AEL Communication System Calculator

This impressive slide chart from 1971 calculates useful properties of an RF link. The example shown on the rule finds signal level, gain, and path loss for smooth earth model.

1. Set 10 kHz on RECEIVER BANDWIDTH under top arrow.
2. Set 40 dB on RCVR INPUT S/N scale across from NF.
3. Read RCVR INPUT SIG LVL as -74 dBm and 44 uV above 50 Ohms on RCVR INPUT IMPEDANCE scale.
4. Set TX/RX RANGE as 100 miles to operating FREQ 100 MHz.
5. Read antenna gain 13 dB (dBi) under 1 W on TX PWR OUTPUT.
6. Read PATH LOSS as 117 dB.