The antenna jack on the Ericsson L21 is RP-MCX, not the normal MCX connector. So in order to make the connection to an external antenna on LMR 400 coax cable with N-Male connector at the bottom (inside the boat) we have to use 2 Wilson Electronics parts. One has the RP-MCX required to mate with the Ericsson L21′s external antenna jack.
We are not the only ones to discover that the RP-MCX plug on the adaptor cable doesn’t snap tight into the jack of the L21. It may need the RP-MCX end shield part stretched out a little bit with fingernail or a small knife. (See video, 2nd link below.) It also needs to be secured with one of those stick on wire tie mount things and a wire tie to hold it in place.
Alan Spicer Marine Telecom
+1 954 683 3426
communications @ marinetelecom.net