Propagation experiments in low-visibility atmospheres

Ruby Laser Multipath Observations

Ruby Laser Transmission Data

These data were taken with coaxial transmitter-receiver alignment, 10 mRad transmitter beam divergence, and 20 mRad cone-angle receiver field of view. The minimum, nominal, and maximum visibilities, (V_min, V, and V_max, respectively) are ad hoc estimates of a homogeneous-path visibility that would produce the same unscattered-light extinction as the Cambridge-to-Waltham path. The signal voltages are based on storage oscilloscope observation of ten laser pulses, corrected for the Wratten filters employed prior to detection.

Holmium Laser Transmission Data

These data were taken with coaxial transmitter-receiver alignment, 5. 5 mRad transmitter beam divergence, and 20 mRad cone-angle receiver field of view. The minimum, nominal, and maximum visibilities (V_min, V, and V_max, respectively) are ad hoc estimates of a homogeneous-path visibility that would produce the same unscattered-light extinction as the Cambridge-to-Waltham path. The signal voltages, v_min and v_max, are the minimum and maximum levels (corrected for the Wratten filters) reached in 15 seconds of boxcar averaging with an effective time constant of 4 sec; v ≡ (v_min + v_max)/2.

Table I

Ruby Laser Multipath Observations

Table II

Ruby Laser Transmission Data

These data were taken with coaxial transmitter-receiver alignment, 10 mRad transmitter beam divergence, and 20 mRad cone-angle receiver field of view. The minimum, nominal, and maximum visibilities, (V_min, V, and V_max, respectively) are ad hoc estimates of a homogeneous-path visibility that would produce the same unscattered-light extinction as the Cambridge-to-Waltham path. The signal voltages are based on storage oscilloscope observation of ten laser pulses, corrected for the Wratten filters employed prior to detection.

Table III

Holmium Laser Transmission Data

These data were taken with coaxial transmitter-receiver alignment, 5. 5 mRad transmitter beam divergence, and 20 mRad cone-angle receiver field of view. The minimum, nominal, and maximum visibilities (V_min, V, and V_max, respectively) are ad hoc estimates of a homogeneous-path visibility that would produce the same unscattered-light extinction as the Cambridge-to-Waltham path. The signal voltages, v_min and v_max, are the minimum and maximum levels (corrected for the Wratten filters) reached in 15 seconds of boxcar averaging with an effective time constant of 4 sec; v ≡ (v_min + v_max)/2.