The 1296 MHz feed is an amateur radio feed intended for Earth-Moon-Earth (transmit and receive, half-duplex). It is a scaling of the design for the 1420 MHz Feed.

The 1296 MHz feed borrows version 2 of the W1XM Control Board Design by Noah Haefner (K9EA). This board provides regulated 12 V power for the LNA, as well as opto-coupled control of the LNA power and TX/RX relay coil.

Currently, we have replaced R6 and R11 with 510 Ohm resistors to make the board controllable by the 3.3 V I/O of the Ettus USRP X300 SDR. Measurements indicate that this modification causes the RX_EN pin to draw around 2 mA from the Ettus's GPIO, which is within the safe 5 mA limit specified by Ettus. The board itself provides opto-isolation and has FETs which switch the higher currents for powering the LNA and relay coil.

Similar to how the board is used for the rest of W1XM, the relay is configured such that it is in the transmit path by default (when unpowered). Putting 3.3 V across the RX_EN_P and RX_EN_N pair switches the relay into the RX path and turns on the LNA. This configuration decreases the probability of accidentally having the LNA in the RF path when transmitting and destroying the LNA.