I direct you to patent number 5159703, described in the US Patent database as a “silent subliminal presentation system”.
This technology expands on an existing technology called subliminal messaging. Subliminal messaging is extremely effective as it forces the mind to feel or think a certain way, and has therefore been used in self help style products as well as military applications.
In the original technology one would place a message in an audio feed where it would say “do/feel this”, and then mask it by playing it at 5 decibels lower than whatever sound is used to as a mask, like music or the sound of the ocean. It remains inaudible to the human ear, yet is loud enough that the human subconscious mind could decode it and receive its underlying message. The problem was that it had to be contained in some type of audible sound used to mask it (hide it from the conscious part of the brain), such as with music or sounds of the sea etc.
This new technology allowed for it to be transmitted through any audio medium without having any masking sound. I.e. one could play it through loudspeakers or PA systems and no one would know they were being subliminally influenced. This was used during the Persian gulf war in Kuwait when army psyops units used loudspeakers to “talk” the enemy out of fighting, at which point they surrendered. The use of such subliminal suggestions instilled a false sense of fear and despair in the enemy, making them believe that they would surely die if they fought, and was quite effective.
During my training in the army I dealt a lot with the different type of support aircraft available in theatre and the various payloads/electronics on-board. The coolest one was (I forget the nomenclature) one that could fly over a city and stop all broadcasts of Tv, radio etc, and replace them with messages transmitted by the plane. This could be used for emergency broadcasts or to jam the enemies equipment and transmit whatever message you wanted.
Imagine what one could do if they used these silent subliminal messages to influence large parts of the population using these planes or other technology capable of transmitting certain frequencies across long distances.
Then look at what is going on with the chemtrails and HAARP. Originally the military proposed research into technology that would use particulate matter ejected from jets to create long (and not dissipating) chemtrails to be used as giant antennae for the use of transmitting messages to submarines or communicating over long distances without having to erect a massive broadcasting station. Now imagine that these antennae are all over the place during spray operations and that they could be used to effectively transmit said subliminal messages over entire countries worth of population.
A silent communications system in which nonaural carriers, in the very low or very high audio frequency range or in the adjacent ultrasonic frequency spectrum, are amplitude or frequency modulated with the desired intelligence and propagated acoustically or vibrationally, for inducement into the brain, typically through the use of loudspeakers, earphones or piezoelectric transducers. The modulated carriers may be transmitted directly in real time or may be conveniently recorded and stored on mechanical, magnetic or optical media for delayed or repeated transmission to the listener.