inductive?

Ha!

As a matter of fact the brewery was too mean to run a replacement mains cable down to the entrance, so the pub sign has a ludicrously ineffective solar powered light.

Bill

You've given me an idea. An extra wheel running on the gate rail turning a generator!

Bill

Replying to Andy and Tweed. I did wonder about a reflective strip. The purpose of the illumination is

1. To have some fun
2. So I can see if the gate's closed without looking on the CCTV (it's in a dark place)
3. To reduce the chance of a vehicle hitting the gate.

Bill

I sure they'd look better on a Christmas Tree!

Ah, that explains it. I wasn't familiar with the gates to Wright Towers.

Several years ago I added some contact strips for the sliding gate at work. I ran the wires to them via a carbon fibre fishing rod sitting half way back from the gate. It lasted for a few years until a more modern, safer, gate was installed. The whip in the rod meant the loop of wire did not sag much as the gate opened.

Could mount a tree on the gate!

Bill

That's the way to do it. Heath Robinson would be proud of you...

recirculating pump on the gate post so there's a continuous stream of water.

Water wheel and generator on the gate so it intercepts the stream when the gate is closed.

We'll all want it in the DIY FAQ... probably under humour :)

Andy

Acquiring a Bicycle wheel with a hub dynamo could be a solution for that method, or just fix an old style bottle dynamo to the gate so that its wheel rubs the rail.

With all your aerial experience can?t you fix one on the gate to get some energy from Radio 4 long wave or something.

GH

It's a pity it isn't possible to rectify UHF with a diode, because the gate has clear sight of Emley Moor.

Bill

You would need a 8kW solar array, and probably 1.5kWh of storage to make that a reliable year round proposition. So not practical on any level.

I was going to suggest a series of reflectors/light-guides/fibre-optics illuminated from one 24W light source when the gate is closed. Anyway a roadsign type of retro-reflector would pick up the vehicle's headlights.

How about if I mount a magnetron on a big satellite dish and point it at a sealed container of water bolted onto the gate? The water boils, powers a little Mamod steam engine that turns a dynamo which charges the battery. Simples.

Bill

Wouldn't a small illegal immigrant to power the dynamo be cheaper?

Owain

Or-- (Lightbulb moment) If I mounted a loudspeaker near the gate and put a microphone on the gate, and played really loud music with a lot of low bass, the mike output should be enough to charge a battery. Simples.

Bill

Or paint the gate up as a shrine and get all the local devotees to come and light candles (for a small donation).

Owain

You sure about that?

I'd expect that you could rectify it with a fast enough diode, and get a few microwatts just like you do off medium wave. What you wouldn't get is any easily translated signal, especially from 256QAM.

Andy

Each of the eight muxes produce something like 15dBmV across the 75ohm terminals of a modest aerial. The bandwidth of each mux is approx 8MHz. Anyone case to make a stab at the total power available?

Bill

Why not take one of Harry's solar panels, silver your satellite dish to reflect and focus a floodlight onto Harry's panel on the gate?