Defence High Frequency Communications Service (English Wikipedia)

Babcock International Group 2012, p. 21. "Defence High Frequency Communications Service" (PDF). High Frequency Industry Association. Babcock International Group. 5 September 2012. Archived from the original (PDF) on 1 October 2017. Retrieved 5 June 2017.
Babcock International Group 2012, p. 9. "Defence High Frequency Communications Service" (PDF). High Frequency Industry Association. Babcock International Group. 5 September 2012. Archived from the original (PDF) on 1 October 2017. Retrieved 5 June 2017.
Babcock International Group 2012, p. 6. "Defence High Frequency Communications Service" (PDF). High Frequency Industry Association. Babcock International Group. 5 September 2012. Archived from the original (PDF) on 1 October 2017. Retrieved 5 June 2017.

hobbydocbox.com

Babcock International Group 2011, p. 12. "Defence High Frequency Communications Service". Doc Box. Babcock International Group. September 2011. Retrieved 31 May 2022.
Babcock International Group 2011, p. 11. "Defence High Frequency Communications Service". Doc Box. Babcock International Group. September 2011. Retrieved 31 May 2022.
Babcock International Group 2011, p. 9. "Defence High Frequency Communications Service". Doc Box. Babcock International Group. September 2011. Retrieved 31 May 2022.
Babcock International Group 2011, p. 26. "Defence High Frequency Communications Service". Doc Box. Babcock International Group. September 2011. Retrieved 31 May 2022.
Babcock International Group 2011, p. 28-29. "Defence High Frequency Communications Service". Doc Box. Babcock International Group. September 2011. Retrieved 31 May 2022.
Babcock International Group 2011, p. 22. "Defence High Frequency Communications Service". Doc Box. Babcock International Group. September 2011. Retrieved 31 May 2022.
Babcock International Group 2011, p. 18. "Defence High Frequency Communications Service". Doc Box. Babcock International Group. September 2011. Retrieved 31 May 2022.

"Flight Information Handbook" (PDF). Portal Aeronautical Publications. National Geospatial-Intelligence Agency. 8 December 2016.

"No 81 Signals Unit, RAF Bampton Castle". National Archives. 13 January 2016. Retrieved 29 May 2017.

Babcock International Group 2012, p. 21. "Defence High Frequency Communications Service" (PDF). High Frequency Industry Association. Babcock International Group. 5 September 2012. Archived from the original (PDF) on 1 October 2017. Retrieved 5 June 2017.
Babcock International Group 2012, p. 9. "Defence High Frequency Communications Service" (PDF). High Frequency Industry Association. Babcock International Group. 5 September 2012. Archived from the original (PDF) on 1 October 2017. Retrieved 5 June 2017.
Babcock International Group 2012, p. 6. "Defence High Frequency Communications Service" (PDF). High Frequency Industry Association. Babcock International Group. 5 September 2012. Archived from the original (PDF) on 1 October 2017. Retrieved 5 June 2017.