Thinking loud / Homeplug

Right some of you know i work on ships, we have finally joined the 20th Century and got internet, it's slow and very limited but that isnt the problem.......

We have a very nice router and some router powered Access Points all well land good, however some areas are a bit blind to the wi-fi, I was toying with getting some homeplug type units and putting then in the system but a few thoughts occur...

We use 3 phase 220v, so for them to work the send and receiver would need to be on the same phase? (the distribution becomes single phase in the DB's in order to balance the load on the phases) I was wondering would the 440-240 transformer block the signal between the phases? How susceptible are these units to noise? What the range on most of these units? Anything else I might need to be thinking about.

We use a similar system for monitoring Refrigerated Containers but that wont interfere as it uses 440v system and the modems are on a different sub system.

Since ships use HF radio for their communications then I would have thought Home Plug/Powerline would be a definite no go. See http://www.ban-plt.co.uk/

given we already use PLT for monitoring the cargo (fridge boxes) then I really cant see the issue, the Radio gear is powered through 24v DC system anyway so no cross connection into the main ac power grid anyway...oh and hardly anything goes on HF Radio Comms now, all through Sat's and BB connections and until last year, all through Dial up ISDN (again through Inmarsat)

The transformers are likely to block most of the data - they are designed to work at 50 or 60Hz and higher frequencies will just not pass through in a clean state but may appear as noise.

You say the monitoring equipment uses PLT and is on a different system. However, both systems will be competing for the spectrum and will see each other as noise on the line and could fail to connect or drop back in speed ... If that happens you would be compromising the cargo and they would certainly be a no-no.

I have seen a few ships with Inmarsat's Fleet Broadband installed and the crew have run additional Cat5e from the main hub down to additional key locations and then connected an additional WAP with 4 ports to those. One had tried some early PLT and could not get any reliable connections if at all.

In reply to a post by deechneg:

We use 3 phase 220v, so for them to work the send and receiver would need to be on the same phase?

I was wondering would the 440-240 transformer block the signal between the phases?

My guess is that you are correct, but I've never used them in that environment.

In reply to a post by deechneg:

How susceptible are these units to noise?

They are, they reduce the available bandwidth depending on the elctrical noise. They actually use a very similar technique to ADSL in the way they operate.

In reply to a post by deechneg:

What the range on most of these units? Anything else I might need to be thinking about.

Range is variable, go for the higer-bandwidth units (200mbps at least) as these appear to provide better range (probably by using a wider range of frequencies.)

Only other thing I can think of is if the ship has US \ UK \ whatever mains outlets, it's probably neater to buy (eg) US ones, rather than mess about with travel adapters.

TBH, I'd be thinking about adding more of the powered access points and improving it that way.

they will not work between phases,
you could run 3 sets separately, one on each phase...

also you can get an access point version:
Billion BiPAC 2073N HomePlug AV 200 Wireless-N Access Point
netgear do one too

Right thanks all.....

The Main Router, has some spare PoP ports as we have 4 AP's already, so i think might just indent for some more AP's and get lecky to run me some more Cat6E cable (we appear to have 1000mtr reel )

Should not be an issue with cargo monitoring, as that system is running on the 440v and as we kind think the transformers will already isolate that, and I would expect the range of the HP not to be big enough....however time to write a requisition

Onward and upward

Are there any 400/220 transformers?

Running phase to phase will give 400v and phase to neutral 220v ...


With the cable, have it terminated in RJ45 sockets on back boxes with patch leads to the APs. Easiest and quickest way to do it.

In reply to a post by deechneg:

The Main Router, has some spare PoP ports as we have 4 AP's already, so i think might just indent for some more AP's and get lecky to run me some more Cat6E cable (we appear to have 1000mtr reel )

Do that. Best solution if you can get the kit.

Have a wander round the ship while using something like inssider, http://www.metageek.net/products/inssider/ , this will let you map where the dead spots are and where APs would be best placed.

I'm pretty much certain that the transformer will isolate the cargo monitoring from your 220v system, but I don't have a massive ship to test that theory.

Hi deechneg,

The domestic mains and lighting will be single phase, though it will be a floating supply. this gives 110v on each leg under normal conditions, though either leg can carry up to 220v if the other leg goes down to earth in fault conditions.

I would go for the wired option for the majority of PC's only going for the wireless option as a last resort. If using wirred connections as long as the cable is run on the opposite side of the cable tray from power cables you should not have any problems. If a number of connections are required in a area it may be more practical to install a switch and then feed to other locations.

Presume that as a Container Carrier you will not be looking a lot of connections as far as power and steel bulkheads, decks and deckheads.

Before retiring I installed and managed the network of about 150-200 points on floating semi sub which had the same problems as a ship.

Hi all,
Thought I would post as I just saw this through my internet trolling.

My name is Daniel and I work for a company called Gentay.

Now before I go on, I want to elaborate that this is not marketing, and although I do work for Gentay I am posting here for informative purposes only. Of course this can and will be taken as marketing by some who view it that way, and yes I may be slightly inclined to due to the nature of the business. If this is unacceptable by the forums, please email me first before taking my post down and I will rectify it to remove what is considered marketing.

Currently Gentay is the largest provider of BPL technology to the Maritime industry. (We don�t use home plugs, we use industrial grade kit that has been adapted to the Maritime industry)

To start off I would like to confirm that the kit not only works over a 3 phase system, but works very well. How well it will work is dependent on the technology itself, whether it uses Capacitive or Inductive coupling and whether it was designed to be coupled with a 3 phase system (and of course backwards compatible).

Many BPL systems can actually traverse the MV grid (usually 2-3 transformers) on a vessel. Although BPL kit requires plugging into a 220v source (and yes there are those that do actually require 440v source) the carrier wave used to transport data is just Capacitants traveling through a system. Think of it like 2 different sized water pipes, in reality the only difference is the space inside for water to travel.

Another point I would like to make is that BPL actually works better on vessels due to the power structure in place. On vessels, power cables are regulated and as such the minimum cables used in Marine Electrical Engineering is 6 core shielded cables. To give you an idea of throughput, on a 10M 6 core shielded cable we can achieve 102Mpbs throughput (in completely optimal conditions, no interference or noise etc..) however in a building where cables are not shielded and the cables have most likely degraded over time we can see Throughput as low as 256Kbps.

Please disregard anyone who says that the increased copper content in degraded cables helps, it doesn't and no study has been conducted showing that it does. In fact it in testing I have seen that it makes it worse as older cables are more likely to have increased noise. Older cables also are more fragile and if there is a hairline crack in the cable, electricity can create an "arc field� in order to "jump" like lightning, although the carrier wave cannot, this leads to a non-functioning BPL system.

I would also like to add that the Atheros based units that are found in cheap home plugs you can buy from computer shops have been tested multiple times and do NOT work. This is due to a mixture of things, most notably the core used to determine use and range. The core is called Spirit; this system was designed for up to 16 CPE's to communicate to each other without the need for a Head End/Gateway/Master Unit. They have a very limited range and limited throughput (Although it states 200Mbps, you will never get anywhere near that, the most I�ve seen is 50mbps or there about.) the second core type is called Alma; this was designed for use in Smart Grids, and is what we use. This system uses a high powered Head End that "injects" a form of carrier field into the distribution using multiple frequencies (which are locked on the home plugs) This not only provides far greater range and throughput, but allows us to frequency notch just in case there is noise or interference. The Second use for Alma is the use of Repeaters which of course help boost the signal around the grid.

I will update/add to my post when required thread and will happily answer any questions any one has in regards to BPL in the Maritime industry.

If you want to email me please contact me at d.merrens (at) gentay.co.uk

Many Thanks

Daniel

Edited by deleted (Wed 29-Feb-12 01:39:42)