TV aerial water ingress

[DIYspanner]

Problem identified.

I've taken the aerial down and there was some drops of water inside the junction box.

The fixing screw head are rusted and when I tried to take on of the screws out that retain the two rings, one screw head snapped off.

A new aerial I think.................. a a log-periodic aerial perhaps?



Would this aerial

http://www.ebay.co.uk/itm/S-A-C-Log...t=UK_ConElec_TVAerials_RL&hash=item2a1d15ad31

perform better than my present aerial which is this one

http://www.ebay.co.uk/itm/PHILEX-WI...t=UK_ConElec_TVAerials_RL&hash=item3f2811a95b

 

[Sam Gangee]

It states gain is "12dB" but that's meaningless. I suspect, with 28 elements, that it's the (now) old fashioned 9.5dBd wideband type.
Do you need wideband or grouped?
See http://www.satcure.co.uk/tech/Aerial_Groups.htm

 

[SimonH2]

Would this aerial

Who knows ?

Where are you ? What transmitter do you use ? How strong is your signal ?
There's no guarantee that the previous aerial was "right" for you, the best way to ensure you get the "right"* aerial to replace it is to work out the answers to the above.
Wolfbane's predictor will give you a good idea of what channels and signal strengths you should be getting, and http://www.ukfree.tv/starthere.php will tell you all about a transmitter (including if there are plans to move it's muxes about in the future.).

Eg, if I knew that I was using group A frequencies now and that was likely to remain the case then personally I'd probably go for a group A Yagi. Now I know that while we're on group C/D frequencies but there are plans to move to group A frequencies in a few years, I'd go for the Log 36 for a new aerial (actually, if it was easily accessible I'd probably still go with a grouped Yagi and replace it when needed).
While the Log appears to be a good wideband aerial, in effect about 3/4 of it is "wasted" if you only need narrowband - so why have all that aerial when for narrowband you can probably get more signal with a smaller grouped aerial.


* Being pedantic, there is no "right", just an optimal (for whatever set of constraints you impose) choice from a list of suitable ones.

 

[DIYspanner]

I've cleaned the aerial's junction box and mounted the aerial in the loft with a new length of cable and all channels appear to be crystal.


Thanks for all the reply posts, much appreciated.

 

[DIYspanner]

ref: http://www.ukfree.tv/starthere.php

Are aerials always mounted horizontally?

This site tells me that the transmitter I use is higher than my house so if I incline the aerial up a bit?


The site also reports that there are no obstructions.

 

[Sam Gangee]

If it has a "V" next to your transmitter name then the aerial should work best with its elements vertical. H = horizontal.

Aerial can be tilted slightly if that improves the signal strength.

 

[SimonH2]

Are aerials always mounted horizontally?

This site tells me that the transmitter I use is higher than my house so if I incline the aerial up a bit?

I assume you mean with the main boom horizontal rather than the elements. For the elements, they need to be horizontal or vertical to match the transmitter - typically main transmitters are horizontal and repeaters are vertical - but always check.

As to the boom, yes in theory it should point in the direction of the strongest signal. If you work out the angle, then unless you are very close and the transmitter is a lot higher than your house, then teh angle is very very small - for me it's something like 1000ft (1/6th of a mile) in 40 miles, which is a small fraction of a degree. But signal propagation is complicated, and the best signal may appear to come from above the horizontal - at least I've read advice that tipping the end up a bit can help in some cases.

The site also reports that there are no obstructions.

Well that's a good start.

 

[DIYspanner]

The splutter has been happening again after the TV has been on several hours.

edit
***
By switching the TV off at the wall for 10 seconds then back on, all is well again.
***

Its a TFT TV with integral Freeview so its basically the same as rebooting a computer I suppose.

 

[Sam Gangee]

As the TV switched itself off (standby?) it must be faulty.

 

[DIYspanner]

My apologies badly worded posting, I purposely switch it off for 10 seconds.

Have edited.

 

[Sam Gangee]

OK, but that still suggests the TV is faulty. The other possibility is interference to or from poorly screened cable.

 

[DIYspanner]

There's three cables

1.
The new one, sky dish quality, new and unused, that I wired from the aerial to the booster in the loft.

2.
The cable from the booster that's been in situ 21 years since the house was built. The cable is basic TV coax cable that feeds into a new Polar Click brand non-isolated TV socket in the sitting room.

3.
The fly lead which I made from sky dish cable as well.


Either an aerial position fine tune perhaps or as you say Sam, a fault on the TV.

 

[DIYspanner]

An auto-retune of the TV has stopped the splutter.


I wouldn't have thought the TV would need it since the aerial was pointed in the same direction but about 3 meters lower when I put it in the loft!