PA,
Follow the link below to the OFCOM UK FAT:
http://stakeholders.ofcom.org.uk/bin...UKFAT_2013.pdf
Annex E.
FREQUENCIES FOR THE OPERATION OF SONOBUOYS
Footnote UK40 and UK48
1. Sonobuoys may be operated in the band 136-174 MHz, subject to the following conditions:
a) During normal peacetime exercises, sonobuoys operating below 162 MHz would not be deployed within 50 miles of the United Kingdom coast.
b) Sonobuoys would not normally be used within a radius of 5 nautical miles of any oil rig or platform.
c) Should the operation of Sonobuoys cause harmful interference to radio services operating in accordance with the UK Frequency Allocation Table,
geographical or frequency assignment restrictions would be imposed on the Sonobuoy operations.
2. Sonobuoys are covered by Footnotes UK40 (for the band 136·0-162·0 MHz) and UK48 (for the band 162·0-174·0 MHz and permitting use near UK coasts on a noninterference basis).
The assignments agreed for Sonobuoys operations in the band 136-174 MHz are listed below.
The channel numbers and frequencies are listed but I have not bothered to post them here (channel 38 and above are below 162.MHz) . In several documents we used to carry these were classified Confidential!!!!
If you look at the FAT at and around sonobuoy frequencies you will see the others who share the allocation.
How many operators were aware of this? I know the GSU and Gp Staff were not!
Please note this is for the UK. The sonobuoy alloaction is not internationally recognised and the EM spectrum is not policed well in other areas of the world. Thus my comment on RFI.