Purchased a great deal, a 4G cellular modem, and it was only €75 euros on Amazon, has external antennas connectors, so it must be good, right?!?

Well, might be a great deal, until you compare it with a higher-end unit, and see that device outperform this fantastic purchase…

When you evaluate your next modem that you want to install on the yacht, you need to understand 3 things that make the modem worthwhile.

1. What category modem is it?

LTE modems (4G modems) are split into UE categories. Basically, defining the advancement of technology. Most modems on the market (i.e. on Amazon) you will find to be Cat-4. This is 150MB down / 51MB up rated chip, with MIMO capability (2 antennas)
The next step you will generically find is a Cat-6 modem (300MB down / 51MB up) and also MIMO (2 or 4 antennas). Next you will find Cat-12 being sold (600MB down / 102MB up) with MIMO. Cat-18 is also being marketed now as the next great step (5G) which is rated at 1174MB down!

The minimum I suggest you consider is a Cat-6 modem, and place 2 antennas on it! No, you will not get 300MB instant connectivity, but it will get you those 25MB that you cell provider gives promises.
Compare it to a Cat-12 modem, same SIM, same location, same providers.. and yes, there is a difference. This is due to the modems capability of throughput, i.e. its ability to combine multiple channels into a single link and provide better data throughput to the cell tower.

Another way of seeing the modem category is by its label, Cat-4 is often simply labelled LTE, whilst Cat-6 is LTE-A and Cat-18 is LTE-A Pro.

• What antenna do you connect to it.

To achieve the range, i.e. the further connectivity from out on the water, the antennas need to be high and have a clear view of the horizon. Also it is best if they have a short cable run, and the antenna is rated with a correct gain not too much and not too little, 5-7dbi is often suggested as best.
Also ensure that the antenna is not located near to another antenna that could cause interference, i.e. another transmit antenna. You should keep those at about 2m distance if you can!

• The right type of SIM card!

A SIM card from the local corner store may look very attractive, but there is a lot of fine print and user Service Level Agreements involved that affect the throughput you are contracting.
A SIM provider, telco or middle man service provider is very much bound by the agreements they have made with the network infrastructure. i.e. you get Telco A card, but are anchored in a harbour where there is only a Telco B cell-tower, well you get lower priority..
The Telco A sells you the card with speed limitation; in their system they limit the card, and of course those who pay more, get better service!
And then you have those roaming agreements, in Europe at least roaming has been “liberised” to remove those costs that go through the roof as you cross the border, but again are you getting the same service level?

So, ensure that you are getting a SIM card that has the high throughput, and is not limited by some fine print fair-usage policy or alike that will limit the card after a couple of days of use!

This article was written by Tim Gorter, Virtual AVIT ETO, www.teletechnics.com. Call me if you have any AV or IT questions (I won’t charge or bite for simple questions!) or need technical support and training for crew assigned to look after their AV & IT system onboard. I want to make sure you understand how it works, and that you get the best out of it. Call for an AV & IT health check, more on teletechnics.com

By Tim Gorter, AV/IT/Wi-Fi Virtual AVIT ETO