I am hearing a frog-like croaking sound on C4FM. I am using an almost new openSPOT 4 PRO and a Yaesu FT5D. The sound occurs frequently, maybe once every 10 seconds or so, when there is traffic on the AmericaLink. It happens regardless of whether I'm accessing the room using an FCS or YSF connector. Since I'm using a Fusion radio, the modem is set for C4FM and no transcoding is involved. To eliminate the radio as the source of the problem, I also have the original openSPOT (aka openSPOT 1). The problem does not occur when I use the openSPOT 1. The frequent sound is quite annoying. I would appreciate any guidance the SharkRF team, or another user, can offer. Thank you!