ASBO (Achmore / Strome Ferry Broadband Organisation)

CBS Feasibility Study

Community Broadband Project for Strome Ferry, Achmore, Portchullin, Ardnarff and Craig




18 March 2013





1       Acknowledgements. 3

2       Summary. 3

3       Introduction. 4

4       Objectives and Statement of Requirements. 5

5       Outline network design. 6

6       Outline Implementation Strategy. 11

7       Eligibility. 12

8       Security. 13

9       Restrictions (a comparison with BT Broadband). 16

10          Bandwidth and speed (latency). 18

11          Contention. 19

11.1      Data downloads. 19

11.2      Streaming video, TV & Movies and monthly download allowance. 20

12          Contracts and charges. 22

12.1      Terminating your BT contract. 22

12.2      Joining the CBS. 22

12.3      Monthly charges. 23

13          Service level agreements and compensation. 24

13.1      Internet Service provider. 24

13.2      CBS. 24

14          Reliability, maintenance and problem resolution. 24

15          Finances. 26

16          Key success factors. 29

16.1      Technology. 29

16.2      Funding. 29

16.3      Community Involvement. 30

17          Next Steps. 31

18          Conclusions. 31

19          Appendix A - Outstanding Decisions for CBS members. 33

20          Appendix B - Statement of Requirements. 34

21          Appendix C, questions and answers from our website. 35

22          Appendix D, possible enhancements to the local BT exchange. 36


1         Acknowledgements


Thanks are due to Professor Peter Buneman and William Waites of Edinburgh University for their encouragement, guidance and patience.

Much use has been made of information from many of the people who attended the Community Broadband Meeting at SMO on Skye.

A special mention should be made of the Tegola and HebNet websites which contain much theoretical and practical information. 

2         Summary


When forty three households are connected to the new system there will be enough income to buy three or four bonded ADSL lines which should provide at least 20Mbps bandwidth, i.e. forty times more capacity than we have at the moment.

The wireless network bypasses the current copper telephone wires and is not subject to the restriction in bandwidth they impose. It will be able to support speeds up to 150Mbps and therefore will be able to cope with any likely enhancements introduced by BT.

The running costs of the system will be between £200 and £300 per month, depending on the number of lines. Forty three subscriptions at £13.50 will provide an income of £580.50 per month.

The surplus income will be used to pay off loans taken out to buy the equipment, maintenance and to fund future enhancements. When all loans are repaid it may be possible to reduce the monthly subscription.

However there will be a severe cash flow problem for the first few months as we implement the system.

Most people want their current BT agreement to expire before switching to the new system. Assuming an even distribution of BT contract end dates and a phased implementation plan covering different groups in the area we would accrue debts of over £1,600 within the first six months of operation; money that could otherwise be spent on equipment.   

To reduce the cash flow problem is proposed that unbonded ADSL lines are used for the first few months, whilst the system is implemented. When most users are connected the connection to the exchange will be switched to bonded ADSL lines. This will keep running costs to the minimum during the implementation period.


3         Introduction


When this project was first proposed it was hoped it might be possible to get two dozen people interested with luck.

The original suggestion of speeds of 5 Mbps and estimate of costs given to the Community Council (CC) was based on less than 24 subscribers.

As of 1/1/2013 we had forty three “signed up” and the CC loan will not be enough to buy all the equipment and services up front.

This feasibility study only covers those forty three households that have made a firm commitment to switch to the new system.

The system is not closed to new entrants and anyone is free to join at any time. However those that “signed up” by the 1st January will be given priority, others will be connected as soon as possible. No provision has been made for any extra equipment that might be required for those that join later. If the network requires a redesign and additional backbone equipment there may be a delay whilst funds are raised.

All costs have been calculated on the most robust design even if other cheaper options exist. For example it might be possible to connect Portchullin without a relay station at Ardaneaskan as there is a direct line of sight from Portchullin to Plockton. However this would be at the limit of the equipment and needs to be tested. In cases like this the more expensive option has been used when calculating the costs.

The system will be built from readily available industrial strength components. The system will comply with all relevant laws and contractual agreements.

Please note the following:-

It may be necessary to find a location for a relay in Ardaneaskan and North Strome; it is very likely when residents there are contacted they will ask to be connected to the CBS. This might mean another dozen or more households. No provision has been made for these additional households in the design or costs in this document. If a relay is required for Portchullin / Craig we will have to discuss this further with the residents of Ardaneaskan and North Strome. It has been agreed that residents of Ardaneaskan and North Strome will be allowed to join the CBS under the same terms as the rest of the members.

Unless stated otherwise the system described below relates to a 20Mbps bonded ADSL system, the separate ADSL line solution is only an interim and will impose restrictions on performance and capacity.


4         Objectives and Statement of Requirements


The Objective is:-

To create a locally managed industrial strength broadband service with speeds increased by at least a factor of 10, whilst reducing the costs by at least 10%.

I.e. at least 5Mbps at £13.50 per household per calendar month

The objectives were agreed and signed off by all participants on 21st Dec 2012

The initial subscription rate will be £13.50 per calendar month, if this is exceeded no one will be held to their commitment to switch to the CBS.

If the objective of a minimum of 5Mbps is not demonstrated no one will be held to their commitment to switch to the CBS.


The Statement of Requirements (SoR) can be found in Appendix B.

The SoR was agreed and signed off by all participants on 31st Dec 2012


5         Outline network design

Schematic Diagram:-



Key to the Schematic diagram:-

This diagram shows the key components in a section of the proposed network.

Wired connections are shown in black, wireless links are shown in red.

Starting in the top left corner there are three telephone lines from the BT exchange to a bonded ADSL router which will be linked to an Ubiquiti dish via an Ethernet cable.

This will then link to a relay station above Achmore via a wireless link and be received by dish A.

The relay station will forward the signal to The Glen and Ardnarff (B & C) and provide access points to cover Achmore and Braeintra.

The bottom of the diagram shows the equipment installed at an individual household.

An Ubiquiti Nanostation which will link to the access point on the hill, this is connected via an Ethernet cable to a Wi-Fi router which replaces the BT Home Hub (see below) which in turn provides connectivity to PCs via Ethernet cables or Laptops via domestic Wi-Fi.

Detailed description of Equipment


The Ubiquiti equipment replaces the functionality of the BT Home Hub which can be viewed as consisting of five components:-

1) An ADSL modem, which connects to the BT telephone socket and the wide area network (WAN).

2) A Wi-Fi access point, which allows other Wi-Fi devices (e.g. laptops) to connect to the domestic (local) network (LAN).

3) A four port switch, which allows wired Ethernet devices to connect to the LAN.

4) A router which decides whether traffic should cross from the LAN to the WAN and vice versa.

5) An USB port

The Ubiquiti equipment provides the same functionality but needs two devices, typically one outside and one inside.

1) A Nanostation is located outside to which must have a clear line of sight to the local access point allowing access the WAN via Wi-Fi, replacing the ADSL modem.

2) An Ubiquiti AirRouter is located inside the property and is connected to the Nanostation via an Ethernet cable.

3) The Ubiquiti AirRouter has a four port switch, equivalent to the BT Home Hub.

4) Either the Ubiquiti Nanostation or AirRouter can decide whether traffic should cross from the LAN to the WAN and vice versa.

5) The Ubiquiti AirRouter has one USB port.

N.B As there is no contractual restriction using the BT Home Hub. When the test bed has been set up a test will be run to determine whether it is possible to continue to use the BT Home Hub.

If the router component of the BT Home Hub can be disabled, it should be possible to connect it to the Nanostation using one of the Ethernet ports. This will save some money on new equipment but there will only be three Ethernet ports available for use on the LAN.

If households decide to purchase their own routers they will be responsible for the configuration and they will have to ensure that they are compatible with the rest of the network.

Domestic installation procedure

1) The householder will decide where they want the service delivered inside the property, in most cases this will probably be the location of the old BT Home Hub.

2) The household will decide where they want to locate the Nanostation. The Nanostation must be in line of sight of an access point which will usually be located at the relay station. The Nanostation may not need to be mounted externally; a window with the right outlook might suffice depending on the signal strength.

The Nanostation needs to be high enough for security (if outside) and to ensure that the line of sight will not be obstructed by passing traffic. E.g. If there is a road between the premises and the relay station then allowance must be made for high vehicles, otherwise just above head height will suffice.

Most properties have an unrestricted line of sight to the relevant access point, however a few properties are partially obscured (mostly by trees) and in these cases assistance will be given to find a suitable location to mount the Nanostation.

3) The householder should decide where an access point can be created through the outer skin of the house if required. This will need to be at least 8mm in diameter to accommodate the Ethernet cable. Power is provided to the Nanostation via the Ethernet cable and a suitable mains power socket will be needed close to the point where the Ethernet cable enters the property.

4) The householder will agree a date for installation at least two months ahead of their BT contract expiring.

5) Equipment will be configured ready to install by one of the technical volunteers.

6) The cable will be terminated with a crimped RJ45 (Ethernet) plug and connected to the Ethernet power adapter which is used to power the device.

7) A technical volunteer will visit with the equipment and help the householder install the Nanostation and external cabling. Typically the Nanostation is fixed to a downpipe using cable ties although other fittings are available.

8) If applicable a Wi-Fi router will be installed.

9) Before leaving the technical volunteer will confirm the installation is working.

10) Apart from the immediate connection to the Nanostation and its power supply all internal cabling will be the responsibility of the household. If it is not possible to route the cable into the property near the existing BT Home Hub a reasonable amount of Ethernet cable will be provided, for internal cabling.  

Backbone Equipment

BT Exchange

Near to the Plockton BT exchange we will look for a location to host a source transmitter for our network. We will buy three ADSL bonded lines; this will give us a maximum speed of a little under 3 x the maximum available from one line, probably around 20Mbps.

Located by the three telephone lines will be the following equipment:-

A mains power supply, protected by ELCB if required

A mains electricity meter, so we can pay for the electricity consumed

A router, provided by the bonded ADSL service provider

Ideally this equipment will be inside at the host site, but if necessary it can be located outside in a waterproof case.

An Ubiquiti Nanobridge M5 AirMAX 22dBi - MiMo 2x2 which must be mounted externally with line of sight to a relay station on the hill between Achmore and Stromeferry.

Relay station above Achmore

At the source of the power for the hill:-

A mains power supply, protected by ELCB

A mains electricity meter, so we can pay for the electricity consumed

On the hill overlooking Achmore:-

This equipment will be located on the hill in a waterproof case.

An Ubiquiti ToughSwitch, which connects all the other equipment

An Ubiquiti Nanobridge M5 AirMAX 22dBi - MiMo 2x2 with line of sight to the BT Exchange in Plockton

A second Ubiquiti Nanobridge M5 AirMAX 22dBi - MiMo 2x2 with line of sight to the relay station in The Glen

An access point consisting of either two Nanostations or two Ubiquiti Rocket M5s and sector dishes which will give 180 degree coverage. Signal strength measurements will decide which is appropriate.


Overlooking Ardnarff–

A mains power supply, probably from the Achmore relay station

An Ubiquiti ToughSwitch which connects all the other equipment

This equipment will be located on the hill in a waterproof case.

An access point for Ardnarff consisting of a Nanostation or Ubiquiti Rocket M5

Finally, what are the health issues regarding the system?

The wireless part of the system uses the same frequency as Wi-Fi, so if you already have that then your house is already subject to microwave radiation.

Here are some details from the website of one of the vendors:-

Are Wireless Networks a Health Hazard?

A lot of wireless networking devices transmit on the same frequencies as Microwave Ovens so you may think so, however, the transmission power levels are so low that the thought that they might be harmful is currently mere speculation, with mobile phones being a much greater potential health hazard.

However it is wise not to stand close and in a direct line with one of the focused transmitters which use a reflective dish to create a concentrated beam.


6         Outline Implementation Strategy


The approach taken in determining the order of connections is to connect the maximum number of users with the least expenditure on equipment. This will maximise income and reduce the need for additional capital funding.


The sequence may be altered as the implementation progresses.


Phase 1, Set up a test bed and demonstration, funded by a loan from the CC.


It is recommended that a loan from the CC is used to fund enough equipment to set up a trial which will bring a signal from Plockton exchange to the hall and that we borrow the minimum capacity required to demonstrate 5 Mbps bandwidth. The demonstration will be available in the hall for a brief period but long enough to allow members of the CBS to satisfy themselves that the system is proven.


Phase 2a, A volume trial with 10 people using the relay above Achmore, to confirm what capacity we will need, funded by a loan from the CC.

Assuming the demonstration is successful it is proposed a volume trial is set up for a limited period with ten users. The trial will be completed with one ADSL line which is one third of the proposed capacity.

Phase 2b, Add another 10 on the Achmore relay.
Phase 2c, Add the remainder to complete all those on the Achmore relay station.

Phase 3a, Create a new relay in the one for Achmore to serve The Glen.

Phase 3b, Add 2 in the Glen.


Phase 4, Add 3 in Portchullin, if a line of sight to Plockton is possible. Else use a relay over the loch at Ardaneaskan (see below).

Phase 5a, Create a new relay above the one for Achmore to serve Ardnarff
Phase 5b, Connect 2 in Ardnarff

Phase 6a, Create a new relay in North Strome to serve Strome Ferry

Phase 6b, Add 5 in Strome Ferry, which will need some experimentation thanks to Z bends and trees!

Phase 7a, Create a new relay at Ardaneaskan, the other side of the loch.
Phase 7b, Connect 2 in Craig, via Ardaneaskan.


7         Eligibility


The scheme will be open to everyone who owns a property or who lives or works in the Strome Ferry & Achmore CC area (i.e. Achmore, Braeintra, the Glen, Stromeferry, Ardnarff and Portchullin).

Others may be admitted to the scheme by discretion.

It has already been agreed to extend the system to Craig. Ardaneaskan and North Strome will be invited to join the system if a relay station is required on the north side of loch Carron.

This will give us more options to connect Craig, Portchullin & Strome Ferry. Additional finances will be required; the costs of providing a service to Ardaneaskan and / or North Strome have not been included in this document. 


8         Security


There are of course various facets to be considered here.

This document concentrates on the security regarding the “non domestic” wireless links in the new CBS.

But it worth noting that even when using BT lines everyone should be aware of the risks using the Internet.

A few words on domestic networks

1) Be aware. The young lady from Nigeria asking for a few hundred pounds to release several thousand is too good to be true but has caught out some people. Your bank asking you to confirm all your account details as there has been an attempt to withdraw money by a third party is another.

2) It’s important to have Internet security set up on all your PCs and laptops with a firewall and antivirus programs and keep them up to date.

3) Do not share data outside your own household network without exercising extreme caution. Facebook is a great place to check for holiday photos if you want to see if people are away from home so you can burgle them.

4) You should ensure that your domestic wireless network, i.e. your BT Home Hub or it’s replacement under the CBS, fully implement the highest level of security possible. Otherwise anyone parked outside your property may be able to gain access to your network.

You can implement WPA2-AES on your domestic Wi-Fi network if your PCs are running Ms Windows XP SP3 or a later operating system.

5) Finally, it’s important to note that an ADSL wired connection is not necessarily more secure than a wireless connection. As most BT cables are either above our heads or running down the side of roads. To gain access all you need is a ladder, a pair of pliers and a screwdriver! Once the cable enters the wider BT network it will be travelling down the same equipment as many thousand other users and probably already uses wireless links.

Specific risks with the new CBS

The CBS will transmit data over a much larger range than domestic wireless routers and therefore needs to be as secure as possible.

All devices that connect to the network will need an id and password; there will be no open hot spots.

The minimum number of people will have access to the security set up of the network.

The system will implement WPA2-AES which is "state of the art" and to date has not been hacked.

WPA2-AES is used by the US government for classified information.

Most secure data exchange between two parties over the Internet works using public and private keys.

The public is used to encrypt the message and the private key is used to decrypt the message. Public keys do not need to be secure as they cannot be used to decrypt the message. Even the sender who encrypted the message would not be able to decrypt it.

An exchange between A and B works as follows:-

A asks B for a public key.

A uses the public key of B to encrypt a message and send it to B.

B decrypts the message using his private key.

B asks A for a public key.

B uses the public key of A to encrypt a message and send it to A.

A decrypts the message using his private key.


The public key is sent unencrypted but cannot be used to decrypt the message. The private key is known only to the participant that needs to decrypt the data.

Anyone using a radio sniffer to capture the messages between A and B will not be able to decrypt the message without the private key.

WPA-AES adds an additional layer of encryption. This layer uses shared private keys and the key changed with every packet of data sent. If someone does manage to crack the first packet they will have to start again from scratch on the second. If they do manage to break through the first layer (WPA-AES) then they will still have to decrypt the message (public / private key) and somehow obtain the private keys.

A more complex scenario is Man in the middle (MITM) where an intruder reads messages between A and B. MITM pretends to be B, to A and pretends to be A, to B.

An intercepted exchange between A and B works as follows:-

A thinks he is contacting B and asks for a public key, but MITM intercepts this and instead he asks B for a public key.

B thinks he is sending his public key to A, but it is in fact intercepted by MITM.

MITM then sends his own public key to A for which he has the corresponding private key.

A believes he is sending a message to B using B’s key; but in fact he is using MITM’s public key which of course means the message can be read by MITM and the system has been compromised.

This risk is reduced as it would be very difficult for someone to gain access to the CBS wireless network and pretend to be one of the legitimate devices. Security can be improved further by installing a RADIUS server.

RADIUS holds a list of all users and devices, it authenticates users and devices before giving them access to the network, it authorises them for certain network services and keep details of what they do. It also provides accounting information. Radius requires a server which must be available at all times. Wired devices can also be authorised using RADIUS.

The BT Home Hub does not support RADIUS and will need to be replaced if we do decide to implement RADIUS.

Once the test bed is set up it will be possible to see if it is practical to implement a RADIUS server.

No provision has been made to buy a RADIUS server in the financial figures in this document.

You can read more about security at:-

Lastly it should be noted that equipment might be stolen, it will mostly be outside and in prominent positions. Unfortunately there is not much that can be done to prevent theft of equipment.

It has been agreed that the CBS will keep the option to implement a radius server to add more security and billing functions. To that end all equipment will be verified as RADIUS compliant.

Members of the CBS will be asked to vote whether RADIUS is implemented.


9         Restrictions (a comparison with BT Broadband)


Although the system will not require a landline telephone it should not be use as a replacement for the landline telephone service. This is because the broadband system may not operate if there is a power cut and in emergencies a landline can be still be used as it has its own independent power supply.

Although the system will not be designed for voice traffic it is likely that in most cases the line delay will be low and it will be suitable for Skype and mobile phone boosters. This can only be determined when the system is fully implemented. 

Although no decision has been made about an ISP to replace BT, the service offered will not offer the same facilities as BT.

The following services will not be available:-


It is possible to continue to use BT’s email service after terminating their broadband package. The BT website states that after terminating the BT broadband contract you will have free access to a basic email system for 90 days. To continue to use BT's email system after that you have to upgrade to a Premium mail account for £1.54 a month.

We will have the option of creating our own domain name(s), which can give us names such as:- or

This can be linked to a free email service or we can set up our own email server.

It has been agreed that the CBS will not set up domain names or a mail server initially.


BT Wi-Fi, BT Openzone, BT Fon

BT Broadband users are automatically signed up to allow some of the BT Home Hub’s bandwidth to be used by others in the area, unless the user explicitly opts out. When a BT Broadband customer is away from home they benefit as they can then get free Wi-Fi from another customer’s Home Hub.

This free service is not available unless the customer has a broadband contract with BT. However it is still possible to buy access to BT’s Wi-Fi service at rates from £5.99 for 90 minutes within 24 hours, to £39.00 for 4,000 minutes within 30 days.

Alternatively buying a pay as you go package from one of the mobile phone companies will cost an initial fee of £20 plus £2 per day (on the days when you use the service) with limits on the amount downloaded.


Online Storage

This will not be available from BT but there are other free alternatives such as Dropbox or we could implement this on our own server.

It has been agreed that the CBS will not implement online storage on its own server.

TV services

YouView TV, instead of being rented from BT this can be purchased with a one off payment.

BT Vision +, this is only available to BT customers on BT Infinity and will not be available under the CBS.


10    Bandwidth and speed (latency)

Bandwidth and speed are generally used interchangeably; however there are a couple of points worth noting to clarify some of the differences.

High bandwidth is important to get large amounts of data moved quickly, typically more bandwidth is needed for downloads than uploads. In simple terms the new system at 20Mbps will move 40 times as much data as the old 0.5Mbps system did in the same time.

In wired systems the data travels down the wires at roughly 160,000 km per hour. i.e. fast enough to travel around the circumference of the earth 4 times in a second. Wireless systems are even faster. The main contributing factor slowing the speed is the processing required to send the signal down the correct wire and to boost the signal over long distances.

Using the “super highway” analogy:-

If traffic travels down two roads at the same speed, a 40 lane road can move forty times as much traffic as a 1 lane road, whatever the speed.

For some applications such as video conferencing or using voice the “speed” is much more significant.

In this case the key component is how long it takes a signal to travel from one end of the “road” to the other and return so you can hear your partner’s response.

Now there is a difference if the traffic moves at twice the speed, you will get a response in half the time. Typically the response is so fast that no delay is apparent, however if there are many processing operations along the road the response may be slow enough to make conversation very difficult or even impossible.

Each relay we install in our network will reduce the speed and we won’t really know whether it is suitable for voice or video conferencing until all the components are in place.

However others that implemented similar systems to the CBS have found that voice and video conferencing work without any noticeable delay.


11    Contention


It is impractical and wasteful to provide every user with the full bandwidth for their exclusive use. All networks, the CBS included will share capacity between users to reduce costs. Most broadband services will have between 20 and 50 users sharing the same capacity.

Contention is caused when two or more tasks runs simultaneously and each slows the other down.

ISPs try to limit contention by levying additional charges above an agreed usage limit per month.

Increasing charges for heavy users reduces the amount of data they download and that allows the ISP to manage contention.

The CBS will also have to manage contention with the network.

What is a reasonable usage quota?


11.1  Data downloads


ISPs typically start to impose extra charges when users download more than 10GB per month.

10GB per month equates to approximately 300 MB per day.

To download 300 MB with our current bandwidth of 0.5 Mbps would take approximately 4,800 seconds which is 80 minutes, or about 1½ hours.

If an internet day runs from 9:00 am to Midnight (15 hours to keep the maths simple) then 10 people could run their maximum download each at 1½ hour intervals and there will be no contention.

With speeds of 20Mbps the time to download 300 MB is reduced to 120 seconds or 2 minutes. If each user was to start their download just as the previous download finished 450 people could download the maximum amount of data permitted in 15 hours without any contention.

As you might expect multiplying the speed by 40 increases the number of people who can use the system by a factor of 40 (allowing for simplified maths)

In the real world data transfers will be taking place at random times and there is a real risk that data transfers will overlap and slow the system.

Does it matter?

With a speed of 0.5Mbps there will be contention if someone else uses the system within 1 ½ hours. For the period they overlap the speed of each is reduced and the time taken increases. If one starts 10 minutes after the other they will each have to wait nearly 3 hours for their download to finish.

Faster speeds mean there is much less chance of two downloads taking place at the same time. If the speed is increased to 20Mbps it is less likely two people will download data within the same two minutes. Even if they do the download might take four minutes rather than two and it’s likely no one will even notice.

It should also be noted that the same contention issues will exist in other parts of the network. I.e. there may be issues of us running against other users logged onto the exchange in Plockton / Lochcarron.


11.2  Streaming video, TV & Movies and monthly download allowance


There is one area where the new system might notice contention problems, streaming TV & movies.

These typically last for an hour or more; standard definition video needs 2Mbps and high definition video 3.2 Mbps bandwidth.

Typically more people watch TV in the evenings and so the chance of a clash is increased considerably.

With a requirement of 3.2 Mbps per user and a total of 20Mbps available, only six people will be able to watch high definition TV at the same time, standard definition would allow ten simultaneous streaming sessions.

1 hour watching a SD TV show will download 650MB of data, a monthly 10GB limit will be used up in fifteen hours. Or thirty minutes per household per day.

1 hour watching a HD TV show will download 1 GB of data, a monthly 10GB limit will be used up in ten hours. Or twenty minutes per household per day.

What will the CBS set as an average download quota?

Assuming an even usage of streaming by every household between 7pm and midnight there are 150 hours available per month.

The CBS bandwidth of 20 Mbps is 2.5MBps or 9GB per hour, in 150 hours 1,350 GB could be downloaded, or 30GB per household.

However in reality some people will never use their capacity each month and there will not be an even load between 7pm and midnight, maybe the peak will be between 9 and 10pm 

This is why we might need to limit everyone’s bandwidth to fit the service we can afford.

Although we will have a good idea of the capacity of the system when we have completed the volume trial, we will only have a complete understanding when the system has been converted to bonded ADSL and has been up and running for some months.

It should be noted that others that have implemented very similar systems have had few problems with contention most have not found it necessary to levy additional charges for heavy users.

As we develop the system and learn more about capacity we will a set corresponding monthly download limit somewhere between 10 and 30GB per month.

We will reserve the right either restrict the bandwidth or to charge those that exceed the monthly download limit more than the standard £13.50 per month..

When we have implemented bonded ADSL we will review the situation and if there is a problem decide whether we want to add more capacity (with additional costs) or continue to charge extra for those that use more than the standard monthly limit.



12    Contracts and charges


12.1  Terminating your BT contract


There is a penalty if you leave BT before the end of the contract period.

The BT contract states they must have 30 days notice in writing.

According to the BT contract any recovery of costs for supplying the BT Home Hub will be waived as long as the customer has completed at least one 12 month contract.

There is a cessation charge of £30 when terminating the BT broadband service unless the customer requests and uses a migration access code which is used to connect to another ADSL broadband service.

Some sites on the web report that BT will waive this charge if it is queried. There might be some leverage as once BT broadband contracts have been terminated there is no need to keep using BT for the phone service. BT might waive the charge if a new phone package contract is agreed.


12.2  Joining the CBS


You should allow two months between leaving BT and joining the CBS. This allows enough time to connect the new equipment, test everything is working and give BT notice. Everyone will be connected to the CBS system at least 5 weeks before their BT contract expires allowing a minimum of seven 7 days to check everything is working before terminating their BT contract.

It has been agreed that 7 days is long enough to test and migrate “domestic” equipment from BT to the CBS?  

There will be a legally binding contract with a minimum period specified to cover costs incurred setting up households. There will be a financial penalty if you leave before the end of this contract period.

It has been agreed the minimum contract length be 12 months?

All equipment will belong to the CBS and will have to be returned should you choose to leave the scheme.

Subscribers will have to set up standing orders / direct debits to minimise administration, i.e. no cheques, no cash payments.

There will be no initial joining fee.


12.3  Monthly charges


The initial monthly charge will be £13.50 per household per calendar month for average use regardless of the location of the property. 10GB per month is the best working figure for average use prior to practical experience. (The volume trial and first few months running live will allow determination of a figure for average use.)

The monthly subscription will be set the day the CBS goes live and at the start of each subsequent year. The monthly charge will be the same for everyone joining during the year. I.e. it makes no difference if a household joins at the start or end of the year.

Once the scheme has been running for a year any new joiners will pay either the monthly rate applying to the year of the CBS or the rate in their equivalent year, whichever is the higher.

I.e. If the CBS is in its second year when a new household joins and the rate has increased to £14.00 from £13.50, they will pay £14.00 monthly.

If the CBS is in its second year when a new household joins and the rate has dropped from £13.50 to £13.00, they will pay £13.50 monthly.

Alternatively late joiners can pay a lump sum if the rate has dropped and then enjoy the reduced monthly rental. In the above example this would be a lump sum of £6 (£0.50 per month for 12 months).

Therefore there will be no advantage to anyone delaying joining the scheme and waiting for the monthly rental to be reduced once the outstanding loans have been paid off.

It has been agreed that late joiners will be given the option to pay a lump sum and monthly subscriptions at the prevailing CBS rate or to pay no lump sum and the monthly rate effective at the CBS start up. I.e. everyone will have to pay their share of the capital costs regardless of how much debt has been repaid.

Anyone that does not pay their monthly subscription will have their connection terminated.

At the discretion of the CBS there will be an option for users to opt out of the workload in return for a small additional monthly payment, likewise there will be an option to reward those that volunteer to do more than their fair share by a reduction on the monthly subscription.


13    Service level agreements and compensation


13.1  Internet Service provider


We will negotiate a service level agreement with our supplier; details of this will follow at a later stage in the project.


13.2  CBS


Once the switch over from BT is complete we will hold spares locally so we can rectify faults as soon as possible.

I would expect us to be able to resolve most problems by the end of the following day.

There will be not compensation if the whole system is out of action for any period of time since we would all just be paying ourselves.

However if part of the system is not available by the end of the following day then the CBS will either credit or refund the monthly subscription charges for those affected.

14    Reliability, maintenance and problem resolution


Others that have used wireless links report that they are very stable.

The system will be designed to use the smallest number of different components possible.

Spare parts for as many components as possible will be held on site.

The goal will be to have as many people as possible trained to maintain the hardware and software.

There will be a maintenance rota to spread the load amongst as many subscribers as possible.

The target will be to repair faults by the end of the following day (see the section on Service Level Agreements)

It has been agreed there will be a maintenance slot every Saturday from 1400 to 1700. Notification will be given by midnight on Thursday if the system is to be unavailable at this time.

Apart from emergency repairs maintenance at other times will be by prior consultation and agreement.

Household equipment


It will be the householder’s responsibility to maintain the clear line of sight (some gardening may be required.)

Before the demo system is removed from the hall members of the CBS will be asked if they want it to be left in place so that anyone that has a problem with their service can keep online in the hall.

This is subject to the approval of the Hall Committee and permission and charges will be agreed with them.

A backup landline system in the hall connected to our BT exchange to provide cover if the whole system is down will be expensive for a very limited bandwidth and so it has been decided this will not be implemented as part of the implementation. It will be reviewed when all subscribers have been connected.

If an individual’s connection to the CBS should fail then they will have the option to move to the hall to continue working. There may be a charge from the hall for this and if so it will be met from CBS subscriptions.

Backbone equipment


It should be recognised that the system will be more vulnerable to failure due to the additional components and the fact that these are more exposed than BT telephone lines.

However there is a lot we can do to reduce the chances of the system being out of service.

Spares will be held locally, so if a component fails it can be replaced it very quickly.

The new system will use more than one telephone line at the exchange, so if there is a failure on one line we will lose some capacity but the system will still function.

All the external wireless components are designed to be left out in very exposed locations in the wet and cold. Other components will have to be housed indoors or in waterproof enclosures. We will have to take great care to ensure that all equipment is secure, protected if required and that all connections are to a high standard. However there are many examples of this type of network being used successfully in locations very similar to our own.

The signal itself will be degraded and the capacity of the network will be reduced by adverse weather, rather like heavy rain affecting satellite TV. However we will be running the network at less than 25% of its maximum capacity and it is very unlikely we will notice these effects.

Future enhancements not included in the initial implementation

Spares will be held to cover as many pieces of equipment as practical including the backbone components.

Power supplies will be isolated from other domestic usage.

Uninterruptible power supplies can be installed which will allow the system to keep working for several hours if the mains power supply fails.

There may be failures in extreme circumstances (e.g. very high winds) and to mitigate this we will design in redundancy so that if one link fails another will come into play. For example if A links to B and A links to C a redundant route between B & C will allow A to connect to B via C and C via B should the direct link fail.

An additional link will be installed to a second exchange, i.e. we will have a link through Plockton and a link through Lochcarron BT exchanges. So if one exchange or link to the exchange fails the system will automatically reroute through the other exchange and keep working albeit with reduced capacity

15    Finances


Please note that the figures quoted below are only to be used to compare the relative costs of the various options. They only cover the capital and revenue expenditure for the proposed network, i.e. buying the equipment, line rental and electricity directly related to the physical network.

There will be additional administration costs which would be the same regardless which implementation plan is adopted.
These will cover at least the following:-

Office, for paper, ink and booking the hall for meetings etc
Administration fees, to set up the holding company etc
Bank fees, for setting up and running accounts etc
Legal fees, for wayleaves, contracts etc
Additional equipment to hold as spares, and possibly some additional capacity to act as backup
Insurance, if applicable to cover loss of equipment etc


The CBS will be set up as a not for profit company.

Funding will come from a loan from the CC and by issuing bonds. The CBS will issue bonds with a value of £50 and terms of either 1 or 2 years are issued; interest will be paid annually at 5%.

For the purpose of modelling an annual interest rate of 5% has been used.

Once the loans have been repaid any surplus income will be used to improve the network. When this is completed the monthly subscriptions will be set to cover running costs and maintenance. 

It is not possible to work out detailed finances without knowing when each household will switch from BT to the CBS. Backbone equipment and broadband capacity will have to be purchased at the start of each implementation phase and typically will provide services for 10 to 15 users. If all users were to sign up on day one the financial picture is very different from one joining on the first day and the rest joining twelve months later.

The following figures have been produced using the outline implementation strategy and assuming an even distribution of dates for joining the CBS. I.e. if there are 12 households on average one will join each month for a year. The figures below are a good indication of the financial position relative to each other. In practise the actual figure may vary somewhat.

All equipment and services have been priced with the exception of mounting brackets for the devices. The included standard mount is to use straps on to a drain pipe, pole or mast. Mounting brackets may be required depending on the exact location of the equipment on some properties, they are £10 each.

No allowance has been made for inflation; all of the financial models assume monthly subscriptions of £13.50 throughout the periods shown.

A brief recap of what is included in each implementation phase; phase 1 - test bed,

phase 2 - Achmore & Braeintra, phase 3 The Glen, phase 4 Portchullin, phase 5 Ardnarff, phase 6 - Stromeferry, phase 7 - Craig. See section 6 for full details.


The delivery dates of the phases in model 1 are determined by the income generated by subscribers.


For models 2 and 3 they are set two months apart which allows time to consolidate one phase before starting the next.


If there aren’t sufficient volunteers to help with the project implementation dates will be delayed.

Three theoretical models have been developed.

1) Implement households using a loan from the CC only, equipment is purchased when monthly subscriptions have provided enough income. ADSL bonding is implemented when all households are connected. The delivery dates of the phases of the project are determined by the income generated.

Phase 2a, starts in month 1

Phase 2b, starts in month 3

Phase 2c, starts in month 16

Phase 3, starts in month 21

Phase 4, starts in month 24

Phase 5, starts in month 31

Phase 6, starts in month 35

Phase 7, starts in month 39


Repayments to CC start in month 43 & are completed in month 55.

2) Implement households using a loan from the CC and by raising money through one or two year bonds. ADSL bonding is implemented when all households are connected.

Phase 2a, starts in month 1

Phase 2b, starts in month 3

Phase 2c, starts in month 5; raise £2,000 in bonds (£400 1 year, £1600 2 year)

Phase 3, starts in month 5

Phase 4, starts in month 7; raise £500 in bonds, (£500 1 year)

Phase 5, starts in month 9; raise £1,700 in bonds (£600 1 year, £1100 2 year)

Phase 6, starts in month 11; raise £1,200 in bonds (£600 1 year, £600 1 year)

Phase 7, starts in month 12; raise £900 in bonds (£300 1 year, £600 2 year)


Total bonds raised £6,300; £2,400 1 year, £3,900 2 year

Repayments to CC start in month 39 & are completed in month 49.

3) Implement households using funds from the CC and by raising money through one or two year bonds. ADSL bonding is implemented at the start of the project. The delivery dates of the phases of the project are determined by the speed we can install equipment.

Phase 2a, starts in month 1

Phase 2b, starts in month 3, in month 4 raise £300 (£200 1 year, £100 2 year) to cover running costs

Phase 2c, starts in month 5; raise £2,300 in bonds (£200 1 year, £2,100 2 year)

Phase 3, starts in month 5

Phase 4, starts in month 7; raise £800 in bonds (£400 1 year, £400 2 year)

Phase 5, starts in month 9; raise £2,100 in bonds (£400 1 year, £1700 2 year)

Phase 6, starts in month 11; raise £1,100 in bonds (£400 1 year, £700 2 year)

Phase 7, starts in month 12; raise £1,000 in bonds (£100 1 year, £900 2 year)


Month 33 raise £1,300 in 1 year bonds to repay earlier bonds falling due for repayment, or alternatively issue some 3 year bonds.


Total bonds raised £8,900; £3,000 1 year, £5,900 2 year

Repayments to CC start in month 46 & are completed in month 54.

The CBS will follow financial model 2; i.e. we will raise additional funds by issuing bonds and during the implementation phase keep running costs to the minimum by restricting bandwidth. As soon as sufficient numbers of subscribers have left BT and joined the CBS we will implement ADSL bonding to allow better use of bandwidth.


The cost of starting with bonded ADSL lines

This model uses the phased implementation plan and assumes an even spread of BT agreements expiring through each implementation phase. It starts with the bonded ADSL lines being purchased after the volume trial and before the next ten subscribers in Achmore are connected.

For the first few months the income will be way behind the expenditure and we will run up large debts. For contractual reasons (see section 12.1) we will have to switch households over at least two months before they complete their BT contracts. The table below highlights the problem:-

Month participants        income                                 expenditure       balance                running total

1                0                                £0.00                 £300.00 -£300.00                  -£300.00           

2                0                                £0.00                 £300.00 -£300.00                  -£600.00           

3                1                              £13.50                 £300.00 -£286.50                  -£886.50

4                2                              £27.00                 £300.00 -£273.00               -£1,159.50

5                4                              £54.00                 £300.00 -£246.50               -£1,405.50

6                6                              £81.00                 £300.00 -£219.00               -£1,624.50


At the end of six months we would accrue a debt of £1,624.50.

It is possible to bond lines incrementally, but again there is a cost penalty. 

However spreading the implementation over twelve months is no bad thing as it would be very difficult for us to set up all the equipment and connect forty three households in a very short period of time.

16    Key success factors


16.1  Technology

A locally managed, wireless broadband service is technically feasible and sufficient capacity at a suitable local exchange can provide users with speeds of 20Mbps at a reasonable cost.

The wireless network component of the network can support speeds up to 150Mbps and when ADSL2+ (which increases telephone line capacity from 8Mbps to 24 Mbps) is implemented locally in Plockton or Lochcarron we can choose whether to upgrade to higher speeds or reduce our costs by buying less capacity.

The wireless links implement the industry standard 802.11n protocol and there is a choice of equipment on the market from several manufacturers. However we have local examples of Ubiquiti equipment being used and this local practical knowledge will be a great advantage when it comes to deciding on the best equipment and understanding its configuration.

For this reason no other manufactures has been considered and it is proposed we use Ubiquiti exclusively.

Should the company Ubiquiti fail we will be able to substitute other manufacturer’s equipment, but we will lose some of the additional features exclusive to the Ubiquiti equipment.


16.2  Funding


Indicative figures have been given for three scenarios, these assume:-

That forty three people subscribe when their BT contract ends with an even distribution over the course of a year. I.e. if we start to connect a group of 12 people in month 4 then it will be one household a month for the following year.

That everyone will have use of the service for free for up to two months. BT require one months notice of termination of contract and prior to that there will be at least a week and up to one month to give time for households to confirm that everything is working as it should.

All loans are repaid in full with an interest rate of 5% per annum.

In summary:-

Option 1, No additional capital apart from the CC loan

Additional capital required £0.

The last phase starts in month 39 and loans are repaid in month 55.


Option 2, Additional capital raised as required bonded ADSL introduced as late as possible

Additional capital required £6,300, or the equivalent of £150 per household.

The last phase starts in month 12 and loans are repaid in month 49.


Option 3, Additional capital raised as required bonded ADSL introduced at the start

Additional capital required £8,900, or the equivalent of £210 per household.

The last phase starts in month 12 and loans are repaid in month 54.


It has been agreed the interest rate on loans will be 5%and the CBS follow financial model 2.

16.3  Community Involvement

This feasibility study has been conducted on the basis that there will be significant input from local volunteers. It is expected that everyone that uses the system will be involved in some way in the implementation and / or running of the system. Without this effort the system is not viable as the revenue generated by forty three users is not enough to pay for support.

With an annual “profit” of £3,500 to £4,000 there is not enough money available to employ someone to manage the system.

Tasks for volunteers

a) Implementation phase

Building relay stations from scaffold tube

Digging trenches and burying cables

Installing equipment at households

Configuring equipment

Participation in the volume trial

Network design

Alignment of equipment


b) Post Implementation phase

Physical maintenance and repair, e.g. checking the security of the relays

Performance and capacity monitoring

Administration, billing etc

Inspection of equipment

Accounting and billing

Software upgrades

Establishing, monitoring and renewing contracts

Monitoring the network for faults

Collecting subscriptions


If these tasks are split over the 43 subscribers then it will amount to a few hours work per year for each of us.


17    Next Steps


There was a review of the Feasibility Study (FS) by all of those who have signed up for the system at a public meeting on the 14th March 2013, all outstanding issues were resolved.


If was agreed to proceed as follows:-

1) Set up a test bed to better understand the limitations of the equipment and how it should be configured.

2) Set up a demonstration where everyone who has “signed up” can verify a minimum of 5Mbps bandwidth.


If the demonstration is a success:-

3) Define volume trial and success criteria of trial

4) Seek participants for trial who will review the trial criteria and commit to subscribe to the service if the success criteria are met.

5) Volume Trial

6) Public meeting to review trial


If it is agreed to proceed:-

7) Set up action group (Leader, technical, legal, administration etc).

8) Set up legal entities to run the CBS, complete agreements and formalise subscriber revenue collection

9) Develop detailed rollout plan

18    Conclusions


A locally managed wireless broadband service is feasible, the technology is readily available, robust and very cheap to implement in comparison to other methods.

A system with bandwidth of 20Mbps is achievable within the £13.50 monthly subscription.

A loan of £5,000 from the Community Council and private finance of £6,900 will provide enough capital to build a system for the forty three users who have “signed up” to the system.

The approach outlined in this document is only viable if enough volunteers come forward to assist with the project. If enough people do not come forward then at best the project will take considerably longer and at worst will never be fully implemented.

The system will be scalable to allow more users to be connected (when they see the error of their ways).

The system will be able to take advantage of any BT network improvements in Achmore, Plockton or Lochcarron.

The network will be capable of providing higher bandwidths than the current copper telephone lines for all users regardless of their distance from the exchange.

The maximum capacity of the system will only become an issue if fibre optic cable is laid to every household in the area.



19    Appendix A - Outstanding Decisions for CBS members


No index entries found.


20    Appendix B - Statement of Requirements.


Statement of Requirements - these were agreed by everyone on the 1st January 2013, and are reproduced here for convenience.


1) The scheme will be open to everyone who owns a property or who lives or works in the Strome Ferry & Achmore CC area (i.e. Achmore, Braeintra, the Glen, Stromeferry, Ardnarff and Portchullin).

2) Others may be admitted to the scheme by discretion.

3) The system will not be designed to replace the telephone service.

4) The system will provide an interface equivalent to the BT home hub i.e. a minimum of Wi-Fi, four Ethernet ports and one USB port.

5) The minimum speed will be 5Mbps (with the usual caveats about peak time loads).

6) The maximum cost will be 90% of the equivalent BT service (I.e. £13.50 per month at today’s prices for “average” data volumes).

7) There will be additional costs for heavy users above “average” data volumes. (The definition of average data volumes will be looked at more closely in the feasibility study & trial.)

8) The speed and price per usage band will be the same for everyone that joins the scheme.

I.e. it will cost the same whatever the location (within the Strome Ferry & Achmore CC area as defined above).

9) The system will not require a landline telephone (i.e. you do not need a BT phone line to join the system).

10) The system will be built from readily available industrial strength components.

11) The system will comply with all relevant laws and contractual agreements.

12) The system will be implemented in such a way as to minimise capital costs. If possible the system will be implemented without the need for grants. All running costs and future enhancements will be covered by users’ subscriptions.

13) The system will be run on a not for profit basis, charges will be set to cover running costs and fund future developments.

14) The system will be set up in such a way to minimise administration cost and effort.

15) Day to day running and troubleshooting will be done by members of the scheme.

16) There may be additional charges levied to any subscriber not prepared to assist with administration and there may be a reduction in charges for subscribers that assist with the implementation.

17) The service will not have all the features offered by the large ISPs (BT).

18) There will be a simple service level agreement which will cover the system being unavailable either due to a problem with "our network" or a problem outside our control.

19) If the service is unavailable for an extended period the monthly subscription may be reduced or waived by discretion.


21    Appendix C, questions and answers from our website


These can be found at:-

If you do not have access to the web printed copies can be provided.


22    Appendix D, possible enhancements to the local BT exchange


The objective of this project is to bypass the constraint of our local BT exchange, but what if our exchange was to be upgraded, would all our effort be wasted?

The Scottish Government have stated that everyone should get 2Mbps by 2015. The next step for an exchange upgrade is usually to full ADSL at 8Mbps. Again the Scottish Government have stated that by 2020 the objective is to have between 85% and 90% of premises with 40-80Mbps available.

There is no commitment from BT or any other supplier, negotiations are ongoing but an announcement is due “early in 2013”.

We could choose to do nothing, our exchange should be upgraded to 2Mbps by 2015, it might then be upgraded to 8Mbps and indeed we might be lucky and be one of those upgraded to 40Mbps – 80Mbps by 2020.

However it is critical to note the capacity bandwidth of our current copper telephone wires depends on their length and condition.

When VDSL (BT Infinity) is implemented speeds of 80Mbps are possible at the exchange but these fall off rapidly dependent on the distance from the exchange.

Indicative speeds are:-

50Mbps at 0.2 miles

25 Mbps at 0.6 miles (1km)

13Mbps at 0.9 miles

8 Mbps at 1.7 miles

6Mbps up to 2.27 

2Mbps up to three miles

1.5Mbps up to 3.4 miles


This is the length of the cable from the exchange in Achmore, not the distance as the crow flies. Old wires and poor connections lower these figures further.

One kilometre, as the crow flies, from the exchange is as far as Fernaig to the west, is about 250 metres short of the turning to Strome on the A890, and to the south east as far as the new road made to give access to the allotments.


Map showing 0.6 mile / 1 km from the exchange



A few people in the centre of Achmore very close to the exchange may see speeds approaching 50Mbps. However no one further than 1km from the exchange will get more than 25Mbps through the telephone wires even if the exchange can run at over 80Mbps, faster speeds need other technologies. (Wireless or fibre optic cable)

Of course BT may choose to upgrade the exchange at Plockton or Lochcarron. We will pick locations as close to the exchanges as possible in which case we might see speeds approaching the maximum.

If either Plockton or Lochcarron are upgraded to VDSL and we have three bonded ADSL lines our maximum potential network speeds would be approaching 150 Mbps potentially giving households speeds in excess of the 80Mbps at the top end of the Scottish Governments aspirations. 

Our proposed system will have the capacity to run at up to 150Mbps across the wireless links, well in advance of any current proposal. We can choose where we connect to the rest of the internet; Achmore, Plockton, Lochcarron, maybe even Broadford. Whichever is the fastest, we can combine several sets of lines into high speed routes giving us speeds up to 80+ Mbps at the doorstep, not at the exchange.

In conclusion, the capacity of the proposed system will only be exceeded when fibre optic cable is installed to every property.

 This may be a problem for future residents as yet unborn; I think we can sleep easy.