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Re: [LUG] Ethernet over 100 metres


On 21/01/14 16:51, Rob Beard wrote:
> Hi folks,
> We're looking at running an Ethernet to link two buildings which are
> quite a distance apart (around 220 metres, possibly around 230 metres
> maybe).
> Now I understand that the official limit on length of CAT5 is 100
> metres, however I'm wondering if anyone has pushed the length any further?

You could probably go a bit over 100m, but certainly not more than
twice that distance.

> The thought I had was to run CAT5 to a waterproof box just under half
> way, in there have a 10/100 switch powered by POE, and run the rest of
> the cable to the other location (this might be about 130 metres).  I'm
> not sure if putting another switch on the cable run (again POE powered)
> would be an option due to it being outside (it could be tampered with,
> or eaten by a horse).

Even if you can manage to make it waterproof you'd still have to contend
with temperatures below 0C. (Potentially above 40C.)

An above ground cable would need catenary. Below ground would really
need to be in ducting. (Expect the ducting to become filled with water.)

> Other than Ethernet (and wireless which probably won't work due to line
> of sight issues), what other options might we have?

You don't need a direct line of site for wireless. You might even be
able to find something which will reflect the signal. (The wavelength
being around 125mm for 2.4GHz and around 60mm for 5GHz.)

> I've even considered 10Base2 coax cabling (is it still available?) or
> Thick Ethernet? (only ever seen that once at school back in the 90s,
> again is that still available?  Can it go faster than 10Mbit?)  Or...

IIRC the maximum length for 10Base2 is 185m. 10Base5 will do up to half
a km, but you might need to find a museum for the parts.

Both would be limited to 10M

> okay, maybe I'm verging on crazy now... Token ring?

Probably from the same source as the 10Base5 kit. But only 4M.
> Fibre was considered but I'm not sure if it would be too fragile to run.

Whilst fibre patch leads might look a little flimsy the 4 or 8 core
cable which is typically run between patch panels is probably at least
as tough as CAT5. If you are still worried SWA fibre cable exists.

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