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In this months ‘My Automated Home’ feature, Nigel Giddings shows us his ingenious set-up that grabs a 3G signal from one corner of his rural idyll, beams it 300 meters back to his house as well as redistributes it to the family.  If you’re in the countryside as well as traditional ADSL or cable broadband is not available, then there’s still hope.  checked out on for all the pictures as well as details.

Submission by: Nigel Giddings – For ten years now domestic clients have had quick gain access to to the Web via ‘Broadband’ provided by ADSL. I’m sure the vast majority of people reading this will have a domestic ADSL connection with speeds exceeding 1 Mbs on the download, some may even have ‘Broadband’ provided by other techniques with some people lucky sufficient to have fibre running at 50Mbs! I would suggest it is impossible for people with this type of connectivity to envision what it would be like to be sent back to the dark ages (the late 90’s) when speeds were determined in Kilobits rather than Megabits…

My household as well as I just recently decided to have a modification of lifestyle, having lived all our lives within 20 miles of London we decided to ‘emigrate’ to Cornwall. We decided to move to a rural part of the county, no town or village life for us. since April we have been living on Bodmin Moor, many of you will have heard of Bodmin Moor as well as the Beast that is supposed to online here, in truth we are a few miles from the hamlet of Bolventor which is the place of Jamaica Inn made famous by Dauphine du Maurier in her book of the exact same name.

The drawback of such a excellent place is that innovation has passed it by. We do have mains electricity as well as water, although a few of our neighbours don’t even have that… We do have telephone service although the cable length is twice that which can support ADSL, I have likewise been told that even dial-up struggles because of attenuation on the line.

A view from the ‘back garden’

Off program I inspected all this out before we moved, however it didn’t stop us. With sufficient effort most things can be overcome as well as the place was as well great to pass by. choices for Broadband included Satellite or ADSL provided to one more place as well as prolonged by point to point WiFi. Mobile (wireless) Broadband wasn’t an choice since the only protection locally was provided by Vodafone as well as only as GPRS (2.5G).

Using 2.5G data – having moved home in April 2010 as well as since much of my time was being taken up with work in the middle east I had made no development with a broadband solution as well as the household were reduced to utilizing 2.5G with USB  dongles as well as GSM handsets  which was much less than adequate. E-mail would dribble in as well as browsing was extremely hit as well as miss, not suitable when your trying to begin a new business. However, even at these low data rates (circa 50Kbs) the household were normally utilizing between 4 and  5GBs of data a month.

A quick solution would have been to set up a satellite link. However, at £1,000 set up as well as a monthly charge of £30 plus it was not a affordable option. This may have been the solution however even at £30 a month you are topped at 3GB download which would not satisfy our needs based on our present usage when restricted to 2.5G. previously when we had ‘Broadband’ via ADSL we would take in 40 ~ 50GB a month.

A glimmer of hope – A recent see by a good friend reopened the discussion on what solution to use. My good friend as well as his other half utilize a number of mobile gadgets with different mobile networks, in specific his other half utilizes a ‘3’ SIM for data. My friend, who was more optimistic about mobile protection in Cornwall than me suggested we take a walk around to see what was available. I was somewhat surprised to see that we had 3G protection at the edge of our site on a piece of high ground. particularly when having reviewed the serving sites on the OFCOM website sometime earlier it suggested all the regional sites utilized by the different operators were 2G only!

 

Coverage plot showing protection of the ‘3’ network locally. The red star shows where we were able to get a signal. I have to congratulate ‘3’ on their prediction s/w. the blue star shows were I live

A bit of further testing showed that it was possible to get a 3.5G signal (HSDPA) with a theoretical maximum download of 7.2Mbs. happy Days!

What to do now? – So having established that ‘mobile broadband’ was offered in the area there was now the problem of exactly how to link it back to the house. Although the signal was still on our site it was 300 metres from the house. The limit for Ethernet over CAT5(e) is 100 metres. I did run into this limit when before at my previous home however was able to set up a simple 100M switch midway to act as a repeater, I was lucky as I had a garden shed with power to home the switch half method along the route. This was installed as a temporary solution (it lasted a couple of years as well as I cut the cable twice accidently during that time while cutting the grass!). The link did experience from a couple of lightning strikes in that time as well as any type of ‘permanent’ solution would requirement protection, either lightning arrestors or even an upgrade to fibre. this time around it was 300 metres without any power choices along the path as well as while I don’t cut the grass, the sheep do that, trying to protect a delicate cable over that distance with rough ground with roaming ruminants would be difficult.

With the advent of ‘Mobile Broadband’ a few fascinating gadgets have likewise been developed. One is the MiFi, a 3G Modem back to back with a WAP (WiFi Wireless gain access to Point) however these are meant for personal utilize with self contained batteries as well as low power outputs. one more choice is a 3G gateway, the Huawei B970 has a 3G transceiver with modem compatible with HSDPA (3.5G theoretical maximum download of 7.2Mbps), a 4 port 10/100 Ethernet switch, as well as developed in WiFi. You can likewise link an analogue telephone line as well as it is powered by a USB lead.

A Huawei B970 sitting on the cars and truck seat while parked at the top of the hill plugged into the cigarette lighter with a USB lead showing Power, WLAN, Signal as well as connection (Blue=3G) LEDs

The obvious thing to do was to utilize a 3G gateway at the hilltop as well as then have a point to point WiFi link back to the house. Power would at first be supplied by a leisure battery with a USB converter up until a more appropriate 230V supply might be provided. (That is one more story…)

The Huawei B970 is not designed for outside utilize so needs to be secured from the weather. since the speed archived on the 3G connection is dependant on signal stamina it likewise made sense to install the Gateway as high as possible in what was a marginal signal area. It was therefore decided to install the system at the top of a 20ft pole.

 
The Gateway found in a box on top of the 20ft pole on the ‘Hilltop’ looking towards
the home 300M in the distance. A power lead is taped to the pole as well as connected
to an 85AH leisure Battery on the ground

A view inside the box with a cigarette lighter 12VDC – USB 5V converter

Bridging the 300 metre divide – With the Gateway 20ft in the air, on a hilltop, in a weather condition proof box (plastic) as well as pointing approximately towards the house, with almost remove line of site, there was not sufficient WiFi signal to reach the home some 300 metres away. The free area loss for 2.4GHz over 300 metres is approx 90dB.

The system levels can be presumed to be:

Gateway Output power 20dBm

Free area loss -90dB

RESULT       -70dBm

Rx Sensitivity -80dBm

A view of the 300M WiFi path, the trees in the right half of the
picture interfere with the LoS (Line of Sight) slightly

By adding all these figures together we get a theoretical ‘margin’ of 10dB in our favour, that is to state the receiver gets -70dBm when it only needs -80dBm. nevertheless in the genuine world the link did not work without an extra high gain antenna. This is most likely since the WiFi output of the Gateway would be nearer 14 or 16 dBm, the losses triggered by encasing the gateway in a plastic box (no outside antenna) take off one more 2 or 3dB as well as the impact of some trees in the line of sight…. As you see things quickly work against you.

Unfortunately the Gateway does not have arrangement for an outside WiFi antenna (although you can link an outside 3G antenna). So the only method to get more gain into the system was to set up a directional WiFi antenna at the house.

There are many as well as different suppliers of WiFi high gain antennas as well as I was careful about a few of the quoted gain figures. having researched the losses as well as acquired some concept of output powers, receiver sensitivity, path loss, rain fade, fiddle factor, I guesstimated that I needed something like 10dB or more extra gain. dB (decibels) is a logarithmic scale as well as 10dB gain really means a multiplication of 10 times. To put it one more way, if you put 100mW into the antenna an antenna with 10dB gain will radiate 100mW x 10 = 1,000mW (1 Watt). note the UK power limit is 100mW (20dBm) as well as refers to radiated power out of the antenna including any type of antenna system gain.

I chosen a seller from e-bay offering a flat panel antenna with a quoted gain of16dBi for £25 inc P&P, that’s potentially 4W EIRP (effective isotropic radiated power) for 100mW input…  or to put it one more method a gain of 40 times. even if the antenna is 16dBi you will have extra losses because of connectors as well as cable (as much as 2 ~3 dB). The supplied cable was 500mm which is good, you see some antennas for sale with cables of a number of metres as well as any type of gain in the antennamight be lost in low high quality coax. You are much better off keeping the antenna tails as short as possible even if this means installing the transceiver outside. I have no method of accurately measuring the gains as well as losses in the system so it is impossible to verify any type of of these figures.

The WiFi client as well as flat panel antenna mounted in a weather condition proof box on the home balcony

A better view of the WiFi client showing the flat panel antenna more clearly

The WAP being utilized previously before it was installed as the WiFi client in the water resistant box.
The Antenna in the photo can be eliminated as well as the outside antenna connected
to the RP-SMA (Reverse SMA) connector

The WAP utilized at the home can be configured as client mode as well as is configured the exact same method you would configure WiFi in a laptop. The link which operates in the 2.4 GHz band has been set to a channel so as not to interfere with the home WiFi signal. Although there are 11 channels in the 2.4GHz band they overlap as well as so it is suggested to utilize channels 1, 5 as well as 11 to prevent co-channel interference. We are ‘lucky’ right here in that there is no other WiFi in the area so we handle our own frequency reuse plan, in a developed up area it is more of a free for all. It is possible to utilize 5GHz instead, which is a much quieter band, however devices for this is not as easily offered so I am going for the KISS principle.

Configuring the system – This is fairly easy, if you have configured WiFi in your own home this complies with the exact same principles. There are a couple of things to think about as this is a point to point link as well as not the typical point to multi-point as utilized in a typical WiFi install.

Security. This is always an issue. A minimum security demand is to utilize some type of encryption, most gadgets support WPA with a PSK (Pre shared Key). many gadgets enable MAC filtering; this restricts which gadgets can link to only gadgets that have been listed in the filter, in this situation the devices at the other end of the link can establish a connection. SSID Broadcasting, this can be turned off to ensure that your devices does not broadcast its existence as well as therefore other devices does not attempt to link as well as it does not show up if people scan (War Drive) while in the area of coverage.

Antenna Gain. It is much better not to over egg the power in the system. What you see as a strong steady signal is interference for others as well as might produce an escalation of power output in the area serving to raise the ‘noise floor’ working against everyone. one more disadvantage of high power is that the number of people in variety of your system boosts as well as might raise the threat of a security breach.

IP Settings. As you can see from the diagram below the link utilizes the personal 192.168.x.x ip variety as well as is different from the primary LAN IP variety (which for me is just an extension of the WAN). My LAN is secured by an ISA server Firewall. putting a hardware router right here would replace the ADSL Modem/Router in an ADSL network as well as would provide similar protection. The 3G router can provide DHCP however this is normally off as gadgets have static addresses as well as all IP web traffic should originate on the LAN as well as be directed via the firewall. It does mean, however, if you configure a WiFi gadget with the 3G gateway settings (and you configure the MAC filtering) that a direct connection can be made to the 3G gateway for testing as well as temporary Web connections.

 CLICK pic FOR full size VERSON – overview of IP settings

The results – The link has been in service for just over a week now. The enhancement in Web gain access to is enormous. utilizing 2.5G (Narrowband) meant that we experienced many timeouts while waiting on pages to tons (Facebook was almost always unusable) as well as downloading updates / applications as well as even keeping the antivirus database as much as date was a problem.

We now have gain access to to services like YouTube, BBC iPlayer as well as other streaming type services, something that just didn’t work before. I am still watching exactly how much data we take in as the Mobile Broadband bundle we have is restricted to 15GB a month as well as we are now averaging 400MB a day which will boost significantly if we utilize these multimedia type services.

As you can see from the Speedtest.net results we are getting a healthy upload as well as download speeds although the latency figures are much higher than you would expect to get from an equivalent ‘Wired’ service. These results have different with the day