Cellular Repeater

[TwoHooter]

Our new ship's computer is hard-wired by Ethernet to a Teltonika RUT950 router. The router is set up to connect as follows:-

1. Via external WiFi when that is available. The router is hard-wired to a Ubiquiti Bullet to bridge the WiFi signal so if the boat is within range it's usually going to be stable.
2. If WiFi is not available or drops out the router automatically tries to failover to a cellular connection on 3G, 4G, or 4G+LTE. It has two SIM card slots so if the regular cellular provider is flaky and someone else offers a better signal a "local" SIM card can be put in slot 2.

The router has its own pair of cellular antennas but it can't be mounted high enough to get the best possible signal. A suitable external antenna has been found, tuned to receive European 3G/4G/LTE frequencies, which can be mounted high on the mast. In this location it will stand a much better chance of picking up a good signal. But the cable run between the mast and the router is about 15m so there will be signal loss in the cable. Therefore a powered Repeater is needed which takes the signal from the antenna and gets it to the router with minimum loss. All totally hard-wired. No broadcasting involved. This isn't about "boosting" the mobile signal for phones. The aim is to give the ship's router (and therefore the ship's computer) the best possible chance of connecting to cellular data. Phones can connect to the router via the router's WiFi which gives us email and Whatsapp, and before long VoLTE (Voice over LTE).

The Repeater is proving difficult. Everyone I have spoken to so far is offering kit which is designed fundamentally to re-broadcast the cellular signal so that phones can pick it up more easily, and that's not what we want. When I ask about hard-wiring Repeaters to the router's SMA antenna connections all I get is waffle. Nobody seems to know whether the boxes they are selling will do that or what the cable specs might be. Some of them aren't even sure how near to the antenna their Repeater needs to be or how far it can send the signal to the router. Ideally we would have the repeater in an IP65 enclosure inside the equipment space at the foot of the mast, about half way between the antenna and the router measured by cable run. Another problem is that when I ask what cellular frequencies a product supports I don't get coherent answers and the published technical data for what I've been looking at leaves a lot to be desired. I've seen "5 band repeaters" where there is no data for what the bands are. I sometimes get the feeling that I know more about this than the vendors which would be funny if it wasn't so frustrating.

Has anyone solved this problem?

 

[BruceK]

No, I haven't, but I empathise with your frustration as I had to do something similar for my house which sits in a deciduous forest and loses all signal in the summer months when the leaves appear. My problem was any booster or amplifier was bonded to a particular or subset of carriers. Nothing universal that I could find that was also in my willing to pay price range. Wilson units start at over $1k. Look at the pro 70. They have recently launched their 1050 that may be worth a peek at and it does give the frequencies. Whether they are European comparable I cant say.

https://www.wilsonpro.com/products/pro-1050#how-it-works

 

[RobbieW]

I'm not sure you'll get what you're looking for, though I've not looked for a couple of years now.

Given your setup, with 15m of antenna cable, you might want to move the LTE 'processor' closer to the antenna. That could involve a small router, powered by PoE, directly attached to a pair of dongles or one of the routers designed for in-vehicle wifi provision via LTE, running router software with the capability to fail over between the two LTE signals. The 'LTE' router then feeds an alternate WAN port on the main router so that that now fails over between the WiFi extender connection and the LTE connection. None of this is especially hard to do but not readily commecially packaged at reasonable cost.

Using a dongle in the saloon I've had usable data connections 5-10 miles offshore but that is very country dependent with UK being one of the worst around Europe for coverage.

For BruceK - in summer is there a place that a pair of yagis could be placed that can 'see' the mast your get service from ? If there is, a similar setup could provide a data service from a SIM connection but not a voice/text service.

 

[jrudge]

Have you confirmed that there is indeed signal loss ?

A domestic house would usually have far more than 15m of cable between the earial / sky dish and the coax is designed to be low loss

You are asking for a repeater and that is what they are trying to sell you.

You are actually seeking an antenna amplifier or aerial booster. They are available for TVs for nothing but I don’t know how sensitive they are to the frequency band. Try just coax. Then if no good try a booster. . They will only cost say £10 from eBay

 

[Deleted User YDKXO]

Not sure it helps at all but we have one of these onboard http://yachtrouter.com/yacht-router-micro/ I see that the same company also offers these http://yachtrouter.com/wifi-extender/

In all honesty I wasnt happy with the Micro Router, the main reason being that every time it goes out of mobile data coverage (say when you are at sea) and then picks up coverage again in another port or anchorage, you have to go through a rather complex set up process again on your computer to link to it. In the end I just gave up and have reverted to using my phone's hotspot. The Micro Router would probably work well if you were a liveaboard in a single location and shuttling between a poor marina wifi and the mobile data network

 

[TwoHooter]

Thanks all.
Terminology is important - I got the "repeater" bit off the internet, haven't specifically been searching or asking for antenna amplifiers. On another forum it was suggested that the proper term is Bi-Directional Amplifier (BDA). I'm looking at those now.
I think the word "booster" would take me down a completely blind alley. Those things are invariably designed to broadcast the cellular signal.
The idea of putting a second router nearer the antenna is good. These have been suggested on another forum:
https://mikrotik.com/product/wap_lte_kit
https://mikrotik.com/product/wap_lte_kit
But so far as I can see the SIM card/s have to be in that router, not the main ship's router in the wheelhouse. I don't fancy climbing the mast to change a SIM card.
Perhaps just try high quality coax and see if there is a signal loss.

 

[Hurricane]

This first bit doesn't answer your problem but...
I've ditched external WiFi now completely.
Still use it internally for all our devices etc of course.
Think about it - why have a WiFi fall over at all - your portable devices (phones and tablets) etc will pick up marina WiFi anyway.

My point is that 4G/LTE is the way to go so a suitable 4G router providing WiFi for your devices is all that is required.
Like RobbieW says (Hi Robbie) can you get the 4G/LTE router nearer the location for an external antenna ?(15m you say).
This is exactly what I had to do.
In fact, I have two routers - the first that connects to the internet and a wired connection to the ships LAN.
There is a reason for this complexity but essentially, the internet one is all that is required for most things.
Anyway, back to your question.
This technology is far more complicated than just introducing a "booster".
Have you read up on MIMO.
Not done much reading myself but I believe that these modern twin antenna LTE systems provide two connections to the 4G/LTE service provider's mast.
Then there is clever software (at both ends) that improves the connection by selecting different antennae at different times.
And I believe that, using these twin connections, they can increase the speed as well.
Anyway, I saw it complex enough not to fiddle.
So, I installed an omni directional LTE antenna and used the 10m (I think) cables provided with the antenna.
There was just enough cable to get the router inside the saloon and the antenna on the FB

Here is a pic of it

That all said, I wonder if you are worrying unnecessarily.
I tested it with the omni directional antenna and the small antenna that came with the router.
There was a difference and I remember thinking that it was probably worth doing but in reality, it probably doesn't make much difference.

IMO, you are doing the correct thing using 4G/LTE - but I would ditch the complex fallover.
LTE is way faster and much more reliable.

Hope that helps

EDIT
That pic shows my (now redundant) external WiFi antenna.
Maybe I should now extend the ships internal WiFi using that antenna!!!

 

[TwoHooter]

Mike,

Sorry for delay in replying.

I don't see any advantage to us in getting rid of WiFi. In your case you have the benefit of European 4G+LTE which, generally, is better than the UK. And I suspect your marina WiFi can't cope with demand. But we have no fixed base and sometimes we find WiFi is a viable option. Some of the places we have been have had good WiFi, it depends on the number of boats trying to connect and for example at Padstow in the autumn we might be the only boat using the connection most of the time. The router may be complex but it's easy to manage and it's all installed now together with the Bullet.

When it comes to antennas, I have been learning about beam forming and directionality and Fresnel zones, but at the end of the day I'm convinced that height matters. The "sticking up thing" as someone called it when I first put a picture of our boat on here is 27'6" (8.4m) AWL and in some places a cellular antenna at that height will be helpful.

It's not the same as boats where access to the antenna is easy and moving the router nearer the antenna is a good solution. I suppose it is a sort of solution on our boat, but I'm still looking for alternatives.

As for whether a 15m cable run is going to result in loss of signal or not I will stand back and let Matt Riches answer that one!

 

[TwoHooter]

I have also put this question on the Cruisers Forum. If anyone is really interested in the subject I recommend you look at that thread.
http://www.cruisersforum.com/forums/showthread.php?p=2625821#post2625821

 

[Anders_P42]

For a 15m cable run you need to use a high quality low loss cable, I'd recommend RF400.

Or mount the router in waterproof enclosure up mast and keep antenna cable very short. That model can be powered via power over Ethernet, but not the industry standard 48V - buy a 24V injector kit. That means you're not running 240V up to the waterproof box, only 24V.

 

[jfm]

...at the end of the day I'm convinced that height matters. The "sticking up thing" as someone called it when I first put a picture of our boat on here is 27'6" (8.4m) AWL and in some places a cellular antenna at that height will be helpful.

Twohooter, just speaking from the hip so to speak I've thought about that and come to opposite conclusion. I also have 8m + available mast height and tried an external mobile phone antenna taped up there and I found it made no significant difference to the miles offshore point that I "lost signal". As I see it you lose mobile phone due to deliberate weakness of transmissions far sooner than because an obstacle or the horizon gets in the way. However if there is more science here than I'm appreciating ( e.g. Height of antenna above the flat surface- sea- that's its placed on) I'm happy to stand corrected/be enlightened. There is a speed thing here too- if you can use mobile 20 miles offshore rather than 15 that's more significant on open water passage at 8 knots than 28. That said if you were running parallel to and some miles off to a coast with lots of masts then it would be handy

 

[michaf]

Here in Australia I had to battle some time to get things right. The islands are just far enough so that the 3G (forget 4G) is patchy and at some places non existent. At first I used an illegal booster, fortunately Telstra is offering one now. And yes, they are going after the illegal ones as they can break the signal for the entire area. They've busted a charter boat the other day. So here are some points on the subject:

1) Get a proper booster, not a repeater, and get a legal one. The difference is a booster will boost the out going signal. It's not enough to get incoming signal if you don't have what it takes to send.

2) Mount your antenna as HIGH as possible. Line-of-sight propagation counts also for Mobile signal, no magic here!

3) Test test test. You need to have stats on the radio signal. Start first with the reception. You need to check RSSI figures, they are minus figures and the closest to 0 the better (ballpark if you can get around -50 you've got good coverage, -100 is barely usable). You can get these figures from your mifi, USB modem or whatever you are using for mobile data. Swap antenna, cable, position etc.

4) Once you get the best signal introduce the booster. The booster has to have a clear admin telling you how much it's boosting. Now antenna separation is crucial. The external antenna is omni directional, the internal antenna is directional. The internal antenna needs to send it's signal away from the external antenna, so you would want to mount it on a ceiling, pointing down for example. The reason why this is important is because if the booster gets it's own feedback, it will not boost at max because it thinks it's got good signal, but it's its own signal! You can take the internal antenna out completely for best results and connect the booster straight into your GSM data modem.

Quick find on boosters in the UK https://www.ispreview.co.uk/index.php/2017/10/ofcom-uk-approve-indoor-car-mobile-signal-booster-devices.html

Our booster is also available outside Australia, here a link for the UK:https://www.cel-fi.co.uk/boosters/celfi-go-x-3g-4g-signal-booster-o2-ee-three-bt-vodafone.html

 

[matthewriches]

One of the jobs really that was left until the end as there is sooooo many different variations, solutions, ideas, non starters, headaches, heartaches and general nonsense about.

I’m sort of on the same idea as you jfm, whereby the signal will just not be there whether the antenna is in the pilot house, up the mast or up a sailing boats mast 45ft in the air.

But as an ongoing trial and error project, I’ve yet to do the calculation but I think it is almost worth sticking a couple of very low loss coaxial runs up and just sucking it to se what happpens. That’s the simple solution, if that gives marginal or better gain then we consider an external device that is put up the mast with a data line to it.

I’m sur TwoHooter will keep this tread updated with our efforts!

 

[TwoHooter]

For a 15m cable run you need to use a high quality low loss cable, I'd recommend RF400. Or mount the router in waterproof enclosure up mast and keep antenna cable very short. That model can be powered via power over Ethernet, but not the industry standard 48V - buy a 24V injector kit. That means you're not running 240V up to the waterproof box, only 24V.

Got the same advice on the Cruisers Forum. Still don't fancy climbing the mast to change the SIM card, and people are saying the RF400 cable is a pig to install. But not ruling either out. Clearly, there is no perfect solution!

Twohooter, just speaking from the hip so to speak I've thought about that and come to opposite conclusion. I also have 8m + available mast height and tried an external mobile phone antenna taped up there and I found it made no significant difference to the miles offshore point that I "lost signal".

Sorry, I didn't make the objective clear. This isn't about offshore connectivity. It's all about keeping the boat's monitoring system connected when we leave it at anchor for a day while we go ashore walking, or leave it for a month in a place like Penzance where there is no WiFi and the cell signal in the harbour is >CSQ9 but up in the town, about 8 metres AWL, there are 5 bars.

1) Get a proper booster, not a repeater, and get a legal one. The difference is a booster will boost the out going signal. It's not enough to get incoming signal if you don't have what it takes to send.

It's likely there are no legal boosters in the UK which will suit us. I have now studied the follow-up to the Ofcom legalisation of repeaters. See below.

2) Mount your antenna as HIGH as possible. Line-of-sight propagation counts also for Mobile signal, no magic here!

YES! That was my starting point. Height matters.

3) Test test test. You need to have stats on the radio signal. Start first with the reception. You need to check RSSI figures, they are minus figures and the closest to 0 the better (ballpark if you can get around -50 you've got good coverage, -100 is barely usable). You can get these figures from your mifi, USB modem or whatever you are using for mobile data. Swap antenna, cable, position etc.

Agreed.

4) Once you get the best signal introduce the booster. The booster has to have a clear admin telling you how much it's boosting. Now antenna separation is crucial. The external antenna is omni directional, the internal antenna is directional. The internal antenna needs to send it's signal away from the external antenna, so you would want to mount it on a ceiling, pointing down for example. The reason why this is important is because if the booster gets it's own feedback, it will not boost at max because it thinks it's got good signal, but it's its own signal! You can take the internal antenna out completely for best results and connect the booster straight into your GSM data modem.

The thing is, I was hoping to avoid something that re-transmits the received signal. I wanted a hard-wired connection from the booster/repeater to the router's WAN port.

[Quick find on boosters in the UK https://www.ispreview.co.uk/index.p...indoor-car-mobile-signal-booster-devices.html

Yes, but see Ferd Browne's comments in that thread.

Our booster is also available outside Australia, here a link for the UK:[URL="https://www.cel-fi.co.uk/boosters/celfi-go-x-3g-4g-signal-booster-o2-ee-three-bt-vodafone.html"]https://www.cel-fi.co.uk/boosters/celfi-go-x-3g-4g-signal-booster-o2-ee-three-bt-vodafone.html

That booster is illegal for use in vehicles (including boats) in the UK.

One of the jobs really that was left until the end as there is sooooo many different variations, solutions, ideas, non starters, headaches, heartaches and general nonsense about. I’m sort of on the same idea as you jfm, whereby the signal will just not be there whether the antenna is in the pilot house, up the mast or up a sailing boats mast 45ft in the air.

Matt, it all depends where you are. Penzance (see above) is a good example. Also Neyland - the signal is worse at low tide than high tide - extra height might make all the difference. Port Eynon is another example. What about my house? Good reception in the front bedroom on the first floor, nothing on the ground floor!

But as an ongoing trial and error project, I’ve yet to do the calculation but I think it is almost worth sticking a couple of very low loss coaxial runs up and just sucking it to se what happpens. That’s the simple solution, if that gives marginal or better gain then we consider an external device that is put up the mast with a data line to it. I’m sur TwoHooter will keep this tread updated with our efforts!

Too true. Ad nauseam

 

[matthewriches]

Well, I made it to the top with a length of shielded CAT5 cable. 4G weatherproof router is going at the top of the mast.