insulation. A quick look at an offcut will reveal all.

Does the aerial give an analouge picture on any of the TVs?

I'm not sure if I've helped you or not with this post really.

Cheers,

Colin

 

[Andy112285]

Yeah I remembered that the tv coax was more expensive than satelite, I just assumed coax was the stuff to go for.

The stuff I've been using is the cheaper stuff you've explained, plastic between the copper core and the copper braid.

Will check to see if there is an anolouge picture and report back later.

BTW that website said my area should be fine for digital tv, I like slap bang in the middle of Southampton so I really wouldn't think that's a problem.

Thanks

 

[Mickymoody]

You don't mention if the TV reception ever worked? You mention faulty aerial? Maybe the wrong bandwidth aerial has been fitted, or is of the wrong polarisation?

I wasn't ever aware that this could occur, until I got talking to a relative that used to make TV aerials, apparently the end cap colour dictates the bandwidth of the aerial, suited to a particular area of the country, and the aerial can be mounted horizontally, ie the bars out left right, or sideways on in some areas (I've never seen that in reality) ie still pointing at transmitter, but bars up/down in orientation.

There is also the possibily, as there don't seem many options available, that the signal is being swamped ie overloaded, and offsetting the aerial, maybe even turning it the wrong way round completely, to capture a signal from a hill may help? Or try a different local transmitter if there is one close enough?

 

[Andy112285]

I'm not sure if the aerial ever worked, I moved into the house and the aerial was in place with about 5 meters of cable haning from the aerial down to the fascia and then cut.

Any idea which end cap coulour for Southampton?

What do you mean by trying a different local transmitter?

Thanks