Improve RFID by killing noise

RFID is great technology, but noisy power and other aggressors can ruin performance. RFID readers using low frequency signals (ca. 130 kHz), like the industry-workhorse TIRIS RFM-007B, are of course very sensitive to noise in that frequency range. Given switched-mode power supplies often generate grunge in this range,  a heavy and expensive linear supply is often needed to get maximum sensitivity. However, the operational cycle of the RFID reader has several phases, only one of which is noise sensitive. They are: high power (transmit, 50ms at 10W), low power (receive, 18ms), and idle phases (up to 33ms depending on firmware). Noise is an issue only during the short receive phase.