Best practice Marine Antenna Installation HD4 MBX


I am looking to install an HD4 MBX (MAX-HD4-MBX-GLTE-G-T) or 5G HD4 MBX (MAX-HD4-MBX5G-T) on a seagoing vessel. I need to populate 16 QMA connectors, but due to space I cannot install 16 individual SISO antennas. Instead, I am opting to go with 4 high-gain long range SISO antennas and 6 lower-gain 2x2 MIMO antennas. Firstly, would this be a sound solution or is there a better way to populate the 16 connectors? If this setup would work, what is the best practice in connecting up all the antennas to the respective modems, i.e connecting connector Main A of each modem to the long-range SISO antennas and the rest divided to the MIMO antennas? What issues may arise when connecting one modem’s connectors to differing gain antennas?

Thank you in advance.

Best regards,

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Hi @5GMBXMan

Which antennas are you considering?
We have a 4x4 high gain maritime antenna which will be available towards the middle of the year.
With this antenna, you would only require four antennas to fully populate a CAT18 or 5G HD4 MBX.

To answer your question about how to connect different antennas, I recommend that you use the same type of antenna for all connectors on a particular modem.

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Hi Sam,

Thanks for the reply.

I am considering four 10dB+ SISO antennas (AX200) and six 7dB 2x2 MIMO antennas (Poynting 402). Unfortunately, I have to install them soon so cannot wait for those 4x4s! What will the gain be of these 4x4 MIMO antennas?

In this case, would you recommend I connect all 4 SISOs to modem A and the 2x2 MIMO’s to modems B, C and D?

Our vessel does not roll more than 3 degrees so I can utilize very high gain antennas.

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do you have any pictures? even draft form! 1x14 thread mount? antennas like poynting or dome?

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@mystery send me an email @ and I’ll send you a copy of the draft.
They are 1x14 standard Maritime mounting and are a rod antenna rather than dome

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email sent! thanks

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My first comment about using such a high gain antenna would usually be about the roll of the vessel but I know your vessel so roll especially underway while at the longer ranges wouldn’t be an issue but also remember that when located in an area where there are hills close to the vessel and the cell towers might be higher up, your high gain antennas would be focused on the terrain around the vessel rather than above it (think of Monaco and Portofino). This is where using a mix of antenna has its advantages.

The major gain of having a 4x4 high gain antenna is that you can have just four physical antennas (containing four elements each) to provide for a CAT18 or CAT20/5G HD4 MBX.


Thanks, well noted on this. I will definitely go with a mixture of antennas.

To go back to my previous question. If I use a mixture of 4 SISO antennas and 6 2x2 MIMO antennas, would you recommend I connect all 4 SISO antennas to modem A and the 2x2 MIMO’s to modems B, C and D? Or could I connect each SISO antenna to connector Main A of each modem and populate the rest with the 2x2 MIMO antennas?

Lastly, what is the release date for the CAT20/5G HD4 MBX?


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I would recommend that antennas of the same type are used on each modem so as you explained above;

connect all 4 SISO antennas to modem A and the 2x2 MIMO’s to modems B, C and D

For 5G MBX availability, please contact your Peplink Parter.

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Thank you, Sam.

Last question, is there any other use of the GPS other than tracking?

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The GPS is used for the following;
-WAN Quality Report (Shows signal quality on a map)
-Event location (WANs online/offline etc - great for understanding cellular environments)
-FusionSIM Cloud - SIM Allocation depending on current country of router

GPS is not essential for the router to function but it does generate some useful information.


Much obliged, Sam, thank you.

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Hello @Sam_Norris
Remember too that GPS can (when using the higher end router models with firmware 8.1.0 & later) can also be used for NTP Timing Reference as a NTP Server, this very useful in the broadcast and security industries, as well as being useful on larger vessels for synchronising timing from a common reference point for various systems.
Happy to Help,
Marcus :slight_smile:


HI Alfa,
I’m just starting to get going on the forum here at Peplink. I’ve done a lot of vessel installs of cellular and other radio equipment.
You need to understand the characteristics of a high gain antenna before you fit them. Primarily, the beam pattern.
High-gains have a long narrow beam, giving them superior range, however, due to the pitch, roll and yaw of a vessel, high gains are really not well suited, as when the vessel rolls, the beam will not be centralised to the mast.
My recommendation to you is to use a medium gain antenna, and use a signal booster/amplifier for you fitment.



Hi Paul
There is a balance between high gain and too much gain on an omni-dirctional antenna.
I have found that for yachts, the sweet spot is between 6 and 9 dBi. If the vessel is larger, more stable and regularly operates further from shore e.g. a ferry then a higher gain antenna would provide longer range.

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Yes I agree,

But you have to take into account the platform size.
You also really need to look at the beam pattern supplied by the antenna manufacturer. I would be making too many assumptions just to say, you should use a high gain antenna.
Depending of the stability of the platform, I would never recommend anyone to install a high-gain antenna. the beam is too thin and interception with a cell mast is too dependant on vessel movement.
Also, cellular RX/TX frequencies are Line-of-Sight, therefore, you have to take into Earth Bulge high of antenna on the vessel, height of the transmitter station and the Geometric distance to the horizon.
These are all things that have to be taken into account when you want to know a maximum theoretical range of a system.
It is far to simple to say you will get more range if you use a high gain antenna, and you would be wrong to tell someone that high gain antenna will give your system more range.
Cellular signals are also attenuated by water, massively, on hot days you will get evaporation from the sea, on cold days you get harsh weather and high waves.
A good system design takes more into account than just antenna gain I’m afraid.
You also need to look at the receiver sensitivity figures, maximum transmit power etc etc

Hello Paul (@paul.smith),
@Sam_Norris has given you some great guidance on the choices available. You may also like to ask your local authorised Peplink Partner for a copy of the Antenna Selection Guide available to them from the Partner section of this forum. It has details especially related to antennas in the Marine Environment.

Your local Certified Peplink Partner can help you with a copy of the Antenna Selection Guide for Peplink Partners . The detailed guide is only available to the Peplink Partners to ensure that you get helped in working through it to get the most suitable antenna solution to your application. Even though we’ve not updated the article recently, it is still very relevant, and the fundamentals are still the same.

Happy to Help,
Marcus :slight_smile:

@mldowling Hi Marcus,
I’m not the one looking for advice, I was giving advice.
I am currently going through my training with Peplink.
While i appreciate what @Sam_Norris is saying, you can’t assume that the OP has a ship the size of a ferry that is a stable platform. Even then, the further you are away, the more noticeable any ships movement will be.
Having read through your article you have made my point exactly, in that a high gain antenna will not have a suitable beamwidth compared with lets say a medium gain antenna due to ships motion moving the beam off the cell tower. This is very much in laymen’s terms, and your article presents the arguement i was trying to make. High gain antennas are not suitable for use on ships due to the very focused beam patterns. You are better to use an antenna with a lower gain figure and an external amplifier unit.

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