What is the link margin value required to compel an enemy jammer at equal distance to a receiving Link 16 terminal to utilize 128 times more power than the transmitting terminal?

The correct link margin value needed for an enemy jammer to utilize 128 times more power than the transmitting terminal is 31 dB. This metric is derived from understanding the relationship between power ratios and decibels (dB).

To determine the dB requirement for achieving a specific power ratio, one can use the formula that states:

[ \text{Power Ratio (in dB)} = 10 \times \log_{10} \left( \frac{P_{j}}{P_{t}} \right) ]

where ( P_{j} ) is the power used by the jammer and ( P_{t} ) is the power of the transmission. Since 128 is equal to ( 2^7 ), the relationship can be calculated as:

[ 10 \times \log_{10}(128) = 10 \times \log_{10}(2^7) = 10 \times 7 \times \log_{10}(2) ]

Given that ( \log_{10}(2) ) is approximately 0.301, the calculation results in:

[ 10 \times 7 \times 0.301 = 21.07 , \text