Reception on a large vessel at sea

One of our users, a crew member on a large vessel, sent us his/her feedback of the coverage of AISRec. A handy antenna, SRH789 positioned outside of the window below the deck, was used. The user said that he/she was amazed by the maximum reception range of AISRec, "It is up to 250 nautical miles". From the left-side picture, a few ships were seen on the AIS radar within 30 nautical miles. On the map of a larger scale, the ships and base stations far away at the huge island were shown that was about 129 nautical miles away from the vessel where the user stayed.