Com-Power model PAM-4000 Preamplifier is intended for improving measurement system sensitivity during EMC compliance testing. It has a frequency range of 500 MHz to 4000 MHz.. It has gain of 28 dB gain. Therefore, It amplifies the signals that were previously hidden below the receiver noise floor of the EMI receiver so that it can be seen and measured. The PAM-4000 has a gain variation of +/-2 dB for the entire frequency range to reduce measurement errors. It can be powered by the rechargeable NimH batteries included when an external power source is not available.