Is LMR-400-FR an appropriate cable for 410-6000MHz (Maritime 40G / MAX HD2 MBX)

The Boat has 60Ft. (~20 meters) of Low Loss LMR-400-FR cable from the wing to the control room. Is this cable appropriate for 5G (410-6000MHz) when using the Maritime 40G antennas with the MAX HD2 MBX router? or should we replace the cable to achieve acceptable or maximum performance?

Cable spec sheet should list losses at different MHZ.

60 feet of cable is a lot. I had a few installation options on a boat. Option A was inside climate controlled area but 40-50 feet was needed. Next option was in a protected area but not climate controlled, more exposed to elements, but 20 feet was plenty. I went with the 20 feet location. It gets very hot though some times, I think it impacts cellular on the hottest days.

I’ve done many marine installations, and my rules of thumb are:

  • LMR-400 if possible (most of the time it’s not)
  • LMR-400 ultraflex minimum
  • Never more than 20’ overall cable length from modem to antenna

The latter usually means considering putting the router/modem not in a central location or convenient power location, but rather as close to where the antennas are as possible. This can be a flying bridge, locker, etc. that reduces the cable length.

If the same router is also providing WiFi throughout the boat, placing it in a closer location to the antennas might compromise the signal, requiring one or more AP One APs or something similar.

If you look at the signal gain from most LTE antennas, it’s between 1dB to 7dB (in perfect conditions, which rarely happen) depending on the brand and frequency. Cables longer than 20’, converters, or other breaks in the cable add considerable loss, some up to 1dB. Combine that with the cables running in chases near high amperage DC power devices, or just general interference, and you’re already dealing with small numbers to maintain.

Having the cables as short as possible, and LMR-400 ultraflex at least will give you the best possible result.

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This is a nice site to compare cables: Comparison Coaxial Cable - Coaxial line 50R | Koax24
H195 is a standard cable used by Poynting and some other manufacturers.
From my experience it is always a good idea to draw circles on a piece of paper for the diameter of each cable you need to bring up to the mast. Do you have the room for all the cables ?
Amount of cables > 5 + cable run > 5m = Get the dome !

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