Rooftop access and power

[tony sayer]

What exactly are you up to?, some sort of wi-fi networking if that so POE is good for that!...

[Weatherlawyer]

Will you be employing failed car thieves?

You might get a lot of sympathy from the police if you do.

[tony sayer]

Why do you need computers for this?..

Works very well, we use industrial grade equipment Alvarion Breeze net and thats fine with POE but the same with anything else!...

Still odd why you need the PC n the roof, can you explain it all a bit more, sounds interesting:)

[Owain]

I would suggest you team up with a TV aerial rigger, or possibly even better a street lighting contractor with a cherrypicker, and get them to do all the high level work. The Health and Safety At Work Act almost certainly applies to what you are doing; even if it doesn't you need to be fully insured for this in case you injure someone or damage someone's property.

Apart from the electrical side (and Part P is likely to apply, but even if it doesn't you need someone who is competent and insured to sign certificates for all mains wiring) you will probably need a working at height certificate, if you are using an access tower you may need a scaffolder's cert, the ladder or scaff etc will need to be BT approved with compliance certificates, as will your safety harness with fall arrester, I think there is a specific cert for operating a cherrypicker (or even working from one), you'd need a written risk assessment ....

Working on your own house is one thing, working on several people's is quite another.

Owain

[The Natural Philosopher]

This is insane.

What you do, is get a WiFi router and run a few meters of cable to a rooftop antenna.

Ditto for the actual computers.

Or if you are close enough,m an external antenna in a window usually works well.

No need to take mains up there, and any aerial rigger will help you get the main aerial rigged.

[David Hansen]

On Tue, 06 Jun 2006 21:11:20 +0100 someone who may be The Natural Philosopher wrote this:-

The OP would do well to explain the problem properly.

How big is the network to be? How many access ports are there to be roughly? How will they communicate with each other? How is the network to be segmented? Is reception required inside, outside or both? From these I think the OP could get some very good advice.

As for antennas, a reasonable starting place is

though many of them are more expensive than the access port they are connected to and the cautions on installation should be noted.

[tony sayer]

In article , David Hansen writes

Best outfit for wireless networking equipment is,

[elyob]

The proper cable is expensive and drops signal horrendously when it comes to metres.

There's no cheap way of doing this, but I do look longingly at rooftops and hope it can be.

I'll look at POE a bit more. I still need the rooftop climbing experience. I saw a "hell" program the other day. The tiler was ripping the roof apart when he brought down the ladder.

I hope to, at least, know a little of what I'm attempting. And do it properly.

Nick

[David Hansen]

On Wed, 7 Jun 2006 00:29:59 +0100 someone who may be "elyob" wrote this:-

I don't think anyone has claimed otherwise. It has been the case throughout the history of radio transmitters. Ethernet is a far better way of moving data around buildings.

However, if there is to be reception in the streets then access points in windows may be adequate. A notional access point in the loft and a short cable to an external antenna is a lot better than equipment outside.

[Andy Luckman (AJL Electronics)]

Quite. If you come to Gloucester, our police even feed and water fugitives.

[John Rumm]

I can't see why you would need a computer or mains outside. At most you would need a small wireless access point or router and an antenna. Placeing the WAP close to the antenna solves the attenuation issue. The router needs be no bigger than a typical masthead amplifier as fitted by aerial riggers all over.

The router/WAP will require a low voltge supply, and PoE is the way to go for remote boxes like this.

Where are you thinking of mounting the kit? On a pole on a gable end wall, or lashed to a chimney stack? A "standard" assembly could be made up on the ground with a short pole, WAP and antenna all mounted. Hence the only roof work would be fixing the pole (and rotating to a suitable alignment), then connecting the data cable.

[Paul Andrews]

Personally, I'd try and find somewhere where it's been done before and get feedback on how they did the installation and the problems they have encountered.

My first thoughts are that it would be advisable to have as little as possible mounted on the roof and to install any electrical equipment inside in a loft. Apart from the obvious advantages of keeping the kit out of the weather, the thought of installing kit like a router on a rooftop horrifies me - not only because of the hassles of running data cables from the roof, power supplies, weatherproffing and all that, but how are you going to sort things out when it goes wrong? At least if you only install kit in a loft space, you won't be up ladders trying to look at blinking LEDs, or checking power supplies in the pouring rain. It really is important that you not only consider how to install this kit, but consider how it will be maintained, because it will go wrong and people will make loud noises to get it fixed - pronto!

Well that's 2p from me..

Paul

[elyob]

Okay, a lot of people are warning against placing outside, and it would significantly increase cost. How then, would someone be able to pass a cable directly through the rooftop and not create a problem with leaking etc. I'm not going to just read it here and rush out with a drill, but just wanted to know whether it's feasible rather than running through the soffit board and back up the roof, which is just too much cable.

However it does look like power over ethernet may be okay, and could be worth a go. Possibly a NEMA 4 enclosure (where can I buy these from at good prices?). Then getting a "very good earth" is what I've been told.

I test ran a box for a year in a friends loft, and apart from the occasional power off & on, it ran fine.

Thanks all for your advice!

[John Rumm]

WiFi coax is thin enough you could simply take it under a tile, come up ten inches or so (so that you are well covered by overlaps from the tiles above) and pop it through a small hole in the sarking.

If you are bringing the antenna connection in on a thin coax then the router/ap can be inside.

[dennis]

A USB stick sealed in a piece of plastic pipe (25mm conduit) with a USB cable down to the computer (or a hub) in the roof space is safe and doesn't suffer from any signal loss. You might even be able to install it through a plastic soil pipe vent without going outside (drill a hole and poke the conduit up, seal with a suitable sealant and some tape).

What sort of range are you aiming for?

[elyob]

Much bigger range, and will be using specialist equipment. Will be using big omni antennas and the like.

i.e.

[tony sayer]

Except that the losses at wi-fi frequencies 2.4 and 5.8 Ghz are very high and need large low loss cables .

Short pigtails are bad enough already!....

[tony sayer]

In article , elyob writes

Can you explain the need to have computers outside on the roof?. This is the bit I cant see the need for unless you have some new way of implementing mesh networks?.

I hope that your not trying to use the wireless card "in" a a PC for that sort of reason if you are then your going about this in a real arse about face way.........

[John Rumm]

You would only need 18" or so in some cases to get through tiles though. Unless you are going for absolute maximum range you could compensate with a slightly higher gain antenna.

[Guy King]

The message from tony sayer contains these words:

It's got to be line of sight so the little demons can wave to each other, innit.