No signal on Aerial Cable

[Nuggets]

I have just fitted a new High Gain TV aerial in the loft which picks up a signal, the meter we have borrowed shows a signal strength of 50.

We are in a 5 year old 3 storey town house and the cabling is already installed. I have connected the cable coming up from downstairs directly in to the aerial if I go downstairs and test signal at the wall socket, I still get 50 on the meter. As soon as I connect the TV coax lead to the wall socket I get 0 signal.

I have tried running a small cable off the aerial in the loft, when tested I get 50 on the meter, if I connect another lead to this the signal goes off again.

It seems that as soon as I make a connection to the cable off the aerial I get no signal, but on its own no matter which cable I use its fine.

Just for clarity I have tried connecting the TV to the aerial wall socket, ignoring what the signal meter says, but the TV also says no signal.

Am I missing something? Can you advise please.

 

[Sam Gangee]

A signal strength of 50 what? It's meaningless without units of measurement. Is it dBuV/m perhaps?

What cable are you using? WF100?
How are you connecting the cable to the aerial?
How are you connecting it to the meter?
How are you connecting cable together?
What plug(s) are you using. Are you fitting them correctly?
Are any wall sockets connected?

See http://www.youtube.com/watch?v=KdBINEM3uS4

 

[Nuggets]

Hi Sam,

The meter is SLx DVB-T Signal Meter, it is 50 dBuV.

The cable is the existing cable fitted by the builder, or I can use a length of seemingly anything, as soon as the second connection is made the signal drops.

We are using 'F' connectors for all connections.

There is a wall socket downstairs which as stated if I feed the cable directly from this (the cable coming up behind the wall) to the aerial and test it at the wall socket I get a reading of 50, if I plug a cable into the socket i get nothing at the end of that cable.

if I do this in the loft with simple short cables using good connections it reads good from the aerial lead, but as soon as another cable is connected , nothing.

 

[xr4x4]

I don't get it?

The socket is faulty?

 

[Nuggets]

If I plug signal tester in to socket it gives a reading of 50!

If I plug a coax lead in to the socket and then plug the signal tester in to the end of that lead it gives no reading!

And don't forget if I go back up to the loft, test the cable from the aerial it gives a reading of 50, if I connect a cable onto that it then reads nothing.

Confused!?

 

[xr4x4]

So your saying that it's when you connect a fly ariel lead tho the socket the signal dies?

It has to be the ariel lead, which your prob gonna say its not, which is why I was confused..

 

[ChrisFrost]

From what you have written then the most likely cause of the signal loss is a short in the coax cable.

Your aerial is okay. Connecting the meter at the aerial is all good, so there's no short here. Your drop to the aerial socket is okay too. But when you connect this secondary bit of coax at either the aerial or the socket then the signal disappears. I'd look for shorts on that bit of secondary coax, or simply replace it.

The short could be something as simple as a stray filament from the shielding braid touching on the centre copper conductor. Alternatively the cable is damaged somewhere along its length. This might be harder to spot.

 

[Nuggets]

Take the socket out of the equation, if I go up in the loft and test a lead which runs from the aerial I get a meter reading of 50, good signal.

If I then connect any length of coax to this lead, I've tried 3 different ones of various makes and types (excluding the cable running downstairs) but all with 'f' connectors (I've even tried different ones) the signal drops off, nothing.

This makes no sense. Someone please tell me I'm not going mad.

 

[ChrisFrost]

How have you joined the cable to the aerial?

 

[Sam Gangee]

Which I already asked.

A signal strength of 50 what? It's meaningless without units of measurement. Is it dBuV/m perhaps?

What cable are you using? WF100?
How are you connecting the cable to the aerial? <----------
How are you connecting it to the meter?
How are you connecting cable together?
What plug(s) are you using. Are you fitting them correctly?
Are any wall sockets connected?

See http://www.youtube.com/watch?v=KdBINEM3uS4[/QUOTE]
And he replied:

We are using 'F' connectors for all connections.

Which is somewhat vague but I took it to mean that the aerial has an 'F' connector and he has correctly fitted an 'F' plug to the short cable and has screwed it onto the aerial.

See http://www.youtube.com/watch?v=2gvZx2C8nnY

.

 

[Sam Gangee]

On re-reading, "Nuggets" seems to be connecting the short lead to the lead that's already connected to the aerial but he doesn't say how. If he's using a threaded adapter then it looks as if that's the culprit.

http://www.satcure.co.uk/accs/page7.htm#jointkit

Nuggets if you upload photos of your connections we might spot the problem immediately.

 

[Nuggets]

Thanks gents,

In the short form example, the cable is being joined with a threaded coupler, 'F' connector either side. Before the connection is made the signal is good, if I test the end of the cable once connected its got no reading.

If however, I connect the cable running up from downstairs directly to the aerial go downstairs test the wall socket I get a good '50' reading. If I then plug the TV lead in to the wall socket and test the other end of that I get a nil reading, no signal.

As soon as the next connection is made I lose signal.

Any clues?

 

[daxi]

If however, I connect the cable running up from downstairs directly to the aerial go downstairs test the wall socket I get a good '50' reading. If I then plug the TV lead in to the wall socket and test the other end of that I get a nil reading, no signal.

Any clues?

The lead between the wall socket & the test meter/TV sounds to be at fault.. Start by making a visual check, make sure there are no shorts between inner core & braid & that everything is tight & as it should be then use a multi meter & check for continuity on both the inner core & outer braid at the end connectors..
It may pay to make sure that the connection between this lead & the wall socket is good using the multi meter to check continuity if the lead is good.

 

[ChrisFrost]

Any clues?

I think we've all given you our best advice "sight unseen" on this. That should have solved the problem in 99.9% of circumstances.

My guess is there's else something going on with this install that has perhaps escaped your attention. The answer now if for someone with the right tools and knowledge to go to site and trouble-shoot this hands-on.

If you are somewhere in between or around the Nantwich~Lymm Chester~Congleton cross then I'd be fascinated to come have a look.

 

[ChrisFrost]

Hmmm.... almost a week now with no further update despite the offer of help.