I recently did a project on my 420 Sundancer to install 12V Internet including running CAT5 ethernet cables to key components. The "network closet" is beneath the cabin circuit breaker panel (same place where the Beam vacuum is located). 1) I purchased a Netgear LB1121 4G LTE modem. I got this item because it accepts a SIM card from AT&T, and I can add this to my existing AT&T family plan. It also runs over PoE (power over ethernet) which enabled me to install it in a remote (high) location for a better signal. It also has an external antenna adapter. 2) I originally was going to mount this in the cabin, but I could only get 2 bars. When I experimented and put it on the arch I got a better signal. So I ended up mounting it with adhesive velcro (I didn't want to drill any holes in case I changed my mind later). I mounted it behind the cockpit TV so that it would not be visible. 3) I bought the external MIMO antenna which fit into the external antenna jacks on the LB1121 modem. This was the item most often paired with the modem on Amazon as well. 4) I velcro'd the MIMO antenna to the fiberglass canopy of the boat. I can therefore remove the antenna when I go home and/or we are not really using the Internet. My preliminary review of the MIMO antenna is that it is pretty useless (does not seem to really add a bar over having no external antenna plugged into the modem). If anybody has used a different antenna I would really love to hear about it. 5) I purchased a PoE injector (Power over Ethernet) so that I could power the modem via the same Ethernet cable that I was using to patch between the modem and the router. I had to do quite a bit of searching to find a PoE injector that ran off 12v instead of household 110v. I wanted the 12v version so I could run the Internet without shore power or generator. 6) I purchased the NETGEAR N600 WiFi router because a) it's input voltage is 12v so I was able to directly wire into the boat 12v power system b) it has both WiFi as well as 4 Ethernet jacks (more about that later). 7) I mounted the NETGEAR WiFi router to the inside of the space under the cabin circuit breaker (where the Beam Central Vac is located). Here is how the CAT5 ethernet cables are set up: a) The Green ethernet cable goes to the PoE Injector and then to the LTE modem. b) Top Blue cable goes to the Fusion stereo (which only supports WIRED ethernet). c) Middle Blue ethernet goes to the mid cabin PS4. When I removed the defunct 2005 DVD player, I modified the cabinet opening to fit a PS4 console. When my son brings the PS4 from home (so he can play Fortnite on the boat - ridiculous I know) he can simply plug it into the spare power cord I bought, the HDMI to the TV and the Ethernet cable and not have to configure anything on the box. d) The bottom blue goes to the Cockpit Samsung Smart TV. e) The Salon Samsung Smart TV is connected via WiFi. f) The Raymarine MFD is also connected via Wifi. 8) I am powering the whole thing from 12V from a Blue Sea Systems 6 circuit sub panel. This sub panel is fed off the "Satellite TV" breaker in the cabin breaker panel. 9) I mounted the sub panel in the same location as the router (described above) and installed blade fuses just above the rating for each component (PoE injector powering the modem / WiFi router). I also ran 12v to near each TV so I have the option of powering each TV off an individual inverter if I don't want to run the generator while not on shore power. VERDICT: The Internet speed is OK - probably on par with setting up your iPhone as a hotspot. The main advantage is that I have a power up and go Internet solution (by just flipping a single circuit breaker) that also works with the Raymarine MFD and Fusion stereo (enabling remote control of the Fusion from any phone associated to the WiFi). The Internet speed is good enough for my son to play his beloved Fortnite as well. As stated above, I am disappointed in the effectiveness of the external antenna. I considered buying the "Glomex Web Boat 4G/LTE Cellular Internet Dome" but it was a good deal of money and I couldn't find any review online from boaters who had actually installed it. For that much money it better give much better Internet than I am getting off the (much cheaper) Netgear LB1121. If anybody on this forum has experience with the Glomex Internet dome I would love to hear what you think!