2. Introduction

Studio to Transmitter Links (STLs) are used to transport audio programme material from a studio or other source to a broadcast transmitter site. They are generally one way wide band fixed links requiring a high quality of service and do not easily share spectrum with other services.

With the growth in broadcast services in New Zealand, the spectrum available for STLs has become congested in high use areas such as Auckland, Wellington and Christchurch. Use of the 100 to 108MHz upper FM Broadcast band for additional broadcast services is further increasing the STL demand for spectrum. The growth in other applications such as short range devices is also creating a demand to share some of the spectrum currently reserved for STLs.

Current allocations for STLs are in spectrum bands at 400 and 900MHz. STLs in the 400MHz bands are narrower band systems generally used for monophonic AM or FM broadcasting. There is not expected to be a significant growth in demand for these systems.

The 900MHz bands provide wider channels which are used for high quality stereo audio signals suitable for FM broadcast services. The demand for these channels is expected to continue to grow, particularly with increased use of the 100 to 108MHz band for FMBC.

The current policy for assigning new licences for STL 1 use was issued in 1995. Since that time there have been significant changes in spectrum demand including:

• changes to the 400 to 450MHz spectrum allocations for fixed and mobile services,
• continuing growth in the number of FMBC stations
• the emergence of new digital technologies
• a significant increase in the availability of short range devices that operate in the 900MHz band.

This paper analyses the current demands on the STL spectrum and identifies several issues which need to be resolved to accommodate future demand.

1 POLDOC Fixed 001 - Studio to Transmitter Links - see Appendix A.