The 72 mile shot was done with equipment that the FCC would nail you for in a minute, which is why it was taken down almost immediately. While there are some RF challenges in shooting over water, they are fairly minimal in their impact, unless your are putting your antennas right at the level of the water.
One other issue that most people don't talk about in a maritime environment is the durability of the equipment. If you are near salt water, you really need to look at the construction of whatever equipment you are putting up. A lot of metals (especially the cheap ones that antennas tend to be made from) start to corrode within minutes of being placed near the ocean. It is possible to overcome most of these issues. We have a WiFi enabled ferry in the Bay area that is working fine. It has WiFi on board, and a WiFi backhaul link (by the way, shots to moving targets are a lot more challenging). Andras Bellak -----Original Message----- From: Andy Middleton [mailto:[EMAIL PROTECTED] Sent: Friday, September 12, 2003 2:12 AM To: SOCALWUG Subject: Re: [SOCALWUG] WiFI over water Ok thanks Chris, this company really seems to be taking advantage of the wireless boom! I'll maybe approch them ( or more likely try it out first, 3 miles is cherry spitting compared to 72 miles), although apart from your quote there seems to be no other indication of water "effect" in their web. ANdy On Thu, 2003-09-11 at 20:17, Chris wrote: > reminds me of that 72-mile WLAN link from san diego to the san clemente > islands. > http://www.computerworld.com/mobiletopics/mobile/story/0,10801,76118,00. html > http://computerworld.com/mobiletopics/mobile/story/0,10801,75830,00.html > quote: > 'Ma agreed. He said 72 miles "is a truly amazing feat," especially over > water, where reflections can inhibit the signal.' > > You might be able to ask them about water issues first hand. > http://hpwren.ucsd.edu/ > > Chris > > > > > ----- Original Message ----- > From: "Jeff Kutz" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Thursday, September 11, 2003 3:04 AM > Subject: Re: [SOCALWUG] WiFI over water > > > > When I first got interested in the subject of WiFi, I read about a link, I > > believe it was in Hawaii, where they went some 20+km over water. They had > a > > picture from one of the sites and it looked like they were quite high over > > the water. It looked like they were going from a hill/mountain to another > > hill/mountain. They didn't report any water-specific problems. They did > use > > a hi-gain antenna but the idea was the long range of the link so this is > to > > be expected. > > > > I would say, "Go for it, and report back....." > > > > regards, > > > > Jeff > > > > > > > > >From: Andy Middleton <[EMAIL PROTECTED]> > > >Reply-To: [EMAIL PROTECTED] > > >To: SOCALWUG <[EMAIL PROTECTED]> > > >Subject: [SOCALWUG] WiFI over water > > >Date: 11 Sep 2003 09:23:15 +0100 > > > > > >Jack, > > > > > >Another small challenge! I'm planning to make a 3 or 4 km link over the > > >sea across a small bay here in Tenerife. One side of the link is fairly > > >high (40-50m above sea-level), but the other is at half the height > > >(20m). In theory I am not infringing the Fresnel zone (at 3 miles is > > >almost 8m), but I am slightly concerned over possible reflections from > > >the sea. I know that normally water absorbes microwaves, so I don't > > >think it will be a problem, but I wondered if, on those days of > > >dead-calm, there could be any reflection; the signal is almost parralel > > >to the water, I am using horizontal polarisation: what is the worst that > > >could happen to the link? > > >Now that we're talking about it, how low can I go with my link? What > > >would happen with vertical polarisation? Are there any "water-effects" > > >that I have to be especially aware of? That I can even take advantage > > >of? Could one "reflect" ALL of the signal? WOuld that be usefull? > > > > > >Sorry if its abit long! > > > > > >Andy Middleton > > > > > > > _________________________________________________________________ > > Express yourself with MSN Messenger 6.0 -- download now! > > http://www.msnmessenger-download.com/tracking/reach_general > > > > � Attention: Any views expressed in this message are those of the individual sender, except where the message states otherwise and the sender is authorized to state them to be the views of any such entity. The information contained in this message and or attachments is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. If you received this in error, please contact the sender and delete the material from any system and destroy any copies.
