WiFi Coverage - Stage 2

Today I've been playing with setting up WDS (WiFi Distribution System) on the two DrayTek VigorAP 910C access points that beam the internet to the workshop. In principle this should enable them to function both as a point-to-point link between house and workshop, and function as access points for wireless devices nearby. For wireless devices in the workshop, this would mean that they could connect to the 910C in the workshop, and have that wireless traffic relayed to 910C in the house, and then onto the router and the wider internet.

Previously I'd used two different SSIDs for the networks on the 2.4GHz and 5GHz bands, as I found it useful to know which band a device was connecting on. But the DrayTek website makes such a big thing about keeping the configuration of the 910Cs exactly the same, even down to the wireless channel they're using, that I decided to set up all of the SSIDs and pre-shared keys on each 910C the same. This would also enable them and the Vigor 2860ac router to use band steering, and bump any capable wireless devices onto the 5GHz band automatically. This in turn would keep the 2.4GHz band as clear as possible, which should all help with the bandwidth of the point-to-point link with the workshop, which is only in the 2.4GHz band.

Setting up the 910Cs for WDS was fairly straight forward in the end. After setting the Operational Mode to AP Bridge - WDS, the settings and rules used for Point-to-Point mode transferred over. But whereas previously wireless devices at the workshop couldn't see an access point, they can now. Unfortunately it doesn't appear that in WDS mode the 910C can internally route traffic from wireless devices connected on the 5GHz band to the 2.4GHz WDS link, just like the point-to-point mode. So there's still a hole in my WiFi coverage at the workshop, in the 5GHz band. Looks like that trench is inevitable.

WiFi Coverage - Stage 1

The WiFi coverage through the house has never been particularly great, probably due to all the internal walls being brick, rather than wood and plasterboard. The broadband router and WiFi access point is in the hallway, near the telephone socket, probably just like a lot of homes. Unfortunately this puts it in between two brick walls that neatly divide the house in half, one of which also incorporates the chimney. The signal strength in the hall is superb, but by the time you get a room away it has dropped off noticeably, and it has completely gone by the patio. When we moved in a few years ago this wasn't a huge issue, but the number of wirelessly connected devices has slowly increased, as have my expectations. Additionally I'm spending more time in my man cave in the workshop, 30 metres or so up the hill from the house. Initially I used some powerline adaptors to serve up internet access from the router in the hallway to the workshop. But the combination of additional RCBs, 30 metres of cable and a second consumer unit meant that the powerline adaptors struggled to both maintain a connection and provide sufficient bandwidth. So a temporary fix was to run a very long network cable through the garden alongside the satellite tv cable, until I get around to digging that trench I was talking about several years ago.

The over-winter fix is the addition of a point to point wireless link, using a couple of WiFi access points, one in the house and one in the workshop. As well as providing internet to the workshop, they should also function as standard access points, eliminating the coverage blackspots in the house and garden. As we have a DrayTek Vigor 2860 router, I ordered a pair of DrayTek VigorAP 910C ceiling/wall mount access points, which would allow me to manage all three items from a single dashboard, and not have to log into each one individually to make any changes. I've been pretty happy with the 2860 router which, whilst being pretty expensive and not having the most intuitive user interface, has been very reliable, gets regular firmware updates from DrayTek, has got the most out of our broadband, and has a wealth of functionality. For example, when (if?!) fibre broadband arrives in our corner of Ironbridge the support for it is already built in.

When the VigorAP 910C access points arrived, the first thing I did was read the MAC addresses off of the labels, and add them to the routers IP binding table, so I'd know which IP address they were using if I ever needed to configure them individually. Then once the access points were plugged in, I opened up the router's management web page and opened up the Central Management section. The two 910Cs were automatically recognised and listed in the status table. The next thing to do is give the access points friendly names, so that you don't have to remember which access point is using which IP address.

The status table also stated that both access points were sent to me with v1.2.0 firmware, the last critical firmware update, but the DrayTek support website was showing a v1.2.1 regular update with a couple of new features and improvements, so I updated both access points as a matter of course. Using the 2860 router's central management feature, you can update multiple access points in one go.

You can also set up a WLAN Profile, which is essentially a template configuration for an access point, which you can then push to all the access points in one go. By doing this I ensured that finger trouble didn't mean that I ended up with different configurations at either end of my wireless link, and things like SSIDs and pre-shared keys were the same everywhere.

Anything you can configure on the access point itself, you can set up in the profile. It would be nice if you could duplicate the wireless settings from the router itself to the access points, but as far as I can see you have to copy the settings over to a template manually.

The long term plan, once that dastardly trench is dug, is to use the two 910Cs purely as access points, and have a wired link between house and workshop. So seeing as the temporary cable was in place, I first set up the access points in AP mode. This also was good to demonstrate the directional antennae in the access points, unlike the router which has omni-directional antennae. The 910C are designed to be wall or ceiling mounted, and so focus the majority of their wireless energy to the front of them. With the workshop being up the hill from the house, I mounted the access point there on the ceiling, with a line-of-sight to the house. At the house I went into the loft and mounted the access point on the side of the chimney, not only facing the workshop but also the patio and garden. There's going to be some energy wasted up into the sky, but the coverage in the house has been transformed, and you now have to go into the lee of the chimney to see any drop off in signal strength.

The next step is that point-to-point link, so that the network cable can be removed from the equation. The VigorAP 910C has several operating modes, one of which is AP Bridge - Point to Point mode.

This mode is only available using the 2.4GHz band, not the 5GHz band, and in this mode the access point doesn't broadcast an SSID so that other wireless clients can connect to it, it simply connects to another 910C access point. There are four key configuration changes to make for this mode. 1) Both ends of the link must be set to AP Bridge Point to Point mode. 2) Both ends of the link must have static IP addresses, and their own DHCP servers turned off. 3) Both ends of the link must be configured to use the exact same wireless mode, channel and channel width. 4) Each end of the link must be configured with the MAC address and security settings of the other end of the link.

Essentially in this mode, any network packet arriving at a 910C is duplicated at the other 910C, and in effect they become transparent to the network. This means that when devices, such as the IP cameras and my desktop PC, boot up at the workshop they can still request IP addresses and other network configuration information from the DHCP server in the router, because every packet transmitted in the workshop is replicated in the house. Just like having a cable, which we now don't.

For the 910C in the house, I've also left the 5GHz band in regular access point mode. So wireless devices in and around the house will connect to either the router or the access point depending on which signal is stronger. At the workshop the 910C cannot internally connect the point-to-point link with the 5GHz access point, so whilst I can turn on the 5GHz access point mode at the workshop, anything that connects can only see the other devices at the workshop, nor the house or router.

When I get the time, I'm going to investigate AP Bridge - WDS (WiFi Distribution System) mode, which apparently enables the 910Cs to be access points in both the 2.4GHz and 5GHz bands, and simultaneously keep the 2.4GHz point-to-point link in place. That would allow me to connect wireless devices, as well as wired devices, to the 910C at the workshop.

Electric Vehicles

There's been a lot of press recently, created by the UK government's policy to prohibit the sale of new petrol and diesel cars from 2040, about the inability of the country's power infrastructure to support a nation's worth of electric cars. Putting aside for one moment that it will likely be sometime between 2050 and 2060 before the last of the new petrol or diesel cars sold in 2040 are no longer in regular use, we still have at least 23 years to come up with a reliable power infrastructure to support widespread EV adoption. Personally I don't think this is a major issue, especially when there's a deadline to galvanise efforts. Also, given that we already have the solutions, in my opinion it is just a case of implementing them at scale.

The first thing to consider is the generation of sufficient electricity for all these additional EVs. Some analysts have calculated that there is a need for handful of new nuclear power stations to cope with the extra demand for electricity. This is based on an assumption of a high peak load when everyone tries to charge their cars simultaneously. Whereas, if every car had a sibling storage battery from which the car was charged, the challenge becomes charging the storage batteries rather than the cars. This is significantly easier, as the storage batteries are always connected, and a simple load balancing algorithm would spread the load on the grid. Ensure that the storage battery has twice the capacity of the EV battery, and you can charge the storage battery at any time of the day or night. This technology already exists, under the banner of Demand Side Management, so if every household across the country had a storage battery tomorrow, the grid would continue to work just fine.

For sure millions of EVs will require more electrical power than is currently generated. And localised micro power generation is a potential solution for this additional power. Even in the northern latitudes of the UK during winter there is solar energy to be obtained from roof top PV panels. When the likes of Ikea can sell you PV panels and a storage battery for a few thousand pounds, you can be sure this is a mature, proven technology. There is still a major need for a country-wide power grid though, as solar and other renewable energies are not evenly distributed. But considering the vast storage battery capacity now available from the paragraph above, the contribution of renewable energy can now be significantly higher than fossil or nuclear. In theory, with sufficient storage capacity, there is no reason why all the country's energy cannot come from renewable sources.

But where are all these batteries going to come from? Are there sufficient rare-earth metals to produce them. This is another bit of scare mongering that has made the mainstream media, perpetuated by journalists that can't even fact check on Wikipedia. For starters rare-earth metals are not rare, as in scarce, but are rare, as in not found conveniently in seams of ore. This does make them more expensive to extract, but also makes them easier to find, because they are pretty much everywhere. Secondly, rare-earth metals aren't widely used in batteries, so there's no need to extract large quantities of these plentiful metals to build batteries. Rare-earth metals are used in electric motors though. But the good thing about that is that electric motors are about the simplest mechanical system you can build, and are extremely reliable. Essentially the electric motor in today's EV is maintenance free for life.

So far my thoughts have been based on the state of current technology. Imagine the world 23 years ago, and now think forward 23 years, noting that the rate of technological development is accelerating. Electric motors and EVs will be more efficient, requiring less energy. Batteries will have higher energy density and charge faster. Micro generation of solar energy will be widespread, as will macro generation from wind, wave and tidal sources. If anything, having stored energy distributed widely around the country will given us a more resilient and robust power infrastructure, not the frail brown-out prone grid the mainstream media portrays.