The radio has a dedicated "INT/EXT" switch. Using an external antenna through the provided jack bypasses the internal preamp to prevent front-end overloading. Grundig SAT 700 File Revision 1 - Grundig Satellit Radios
Do not connect an external active antenna (like MLA-30) directly without a DC blocker – the BNC input has 12V DC for Grundig’s active antenna option. Use a capacitor in series (0.01µF) or an external antenna adapter. grundig satellit 700 manual
: Use this on AM/SW to reduce fading (selective fading) and interference from adjacent stations. The radio has a dedicated "INT/EXT" switch
Use this to reduce selective fading on AM and SW. grundig satellit 700 manual