This is a partial recording, the transmissions were already in process when I started recording. Sorry about that.
This is an unusual set of transmissions on the US military HF-GCS (High Frequency Global Communications System) network. The HF-GCS is a military only communications network, used by all US military services. It is not part of the civil aviation communications systems. It is very unusual to hear civilian traffic on this network, but it does happen occasionally.
In this case, FEDEX 624, enroute from Boise, Idaho, to Memphis, Tennessee, uses 11175 kHz to ask MAINSAIL for a radio check. Near the end of the video FEDEX 624 asks MAINSAIL where he is located. MAINSAIL never answers that question ;)
The HF-GCS is maintained and operated by the US Air Force, however all US forces have access to the system.
Recorded at my location in the Mojave Desert, of California, USA, on 02 February, 2024, 1533 UTC.
Disclaimer: Many of the radio reception recordings on this Youtube channel pertain to unusual, uncommon, unknown, or mystery signals that might be found on radio, both shortwave and VHF/UHF. Among the subjects covered are numbers stations, utility stations, military transmissions (both in the clear and encrypted / encoded), aviation, maritime, ham radio, CB radio, radars, ionosodes, propagation beacons, ditters, dashers, whistlers, and just about anything else that might transmit, in any mode, USB, LSB, CW, Morse Code, FM, AM,FMCW, LFMCW, etc. Think of it as SIGINT (signals intelligence) / COMINT (communications intelligence) / ELINT (electronic intelligence) lite, the hobby version. All the recordings are made by me, most often at my home. Although there are a few mysterious things to be found here, you will not find anything paranormal, extraterrestrial, spiritual, or mystic. However, everyone can have their own interpretations of the sounds heard, make of it what you will.
