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Old 23-02-2011, 04:48   #706
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Re: Long-Distance WiFi Device

Quote:
But if you sail around you're not gonna scan the band for a station when you sight the next island, do you?
The island hoppers and world cruisers I have helped do almost exactly that. Once the anchor is set and the boat squared away they do a site survey looking for a usable signal. Many times there is no "hotspot". Just a wireless router in a villa on the hill that was left open.

As far as sensitivity goes, quite often a high power client like the Bullets will be connecting to a much lower power access point and receive sensitivity becomes more important than transmit power. Above about 36Mbps the 2HP and the M2HP are about equal but when you want to pull in weak b/g signals at a long range there is a significant difference. At 5.5Mbps the M2HP sensitivity is -83 dBm. At 5.5Mbps the 2HP sensitivity is -95dBm. That is about 4 times more sensitive and, under certain conditions, can add 30% or more to the range. Compared to 54Mbps 5.5Mbps may sound slow but the fastest ADSL connection is only 3Mbps.
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Old 23-02-2011, 07:30   #707
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Re: Long-Distance WiFi Device

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Originally Posted by Gashmore View Post
The island hoppers and world cruisers I have helped do almost exactly that. Once the anchor is set and the boat squared away they do a site survey looking for a usable signal. Many times there is no "hotspot". Just a wireless router in a villa on the hill that was left open.
Yes, so they do it after the anchor is set, not while underway upon sighting the island. When your anchor is set, you're not sailing anymore and you easily can rig something at the railing or with a halyard for the few cases where the railing ain't good enough.

Quote:
At 5.5Mbps the M2HP sensitivity is -83 dBm. At 5.5Mbps the 2HP sensitivity is -95dBm.
You must have documentation that is in error. The radios are way better than -83dBm at 5.5 Mbps and at 1 Mbps they will be more sensitive than the level of background noise, meaning it is the antenna that will have to make the difference, not the receiver.

It's obvious to me that you never tried and/or compared the M2 with the 2hp. If you do, you will find that the M2 will at least equal the older model and in many cases will provide a higher quality link, like experiences posted in this thread start to show.

cheers,
Nick.
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Old 23-02-2011, 08:18   #708
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Re: Long-Distance WiFi Device

Sure you can rig it all up every time. I have done several that way for bare boaters. I machine an acetal cap for the antenna with a loop in it to make hoisting easier. Run the cable out a hatch or the companion way, haul the antenna and Bullet up the flag halyard and plug everything up. Then when it starts raining, pull the cable out so you can close the hatch. A permanent installation as high as possible is so much nicer.

In fact I have installed a couple of M2HPs on boats cruising the ICW and took one with me last Fall for Foxy's Catfight to compare it to the 2HP. Anchored at Monkey Point with the rig hauled up the flag halyard the 2HP saw 8 signals of various strengths and was able to connect (a least to the point of requiring a key) to all that had a signal strength better than -90dBm. The M2 was unable to connect below about -85dBm.

There is nothing wrong with the M series. It is just that in many situations the 2HP is a better choice.
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Old 23-02-2011, 08:23   #709
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Re: Long-Distance WiFi Device

[QUOTE=Gashmore;624522]While by convention antenna parameters are expressed in terms of transmission, gain is the same in either direction/QUOTE]

So back to this antenna gain thing: Is there a suggestion then that when comparing say an 8/9dBi gain omni to a 5/6dBi that you'll see a 3dBi gain on the receiver?
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Old 23-02-2011, 08:33   #710
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Re: Long-Distance WiFi Device

Regarding Ubiquiti products:
Quote:
Originally Posted by s/v Jedi View Post
I have never seen any modifications made using the software development kit
Nick buddy: Please tell us that ain't true? Do you not know of at least two Bullet based product offerings that have chucked the standard Ubiquiti firmware in favour of their own?
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Old 23-02-2011, 09:29   #711
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Re: Long-Distance WiFi Device

Quote:
Originally Posted by Gashmore View Post
The real advantage of a high gain antenna is on the receive side. Unlike transmitted power, receive sensitivity does not change. An 8dBi antenna will be able to pull in weaker signals than a 5dBi antenna. The link may be slow and the transmit power a dB or 2 higher than the FCC would like but at least it can be maintained.
Two quick points:
First:
FCC regulations require a minimum of 6dBi gain in order to allow power output up to 36dBm. Less than 6dBi gain antenna and you'll be required to drop the power considerably. Less than a 6dBi gain antenna is not legal to drive high power due to too broad a radiation pattern.

Second:
There are many devices that use the unlicensed 2.4Ghz band and for purposes other than wi-fi. These include WRAM mikes used in some of the modern VHF radios. Just because you don't see a wi-fi signal showing up in your site survey does not mean that there are no services operating close by using it. Consider this as well: You're in an anchorage and there's an AP, but it's weak. So you crank it up a notch or two (probably more) to connect. You may think that it's only 1db or 2dB but that translates into a significant increase in power For example: 36dBm (4W) to 37dBm (5W) or maybe to 38dBm (6.3W) EIRP. Now you may affect all the local signals, wifi or not, that are on this band. My conclusion: There is never a justifiable reason to exceed limits. You just can't be sure what else you may be affecting.
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Old 23-02-2011, 12:55   #712
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Re: Long-Distance WiFi Device

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Originally Posted by mlahrkamp View Post
The M2 was unable to connect below about -85dBm.
There was something wrong then. Here you can see a list of connections on a M2 and there's a -89dBm link right there with the M2 sending at 6.5 Mbps (click the picture for a bigger version).

Also, here you can see how much noise you get around a busy WiFi network. There are 9 active access points and this is just one of them. Noise is around -86 to -90 dB while the noise on the 5 GHz network is only -93dB or less.

With all this noise and so many stations, the M-series with MiMo and diverse antenna arrays (both horizontal and vertical polarization) rule here.



cheers,
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Old 23-02-2011, 13:01   #713
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Re: Long-Distance WiFi Device

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Originally Posted by mlahrkamp View Post
So back to this antenna gain thing: Is there a suggestion then that when comparing say an 8/9dBi gain omni to a 5/6dBi that you'll see a 3dBi gain on the receiver?
When you see a station at -83dB with the 6dBi gain antenna, it will become a -80dB station after you switch to the 9dBi antenna. The receiver doesn't change but the signal coming from the antenna is twice as strong.

Quote:
Nick buddy: Please tell us that ain't true? Do you not know of at least two Bullet based product offerings that have chucked the standard Ubiquiti firmware in favour of their own?
I know of other software that will run on the Ubiquity radios but did not see that used by marine-oriented products which use Ubiquity hardware. Those expensive yellow box things run standard AirOS as does wififorboats.com and iirc also island time pc kits use un-modified AirOS.

cheers,
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Old 23-02-2011, 13:23   #714
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Re: Long-Distance WiFi Device

Quote:
Originally Posted by s/v Jedi View Post
When you see a station at -83dB with the 6dBi gain antenna, it will become a -80dB station after you switch to the 9dBi antenna. The receiver doesn't change but the signal coming from the antenna is twice as strong.
To be more clear, it takes 3dB to double the strength, but 6dB to double the range. Anyway, anyone else with an opinion? Has anybody actually tried or measured it in reality?

Quote:
Originally Posted by s/v Jedi View Post
I know of other software that will run on the Ubiquity radios but did not see that used by marine-oriented products which use Ubiquity hardware. Those expensive yellow box things run standard AirOS as does wififorboats.com and iirc also island time pc kits use un-modified AirOS.
RogueWave from Wave Wifi is one and another is... who else now? Come on now Nick, you can say it, we know you know.

Chuckles,
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Old 23-02-2011, 13:29   #715
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Re: Long-Distance WiFi Device

Posting #712 by Jedi references a quote that was never made by me (was by Gashmore). Nick buddy, how are you using the quotation feature in this forum?

Regards,
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Old 23-02-2011, 14:35   #716
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Re: Long-Distance WiFi Device

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Originally Posted by mlahrkamp View Post
Posting #712 by Jedi references a quote that was never made by me (was by Gashmore). Nick buddy, how are you using the quotation feature in this forum?
Yes sorry. I was using the multi-quote feature but then decided to put the picture in and make separate posts instead. As I had 5 quotes by then, I somehow managed to screw it up

ciao!
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Old 23-02-2011, 14:56   #717
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Re: Long-Distance WiFi Device

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RogueWave from Wave Wifi is one and another is... who else now? Come on now Nick, you can say it, we know you know.
Sorry, I really don't know

When I was building the WiFi network for the marina here, the firmware for the M-series was still so-so and I was ready to switch to DD-wrt which was ported to Ubiquity radios. But Ubiquity came with AirOS updates quickly so I never made the switch.

cheers,
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Old 23-02-2011, 16:26   #718
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Re: Long-Distance WiFi Device

I run DD-WRT the WRT-54G routers I've had. I have not paid the $20 for a license to operate it on the Bullet. I note that you can buy a nano with DD-WRT pre-installed. Does anyone know of third party software (free) that will run on the bullets?

I have both the 2HP and the M2HP on board so I'm happy to report that there is no clear winner! Sometimes one works where the other fails and other times it's the other way around.

For now the 2HP is in the place of honor at the mast head, hooked up to an antenna that I'll just shut up about now to avoid more hate mail. heh heh

George
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Old 23-02-2011, 16:39   #719
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Re: Long-Distance WiFi Device

And don't scoff at warboating until you have tried it! heh heh It *does* figure in on where we anchor now sometimes. I often seek a wifi report from Kerri as another piece of the puzzle when looking to drop the hook.
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Old 23-02-2011, 17:02   #720
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Re: Long-Distance WiFi Device

Furthermore (sorry about the flood), wifi at the helm computer was a big benefit today as I had active Captain up and we are anchored where the chart says 4 feet but there is actually 10ish.

So will we be "looking" to see what's there as we approach Rum Cay in a few weeks? Yeah... probably.

If I only had the one device would I permanently mount it at the mast head. No. I just love the directional antennas and the options they open up too much.

George
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