Antenna Pattern and RF Safety Information

0559-EX-ST-2019 Text Documents

Higher Ground LLC

2019-04-05ELS_226964

Antenna Pattern:

The antenna is a parabolic reflector with a 0.6 meter diameter and a mainbeam gain of 28 dBi.

The antenna pattern is determined based on the below equation:

2𝐽1(𝑥) 2
𝑔(𝜃) = 𝑔𝑚𝑎𝑥 ( )
𝑥
Where
𝜋𝑑
𝑥= sin 𝜃
𝜆
𝜃 = 𝑎𝑛𝑔𝑙𝑒 𝑜𝑓𝑓 𝑏𝑜𝑟𝑒𝑠𝑖𝑔ℎ𝑡
𝐽1 = 𝑓𝑖𝑟𝑠𝑡 𝑜𝑟𝑑𝑒𝑟 𝐵𝑒𝑠𝑠𝑒𝑙 𝐹𝑢𝑛𝑐𝑡𝑖𝑜𝑛
Accordingly, the antenna pattern is shown graphically below.

Antenna Gain (dBi)
30

20

10

0
-90 -70 -50 -30 -10 10 30 50 70 90
-10

-20

-30

-40

The antenna pattern, combined with the spread spectrum nature of the transmitter will ensure that the
station is always in compliance with the PFD levels required under Section 25.218 of the FCC Rules in
order avoid interference to any adjacent two-degree-compliant space stations.

RF Exposure Determination:

In the mainbeam of the antenna, the EIRP will be PT + G = 30 dBm + 28 dBi = 58 dBm (631 Watts).

The limit for General Population/Uncontrolled Exposure is 1 mW/cm2 as given in Section 1.1310 of the
FCC Rules.

The permitted power density is used as a threshold in order to determine the minimum safe distance
using the equation below:
𝑃𝑜𝑤𝑒𝑟
𝑃𝐷 =
4𝜋𝑑
631 𝑊
0.001 𝑊/𝑐𝑚2 =
4𝜋𝑑
𝑑 = 224 cm

Thus, Higher Ground will ensure that no person is within 2.24 meters of the antenna any time the
experimental station is in operation.

Document Created: 2019-04-05 10:29:25
Document Modified: 2019-04-05 10:29:25

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