Trying to connect TWO ground level indoor city office suite that are
20 miles (32 km) apart wirelessly. They are not in line of sight. At one site, no equipment can be placed outdoor, and no antenna can be put up. Ideally no outdoor equipment or antenna at second site either. Any help would be appreciated. Thank you for your time. (I initially looked at proxim tsunami 10, but kinda expensive, etc...)
Depending on your location, we are in an area that has Verizon BroadbandAccess (avg 500 Kb) and have the Audivox pc5220 cards at each end (along with VPN software) always on x.25 wireless connection. When we want to add additional offices, or people with laptops, no problem, takes about a day to set up a new system. In case you are curious, it's a real estate firm, we keep adding offices in new areas, and the agents love mobile access to the network with their laptops.
Due to my lack of knowledge and faulty understanding, I just figured the device can use their case as an antenna, or work without an antenna. As an aside, I also get confused with terms such as: 0dbi gain antenna, build-in antenna, integrated antenna, embedded antenna, etc. Got lots to learn... Ideally, I am looking for a set of device to wirelessly connect my indoor suite that's 20 miles away; that has no line of sight, using only small-short build-in/integrated/embedded antenna from the device. Many thanks for for your suggestions and solutions.
Thanks for all the help and suggestions. At this time, I guess it's just not possible to get "a set of device to wirelessly connect my indoor suite that's 20 miles away; that has no line of sight, using only small-short build-in/integrated/embedded/internal antenna from the device". It seems, if no (or almost no) antenna is a must, then the best solutions today is to go thru the big teleco's cell network (a middleman's network with monthly fees) into the internet then connect the two sites together. Thank you.
There is another couple possibilities, unfortunately, they both cost monthly fees/money. If you are in an area that has cable internet, and both sites already have/can get cable installed, you can use that, or if available in your area, you can also do DSL.
Yeah sure. You like hearing yourself talk! Which is true of most geeks. And in fact *I* enjoy reading your mumblings!
But, when the OP says half a dozen techie terms overwhelm him, there is no point in responding with dozens more equally meaningless terms.
Why not give the OP the *benefit* of your technical experience, which is to say a *clear* expression of the conclusions you come to.
Once that is out of the way, yeah... go right ahead and open it up for discussion with others who enjoy the technical challenge that the OP's situation presents. But don't start and end with that and never bother to actually _help_ nice fellow who gave us the interesting scenario to play with!
Yer just a luddite. Haven't you heard of the latest science, called physics? It has shown that if the world were round, it would have to spin, and if it was spinning that bowling ball would *not* roll down hill at all.
Nope, it would be subject to centrifugal force, and be flung into outer space!
Therefore, the world is indeed obviously flat. And, unlike some people I know, it doesn't spin either.
Most of the terms you list are the "gain" of the antenna. In general, the antenna gain is measured in dBi or decibels over an isotropic reference, which is just a hemispherical pattern antenna with unity gain. 3dBi gain is twice the power delivered. 6dBi is 4 times. 9dBi is 8 times. And so on. When comparing antenna gains, power levels, or losses, the term is dB or decibels, which is just a ratio. 2 times is 3dB. 1/2 is -3dB. 1/8 is -9dB. 6dB gain will go twice the distance. -6dB loss will cut your range in half. This is not a complete explanation but might help.
You didn't bother to describe your preformance specifications. If you can tolerate slower speeds, 20 miles is possible. Not having line of sight may be fatal but will vary depending on where and how much of an obstacle is in the way. The antennas can be indoors as long as they go through glass windows. You'll need someone (me?) to calculate the path loss, fade margin, and evaluate the NLOS path, to determine if this even has a chance at working. Email the exact lat-long, to as much accuracy as you can get, and the altitude of the antennas above ground level, and I'll grind out a path profile. If you don't have about 190ft elevation at each end of the link, forget it as the earths curvature (67ft) plus the Fresnel Zone clearance (130ft) requirement will mean the path will hit the ground at midpoint.
If you can tolerate either 112Kbits/sec thruput, or 750Kbits/sec (depending on model), the older 900MHz point to point radios might work. See:
are other 900MHz wireless vendors but these are the ones I can recall. I've never done a 20mile NLOS (non line of sight) link and suspect that it can't be done unless the obstructions are fairly modest. However, it is worth investigating.
Well, I just really hate to agree with you, but this time you're correct. 20 miles, NLOS, and no external antennas is fairly close to impossible. However, running the numbers doesn't take that much time and effort and is often fun to see how close one can get. In some cases, it's only a minor change to make it work.
At this very moment, I'm fighting the numbers over a rather nasty 12 mile path at 5.6GHz. The limitations are such that using conventional hardware and antennas, the fade margin is only about 12dB. Not enough. So I play with bigger antennas, more power, better receiver, lower bandwidth, fat coax, exotic modulation schemes, and alternative vendors. As it stands, I can only change *ONE* of the aformentioned or I go over budget. That's the kind of problem I enjoy doing. (OK, I'm weird). It may be a waste of time, but I think it's fun.
As for the geek show, I like to explain my terms, buzzwords, and logic as I go along. Not exactly perfectly organized and perhaps a bit heavy on the buzzwords, but it is what geeks do.
Incidentally, the earth is still flat. If I roll a bowling ball and the earth were round, it go faster and faster as it approaches the edge of the earth until it falls off. With a flat earth, it would just slow down and stop, as it obviously does.
Guilty as charged and thanks. At least someone reads my stuff.
Actually, I was rather careful NOT to lay the buzzwords on too thick. I did't toss in the traditional 10log(ratio) calculation for converting ratios to decibels. I defined all my terms as I went along. I used many more examples than definitions. I was repetative to emphasize the important points (i.e. 3dB is twice, -3dB is half power). I even added something useful, like 6dB is twice the range. If anything, it was a rather simple explanation of decibels and antenna gains.
I don't do that very often. I prefer to offer the OP some data, my logic, some details, and let them make their own conclusions. The extreme case of what you advocate is the unsubstantiated one line judgement, which I detest. Should I have said "Don't bother trying this because I think it won't work"? That's clear enough and is derived from my many years doing wireless. However, it doesn't explain anything, how I came to that judgement, and offers nothing in the way of an education. I suppose I could have added that line to my long explanation, but I would thought that the OP would read the details, see the problems involved, and draw his own conclusions.
Perhaps you're right. I'll start my subsequent posting with an overall judgement and pontification and then supply the details, instead of the reverse order. Incidentally, I do try to answer the interesting questions as I'm really bored with Windoze related wireless issues and problems.
Certainly not. I'm an active proponent of science and a believer that given enough scientific research funding, I can prove anything. Science is a good thing.
Thank you. I knew you would eventually come to the correct conclusion. This also explains my dismal bowling scores. As Newton said, "an object in motion will remain in motion until someone steals it" which might also explain the disappearance of the bowling ball off the edge of the Earth. The spin of the flat Earth is rather small, as I notice is it much more difficult to go to work in the morning, than to return in the opposite direction in the evening. Obviously, some force must be at work here.
Incidentally, today and the next 3 days are when the sun goes behind the geosynchronous satellite belt and causes an outage in DBS (dish) receivers and DirecWay satellite internet. The calcs are available at:
you live in a forest (like me), then it's often difficult to determine the optimum location for receiving a specific satellite. At the calculated time (varies with satellite and lat-long), wherever the sun shines on your roof, is where a dish can be located. Have fun, and don't look directly at the sun (or do my dumb stunt of pointing my digital camera at the sun).
Incidentally, the Panamsat calculator has a bug. It won't accept dish diameters less the 1.0 meters. Use 1.1 and it will work.