I want to experiment with using the Bias-T function to switch some outboard modules without having to tap it from the antenna connector.
You can also use an external DC-block, a capacitor in series (depending on your lowest frequency 100nF-470nF, ceramic).
Imho there is no circuit drawing of RSP1A available but you can find pictures of the pcb.
Reason: No reason
RFsystems DX-10 (14kHz to 50MHz), resistive splitter 1/4, 1:16 transformer on Hi-Z of RSP2
ICOM Discone AH-8000 (10MHz to 2GHz)
12m above ground