AEW Nimrod AMRICS
Trevor Sanderson, recently retired from ESA writes:
I am interested in aircraft communications and have written several articles on WWII aircraft communications. (I worked briefly for EASAMs many, many years ago, and also worked as a summer student in Brough on the Buccaneer simulator, alongside the analog computer staff from Elliott’s).
I am researching the AMRICS system used in the cancelled AEW Nimrod communications system. I am trying to put together a basic AMRICS system. Surprisingly, in the last 4 or 5 years, I have managed to collect together many of the parts, enough to make up a working system. So far, I have powered up the control units and connected them to a small microcomputer, and managed to work out the protocol used to control them. My next step is to control an AD120 VHF transceiver to the system with a serial to parallel converter.
The most difficult part is interfacing the volume control in the units. I read in a chapter written by Thomas T Brown of GEC Basildon, in the 1989 book ‘Aircraft Avionics’ that “AF gains are remotely controlled manually by variable gain op-amps in the central unit”. Incidentally, I approached the MOD under the Freedom of Information Act, and was able to obtain from them the AMRICS maintenance manual Air Publication. Can you help and tell me how these op-amps worked?
If you can help, please contact the MVA secretary.
Following the publication of this request we had a response from David Harris and put him in touch with Trevor Sanderson. We then received this e-mail from Trevor.
‘You will be pleased to hear that I have just been in contact with David Harris. He was not only able to answer my question, but turned out to be the person responsible for the whole communications system (called AMRICS) on the Nimrod AEW. As you can imagine, we just spent the last hour or so talking on the phone about it. He can remember an enormous amount of detail about the system, not only to the names of the individual units, and their reference units, but also to details of how they worked.
Thank you again for being so kind as to include my request in your newsletter,
With kindest regards,