Inexpensive point-to-point solution needed

On Sat, 20 Dec 2008 05:01:07 -0800 (PST), snipped-for-privacy@gmail.com wrote in :

No way to know for sure without actually trying.

It may or may not help and warrant the cost. I'd personally try cheap dishes.

As Jeff wrote, you presumably mean dBm, unless you're thinking of SNR, and reported signal strength often varies all over the place. In addition, signal quality is at least as important as strength or SNR. I'm using an Atheros chipset at the moment, and the reported SNR is varying between 23 and 35. It's not really all that helpful, especially as compared to testing the link for speed, errors and throughput.

Again, no way to know for sure without actually trying, but it might well make sense to try a single directional antenna before spending the money on a second one.

On Sat, 20 Dec 2008 07:05:41 -0600, "Lloyd E. Sponenburgh" wrote in :

Are you sure about those numbers? I would have thought higher.

Moisture Content (M.C.): The weight of water contained in wood expressed as a percentage of the weight of the oven dry wood.

Moisture content of Redwood has been known to vary from a low of around

I take that to mean it could vary from 28.5% up to nearly 78% water.

More than half is "mostly".

I've been heating with firewood for the last 35 years. I can assure you that there is a huge difference in weight between green and dry firewood. Googling...

at the bottom of the table, I find: * Dry weight at 12 percent moisture content. * Green weight at 40 to 60 percent moisture content. All moisture contents based on "wet" wood basis. Note the differences in weights between green and dry.

My guess(tm) is that the denser woods, such as oak and madrone, are at the low end of the moisture content scale, while the light woods, such as pine, are closer to the high end of the range. Still, 40 to 60% is quite a bit of water. Note that this is by weight, not volume. Since water is denser than wood fiber, my guess is that the volume of water in a tree would be even a larger percentage.

You can see for yourself how water attenuates 2.4GHz by just placing a wet towel around the antenna. I've done this as a fast and cheap RF attenuator. Unlike aluminum foil, which reflects the signal and bounces it around, the wet towel absorbs the signal. Try it.

Jeff Liebermann fired this volley in news: snipped-for-privacy@4ax.com:

Noooo... Just the opposite is true. Think about it.

The Californika Redwood association seems to think that very high moisture contents in green redwood (over 45%) normally only occur AFTER the wood is dead (cut), but still green, and exposed to water.

In any case, that wasn't my point. It was just that the "typical" moisture content is under 50%, and that doesn't constitute "most".

Just a nitpick, and of no importance in the discussion.

The whole discussion has devolved from the OPs question.

He gets marginal service from a cheap consumer wireless AP at his neighbor's house -- trees or not, hills or not, distance regardless.

Anything he can do to improve the signal strength or directionality of the transmitter, or the sensitivity of his receiving equipment, is going to improve that situation.

LLoyd

On Sat, 20 Dec 2008 18:30:20 -0600, "Lloyd E. Sponenburgh" wrote in :

True, not that it's relevant to the issue.

Citation? (2nd request)

Amen.

Probably, not certainly.

Which is why dB measurements (such as provided with better computers) are so necessary to learn what does and does not exist and what adjustments work best. 'Five bars' is for those who want to feel they know what the signal is while knowing almost nothing. With dB measurements, the OP has a number for a weak signal AND then fixes things to obtain at least 10 or 20 dB improvement using directional antennas.

It is a design. Therefore experimentation and numbers are always required. Little to zero reason to believe the directional antenna will fail. Only question is how good it will work. Can it be installed to provide full data speeds at all times? Or will slower data rates occur? That is the real unknown. OP is encouraged to report back what he has learned. Why? Newsgroups are about sharing information bidirectionally.

On Sun, 21 Dec 2008 06:36:13 -0800 (PST), snipped-for-privacy@gmail.com wrote in :

Again: ... signal quality is at least as important as strength or SNR. I'm using an Atheros chipset at the moment, and the reported SNR is now varying between 21 and 37. It's not really all that helpful, especially as compared to testing the link for speed, errors and throughput.

I've seen a number of cases where directional antennas did not make for a reliable link, as when interference was along the same signal path -- the directional antenna increased the amount of interference as much as it did the amount of signal, making for no real improvement -- and that's by no means the only possible problem.

To most people that's what "work" means -- having a useless signal is ,,, well ... useless. ;)

That's great when it happens, but newsgroups tend to be more unidirectional, and filled with more noise than a Wi-Fi link would tolerate. ;)

The tricky newsgroup bit is separating the signal from the noise. A good start is to pay close attention to Jeff. He can pontificate and ramble a bit, and has a bias or two, as we all do -- no offense intended, Jeff :) -- but unlike most here, he is a genuine expert that gives sound, useful advice in a consistently positive and often humorous way. I should do as well. :)

...

For what it's worth... just in case you didn't know, you all are trying to correct "w_tom". It's an impossible task, evidenced by his never-ending "surge protector" discussions.

On Mon, 22 Dec 2008 20:43:36 GMT, John Doe wrote in :

Indeed.

Assuming you by "quality" mean packet loss and packet resend portion. Did you know that rapid change of SNR gives away the very same info as with what you call by the the undefined, inaccurate, unquantified consept "quality"?

BTW, "quality" is something used on basestations if made by ppl who believe alot of their boxed will be installed by blond secretaries equaly clueless as you, not knowing how great portion of payload can be packetloss for the link to be acceptable. That is if you neither know how to find the best channel to use. Not that they who made

If an interfering source increases just as much as the signal, with a more narrow beam, your interference must be in exactly the same direction as the signal, and if we are using 360' in two dimentions as our statistical measurement, it means that for this to happen instead of decreasing the unwanted signal, got a chance of 360:1. This means that a directional antenna is better in 359 of 360 random choices, and the last one it's equally good. This is even more so if it's a modern AP where you can decrease the sensitivity, so that the AP is ignoring the beam that got stronger after a more directional antenna. Adding more cable does close to the same trick only that you will decrease power as well.

I have seen all your links, and if they are not partly useless because of misunderstood theory or because they are inaccurate or even irrelevant to the question you are posting them as an answer to, it's obvious that you didn't understand what the link said. In fact, you have posted so much crap about wireless that there is no longer doubt you're a clueless moron introducing more frusteration with your useless info than help. Next time you're thinking about suicide, STOP! Find a gun and do it!

I wrote most of the calculations and theory sections. Which parts do you find to be erronious, inaccurate, or misunderstood? Please note that the FAQ is a wiki, which allows user contributed constructive edits, changes, comments, additions, and interpretations.

On Mon, 22 Dec 2008 14:19:16 -0800, Jeff Liebermann wrote in :

I admire your patience, but you're wasting your time.

You choose three pieces of useful information for a guy who are putting up something wrireless, that you think is not inaccurate and we go from there.

You accuse me of being erroneous, inaccurate, and perpetuating misunderstandings. Now you expect me to also supply the evidence? You made the accusations, therefore you can substantiate them without my assistance.

I will admit that there are some personal opinions and anecdotal evidence mixed into the FAQ. Those are based on experience and many not be completely accurate. There are also some areas that certainly could use some improvement. Otherwise, the calculations, recommendations, lists, and URL's are quite accurate. They're also intended to be slightly above the typical home users level and sufficient for explaining how things function. The FAQ is not intended to be a tutorial on how to setup a wireless network. It merely archives common questions that are asked in alt.internet.wireless to avoid repetition and perpetual explanations.

No, you have already done that. I just wanted you to choose three parts of the evidence that you think will impossible for me to poke a hole in. I'm not trying to turn around the burden of proof. You see, for me it's not enough to win, but to destroy the enemy. This is my first step doing so.

Sorry, but I don't want to play your game. Three random topics from the FAQ will result in an endless discussion of ever decreasing interest, with the added bonus of guaranteed topic drift. At best, it might demonstrate your knowledge of wireless, which doesn't interest me. What is certain is that at no time will such a discussion ever touch upon your original assertions that my calculations and theory in the FAQ are erroneous, inaccurate, and misunderstood. If you cannot or will not supply the details to substantiate your accusations, then either apologize or be silent.

Just tell when you change your mind. I'm ready at any time.

Jeff Liebermann fired this volley in news: snipped-for-privacy@4ax.com:

Jeff, he's already offered that he'd like to be shot if he must apologize -- so take the initiative: Shoot him.

LLoyd