Marine Cellular Amplifiers and Marine Wifi

[DotDun]

Just curious....

Does anyone know the practical timing limit for LTE? This would dictate how far away you could expect to actually work.

[Maine Sail]

Originally Posted by laika

I am currently looking at the Yagi version of that for my boat. I have not reached out to Wilson yet, but I imagine they would not have a problem selling the amplifier unit standalone?? I would also want to DC power adapter rather than the standard AC.

If I do end up buying from them, I will need to cobble together my own kit from their various products, as they do not yet offer a 4G version of their standard marine package.

You just buy the Mobile 4G kit then add the marine antenna, LMR 400 cable and the adapters to go from the type N on the cable to the SMA on the amp... The Mobile 4G comes with the inside antenna and the 12V to 6V adapter..

[Maine Sail]

Btw I just installed another of the Wilson Mobile 4G kits and it has quite good performance. I used the LMR 400 cable, marine antenna and the two terminals needed to go from type N to SMA. The "candy bar", or internal antenna, is about 12" from the phone and the cell antenna on the top of the spar.

Verizon 4G Performance (Coast of Maine)

Cell Amp Switched Off = *no 4G only 3G at -115dBm

Cell Amp On = -77dBm 4G *locked in 4G and held it for at least 30 min

When I switch the amp off it holds 4G for a bit but once it hits about -116 to -118 it drops 4G and goes to 3G.. With the Wilson Mobile 4G amp it is holding 4G signals consistently below -80dBm. This is an approximate -35 to -40 dBm gain....

Because this amp works with all carriers and does 4G, and has good performance it has become my go to cell amp...

[Canibul]

so, LTE in the USA, but isn't everything from the Bahamas south more GSM and likely to be so for a while?

[laika]

Thanks, Maine Sail! Very helpful info.

Ryan

[JayH]

Originally Posted by Canibul

so, LTE in the USA, but isn't everything from the Bahamas south more GSM and likely to be so for a while?

The Bahamas is rolling out LTE. Currently available in the more populated areas.

BTC : Roaming

[DotDun]

Originally Posted by Maine Sail

Btw I just installed another of the Wilson Mobile 4G kits and it has quite good performance. I used the LMR 400 cable, marine antenna and the two terminals needed to go from type N to SMA. The "candy bar", or internal antenna, is about 12" from the phone and the cell antenna on the top of the spar.

Verizon 4G Performance (Coast of Maine)

Cell Amp Switched Off = *no 4G only 3G at -115dBm

Cell Amp On = -77dBm 4G *locked in 4G and held it for at least 30 min

When I switch the amp off it holds 4G for a bit but once it hits about -116 to -118 it drops 4G and goes to 3G.. With the Wilson Mobile 4G amp it is holding 4G signals consistently below -80dBm. This is an approximate -35 to -40 dBm gain....

Because this amp works with all carriers and does 4G, and has good performance it has become my go to cell amp...

Per my earlier question about timing. Just a word of caution, db is not the only factor. Timing could limit range regardless of signal strength. My (uneducated) belief is range will be changed dynamically based on loading of the cell. In a limited search it appears LTE has (3) timing ranges, the longest supporting out to 100km while the shortest is just 15km. It's unclear to me how the timing bits are controlled, by the cell tower or end-device.

[El Rubio]

Originally Posted by DotDun

Per my earlier question about timing. Just a word of caution, db is not the only factor. Timing could limit range regardless of signal strength. My (uneducated) belief is range will be changed dynamically based on loading of the cell. In a limited search it appears LTE has (3) timing ranges, the longest supporting out to 100km while the shortest is just 15km. It's unclear to me how the timing bits are controlled, by the cell tower or end-device.

When an LTE connection is established, your device will measure the signal strength received and has been told by the cellsite what power level it is transmitting at. Your device calculates the propagation loss over the air and adjusts its power out to meet what the cellsite wants. The cellsite will calculate the propagation delay and use the timing advance setting to align the data packets. There is a setting at each cellsite for propagation delay. It really depends what the carrier sets it to. It's also part of the reason LTE is so much more efficient and can't be set to maximum everywhere.

The main thing is the carriers don't have license to cover offshore and, at least in the US, don't really even try to. On the gulf coast, there is an offshore carrier that would be pretty upset if the land based carriers pointed antennas in their direction. I've had to deal with an oil company that thought a land based carrier's LTE signal was causing interference to their offshore operations in the same frequency band. Turned out to be atmospheric, but the point is there are rules that the carriers have to adhere to that will affect offshore use.

I forget the exact "theoretical" specification, but I think the max range is 300km. Line of sight over the horizon becomes an issue even when the prop delay is favorable due to shorter cellsites. Nobody builds boomer cellsites anymore, especially LTE near the coast.




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[CarlF]

Yes, the cell companies are rapidly moving away from tall towers. That's because a single tower can only support a certain number of clients. To meet the rapid increase in the number of devices,you want lots of mini "towers" that don't overlap too much.

So, the cell companies are moving to inexpensive, short range transmitters - hung on telephone poles, inside malls, and so on. I've heard of one project that will have twenty "towers" in a single college football stadium.

This trend is not good news for cruisers.

[CarlF]

Here's a question for those who understand LTE propagation and signal loss better than I.

Which would be better for LTE range?

1. A masthead omni antenna 50ft off the water with 80 ft of LMR 400 cable down to the amplifier.

2. A directional panel antenna on a swivel bracket under the dodger (e.g. 6ft off the water) with 6 ft of good cable to the amplifier.

The directional antenna would have about a 35 degree reception width so it would work at anchor or underway on a reasonably straight course. It would also be a direct connect to the cell phone or mifi to avoid interference between two antennas.

[El Rubio]

Go for the height. Height increases your line of sight and eliminates more obstructions. The narrow beamwidth antenna could be a pain to constantly tweak swing on an anchor or moved perpendicular to a cell.

I'm not certain what device you're using, but there are some issues presented by using the amp. First, your device may not have a direct antenna connection. It's absolutely better of it does. I have a netgear mifi that does have external antenna connections. The problem with connecting it to an amp is MIMO. MIMO is a technique used in LTE which utilizes multiple antennas to receive, more than one data stream. The data rates increase exponentially with implementation. My netgear has two antenna connections for mimo operation. That isn't going to work through the amp. This doesn't mean you can't use the amp for 4G, just that in the near future, you would notice it slower than your direct connecions.

Even with a direct connection on an amp, turning the gain wide open still can cause problems. Some of these things are rated 40-60dB gain. For every 10dB of gain, there is a ten fold increase in amplitude. The problem is the amp is typically increasing the noise floor by the same amount. In other words, the signal is improving, but the so is the background noise. More gain isn't always a good thing and you can create noise that hinders other users on the cellsite. This is a serious problem for carriers and they actively track down interference sources. Follow the instructions on your amp regarding gain settings and you should be ok.


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