This presentation is about managing the impact of wind turbines on DFS radio navigation in the Schleswig Holstein region, Germany. It was given at Wind Energy Hamburg in 2014 by Mike Watson on behalf of Pager Power.

1. Managing the impact of Wind Turbines
on DFS radio navigation in Schleswig Holstein
Wind Energy Hamburg, September 2014
Prepared for UKTI
Mike Watson mike@pagerpower.com 00 44 1787 319001
www.pagerpower.com

2. Topics
1. Introduction
2. Radar Assessments
3. Radio Navigation aids in Schleswig Holstein
4. DVOR radio navigation aids and Michaelsdorf DVOR
5. Wind Turbine Interference
6. Why it may not be issues
7. Recommendations

3. Who is Pager Power?
Pager Power specialises in assessing and solving
issues that can arise with any combination of wind turbines, radar,
radio communications and construction interaction.
Pager Power has been involved in resolving radar and
communications issues on 24% of the UK’s operational wind
turbines.
Pager Power has worked in over 30 countries. Software works
worldwide.

4. Radar Line of Sight Assessment

5. Radar Detectability Calculation

6. ID Name Type Maximum assessment distance (km)
SLT WESTERLAND/SYLT Non Directional Beacon NDB 1
ALS ALSIE VHF Omni Range VOR 15
FLB FLENSBURG Non Directional Beacon NDB 1
SWG SCHLESWIG DME TACAN 3
HNT HOHN DME TACAN 3
HN HOHN Non Directional Beacon NDB 1
MIC MICHAELSDORF VHF Omni Range VOR (DVOR) 15
LUB LUBECK VHF Omni Range VOR 15
LYR LUBECK Non Directional Beacon NDB 1
HAM HAMBURG VORDME VORTAC 15
FU HAMBURG Non Directional Beacon NDB 1
HOS HAMBURG Non Directional Beacon NDB 1
GT HAMBURG Non Directional Beacon NDB 1
LBE ELBE VORDME VORTAC 15
NDO NORDHOLZ Non Directional Beacon NDB 1
KIL KIEL-HOLTENAU Non Directional Beacon NDB 1
DHE HELGOLAND VORDME VORTAC 15
HAMBURG Meteorological Radar 20
ALF ALSTER DME TACAN 3
EDDH Hamburg Airport with VDF 10
LUD LUBECK DME TACAN 3
EDHL Lübeck Blankensee Airport with VDF 10
EDXW Sylt Airport with VDF 10
EDHK Kielt Holtenau Airport with VDF 10

8. DVOR Ground
Station
Combined
Signal
VOR
Pilot tunes into VOR and selects
bearing. Cockpit instrument
shows aircraft’s deviation from
selected bearing.
Reference and Variable 30Hz
Signal Modulation Combined
Phase Angle between reference and
variable Signals is zero when
receiver is at Magnetic
North
Aircraft VOR receiver calculates
bearing from VOR by measuring
phase angle between reference
and variable signals.

10. 112.20 MHz
30 Hz
Central
Antenna
Antenna
Switch
52 x
Switchable
Antenna
1020 Hz
CW
Modulation
MIC
(morse)
Anti-clockwise
Amplitude
Modulation
Amplitude
Modulation
Amplitude
Modulation
112.20 MHz
+ 9960 Hz
112.20 MHz
- 9960 Hz
Michaelsdorf MIC
DVOR Operation (Simplified)

11. Radio Beacon
Carrier [Desired, Wanted]
Interference
[Undesired, Unwanted]
Carrier to Interference Ratio is the ratio of the
strength of the direct signal from the Beacon
relative to the reflected signal from the
wind turbines
Wind Turbines

12. 600m
3000m
1.0
15000m
52.4m
Wind Turbines only
ICAO EUR DOC 015
VOR BRA Dimensions

13. Why it may not be an issue #1
1. All communications systems are designed to deal with
interference and noise.
2. [example] When we speak we can raise our voices, repeat our
selves or ask if someone has understood.
3. Radio systems are designed to work in spite of noise and
interference. Various modulation and filtering techniques used.
4. DVORs are much better at dealing with interference than
CVORs.

14. Why it may not be an issue #2
1. Impact is dependent on bearing error and how long the error
occurs for.
2. Receiver may not respond to short (<1 second) errors
3. Pilot (or autopilot) may not respond to short (<5 seconds) errors
4. Aircraft takes time to reposition following pilot (autopilot) inputs.
5. It is the size of error and time period together that matters. It is
worth determining what time periods and bearing errors matter.

15. Why it may not be an issue #3
1. Impact is dependent on amount of radio energy reflected by the
wind turbine.
2. The reflection characteristic is called Radar Cross Section
[RCS].
3. We need a single figure for calculations.
4. Unfortunately highly variable – worst-case figures (e.g. 3000
m2) much much larger than mean figures (e.g. 100 m2).
5. Develop a case for the mean figures

16. What should I do if I have a DVOR issue?
1. Do not ignore it!
2. Engage with the operator (DFS?)
3. Establish the life of the DVOR
4. Assess the impact of your wind turbine
5. Negotiate and/or challenge

17. How can Pager Power help you?
Pager Power specialises in assessing and solving issues that can
arise with any combination of wind turbines, radar, radio
communications and construction interaction.
Pager Power has been involved in resolving radar and
communications issues on 24% of the UK’s operational wind
turbines.
Pager Power has worked in over 30 countries and its software works
worldwide.
We enjoy what we do and we want to help!

18. T H A N K Y O U !
Wind Energy Hamburg, September 2014
Mike Watson mike@pagerpower.com 00 44 1787 319001
www.pagerpower.com