communication link desk study

Communication Link Desk Study

Njord Wind Developments Ltd

Rhoscrowther Wind Farm

September, 2020

Communication Link Desk Study Rhoscrowther Wind Farm 2

ADMINISTRATION PAGE

Job Reference: 10107B

Date: 31st July, 2020

Author: Andrea Mariano

Telephone: 01787 319001

Email: [email protected]

First Reviewer: Danny Scrivener

Second Reviewer: Kai Frolic

Date: 31st July, 2020

Telephone: 01787 319 001

Email: [email protected]; [email protected];

Issue Date Detail of Changes

1 31st July, 2020 Initial issue (10107C)

2 13th August, 2020 Second issue – Arqiva response

3 27th August, 2020 Third issue – Minor amendments

1 September, 2020 Update considering a tip height of 126.5m – completed

by Danny Scrivener

Confidential: The contents of this document may not be disclosed to others without permission.

Copyright © 2020 Pager Power Limited

Pager Power Limited, Stour Valley Business Centre, Unit 2, Brundon Lane, Sudbury, CO10 7GB

T:01787 319 001 E:[email protected] W:www.pagerpower.com

https://www.pagerpower.com/


EXECUTIVE SUMMARY

Report Purpose

Pager Power has been commissioned to investigate the potential impact of a proposed wind

farm development upon fixed wireless (point-to-point links) communication links in the

surrounding area. The proposed development is located near Pembroke in Wales. The proposed

development is composed of five wind turbines with a tip height of 126.5m above ground level

(agl). The structures could interact with wireless radio signals and cause interference.

Results

Consultation was undertaken with Ofcom in order to identify the relevant link operators.

Historically this has been a routine process, however during 2018 Ofcom has been reviewing

the process against GDPR requirements. Therefore, consultation was undertaken with Pager

Power’s contacts within numerous UK link operators.

BT and Ericsson have confirmed they have no concerns regarding potential impacts and did not

provide any link information. Atkins has not raised an objection but has forwarded the enquiry

on to Welsh Water. However, no details have been provided yet. Airwave requested its own

assessment1.

The following operators have provided detailed responses requiring further investigation: JRC2,

Arqiva and Vodafone.

Arqiva has reviewed the proposed turbine location information and concluded that they have no

objection towards the proposed development. However, the developer should inform Arqiva if

the turbines move any further towards their site at Greenhill.

The Vodafone link has been assessed and it will not be affected by the proposed development.

The proposed turbines are outside the recommended safeguarding zones for diffraction effects

meaning that impacts due to blocking of the signal are not predicted.

Some of JRC links might be affected, however JRC has not provided the relative details for the

assessment which have been requested. No mitigation requirements have therefore been

identified for Vodafone.

Mitigation and Next Steps

No mitigation is required for the communications infrastructure assessed within this report.

Details of potential mitigation strategies can however be found in Section 4.2. Consultation with

the JRC is ongoing.

1 Airwave does not typically respond to link enquiries or provide technical information citing confidentiality concerns.

Airwave does offer their own paid assessment of their link network 2 The initial response noted that there were potentially affected links, technical information has not been made available

at the time of writing.


LIST OF CONTENTS

Administration Page ...................................................................................................................... 2

Executive Summary ....................................................................................................................... 3

Report Purpose ............................................................................................................................... 3

Results .............................................................................................................................................. 3

Mitigation and Next Steps ............................................................................................................ 3

List of Contents .............................................................................................................................. 4

List of Figures ................................................................................................................................. 5

List of Tables ................................................................................................................................... 5

About Pager Power ....................................................................................................................... 6

1 Background ........................................................................................................................ 7

1.1 Introduction ......................................................................................................................... 7

1.2 Assessment Requirement ................................................................................................. 7

1.3 Wind Development Location ........................................................................................... 7

1.4 Co-Ordinate Data ............................................................................................................... 8

2 Consultation....................................................................................................................... 9

2.1 Process ................................................................................................................................. 9

2.2 Responses ............................................................................................................................ 9

3 Technical Assessment ................................................................................................... 11

3.1 Methodology ..................................................................................................................... 11

3.2 Link Operators .................................................................................................................. 12

3.3 Link Paths ........................................................................................................................... 14

4 Mitigation ........................................................................................................................ 16

4.1 Mitigation Requirement .................................................................................................. 16

4.2 Mitigation Options ........................................................................................................... 16

4.3 Process ............................................................................................................................... 16

5 Conclusions ..................................................................................................................... 17

5.1 Findings .............................................................................................................................. 17


5.2 Mitigation and Next Steps .............................................................................................. 17

LIST OF FIGURES

Figure 1 – Proposed wind farm development wind turbine locations ............................... 7

Figure 2 – 2D link profile charts – Arqiva and Vodafone ................................................... 14

LIST OF TABLES

Table 1 – Proposed turbines co-ordinates ............................................................................... 8

Table 2 – Consultation summary ............................................................................................. 10

Table 3 – JRC links ...................................................................................................................... 12

Table 4 – Arqiva links ................................................................................................................. 13

Table 5 – Vodafone links ........................................................................................................... 13


ABOUT PAGER POWER

Pager Power is a dedicated consultancy company based in Suffolk, UK. The company has

undertaken projects in 48 countries within Europe, Africa, America, Asia and Australasia.

The company comprises a team of experts to provide technical expertise and guidance on a range

of planning issues for large and small developments.

Pager Power was established in 1997. Initially the company focus was on modelling the impact

of wind turbines on radar systems. Over the years, the company has expanded into numerous

fields including:

• Renewable energy projects.

• Building developments.

• Aviation and telecommunication systems.

Pager Power prides itself on providing comprehensive, understandable and accurate

assessments of complex issues in line with national and international standards. This is

underpinned by its custom software, longstanding relationships with stakeholders and active role

in conferences and research efforts around the world.

Pager Power’s assessments withstand legal scrutiny and the company can provide support for a

project at any stage.


1 BACKGROUND

1.1 Introduction

Pager Power has been commissioned to investigate the potential impact of a proposed wind

farm development upon wireless communications infrastructure (point-to-point links) in the

surrounding area.

1.2 Assessment Requirement

The proposed development will introduce wind turbines in a rural area – these could interact

with wireless radio signals and cause interference in the surrounding area. This report has

assessed the potential impacts following consultation with the appropriate link operators.

1.3 Wind Development Location

The proposed development is located around Pembroke in Wales and will consist of five wind

turbines. Figure 1 below3 shows the turbines locations.

Figure 1 – Proposed wind farm development wind turbine locations

3 Copyright © 2020 Google.


1.4 Co-Ordinate Data

The wind turbines co-ordinates used in this assessment are shown in Table 1 below.

Turbine Easting Northing Hub height

(m agl)

Rotor

diameter (m)

Tip height (m

agl)

T1 191098 202098

69 115 126.5

T2 191390 201943

T3 191574 201830

T4 190861 202196

T5 191577 201601

Table 1 – Proposed turbines co-ordinates


2 CONSULTATION

2.1 Process

Historically, Ofcom has provided on request a list of parties that operate licensed fixed links

within a given search radius of a defined location. During 2018, this process was under review

following GDPR requirements. Therefore, consultation was undertaken directly with the most

prevalent operators4 in order to obtain link details. At the time of writing, no further information

from Ofcom has been made available.

2.2 Responses

The responses received at the time of writing are summarised in Table 2 below.

Operator Response Remarks

Arqiva

Arqiva will not raise an objection.

However, the developer should

inform Arqiva if the turbines move

any further towards their site at

Greenhill.

First request for links ends submitted on

the 17/07/2020.

Second request for links ends submitted

on the 24/07/2020.

The Arqiva links have been assessed

within Section 3.

Atkins Atkins has enquired Welsh Water

for link in the specific region.


the 17/07/2020.

BT

The project should not cause

interference to BT’s current and

presently planned radio network.


the 17/07/2020.


on the 24/07/2020.

No impact expected.

Ericsson No objection to the proposal


the 17/07/2020.


on the 24/07/2020.

No impact expected.

4 Based on Pager Power’s experience and contacts database.


Operator Response Remarks

JRC JRC is consulting with WPD with

regards to the links.


the 17/07/2020.

Latest response received on the

25/08/2020.

Consultation is ongoing.

Airwave -


the 17/07/2020.


on the 24/07/2020.

Third request for links ends submitted

on the 28/02/2020.

Airwave requested its own assessment5.

Vodafone Vodafone has a link in the vicinity

of the proposed development.


the 17/07/2020.


on the 24/07/2020.

The Vodafone links have been assessed

within Section 3.

Table 2 – Consultation summary

5 Airwave typically does not provide link information on request, instead offering a separate paid assessment where

required. Chaser has been sent.


3 TECHNICAL ASSESSMENT

3.1 Methodology

Microwave and UHF6 wireless communication links are used to transmit information between

two antennae via radio waves within a particular frequency band.

Obstructions sited between two link antennae can partially block the radio signal passing

between them, thereby reducing the functionality of the link. This can occur even if the

obstruction is in not directly between the antennae but close to the link boresight7.

The exclusion zones associated with the identified links have been calculated based on the

telecommunications data provided. Further 2-dimensionel clearance calculations have then been

undertaken to determine the extent of any clearance or infringement of the proposed

development. The following subsections present an overview of the interference mechanisms

and methodology.

3.1.1 Fresnel Zones

A Fresnel Zone takes the form of an ellipsoid surrounding a link path and represents the area in

which obstructions should not be sited in order to avoid diffraction losses. The width of the zone

at any point along the link path is determined by the Fresnel Zone number, the frequency of the

link and the distance from each link end. The width of the zone is maximal at the midpoint of the

link path.

3.1.2 Diffraction – Microwave and UHF Links

Obstructions such as building developments which are sited in between two microwave link

antennae can partially block the radio signal passing between them, thereby reducing the

functionality of the link. This can occur even if the obstruction is not directly between the

antennae but close to the link boresight. This kind of blocking is called ‘diffraction’.

There are various approaches to safeguarding microwave links against from obstruction via

building developments. The most common approaches are:

1. Implementation of a fixed stand-off distance around the link boresight;

2. Safeguarding the relevant Fresnel Zone (discussed below).

The first approach is used by many operators who request a set buffer distance. Set stand offs

are occasionally conservative and produce a large exclusion zone distance. The second approach

is to assess an obstruction on a case by case basis to calculate the most accurate exclusion zone.

6 Ultra-High Frequency 7 This is the straight line between the two antennae.


Pager Power considers 60% of the First Fresnel zone when considering the effect of a static

obstruction upon microwave and UHF links8.

3.1.3 Reflections – UHF Links

Obstructions can affect UHF links by reflecting the signal between transmitter and receiver. This

is not a significant concern for microwave links because they are highly directional. Reflection

and diffraction effects are likely to be the most significant concern.

3.2 Link Operators

3.2.1 JRC

The text of the JRC response is reproduced below:

“JRC analyses proposals for wind energy developments on behalf of the UK Energy Industry. We

assesses the potential of such developments to interfere with radio systems operated by UK and Irish

Energy Industry companies in support of their regulatory operational requirements.

The Energy Industry considers that any wind energy development within:

* 1000m of a link operating below 1GHz; or

* 500m of a link operating above 1GHz, requires detailed coordination.

For turbines with a blade diameter of 32m or less this distance is reduced to:

* 500m for links below 1GHz; and

* 300m for links above 1GHz before a detailed coordination is required.

There is an EXCLUSION ZONE around most Base Station sites of 500m, i.e. no development is

permitted. This will be evaluated on a case by case basis for smaller turbines.

Unfortunately, part (or all) of the proposed development breaches one or more of these limits. “

The link details provided are presented in Table 3 below.

JRC links

There are five links potentially affected by the proposed development:

460MHz Telemetry and Telecontrol: 3

1GHz Microwave Point to Point: 1

Table 3 – JRC links

The link details were not supplied by the JRC at the time of writing.

8 Manning, T. (1999), Microwave Radio Transmission Design Guide, Artech House Books


3.2.2 Arqiva

The text of the latest Arqiva response is reproduced below:

“[…]We have plotted your turbine locations and conclude that in their current position, we are happy

for this development to proceed however, if the turbines move any further towards our site at Greenhill

[192490 – 201570], we would wish to be further informed so we can undertake a further impact

analysis.”

In an earlier response Arqiva has provided links details which have been assessed. The link details

provided are presented in Table 4 below.

Arqiva Links

Microwave Links:

Link: Greenhill-Carmel SITE A 192490E 201570N SITE B 257686E 215342N

Link: Greenhill-Preseli SITE A 192490E 201570N SITE B 217201E 230665N

Table 4 – Arqiva links

3.2.3 Vodafone

The text of Vodafone response is reproduced below:

“Vodafone require 100m clearance from tip of any turbine blade to fixed link radio path.

** Using the co-ordinates listed below the closest link is VFE66347 Site A Eastings 192,493 Northings

201,583 36 mtr high to Site B Eastings 190,579 Northings 206,018 15mtr high frequency is 28 GHz.”

The link details provided are presented in Table 5 below.

Vodafone Links

VFE66347 (28GHz) SITE A 192493 201583 (h 36m) SITE B 190579 206018 (h 15m)

Table 5 – Vodafone links


3.3 Link Paths

3.3.1 Overview

The exclusion zone for each link is shown by two lines, marking the edges of the Fresnel zones.

An additional 25 metre buffer has been applied to allow for uncertainties in the coordinate data.

3.3.2 2D Link Path Profile Chart

Error! Reference source not found. below shows the 2D link profile charts for the identified

Arqiva and Vodafone link paths.

Figure 2 – 2D link profile charts – Arqiva and Vodafone


3.3.3 2D Link Path Analysis Conclusions

None of the proposed turbines are inside the exclusion zone associated with the Arqiva links or

the Vodafone link assessed – based on second Fresnel zone and an additional 25 metre buffer.

The wind turbines are outside of the Greenhill mast buffer zone which has a radius of 250m.

Possible diffraction losses are not predicted under these conditions.

Issues with the unidentified JRC links may still remain.


4 MITIGATION

4.1 Mitigation Requirement

Based on the link data that has been identified through consultation, mitigation requirement is

not expected to be necessary for the infrastructure assessed within this report.


assessment and consultation is ongoing.

A high-level overview of the most common mitigation options is presented in this section for

reference purposes.

4.2 Mitigation Options

The options below should be considered in the event that a potential impact is identified.

4.2.1 Re-networking the link

This is a solution whereby the link path is diverted via an additional mast so that it avoids the

wind development. The requirement for this solution is a suitably located telecommunications

mast that has radio line of sight to both existing link ends. Ideally, the additional site would be a

telecommunications mast already owned / utilised by the affected link operator.

4.2.2 Increasing the antenna height

This is a solution whereby the link path is diverted via an additional mast so that it avoids or

reduces infringement from the new obstruction. The suitability of this solution depends on the

level of link infringement in three dimensions.

4.2.3 Use of an alternative technology

This is a solution whereby the microwave link is replaced with an alternative that is not affected

by the wind development. The most common options are:

• A leased line (copper cable).

• A satellite link.

• A fibre-optic connection.

• UHF Telemetry.

4.3 Process

Currently no mitigation is required. Mitigation options may need to be explored if an impact upon

JRC infrastructure is identified.


5 CONCLUSIONS

5.1 Findings

Consultation was undertaken with Ofcom in order to identify the relevant link operators.

Historically this has been a routine process, however during 2018 Ofcom has been reviewing

the process against GDPR requirements. Therefore, consultation was undertaken with Pager

Power’s contacts within numerous UK link operators.

BT and Ericsson have confirmed they have no concerns regarding potential impacts and did not

provide any link information. Atkins has not raised an objection but has forwarded the enquiry

on to Welsh Water. However, no details have been provided yet. Airwave requested its own

assessment9.

The following operators have provided detailed responses requiring further investigation: JRC10,

Arqiva and Vodafone.

Arqiva has reviewed the proposed turbine location information and concluded that they have no

objection towards the proposed development. However, the developer should inform Arqiva if

the turbines move any further towards their site at Greenhill.

The Vodafone link has been assessed and it will not be affected by the proposed development.

The proposed turbines are outside the recommended safeguarding zones for diffraction effects

meaning that impacts due to blocking of the signal are not predicted.


assessment which have been requested. No mitigation requirements have therefore been

identified for Vodafone.

5.2 Mitigation and Next Steps

No mitigation is required for the communications infrastructure assessed within this report.

Details of potential mitigation strategies can however be found in Section 4.2. Consultation with

the JRC is ongoing.

9 Airwave does not typically respond to link enquiries or provide technical information citing confidentiality concerns.

Airwave does offer their own paid assessment of their link network 10 The initial response noted that there were potentially affected links, technical information has not been made available

at the time of writing.

communication link desk study

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