216 RADIO WAVE PROPAGATION EXPERIMENTS 
replace the exponential by its value at the middle of pressure may be written 
the height range. This approximation does not lead 
to an error of more than 0.1 M units at these low CD Gel ; (21) 
altitudes. Pp kT 
PressuRE versus HricHT where g = acceleration of gravity, 
The differential equation connecting height with R = gas constant for air. 
TABLE 9. p/p for h from 50 m (164 ft) to 2,000 m (6,562 ft) and t* from —30 C (—22 F) to 40 C (104 F). 
Nee We 
h (m)\. —30 -25 -20 -15 -10 —5 +0 +5 410 +415 +20 +25 +30 +435 +40 Jr (ft) 
50 | 0.9930 0.9931 0.9933 0.9934 0.9935 0.9936 0.9938 0.9939 0.9940 0.9941 0.9942 0.9943 0.9944 0.9945 0.9946 164.0 
100 | 0.9860 0.9863 0.9866 0.9869 0.9871 0.9874 0.9876 0.9878 0.9880 0.9882 0.9884 0.9886 0.9888 0.9890 0.9892 328.1 
150 | 0.9791 0.9795 0.9799 0.9802 0.9807 0.9810 0.9814 0.9817 0.9821 0.9823 0.9827 0.9829 0.9832 0.9835 0.9837 492.1 
200 | 0.9723 0.9727 0.9734 0,9738 0.9744 0.9748 0.9753 0.9757 0.9761 0.9766 0.9770 0.9774 0.9777 0.9780 0.9784 656.2 
250 | 0.9655 0.9662 0.9668 0.9674 0.9681 0.9686 0.9692 0.9698 0.9703 0.9707 0.9713 0.9717 0.9722 0.9727 0.9730 820.2 
300 | 0.9587 0.9595 0.9603 0.9610 0.9618 0.9625 0.9632 0.9637 0.9644 0.9650 0.9656 0.9662 0.9667 0.9672 0.9678 984.3 
350 | 0.9519 0.9529 0.9538 0.9547 0.9556 0.9564 0.9572 0.9579 0.9586 0.9593 0.9600 0.9607 0.9613 0.9619 0.9625 | 1,148.0 
400 | 0.9453 0.9464 0.9474 0.9484 0.9494 0.9503 0.9512 0.9519 0.9529 0.9537 0.9544 0.9551 0.9559 0.9566 0.9572 | 1,312.0 
450 | 0.9387 0.9399 0.9410 0.9421 0.9432 0.9442 0.9452 0.9462 0.9471 0.9480 0.9489 0.9497 0.9505 0.9513 0.9520 | 1,476.0 
500 | 0.9321 0.9334 0.9347 0.9359 0.9371 0.9383 0.9394 0.9404 0.9414 0.9424 0.9434 0.9443 0.9452 0.9460 0.9469 | 1,640.0 
600 | 0.9191 0.9206 0.9222 0.9236 0.9250 0.9263 0.9277 0.9289 0.9301 0.9313 0.9324 0.9335 0.9346 0.9355 0.9366 | 1,969.0 
700 | 0.9063 0.9081 0.9098:0.9115 0.9131 0.9146 0.9161 0.9176 0.9190 0.9203 0.9216 0.9229 0.9241 0.9253 0.9264 | 2,297.0 
800 | 0.8936 0.8957 0.8976 0.8995 0.9013 0.9030 0.9047 0.9063 0.9079 0.9095 0.9109 0.9124 0.9138 0.9151 0.9164 | 2,625.0 
900 | 0.8812 0.8834 0.8856 Q.8876 0.8897 0.8916 0.8935 0.8953 0.8971 0.8987 0.9004 0.9019 0.9035 0.9050 0.9064 | 2,953.0 
1,000 | 0.8688 0.8712 0.8737 0.8760 0.8782 0.8803 0.8824 0.8843 0.8863 0.8881 0.8899 0.8917 0.8934 0.8950 0.8966 | 3,281.0 
1,500 | 0.8099 0.8133 0.8166 0.8198 0.8230 0.8260 0.8289 0.8317 0.8344 0.8370 0.8395 0.8420 0.8444 0.8467 0.8490 | 4,921.0 
2,000 | 0.7549 0.7592 0.7633 0.7674 0.7712 0.7749 0.7786 0.7821 0.7855 0.7888 0.7920 0.7951 0.7981 0.8011 0.8039 | 6,562.0 
—22.0 —13.0 —4.0 45.0 +14.0 +23.0 +32.0 +41.0 +50.0 +59.0 +68.0 +77.0 +86.0 +95.0 +104.0 \/ (ft) 
*t = temperature averaged from the ground to the height h. tF \ 
Taste 10A. u for h from 10 m (82.8 ft) to 150 m (492.1 ft); F from 250 to 370. Values to be subtracted from F to 
obtain Fp = (n — 1) 108 
F Ye 
h (m) 250 260 270 280 290 300 310 320 330 340 350 360 370 fi h (ft) 
10 32.8 
20 65.6 
30 98.4 
40 131.2 
50 164.0 
60 196.9 
70 229.7 
80 262.5 
90 295.3 
100 328.1 
110 360.9 
120 393.7 
130 426.5 
140 459.3 
150 492.1 
TaBLE 10B. w for h from 10 m (82.8 ft) to 150 m (492.1 ft); F from 370 to 500. Values to be subtracted from F to 
obtain Fp = (n — 1) 106. : 
F 
FAA) 370 380 390 400 410 420 430 440 450 460 470 480 490 500 Fi h (ft) 
10 32.8 
20 65.6 
30 98.4 
40 131.2 
50 164.0 
60 196.9 
70 229.7 
80 262.5 
90 295.3 
100 328.1 
110 360.9 
120 393.7 
130 426.5 
140 459.3 
150 492.1 
