Key
| Heavy Anti-Aircraft Site |  | Light Anti-Aircraft Site |  | Airfield |  | RDF Tower |  |
| Site No. | Name | OS Grid Reference |
| H9 | Martlesham | TM 254 481 |
| H10 | Brightwell | TM 251 427 |
Coding sequence integral with Harwich & Ipswich
Gun Strengths
Battle of Britain & the Blitz
| Dates | 3 inch |
| May 40 – May 41 | 4 |
Heavy AA Regiments known to have occupied sites in this GDA
| Dates | Units |
| Jun 40 – May 41 | 99 Heavy Anti-Aircraft Regiment |