WIFI Amplification, Feb 2012: How Far , How Fast , How Much ?

[CarinaPDX]

Looking at the specs the Rogue is a Bullet 2 HP (802.11b/g). The Bullet M2 adds 802.11n (for higher speeds) and has a faster CPU and more memory. In these applications there is little or no benefit to going to the M2 (the higher-speed n spec reverts to b/g if there are any b/g-only clients or the AP is b/g).

[s/v Jedi]

Originally Posted by CarinaPDX

Looking at the specs the Rogue is a Bullet 2 HP (802.11b/g). The Bullet M2 adds 802.11n (for higher speeds) and has a faster CPU and more memory. In these applications there is little or no benefit to going to the M2 (the higher-speed n spec reverts to b/g if there are any b/g-only clients or the AP is b/g).

The benefit of the Bullet M2 is that it outperforms the Bullet 2hp in every mode.

ciao!
Nick.

[CarinaPDX]

Originally Posted by s/v Jedi

The benefit of the Bullet M2 is that it outperforms the Bullet 2hp in every mode.

That is moot. It has been discussed on some of the more technical forums, and many posters think the 2HP is better on b/g. If one were to look at the spec sheet it would appear to support that the 2HP is (a bit) better, but that is misleading because the n-spec is more demanding. We could head on down this rabbit hole to little effect. For users of b/g these two units perform close enough that it is not an issue. If you have proof to the contrary (say >3dB difference) in a test environment (no anecdotes, please) then please post.

When the M2 first came out there were problems with it that argued for sticking with the 2HP; those seem to be well in the past. The DD-WRT folks suffered with their alternative M2 firmware but seem to have the major problems resolved at this point. There is little practical difference between the two for most cruisers. Since there is also little price difference, either is a good choice.

I should add that many users (of either model) will likely benefit by lowering the transmission power. When adding an 8-12dB antenna to a 600-1000mW transmitter in a marina with a similar setup there is likely to be overdriving of the receivers and a lowering of throughput. The high gain antennas help with both receive and transmit - there really is no need to put out that kind of power over short(-ish) ranges. And, technically, it is illegal as it exceeds the standards in the US and EU, at a minimum.

[s/v Jedi]

Originally Posted by CarinaPDX

That is moot. It has been discussed on some of the more technical forums, and many posters think the 2HP is better on b/g. If one were to look at the spec sheet it would appear to support that the 2HP is (a bit) better, but that is misleading because the n-spec is more demanding. We could head on down this rabbit hole to little effect. For users of b/g these two units perform close enough that it is not an issue. If you have proof to the contrary (say >3dB difference) in a test environment (no anecdotes, please) then please post.

When the M2 first came out there were problems with it that argued for sticking with the 2HP; those seem to be well in the past. The DD-WRT folks suffered with their alternative M2 firmware but seem to have the major problems resolved at this point. There is little practical difference between the two for most cruisers. Since there is also little price difference, either is a good choice.

I should add that many users (of either model) will likely benefit by lowering the transmission power. When adding an 8-12dB antenna to a 600-1000mW transmitter in a marina with a similar setup there is likely to be overdriving of the receivers and a lowering of throughput. The high gain antennas help with both receive and transmit - there really is no need to put out that kind of power over short(-ish) ranges. And, technically, it is illegal as it exceeds the standards in the US and EU, at a minimum.

The better performance of the M2 has been reported many times in the threads here at CF.. I see no reason to repeat all that again.

Edit: I agree there were many problems after the introduction. That is years behind us though and the Ubiquity M series is the current product that gets all the development effort. The old series will be discontinued.

ciao!
Nick.

[CarinaPDX]

s/v Jedi-

I just spent a few hours looking through the old wifi posts at your suggestion - I should have known better. There were a couple of people who tested the two versions and found the 2HP better, and a couple of people found the M2 better (you being one of them - multiple posts don't count). I did find an interesting post that said this:

I can't detect any difference between the Bullet2hp and the BulletM2 when I put it in 802.11g mode.

It was posted by s/v Jedi - OH- that be you! (OK, to be fair, followed by

When I allow it to go to 802.11n mode I see performance improve.

)

I stick with my earlier statement: there is little difference between the two in performance as a b/g client. To anyone putting together their own system, I would recommend the M2 (as I have done for my own current rig). But I don't think the packages that have the 2 HP included should be considered inferior or a reason not to buy them, which was what I was getting at.

The introduction of 802.11n devices (by all vendors) was a terribly flawed affair, which delayed the replacement of the b/g devices. I agree that the time is coming fast, now that n devices are working well (a fairly recent development), that b/g-only devices will be discontinued. The only reason I can think of that products like the Rogue haven't been updated to the M2 is that it runs a very different version of the AirOS. That means that the customized OS on the Rogue has to be redone with the newer OS's SDK. More time and money to be invested. And with no substantive improvement in performance, that is hard to justify. Soon they may not have a choice.

I should add for clarity for anyone else following this thread, the Rogue's OS is not just a rebadge of AirOS. It is an easier to use version specifically for use as a client, which may be of value to non-techies.

[s/v Jedi]

The reason that I detect no difference is that I get maximum speed & throughput in either case. The people who tried long range connections did report better results with the M2. I think the new generation of radios with their faster CPUs are better equipped to deal with difficult connections caused by range, interference etc.

Even if b/g mode is equal, the M2 gets you n-mode with 130Mbps speeds plus MIMO technology. It is that MIMO technology that really makes a difference with range. N-mode outperforms everything at any speed setting at any range. Here in Shelter Bay marina, about 40-50% of all connections are n-mode faster than 100Mbps. Whenever there is a problem, it is caused by an old b-mode client. It's time to put that old generation of hardware in the musea.

ciao!
Nick.

[jr_spyder]

Back the antenna placement question, are there any issues as to how close it can be to VHF and/or AIS antennas?

[s/v Jedi]

Originally Posted by jr_spyder

Back the antenna placement question, are there any issues as to how close it can be to VHF and/or AIS antennas?

Yes, keep them vertically separated. Same for radar.

ciao!
Nick.

[CarinaPDX]

Originally Posted by s/v Jedi

Even if b/g mode is equal, the M2 gets you n-mode with 130Mbps speeds plus MIMO technology. It is that MIMO technology that really makes a difference with range. N-mode outperforms everything at any speed setting at any range.

I know that you know better - the Bullet products don't have MIMO (Multiple Input Multiple Output) because it requires multiple antennas and Bullets only work with a single antenna. If the AP has MIMO then using an M2 would be faster, but that is very rare. If you want to make the arguement that the Rocket (with its 2x2 MIMO) like you are using on your own boat works better than either the M2 or 2 HP then you are on solid ground (so to speak). If I were buying new for permanent installation the Rocket would probably win out. And there is an advantage to the larger community to move people up to 802.11n even if they personally don't benefit, just to reduce the times when the older radios drag down the system performance for everyone (again, pretty rare to find a marina with a big enough "pipe" to push the specs on g, much less n). Still, if a non-techie asked me for a recommendation I would feel comfortable that a package that included a 2 HP (given no M2 option) would be the best fit, unless I knew that the boat would be staying in a marina like the one you rigged with 802.11n (and there would be someone who could help with technical problems).

I have some experience here: I built, and helped a few others to build, a custom client using a Linksys WRT54G with DD-WRT firmware, a 14dBi directional patch antenna and an 8dBi omni antenna. This was nearly 10 years ago. Technically, they worked better than anything else available at the time at retail. The most technical of my friends needed a little help initially but was on his own pretty quickly. The two least technical suffered: one gave his system to another cruiser (who did know how to use it) and the other still contacts me occasionally for help. So now I am a lot more appreciative of vendors who offer an easier-to-use package, and the hand-holding as needed, and THAT is more important than having the latest technology for many cruisers.

[s/v Jedi]

Originally Posted by CarinaPDX

I know that you know better - the Bullet products don't have MIMO (Multiple Input Multiple Output) because it requires multiple antennas and Bullets only work with a single antenna. If the AP has MIMO then using an M2 would be faster, but that is very rare. If you want to make the arguement that the Rocket (with its 2x2 MIMO) like you are using on your own boat works better than either the M2 or 2 HP then you are on solid ground (so to speak).

It's a mess with terms; technically, we would have to call the Bullet M2 talking to our AP's a SIMO/MISO link. Instead, we say MIMO 1x1. You do not need multiple antenna's to profit from MIMO... it gets better with multiple antenna's though. Also going to n-mode gives a significant improvement, i.e. you notice it while working with the link.

The outdoors APs in Shelter Bay marina are Ubiquity NanoStation M2's with 2x2 antenna arrays. All MIMO equipment loves them.

Clients with NanoStation M2 just get 130Mbps full duplex links with 100% quality level. Pretty hard to beat with public access points that have to adhere to standards for channel width etc.

ciao!
Nick.

[jr_spyder]

Originally Posted by s/v Jedi

Yes, keep them vertically separated. Same for radar.

ciao!
Nick.

I was afraid of that. I'll be adding one of the Bullet solutions to my boat before it goes back in the water, and while the mast is down. Right now the mast has three antennas on the top: VHF, an old dedicated DSC that I will mount/use for AIS (these are 3 - 4' apart), and an old cell antenna between the other two. I was hoping to use the cell mount and run CAT5 from there, for the bullet. Typical usage will be very little VHF in the marina, and steady Internet connection, and vice versa at sea.

What kind of trouble would I see if these antennas are as I planned before I asked this question?

Thanks,

JR

[s/v Jedi]

Originally Posted by jr_spyder

I was afraid of that. I'll be adding one of the Bullet solutions to my boat before it goes back in the water, and while the mast is down. Right now the mast has three antennas on the top: VHF, an old dedicated DSC that I will mount/use for AIS (these are 3 - 4' apart), and an old cell antenna between the other two. I was hoping to use the cell mount and run CAT5 from there, for the bullet. Typical usage will be very little VHF in the marina, and steady Internet connection, and vice versa at sea.

What kind of trouble would I see if these antennas are as I planned before I asked this question?

Thanks,

JR

Your masthead should have one antenna, for the VHF. Do not put an AIS or any other antenna up there.

You can put the AIS antenna on a spreader, radar arch, mizzen mast or even the pullpit. All of those will lead to better results than both at the masthead. It does not matter if both are in use simultaniously or not; they are coupled inductively.

A wifi Bullet with omni antenna attached, you can hoist on a flag line under the spreader. Use some small stuff to tie a loop to the top of the antenna to hoist with and a loop at the Bullet connector position to lead the flag line through for stabilizing it.

ciao!
Nick.

[Auspicious]

No one seems to have mentioned that 802.11n straps multiple WiFi channels together to attain the local speed (from the client to the AP). That greatly increases interference to b & g clients. It also limits the number of n clients that can function within range of the AP. Since Internet speed is limited by the backhaul connection anyway, 802.11n is not a good solution for cruisers. Your connection won't be any faster with n and you'll interfere with everyone else.

[s/v Jedi]

Originally Posted by Auspicious

No one seems to have mentioned that 802.11n straps multiple WiFi channels together to attain the local speed (from the client to the AP). That greatly increases interference to b & g clients. It also limits the number of n clients that can function within range of the AP. Since Internet speed is limited by the backhaul connection anyway, 802.11n is not a good solution for cruisers. Your connection won't be any faster with n and you'll interfere with everyone else.

You are mistaken. N-mode _can_ operate in wider non-standard channels, as well as narrower non-standard channels (5, 10 or 40 MHz instead of 20 MHz) but normally use exactly the same 20 MHz channels as b/g modes.

It is in fact the b-mode clients who hurt total air-bandwidth and which should be banned. When you want maximum number of standard clients on an AP, n-mode gives by far the best results. For Ubiquity hardware this is 30 simultaneously clients. If you use the Ubiquity Rocket with Airmax enabled (non-standard, clients must be Ubiquity M-series), you can have 60 simultaneous clients, because Airmax eliminates the "hidden node" problem, which is the source of all wifi evil

ciao!
Nick.

[Jengordon]

It looks as of the land and sea bullet is the way to go for offshore wifi? Is there any other manufacturer we should be considering? Thanks!