Wireless Bridge 4~5 miles

I have no idea what the best sources for you might be. Are you located in Borneo, Tokyo, or closer to Moscow? :-)

The best advice I can give you is to use google and spend a few hours reading up everything you can find on the subject.

$54/dish is a good price, but do you really need 5 of them?

See:

a better selection of antennas.

I would not use the WAP11, but instead use WAP54G radios. The WAP11 client mode has a nasty habit of only talking to other WAP11 access points.

If you don't want to waterproof your access points or deal with lossy coax cable, try an integrated bridge/antenna combination:

they much more expensive but they save time and effort in construction.

If you wanna do it thyself, see:

7 pages. See tiny "next" in lower right).

I don't believe it. At 5 miles, you'll have to be over about 20ft (my guess, not calculated) high at each end to avoid hitting the earths curvature and maintaining the Fresnel zone clearance. You'll need to have more than just optical line of sight. You'll need to have Fresnel zone clearance, which is about 2.1 meters radius at midpoint.

Your major problem might be interference. 24dBi dish antennas are a good choice as they have a very narrow beamwidth. However, if you have any source of interference between the endpoints or inline with the path, you're going to have big problems. If you're shooting over a metropolitan area, I don't think it will work well. If rural, probably no problem. Do a site survey (sniff for other users) first.

Describe the area, path, bandwidth requirements, etc and I can run the numbers. If you don't have optical line of sight, forget it. If you have an obstructed path (trees, buildings), forget it.

I would NOT advise building your own dish antennas. At 5 miles, you'll need all the gain you can get. However, there are web piles with instructions on how to convert Primestar and MMDS dishes to

2.4Ghz. You can also come close with large home made panels, but accurate array phasing is a serious exercise. Note that most of the following are for building 8-14dBi antennas. 24dBi is a much bigger challenge. (The antennas grow twice as big for every 3dB of gain). Dimensions and construction also get very critical at higher gains.

From my bookmark collection:

There's probably a bunch more that I didn't bookmark. Anyway, I strongly suggest that you:

1. Do the calculations for fade margin.
2. Determine if you have line of sight and Fresnel zone clearance.
3. Buy a commercial dish antenna or integrated unit.

Don't waste your money. Check the following links -

A great antenna series and cheap. Simply mount the "indoor bridge" components in rear antenna compartment.

This radio/bridge has a detachable antenna. Simply match the antenna connector type supplied with the antenna to the radio antenna output connector. Sanao has point-to-point as well as point-to-multipoint configurations.

You also need an Ethernet power injector (POE). This will allow you to remote the antenna/radio up to 300+ feet from your Ethernet switch with cheap outdor CAT-5 type cable.

Watch the wordwrap on the URL's above. This config has worked great for me up to 11.5+ miles LOS and down to -10 deg F.

Direct Sequence Spread Spectrum is tolerant of some interference but there are limits. If possible check which channels are already in use in your area. Components are available from many fixed wireless suppliers. Do a search with Google etc.

Interesting post, at least for me... for reasons totally off topic. But interesting anyway!

There isn't really enough bandwidth in the entire HF spectrum to do much with!

Wow! I've never dealt with a digitalized tropo system. Or for that matter anything like a "modern" tropo system.

However, in the 1960's I came to Alaska to work on the White Alice Communications System (WACS). Today of course there are only a few relics left of it. (At Bethel Alaska, one of the sites that I worked at, they kept one of the six antennas when it was dismantled. Those antennas were 60 foot parabolic "billboard" antennas, 75 feet high at the top, and on the flat tundra that antenna is a land mark visible for miles around! So one of them still stands.)

And here in Barrow the old DEWLINE radar site still operates as a LRRS (Long Range Radar Site), but of course no longer uses any tropo. But the 30 foot dish antennas are still there. (I think there is a picture on my web site that show them, in fact.)

The WACS system was designed in the early 1950's and the initial stages were built between 1954 and 1956. It was analog of course, and could handle a maximum baseband of 552 KHz (Two supergroups plus one K carrier group, for 132 voice channels). There were a few 1 KW sites, but most paths used 10KW PA's (generally run at about 2-3 KW output). There were 2 or 3 50 KW sites too.

All of it was in the 700-1200 MHz range.

I spent almost 15 years maintaining such tropo systems and the various telephone equipment that was associated with it. The idea of "tweaking" and antenna to get better reception is just wild!

I "worked" for a decade at the Aniak site (it was also called "hobby lobby", because it was the smallest site in the system, and we errrr, enjoyed ourselves), where we had two shots, one of which was the worst regular 10KW path in the entire system, and the other was the best regular 10KW path in the entire system! The good path could actually run 365 days a year using the 5W exciters. We did it for months at a time on occasions, and if the signal began to fade we'd do a hot switch of the transmitter to the other antenna. Both antennas never faded at the same time. Normally the receivers used dual diversity with baseband combiners, and the transmitters were set up to feed one or the other of the two antennas, with a low power backup feeding the other antenna. So that path normally had a 10KW amplifier (maybe 2KW output) on one antenna and a 5W exciter on the other. But since the other path required several hundred watts at a minimum to maintain, if one of the three 10KW amps was down, we'd put the two remaining ones on the bad path and let the good one run with a 5W exciter.

Those may have been "the good ol' days", but I'll tell you what... I got *damned* tired of changing tubes!

It's *all* FM.

FWIW Here's an "open source" design and parts kit for a 10mb optical datacomm link system. The range is a little short but there may be a speed/distance tradeoff or someone may have hackked a long range version.

Check out this link....

(regular Cisco Item, not available at box stores)

Links with no extra stuff of up to 1 KM, and with integrated antenna 7.5 miles....

It is very long, and uses a lot of technical terms and descriptions, but even if you use something else, it's a good thing to look at and learn some basics.. Sample Table of Contents Table Of Contents Overview Introduction to Technology Channels and Data Rates Regulations Cisco Aironet 1400 Series Bridge Product Overview

1400 Series Bridge Low-Power Version Applications VLANs QoS Security Feasibility Study Determining Line of Sight Weather Fresnel Zone Determining the Coverage Distance Required Using the Outdoor Bridge Range Calculator Site Survey Interference Study Possible Interference from Devices in the Same Band Interference-Reducing Features Installation Guide Identifying the Components Installing the Bridges Mounting the Bridges Routing the Cables Lightning Protection First Time Installation and Linking the Bridges Testing Maximum Operational Level Configuring the Root Bridge Configuring the Non-Root Bridge Distance Setting Aligning the Antenna Link Test Configuring the Power Injector Weatherproofing the Connectors Stacking Bridges for More Throughput Installation and Alignment Configuration on the Wired Side for Stacked Bridges Appendix

I am going to try to bridge a network 4-5 miles using wireless equitment. I am looking to advice as what to buy at a reasonable price. I was planning on using wap11 ap and clients with a parabolic or panel antenna such as this

Will this work? Anyone have better advice?

Thanks!!

I believe I do have line of sight. As the ground is lower between the two points. I will have to double check this evening. Where do you sugest the best place to pick up some of this equitment is?

Thanks

Very nice... exactly the kind of stuff I was looking for. Are there any websites with expermentation of antenna's and their capablities?

"Floyd L. Davidson" wrote

I don't have any need for 802.11 long-hauls, but these recents threads on the subject has sparked an interest on the subject.

I wonder what type of 802.11 activity is going on within the ham radio community. I would imagine that if you downconvert 802.11 to HF for transmission, impressive distances could be obtained (?).

I haven't worked with any commercial microwave stuff, but have worked tactical and fixed microwave (SHF) terminals when I was in the military. To extend beyond the visual and radio horizons, these particular terminals could crank out 1 to 2 KW in order to take advantage of the troposcatter phenomenon. Links ranging between 100 to 150 miles were easily obtainable, and (for the most part) pretty reliable and stable -- although they were also subject to same limiting conditions as you noted (weather, temperature inversions, ducting, multi-paths, terrain, etc). For the most part, they were pretty rock solid. It wouldn't be uncommon for a terminal, over in the desert, to be in operation for literally years. Once a link was established, the most common "tweaking" I would have to do would be perhaps to slightly raise the antennas (parabolics) in the early AM in order to peak up on the signal. Even then, the receive signal levels were still strong enough to keep the link. Peaking up just ensured that the bit error rate didn't drop off. The connection between the antennas and the terminal were, of course, waveguides. (Also worked with satellite long-haul terminals, which required more coordination but didn't rely as much on RF "voodoo" as troposcatter.)

One of these days I need to get involved with ham. HF's characteristics aren't too familiar, so a lot of it comes across to me as "black magic". I remember our HF guys regarding HF as much of an art as a science. Cool stuff though!

Im in a mountain valley called heber valley near SLC, Utah. The two locations are one in Midway Utah, and the other in Daniels, Utah. Because they are both kind of on the benches I believe line of sight is possible.

Er, ever heard of hills? Even a shallow river valley would be more than

20ft deep, and would meet this requirement... :-)

The other option would be to go to something like 802.16 instead of

802.11 for the network. It is designed to go l> "root" wrote:

In 1976 the USAF turned over the White Alice system to RCA Alascom with some sort of termination contract. I don't remember the exact sequence now, but essentially they were required to replace it and in the process took possession of real estate, buildings, etc. for $1.

The actual termination date was in 1979 if I remember right.

However, not all of it was physically replaced. Even some of the tropo lasted a short time beyond that, though not much of it. But there were TD-2 (4 GHz) microwave systems that had been installed in the early 1960's that were still operating into the late 1980's.

If you remember his name, let me know!

The 50KW shots had 120 foot billboards! The 50KW shot from Fort Yukon to Barter Island (the village of Kaktovik in the Arctic National Wildlife Refuge), which linked the Alaskan DEWLINE to the rest of the world, was one of the last links to be turned down. It was also one of the last sites to be dismantled too, several years later.

Look down about 1 line up from the bottom, in my signature!

However... it turns out that picture is not on my web site after all.

Here's a web page that is *loaded* with images and technical information about WACS. Lots of old friends...

Wow, thats really cool stuff! I remember reading about the WACS in one of my "upgrade training" volumes while in the military. (If I remember that reading correctly, WACS was replaced by satcom in the early ~1980's?) I also seem to recall that I had in instructor at Keesler AFB who was an older gentleman that had worked WACS. He taught our microwave/satcom block that covered microwave analog/FDMA systems. He was a very nice, laid-back, guy and was extremely knowledgeable when it came to just basic electronics and RF theory. He also had a wondeful style of teaching (to include humor) that I was able to learn more from than any other instructor, including university classes I have taken later. Some days he would spend half the class time talking about boating/fishing out on the Gulf, which was his second passion after radio. LOL. (Learned a lot about that too!) Unfortunetly, I can't recall his name. :/

Those large parabolics, even if offline, are really cool! The largest parabolic I worked with was a 20-foot dish that was used with tactical satcom. Anytime we had brass or VIPs on site, they would always ask to get photographed with us in front of the 20-footer, as it was the most "photogenic" piece of equipment on site. Fixed 60-footers definetly make good photography!

Thanks for sharing! What is your website, btw? I'd love to see the pics!

Cheers!

I have an eight mile shot and an eleven mile shot running in Ogden. They've been fairly stable for over 3 years now. I'm using 24dBi parabolic antennas and SMC's 802.11b bridges. Just recently I tried to install YDI's bridge in a box product for a 4 mile shot. Very problematic and not stable at all. Their customer service is also the worst I've dealt with. I would _NOT_ recommend them or their products.

Your 4 or 5 mile shot in Heber should be just fine. Assuming there's not a lot of interference around.

Gordon Montgomery Living Scriptures, Inc snipped-for-privacy@lsi.com (anti spam - replace lsi with livingscriptures) (801) 627-2000

About the same time they converted some of the AC&W sites to FAA.

Some of those site names ring bells. Kotzebue is one of them. I managed not to go to Alaska, milking my time at one of the "remote" sites in CONUS. We had guys on site over 20 years. You only "had" to stay 18/24 months because it was remote, so if you volunteered, you just sort of stayed.