I recently climbed Mt. Lassen in California and was able to directly make contact with my family back at our base camp 29.6 miles away, no relay units in between at the time and I wasn’t even using my modified gotennas with external directional antennas, just regular stock GoTenna’s! I was very surprised that it worked considering I did not have a perfectly unobstructed line of sight. I was able to ping, send messages, and even share my position. Very impressed with the capability of these devices. Hopefully more users make plans to setup perminant solar powered relays on mountain tops because dang does it work!