Take a look at the Harvard LeafNut system. Basically, all street lighting is controlled by a central computer, and the central computer communicates with the huge branch nodes located on specific lanterns via a mobile phone signal. These big branch nodes then communicate with a number of lanterns fitted with antennas via a radio frequency signal. So basically the branch node is a bit like a telephone exchange for lots of individual lanterns.

There isn't anything to stop existing lanterns being fitted with radio frequency nodes, including the Harvard LeafNut antennas, but when it comes to LeafNut antennas, fitting them to existing lanterns is a bit like fitting a minicell, so more fiddly than plugging in a photocell into a NEMA socket, although radio frequency NEMA nodes are available from companies such as Mayflower and Royce Thompson. It also depends on what the council wants from radio frequency. Radio frequency is most advantageous when it can be used to dim lamps and communicate information about lamp burning hours or the status of the lamp (on/off/failed), rather than merely being a means of switching a lantern on or off.

Councils often say the benefits of radio frequency are that burning hours can be kept to a minimum and dayburning made a thing of the past, although I have seen dayburning radio frequency controlled street lighting and there weren't any street lighting crews in sight, and given that it was a Saturday daytime in a town centre I don't expect that would have been the least disruptive time for maintenance anyway.

Well, all I know about is the Zodion 'Vizion' system, as I read up about it after I got my QSM with it fitted! Essentially, the system is set up with one lantern having the pigeon-sized controller sitting normally where the photocell goes (and the zodion one uses the same sized hole as a minicell), and then you have anywhere between 1-200 additional lanterns with radio antennas fitted. The engineer who sets up the system can then log in to a special section of the Zodion website (yearly fee applies for use of "the host") whereby they can set data and instruct the controller what information to relay back to the site, and what commands are applied (ie part night dimming, dim levels etc). This information is sent from the website server via WiFi and 3G to the pigeon-sized controller (the controller, I think, has it's own little WiFi moden inside), and the controller then makes sense of the data and relays it back to the lanterns via the antennae. Each antenna is connected to the special ballast via a data cable, and so 2-way information can be passed. If a radio controlled lantern is dayburning, that will be because it has lost it's connectivity to the system - and the ballast is "fail safe" so it'll switch the lamp on if a radio connection is lost. When the full York system now present along Coney Streer, St Helens Square, New Street, Market Street, Spurriergate was first set up, there was a period of 2 weeks whereby random lanterns were dayburning.

Most lanterns can be adapted, as it only required changing ballasts and using a minicell-sized hole (20mm) for the wireless device (which may also include fitting a part blanking plate to the NEMA socket hole so that it is reduced to a 20mm hole). Quite why the older lantern is being used as the controller I have no idea - but when York were trialling the system, the main controller ended up on loads if different lanterns - every other week it was on a different light, before finally settling on the QSM I now own.



That's briliant, that there are three of them!

It is becoming more widespread, although it is still unusual at the moment. The technology has proven itself, but the capital cost of installing radio frequency systems is relatively high, and many councils cannot yet justify the relatively high costs of the systems. Street lighting PFIs are one area where radio frequency is becoming popular. For example, the new Surrey PFI is using radio frequency, and the South Coast PFI will also use radio frequency. One day it is likely that radio frequency will become almost standard, probably once the cost becomes more attractive. I expect that in the early days of photocells that uptake was probably slow due to photocells being more expensive than time switches, but photocells soon became established and commonplace.

Another place using radio control is North Lincolnshire... though they're using the Zodion system.

Ipswich also uses what looks like the Harvard system, although it was only in one area on what looked to be a newish road alignment. Plymouth is also starting to use radio switching.

A giveaway for me, in my area, that radio-controlled switching had been fitted to existing or new lanterns was that all the lanterns in the section would dayburn for a few days after the system was fitted. Why does this always happen? They're all fine now.

Interestingly, although all new Vectras (and some existing ones) in Cleveleys were fitted with radio-control towards the end of 2009, Beach Road which was very recently relit with Vectras does not have radio-controlled switching but has ordinary minicells. Perhaps the other sections are a trial although if so, they're a pretty big trial taking in many main roads around Cleveleys, Carleton and Poulton!

Btw, I believe Lancashire uses the Harvard LeafNut system (daft name alert! ).

I can only think that the lanterns dayburn because either
(1) the lanterns aren't communicating properly with the controller, or
(2) the data for switching times hasn't been sent at the time, or some other configuration of the controller hasn't been properly finished.

I reckon number 2 is the most likely scenario since the dayburning has happened with every scheme that has been introduced for a few days. Perhaps there is a delay before the data is sent to the lanterns.

I know the zodion system has a delay... their write-up states that data can be sent to lanterns "in as little as a couple of hours", thus 2hr is the minimum time (apparently) that data is sent from the server to the lights.

I've noticed this the other day in Mirfield as a couple of lanterns there have ariels for the RCS and apparently there is a row of Arcs between Cleckheaton and Heckmondwike with them too.