http://tighar.org/wiki/Frequency,_wavelength,_and_antenna_tuning#Daytime.2Fnighttime_frequenciesThank you for your information. I must, however, tell you that, and using your words, "If a broadcast is made, it is always heard." I believe you are stating that I believe this is true. Marty, I have never said this.
I didn't say that you SAID it.
I said that this
premise is essential for the argument you are making.
- No broadcast was received.
- Therefore, no broadcast was made.
- Therefore, the plane went down in the ocean.
It is a fact that no broadcast was logged in any logs to which we have access.
Reasoning from this fact depends on understanding the nature of radio transmissions.
Wrong assumptions (premises) about radio transmissions will lead to wrong conclusions about the meaning of the fact on which we agree.
That people often make broadcasts that are not heard is a matter of fact.
"
Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another, or into various parts of the atmosphere. As a form of electromagnetic radiation, like light waves, radio waves are affected by the phenomena of reflection, refraction, diffraction, absorption, polarization, and scattering. Understanding the effects of varying conditions on radio propagation has many practical applications, from choosing frequencies for international shortwave broadcasters, to designing reliable mobile telephone systems, to radio navigation, to operation of radar systems."
The reflective qualities of the ionosphere change as the sun rises. This affects propagation. Amelia was heard loud and clear on her
"nighttime frequency" (3105 kHz). In her
last intelligible message, she indicated that she was changing to her "daytime frequency" (6210 kHz). The Coast Guard never heard anything on that frequency at all. Some people think that means that the ship went down after that last transmission. TIGHAR believes that she did what she said she would and that the transmissions on her daytime frequency were not heard--just as they had not been heard the day before for the first four hours of her flight away from Lae.
That no intelligible transmissions were heard after Earhart announced she was changing frequencies
could mean that they crashed in the ocean; it could also mean that the atmospheric conditions were not conducive to reception at Howland Island on that day at that time.
It is meaningless to try to perform an experiment by broadcasting from a replica of the Electra using replica transmitters to try to reach a replica of the Itasca and of the station on Howland Island. Experimental method requires "controlling the variables." It is impossible to know exactly what equipment was on board the aircraft; it is impossible to know exactly what equipment was on the Itasca; it is impossible to duplicate the antennas on the aircraft and on the two receiving stations at Howland; it is impossible to know the atmospheric conditions on 2 July 1937; it is impossible to arrange to duplicate those conditions today; it is impossible to know where the Electra was when AE's transmissions were received; it is impossible to fly a replica aircraft on the course that she took on 1-2 July 1937.
These, too, are matters of fact.