Table I
Ruby Laser Multipath Observations
Date | Visibility | Pulse Characteristics | Weather Conditions |
---|
|
---|
| from Cambridge | from Waltham | type | duration | |
---|
11/21/75 | 3 miles | 3 miles | i | 150 nsec | heavy rain |
2/18/76 | 1 mile | 0. 25 mile | – | – | heavy fog with light rain; unable to see any signal |
3/3/76 | 2 miles | 2 miles | i | 150 nsec | fog with light snow; signal faded out as visibility decreased to
mile at both terminals |
3/5/76 | | 5 miles | iii | 300-500 nsec | fog in Cambridge |
5/12/76 | 2-3 miles | 4 miles | iii | 200-400 nsec | fog with light rain |
6/1/76 | 6 miles | 6 miles | i | 150 nsec | light rain |
7/21/76 | 3-4 miles | 2-3 miles | i | 150 nsec | fog with light rain |
9/17/76 | 0. 5 mile | 0. 5 mile | – | – | fog and rain; unable to see any signal |
10/1/76 | 6 miles | 6 miles | i | 150 nsec | haze and fog |
10/6/76 | 3-4 miles | 2 miles | i | 150 nsec | fog |
10/8/76 | 6 miles | 6 miles | i | 150 nsec | haze |
10/20/76 | 6 miles | 2-3 miles | i | 150 nsec | fog and rain |
10/20/76 | 6 miles | 0. 5-1 mile | i | 150 nsec | heavy fog in Waltham |
11/5/76 | 3-4 miles | 0. 1-1 mile | ii | 150-200 nsec | fog in Waltham; at lowest visibility unable to see any signal, as fog lifted pulses had 150-200 nsec duration in 1 mile visibility |
11/10/76 | 7 miles | 5-6 miles | ii | 150 nsec | haze |
Table II
Ruby Laser Transmission Data
Date | Visibility in Miles | Signal Voltage | Point No. |
---|
|
---|
| from Cambridge | from Waltham | Vmin | V | Vmax | vmin | v | vmax | |
---|
10/1/76 | 6 | 6 | | 6 | | 250 | 460 | 800 | 1 |
10/6/76 | 3-4 | 2 | 2 | 3 | 4 | 0. 16 | 0. 40 | 0. 70 | 2 |
10/8/76 | 6-8 | 6-8 | 6 | 7 | 8 | 40 | 68 | 140 | 3 |
10/18/76 | 10-12 | 10-12 | 10 | 11 | 12 | 300 | 420 | 800 | 4 |
10/20/76 | 6 | 3 | 4 | 4.5 | 5 | 0.40 | 1.70 | 5.00 | 5 |
| 6 | 0.5-1 | 2.6 | 3. 3 | 4 | 2.00 | 3. 80 | 6. 00 | 6 |
10/22/76 | 10 | 10 | | 10 | | 200 | 600 | 1000 | 7 |
10/26/76 | 8 | 10 | 8 | 9 | 10 | 200 | 1410 | 2500 | 8 |
11/5/76 | 3-4 | 1-2 | 1 | 2 | 3 | 0.50 | 1. 25 | 2. 50 | 9 |
| 3-4 | 0. 1 | 1 | 1. 5 | 2 | . 07 | . 12 | . 22 | 10 |
11/10/76 | 7 | 5-6 | 5 | 6 | 7 | 75 | 130 | 200 | 11 |
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
Date | Visibility in Miles | Signal Voltage | Point No. |
---|
|
---|
| from Cambridge | from Waltham | Vmin | V | Vmax | vmin | v | vmax | |
---|
8/26/76 | 8 | 8 | | 8 | | 3. 30 | 3. 95 | 4. 60 | 1 |
9/2/76 | 6 | 4-8 | 4 | 6 | 8 | 0. 70 | 0. 82 | 0. 950 | 2 |
| 8 | 4 | 4 | 6 | 8 | 1. 30 | 1. 50 | 1. 70 | 3 |
10/1/76 | 6 | 6 | | 6 | | 5. 20 | 7. 10 | 9. 00 | 4 |
10/4/76 | 15 | 15 | | 15 | | 7. 60 | 9. 30 | 11. 00 | 5 |
10/6/76 | 3-4 | 2 | 2 | 2. 7 | 3. 5 | 0. 12 | 0. 46 | 0. 80 | 6 |
10/18/76 | 10-12 | 10-12 | 10 | 11 | 12 | 2. 80 | 3. 40 | 4. 00 | 7 |
10/29/76 | 10 | 10 | | 10 | | 2. 40 | 2. 70 | 3. 00 | 8 |
11/5/76 | 3-4 | 2-3 | 2. 5 | 3 | 3. 5 | 0. 100 | 0. 112 | 0. 125 | 9 |
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.