TV aerial water ingress

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The aerial junction box seems to be suffering from rain getting in and causing partial signal loss.


Would it be practical to smear grease over the connections?
 
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Grease will help a little but do nothing for the water already in the cable.

Grease and then an outer wrap of self amalgamating tape will provide a more water-proof joint. Just make sure to wipe any excess grease off the joint otherwise the tape won't stick to itself.

A better solution is to replace the cable from the water ingress point down and then make a proper seal.
 
Thanks for the advice Lucid

When the weather dries up I'll get up the ladder and investigate.

The cable is jointed to the aerial inside a circular box. The box has a lid that clips over it and the cable passes through grommet in to the box.

If it is water as I suspect and its entered the cable, I run a new cable.

Is the following a decent aerial for low reception?

http://www.ebay.co.uk/itm/New-Premi...t=UK_ConElec_TVAerials_RL&hash=item5404e14e8d
 
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I've tested the coax connector on the end of the aerial cable in the loft with an ohm meter.

The reading between the center pin and outer body is about 100k ohms.

What should the reading be between the center core and outer?
 
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Oh, dear, where do we start?

Firstly, if your existing aerial was working OK and the connections aren't badly corroded, there's no point in changing it. Simply replace the cable.

Secondly, without knowing your postcode, we don't know which transmitter you are using so it's impossible to recommend a suitable aerial.

Thirdly, the eBay aerial has only 7 elements in the photo so, despite its claims of "12-14dB Gain" I'd bet that its actual gain is no more than 5dBd. In fact it looks as if it could have a built-in amplifier, which is not going to help a weak signal. The purpose of an amplifier is to allow you to use a very long cable or to split the signal to several rooms - assuming (in this case) that your signal is strong enough.

The eBay aerial is a wideband "Yagi" type, for which much of the gain is concentrated in the useless "4G" band (60 - 68 ). All in all, not an ideal choice - especially if you don't need a wideband aerial.

The cable insulation resistance should be infinity.
 
Thanks for the posting Sam


I rather suspect testing of the cable should have been infinity and the 100k ohms reading makes me think there's dampness in the aerial junction box.

The cable in question is actually Freeview cable installed by a professional about 10 years ago - the cable has foil under the outer braiding.


The TV transmitter I use is Pontop Pike and I'm about 8 miles away, at the 4.30 o'clock angle from the transmitter.

This is similar to the aerial I have

http://www.ebay.co.uk/itm/PHILEX-4G...t=UK_ConElec_TVAerials_RL&hash=item3f28082aa1


Which aerial would you recommend please?


Are these TV fly leads decent?

http://www.ebay.co.uk/itm/1-5M-TV-A...ion_Video_Cables_Adapters&hash=item233119ab24
 
Links in this post may contain affiliate links for which DIYnot may be compensated.
You can make your own fly leads: http://www.satcure.co.uk/tech/tvplugs.htm

In theory, your aerial should be a "Group CD" type - although this is actually outdated because it still includes channels 60 - 68, which are not needed. But nobody makes anything closer so either a Group CD aerial or a log-periodic with a 4G filter would be best.

Without knowing your signal strength I can't be specific but I suspect a V10-36L would be fine. This is a "wideband" but cuts out the unwanted 4G channels 60 to 68.
http://www.satcure.co.uk/tech/best_aerial.htm
 
I would suggest a trip over to http://www.aerialsandtv.com and have a good browse.
Bear in mind that some aerials present a dead short at DC - so testing across the end of the coax isn't always meaningful. But 100k is neither one nor the other so it does suggest something isn't right.

As for cable, I'd suggest a good foam dialectric - water will wick along it a lot less quickly than down an air-spaced cable. It does sound like you have decent cable though - yes you should have both a copper wire braid and a copper foil.
 
I'd suggest a good foam dielectric - water will wick along it a lot less quickly than down an air-spaced cable. It does sound like you have decent cable though - yes you should have both a copper wire braid and a copper foil.
It seems to me that he has cable with water inside, which renders it useless. ;)
 
I'm going to mount the aerial in the loft as that apparently is its intended use.

A thought has occurred to me. When I installed the aerial, taking the old one down, I left it dangling on the cable which meant the cable was kinked around a cable clip in the wall.

Perhaps this caused some damage to the cable.
 
it wouldn't help, and leaving anything dangling on its cable is best avoided.
 
The aerial junction box seems to be suffering from rain getting in and causing partial signal loss.


Would it be practical to smear grease over the connections?


You need a drip loop.
 
Would I be right in thinking aerials with F connectors and a plastic protective over gland are a better type of aerial than those like mine where the cable passes through a grommet into the termination box ?
 
Actually I'd been thinking the other way round. The next aerial I buy will probably have an F connector - so you them have the problem of sealing the F plug both to the outside of the cable and to the socket.
 
ref: You need a drip loop.


If the cable travels up towards the aerial as with mine since the aerial is on the chimney stack, this effectively is a drip loop provided of course that the cable in to the junction box is running upwards ?
 

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