TV in bathroom - regs and safety

[SimonH2]

You never said this was a case where a masthead was not needed.

It should have been obvious from the way I was describing the installer as a cowboy for fitting one.

Why only 4 feet of coax? An aerial should be mounted well clear of the roof line. A typical mast/pole is 6 feet long. Then the cable has to get into the loft.

The purpose, as you claim to know, of the masthead amp is to boost the signal to compensate for losses in the cable. It also should not be mounted too close to the aerial or there's a risk of feedback - boosted signal leaking from the cable (and possibly amplifier) being picked up by the aerial. The mast is in fact fairly high (much longer than 6 foot) but there's only a few feet of cable between the amplifiers (the mast "head" amp being fixed right at the bottom) - hence my comment about there not being a lot of attenuation to compensate for in about four foot of cable.

 

[JohnW2]

Bit rough though

Functionally, it's fine, and does the job. If you're talking about aesthetics, who cares about 'looking rough' in a loft?

However, for those few who do care, I'm sure one could easily fashion a much more aesthetically-pleasing device, but I have better things to do with my time, particularly given how very rarely anyone goes into my dusty loft! Just a bit of bent plastic attached by the faceplate screws would look fairly neat - but what you've seen, which involved just a couple of solder tags and three or four cable ties, only took a minute or two to do. If I had had (if they exist) a long cable tie thin enough to go through the holes in the solder tags, I could have used just one, and the result would have been fairly neat.

Kind Regards, John

 

[ban-all-sheds]

Functionally, it's fine, and does the job. If you're talking about aesthetics, who cares about 'looking rough' in a loft?

How much of a problem do you have with uncontrolled access to your loft that you need to fix the wallwart in like that to stop people unplugging it so that they can power something else?

 

[JohnW2]

Recognised by who? Fuses of the following sizes are produced by various reputable manufacturers and marked with BS1362. Surely these are officially recognised? ...

Yes, it appears that any rating up to 13A is allowed by BS1362, although 3A and 13A are 'preferred' which I guess is what winston was referring to ...

The current version of the fuse standard, BS 1362:1973, allows any fuse rating up to 13 A, with 3 A (coloured red) and 13 A (coloured brown) as the preferred (but not mandated) values when used in a plug. All other ratings are to be coloured black.

However, if the Wikipedia is correct in what it says about BS1362, if you use anything other than 3A or 13A, the Standard imposes no requirements is terms of performance characteristics ....

The standard specifies breaking time versus current characteristics only for 3 A or 13 A fuses.

• For 3 A fuses: 0.02–80 s at 9 A, < 0.1 s at 20 A and < 0.03 s at 30 A.
• For 13 A fuses: 1–400 s at 30 A, 0.1–20 s at 50 A and 0.01–0.2 s at 100 A.

Don't forget the appliance manufacturers decided that a 13A fuse can protect a 0.75mm2. Look in the regs and that is not to BS7671.

To be fair, I think that anything that happens downstream of a BS1363 socket is probably outwith the scope of BS7671.

Kind Regards, John

 

[JohnW2]

How much of a problem do you have with uncontrolled access to your loft that you need to fix the wallwart in like that to stop people unplugging it so that they can power something else?

You (and presumably also Iggifer) don't seem to understand ....

... I do not have such an object in my loft, and would not personally bother to use one. The photo was of something I mocked up in a couple of minutes this morning (note the cardboard 'wall' to which the socket is attached!) to answer winston's question ("how do you do that") when I mentioned the possibility of making a wall wart "not removable without the use of a tool" (if one shared winston's concerns about misuse of the socket).

I do, however, usually label any such dedicated sockets in my loft or anywhere else (probably just with a Sharpie in the case of the loft!).

Kind Regards, John

 

[winston1]

Why ? and loft aerials ? what about them

My aerial was mast mounted before the re-thatch, moved to be at the side of the stack and the signal is just as good. 14 miles from Sandy Heath

View attachment 125841 View attachment 125842

The broadcasters recommend outside aerials 10 metres high.

I take it then that you, or your aerial installer, has the equipment to measure it then.

 

[winston1]

It should have been obvious from the way I was describing the installer as a cowboy for fitting one.

The purpose, as you claim to know, of the masthead amp is to boost the signal to compensate for losses in the cable. It also should not be mounted too close to the aerial or there's a risk of feedback - boosted signal leaking from the cable (and possibly amplifier) being picked up by the aerial. The mast is in fact fairly high (much longer than 6 foot) but there's only a few feet of cable between the amplifiers (the mast "head" amp being fixed right at the bottom) - hence my comment about there not being a lot of attenuation to compensate for in about four foot of cable.

Some masthead amps are actually built into the junction box on the aerial. Fuba and Triax both do that.

 

[JohnW2]

The broadcasters recommend outside aerials 10 metres high.

It's obviously impossible for them to generalise. I can see the mast of the repeater from which I get my TV signals from second storey windows in my house. With that line-of-sight path, I don't need (and don't have) a mast of any length.

Kind Regards, John

 

[bernardgreen]

The broadcasters recommend outside aerials 10 metres high.

Please provide evidence to support that statement, specifically that broadcasters recommend it.

I take it then that you, or your aerial installer, has the equipment to measure it then.

I installed it ( using the thatcher's ladders for access ), Google Earth assisted with the direction and a TV provided information about signal strength and quality.

 

[SimonH2]

Some masthead amps are actually built into the junction box on the aerial. Fuba and Triax both do that.

On SOME models, specifically those made for VERY weak signal locations. Furthermore, thinking (from memory) of something like the DAT45 or DAT75, the instructions specifically state that use of the builtin amp is optional - it'll work if powered, or not work if not powered. That does not invalidate what I said - that for most installations there isn't a need for masthead as well as a distribution amp, but people fit them because they erroneously think it'll make things better

The broadcasters recommend outside aerials 10 metres high.

Citation please. I strongly suspect that the general recommendation is to mount them "as high as practical" and "as high as is needed for the location". 10m is, roughly, the height of the chimney on an "average" 2 storey house - so it's not surprising that many sites (eg Wolfbane's reception predictor) default to that.
Where I live, some parts of town are shaded, so need a very tall pole; other parts of town work fine with a loft mounted aerial. If, like JownW2 you have LOS without even any pole, then you don't need it, and there are those who don't even need an aerial as they get a very strong signal and a bit of wire stuck in the aerial socket is good enough - ah, those days of fiddling with the loop of wire or the rabbit ears.

I take it then that you, or your aerial installer, has the equipment to measure it then.

As you suggesting that measuring the height of an aerial is a technically difficult task ? I think most of us possess the equipment (tape measure) to do it

 

[bernardgreen]

As you suggesting that measuring the height of an aerial is a technically difficult task ? I think most of us possess the equipment (tape measure) to do it

A stop watch to measure the time taken to reach the ground in vertical free falll then apply S= ut+ 0.5(at²) S = height, u initial velocity=0, a = acceleration due to gravity, t =time

Not the best way to do it

 

[winston1]

Please provide evidence to support that statement, specifically that broadcasters recommend it.

Google is your friend.

I installed it ( using the thatcher's ladders for access ), Google Earth assisted with the direction and a TV provided information about signal strength and quality.

Must have been difficult getting your TV up the thatcher's latter. And a waste of time as the TV provided information is a very poor guide, and different TVs give different results.
So you have't got proper equipment to measure it then? What was the bit error rate for example?

 

[winston1]

If, like JownW2 you have LOS without even any pole, then you don't need it, /QUOTE]

That is a very poor generalisation. There is a great difference between a 500kW transmitter LOS 1Km away and a 1w relay LOS 10Km away. The first will give severe overloading with a bit of wire and the second will require a high gain aerial.

ah, those days of fiddling with the loop of wire or the rabbit ears.

So called rabbits ears are VHF aerials for DAB or FM radio, so completely unsuitable.

 

[bernardgreen]

and different TVs give different results.

They sure do.....

Must have been difficult getting your TV up the thatcher's latter.

Clutching at straws are we ? ?

 

[Iggifer]

You (and presumably also Iggifer) don't seem to understand ....

No I don’t think that’s your actual setup, I just thought what BAS had written was pretty funny, not just in terms of what you’ve said, but in terms of the whole 13A outlet on a 6A MCB.