Sugarloaf (Christchurch)

Sugarloaf communications tower
File:Sugarloaf Christchurch.jpg The Sugarloaf communications tower viewed from Bowenvale Valley
Highest point
Elevation
Coordinates
Geography
Sugarloaf Location of Sugarloaf in Christchurch, New Zealand
Location	Christchurch, New Zealand
Geology
Mountain type	Basalt volcanic rock

The Sugarloaf in Christchurch's Port Hills is a landmark to the south of the city. The Sugarloaf communications tower is an iconic transmission mast located on top of the hill.

Geography

The tower is situated at an elevation of 493.78 m on the top of the Port Hills, near Dyers Pass. This area is officially known as Sugarloaf Scenic Reserve. This reserve land occasionally doubles as a sheep farm and includes a car park lookout point for general public use.

Communications tower

With a height of 121 m, the lattice steel structured tower is founded on a 5 metre deep concrete pad underlain by basalt volcanic rock. It is situated approximately 50 m behind the main transmission building, which combined with the tower is visible from most parts of Christchurch city.

Visual Appearance

At a closer glance, the red and white tower includes an array of antennas including parabolic dishes, dipoles and microwave links. The tower has three main service decks for authorised technicians only with access ladders that run vertically along the eastern side. At night the tower is illuminated with three red beacons which span across the mast from top to bottom. On a clear night and viewed from the city you can often see the beacons and some fluorescent lighting coming from a room inside transmission house.

Transmission House

The tower is located 50 m behind a single storey transmission building which houses multiple transmission gear. The main equipment room is fully air conditioned and known to local technicians as the great transmitter hall. The building is approximately 40 m in width and 20 m in depth. On the roof of this building there are several satellites, small antennae and multiple parabolic dishes for private WiFi networks. There are two main shielded cable runs that go between the transmission house and back to the tower. This building has been unmanned for several years.

Site Access

The entire transmission site is surrounded by a mesh security fence and a continuous hedge mixed with foliage. Access to the tower is highly restricted to authorised personnel only and climbing the tower is strictly prohibited. Vehicle access to the actual site itself is restricted via a locked gate, however there is a car park lookout point located 200m in front of the tower with panoramic views of Canterbury. Access to this reserve is permitted to the general public until approximately 6:00PM. After this time the gate between Summit Road and Service Lane is locked until the following morning.

Technical Aspects

There are six main antennas that transmit TV and FM signals in the 45 MHz to 800 MHz range. The composite total power fed to all of the transmitting antennas is approximately 64 kW while the antenna gain values range from 7.8 to 16.5 dBd. Multiple services operate off the tower including television, radio, emergency response, aviation, cellular and other data signals.

The tower covers much Christchurch and central Canterbury, for example the DVB-T signal reaches as far as Waipara in the north, the foothills of the Southern Alps in the west, and the Rangitata River in the south. However, not all of the central Canterbury region is covered by this tower. The nearby village of Akaroa (and most of the settlements near Akaroa) have limited to non-existent TV reception and variable radio reception. This long term problem could be solved by the construction of a second tower at least 10 km away from Sugarloaf Mountain, but it is unclear if this option has ever been given technical consideration. Likewise, the Christchurch suburbs of Redcliffs and Sumner have limited coverage from Sugarloaf, with radio (and formerly analogue television) provided through a low-power repeater in the suburb of Southshore.

Transmission Frequencies

The following table contains television and radio frequencies currently operating at Sugarloaf:

TV Channel	Transmit Channel	Transmit Frequency	Band	Power (kW)
World TV digital	28	530 MHz	UHF	50
SKY digital	30	546.00 MHz	UHF	50
MediaWorks digital	32	562.00 MHz	UHF	50
TVNZ digital	34	578.00 MHz	UHF	50
Kordia digital	36	594.00 MHz	UHF	50
Radio Station	Transmit Channel	Transmit Frequency	Band	Power (kW)
Mai FM		88.9 MHz	VHF	32
Radio New Zealand Concert		89.7 MHz	VHF	80
Tahu FM		90.5 MHz	VHF	16
ZM		91.3 MHz	VHF	80
More FM		92.1 MHz	VHF	80
The Sound		92.9 MHz	VHF	50
The Rock		93.7 MHz	VHF	80
The Breeze		94.5 MHz	VHF	32
The Edge		95.3 MHz	VHF	32
Jacked FM 96.1 (New Zealand Broadcasting School)		96.1 MHz	VHF	16
Plains FM		96.9 MHz	VHF	5
The Hits		97.7 MHz	VHF	80
Radio Live		99.3 MHz	VHF	32
Newstalk ZB		100.1 MHz	VHF	1.6
Radio New Zealand National		101.7 MHz	VHF	16
Kiwi FM		102.5 MHz	VHF	40
Niu FM		104.1 MHz	VHF	16
Pulzar FM		105.7 MHz	VHF	16
Radio Hauraki		106.5 MHz	VHF	16

Former analogue television frequencies

The following frequencies were used until 28 April 2013, when Sugarloaf switched off analogue broadcasts.

TV Channel	Transmit Channel	Transmit Frequency	Band	Power (kw)
TV One	3	62.25 MHz	VHF
TV3	6	189.25 MHz	VHF
TV2	8	203.25 MHz	VHF
FOUR	11	224.25 MHz	VHF
CTV	44	655.25 MHz	UHF
Prime TV	62	799.25 MHz	UHF

Case Studies

An RF emissions report conducted on 9 February 1998 by the National Radiation Laboratory found that maximum exposure levels of 8 μW/cm2 were detected in the car park area, immediately below the Sugar Loaf antenna. This is 4% of the maximum of 200 μW/cm2 specified for public exposure levels in NZS 6609.1:1990. As the distance from the antenna increased, the exposure levels decreased markedly and, in general, were below 2 μW/cm2. The report concluded that the site is operating in accordance with NZS 6609.1:1990.

Gallery

Sugarloaf Mountain communications tower

The Sugarloaf Communications tower stands 121 m high. The Sugarloaf Communications tower stands 121 m high.  Sugarloaf Communications Tower showing cable runs from back of building to base of tower. Sugarloaf Communications Tower showing cable runs from back of building to base of tower.  Close up view of Sugarloaf Communications Tower. Close up view of Sugarloaf Communications Tower.  A gate prevents access to the transmitter site for private vehicles. A gate prevents access to the transmitter site for private vehicles.  View of the tower from the carpark in 1990, showing old signage. View of the tower from the carpark in 1990, showing old signage.

Management

The tower and building are currently owned and maintained by Kordia, previously known as Broadcast Communications Limited (BCL NZ).

External links

• Sugarloaf Communications Tower as seen in Google Maps
• Panorama View from Sugarloaf Scenic Reserve
• Kordia Limited
• Christchurch City Council Reserve Information
• Port Hills Visitor Information
• Digital Switch Over Information for New Zealand
• 1998 RF Emissions Report for The Sugarloaf Communications Tower (Adobe PDF Format)
• 2005 Tower Upgrade Contract (Adobe PDF Format)
• Sugarloaf Scenic Reserve Dog Control Map (Adobe PDF Format)
• Sugarloaf Freeview coverage