FINAL REPORT - Stakeholders - Ofcom

It should be noted that a number of the specific recommendations have already been
implemented or planned by service providers. In particular, the use of solid state systems
with pulse compression is becoming more widely adopted.
3.2.10.1 Specific Measures to Release Spectrum
Recommendation 3.1: Ofcom in association with the CAA may wish to consider whether
it is feasible to replace the UHF Primary radars in Channel 36 in favour of S band or L
band equipment. It is necessary to review the review the operational requirement for
these systems and the appropriate timescale for replacement with the relevant operating
authorities. It could be implemented as part of the normal equipment replacement cycle.
Recommendation 3.2: The possibility of moving surface movement radars currently in
Ku Band to X band should be considered thereby releasing Ku band for other
applications. The cost of this is estimated at around £9m (project costs). The amount of
spectrum released needs to be confirmed with the MoD. It could be implemented as part
of the normal equipment replacement cycle.
Recommendation 3.3: In the longer term, alternative systems with the potential to
release spectrum should be further evaluated and developed.
3.2.10.2 General Improvements to the Spectral Characteristics of Primary
Radar
Recommendation 3.4: A long term policy to replace magnetron transmitters should be
adopted. Such improvements could be instigated by CAA and Ofcom under the terms of
the licensing agreement. The cost of replacing magnetron systems is estimated at £66m
(S band and X band approach radars) and could be implemented under the normal
replacement cycle. Increases in spectral efficiency are likely to be offset by increasing
demand for radar services.
Recommendation 3.5: In the short term, consideration should be given to equipping
magnetron transmitters with low pass filters to meet the current emission mask. This
approach may be necessary where the systems concerned have a long life expectancy.
Costs are in the range £20k to £100k per installation.
Recommendation 3.6: The current unwanted emission mask should be adopted as the
medium term goal for primary radar systems.
Recommendation 3.7: Pulse compression should be the technology of choice for future
primary radar systems for both operational requirement and spectrum reasons.
Recommendation 3.8: Solid state transmitters should be adopted for future systems
given the ability to control pulse rise and fall times to minimise the out of band emissions
and the single channel fail soft capability to minimise frequency requirements. This
approach is also preferred for operational requirement reasons.
3.2.10.3 Band Sharing
Recommendation 3.9: More visibility of spectrum used by the military in the L and S
bands may assist the delivery of improved spectrum efficiency. Ofcom should consider an
initiative in this area.
Recommendation 3.10: The overriding recommendation in the area of band sharing is
for the development of a methodology which can assess the feasibility of band sharing.
This would lead to a more strategic approach to the identification of band sharing
opportunities. These developments should be carried out by a group representing all
interested parties.
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