Extend wifi antenna range

[Andy]

Could I extend the range of this wifi antenna by extending the wire lengths ?

Not sure why there are 8 wires for an antenna.

http://i1289.photobucket.com/albums/b516/drew77580/antenna_zps765323b0.jpg

Andy

 

[Andy]

From: "Andy" <[email protected]>









No.



--

Dave

Multi-AV Scanning Tool - http://multi-av.thespykiller.co.uk

http://www.pctipp.ch/downloads/dl/35905.asp

Actually there is a way.

Wrap 5 or 6 coils of wire around antenna and cut 8 ft. piece of wire.

Doubled speed.

 

[Paul]

Could I extend the range of this wifi antenna by extending the wire lengths ?

Not sure why there are 8 wires for an antenna.

http://i1289.photobucket.com/albums/b516/drew77580/antenna_zps765323b0.jpg

Andy

Why not figure out what a quarter wavelength at that frequency would be ?
The length could be optimized for resonance at a particular frequency.

There are some low frequency antennas, where the longer the wire, the
better. But your antenna is for two and a half gig, or five plus gig,
which is microwave frequencies. A good, high gain antenna, may not cover
both bands at the same time. So you'd at least want to check the
Wifi device, to see if it operates at one band or two, or, has separate
antenna connectors for the bands.

This article is intended to give you some idea of the complexity.

http://www.hamuniverse.com/yagibasics.html

And this software, is a simulator for simulating antennas. In
fact, some antenna people, will not buy an antenna over the
Internet, unless they can get the dimensions and simulate it.
Data entry for antenna simulation, is a big detractor from
using this stuff. (Lots of typing...)

http://www.qsl.net/4nec2/

Now, I've built an antenna, from scratch. I had the plots and
predictions as to what frequency it would cut off at. Instead
of behaving as the simulator predicted, it "wasted gain" at
high frequencies, and allowed me to pick up television from
another city. It wasn't supposed to be able to do that. To
its credit, the beam width of the antenna was pretty close.
The antenna was around 15 degrees, and a bitch to point. To
be practical, such an antenna should sit on a rotator. When
your antenna is that directional, it may need to be shifted a
degree or two now and then, for optimum results.

When you get a Wifi device, it comes with an omnidirectional
antenna. Antennas are three dimensional beasts, and the omni
makes a donut pattern. In fact, if you had a Wifi laptop
in the basement, directly below the original antenna, there
might be no signal there, as the antenna lobes don't point
there. It's important to know what the radiation pattern looks
like, before "attempting something dumb". If the antenna
has a dead spot in the pattern, you must avoid it.

Similarly, if you live in a house with two floors to it,
then buy an extremely directional antenna, there may be no
radiation pattern below the horizon. And then an attempt to
reach the other floor might fail. In fact, the antenna may
need to be tipped or rotated.

Even when a transmitter site and receiver site are reasonably
horizontally oriented (same elevation), the antenna may still
need to be tilted for optimal signal. This is caused by
"bending". You can find web sites that discuss the effects of
nearby objects, and the suggestion to not blindly accept
perfectly vertical as the best choice.

Obviously, if you have four receivers, all in different directions
and heights, you can't really use a single directional antenna
to reach all of them. But as I understand your application,
which is "point to point beaming" between two units, carry
on with your extreme directional testing. If you select
the very best antennas, you'll "need a laser to align them".
Getting optimal antenna position is that difficult.

And the best antenna, cannot defeat a Faraday cage. If
there is a metal door frame or something similar in the way,
a high gain antenna might not defeat that. It helps, if you
have some kind of software for your Wifi card, that can
give an indication of signal strength, as you "walk away"
from your router.

Paul

 

[David H. Lipman]

Actually there is a way.

Wrap 5 or 6 coils of wire around antenna and cut 8 ft. piece of wire.

Doubled speed.

LOL - too phunny...

 

[J. P. Gilliver (John)]

Why not figure out what a quarter wavelength at that frequency would be ?
The length could be optimized for resonance at a particular frequency.

A whole wavelength is 125mm @ 2.4 GHz, 80 @ 5. It's c/f, where c is the
speed of light (about 300 000 000 m/s). Practically aerial elements are
a little shorter.

You can get directional aerials for 2.4; the simplest ones are longer,
which increase the gain in a ring horizontally around them (assuming
they're vertical) at the expense of vertically. (No aerial gives you
gain overall - it's always increased somewhere at the expense of
somewhere else.) [These longer ones aren't just a longer piece of wire
inside though.] Next up are dishes - Hawking sell a few - and even a
Yagi (TV aerial type of thing) - I think Swann do one.
[]

And the best antenna, cannot defeat a Faraday cage. If
there is a metal door frame or something similar in the way,
a high gain antenna might not defeat that. It helps, if you
have some kind of software for your Wifi card, that can
give an indication of signal strength, as you "walk away"
from your router.

Though to be a good Faraday cage, it has to have a mesh finer than the
wavelength, which at 2.4 GHz isn't a doorway (-:. I continue to be
surprised that my SatNav works fine almost on the floor of my car.

 

[J. P. Gilliver (John)]

In message <[email protected]>, Bill in Co

Same here. (an ex-amateur radio op, amongst other things)

Hi! (That's why I was taken with the Yagi offered. Plenty on ebay. I
think some of them claim up to about 14 dB.)
[]

window, since antenna gain comes from directionality, just like a lens.
Indeed!
[]

Even when a transmitter site and receiver site are reasonably
horizontally oriented (same elevation),

... should probably add this:
aka horizontal polarization, as opposed to vertical polarization (as from a
1/4 wavelength vertical antenna, for example)

No, he meant - and said, actually! - same height. For which vertical
polarization would eliminate one axis of doubt ...
.... apart from that, of course.
[]

I sometimes tell people using cell phones to get next to a large window in
the hopes of minimizing dropouts caused by any metal conductors in the
rooms. I don't have enough data to confirm it works, but it just makes
intuitive sense to me.

Agreed. I don't think it's as much the cage - see my earlier comments
about wavelength - as just energy absorption (which ought to be
re-radiated, but who knows in what direction).

 

[Paul]

A whole wavelength is 125mm @ 2.4 GHz, 80 @ 5. It's c/f, where c is the
speed of light (about 300 000 000 m/s). Practically aerial elements are
a little shorter.

So maybe there's "more than meets the eye", to that antenna ?

Antennas need relatively good precision, when building them,
to get close to the simulated results. The cantenna designs
for example, benefit from proper machining. Rather than just
punching a hole with a pencil and ramming the feed into it.

That's also a problem with the simulated results. They
seldom take into account the dielectric constant of the
mechanical framework, or the impact of framework elements.
Some frameworks, the shape of the framework is selected,
because it's known not to interfere with antenna performance
(direction 90 degrees to elements). If you run mechanical
elements in the other direction, they upset the antenna specs.
It's a bit tricky for guys like me, with
drill/saw/sander in the basement My antenna,
the framework wasn't strong enough to hold it
properly, so I had to add to the framework to
make it strong enough.

Paul

 

[Paul]

(except directionality, of course)

This is the part that I want amateur antenna makers here to
realize. Is that frequently, you're changing a weak antenna
that works in all directions, into an antenna that "works like
a laser", and only allows one PC to be connected.

If you use nothing but directional antennas, and Wifi PCs
are all over the house, your coverage pattern will be
quite spotty, and there'll be "no roaming for you"
as you walk around the house with the laptop.

If you make the antenna more directional in the Z axis, so
the antenna works on the main floor of the house, and
not on any other floor, then you can't "roam upstairs".

If the computers are in fixed locations, you're only
trying to reach one computer in a remote location,
that's when directional wizardry comes to the rescue.

And if your house has metal door frames, metal 2x4 construction
instead of wood (metal 2x4s behind gypsum board), there can
be lots of reasons for a house to be completely attenuating
remote reception. But you'd probably have a hint of that,
if other kinds of radios do poorly.

*******

There was no radio reception (or TV for that matter) at
work, because of the framing used in the building. As well,
there were strong carrier frequencies due to equipment leakage.
While any individual box would meet FCC part 15, if you have
thousands of RF sources, sooner or later, that's a problem.
When I attempted to tune an FM radio at work, there
was a carrier so strong, the radio would go "quiet" at
exactly 100.0MHz (AGC reacting to input overload). And
that's a ton of "computer crystals" doing that.

I had to listen to "Internet Radio" to listen to music.

Paul

 

[J. P. Gilliver (John)]

That sounds a bit excessive for a Yagi. +10 db gain sounds more realistic
(at least for a 3 element beam), at least as I recall. You can add more
elements (directors, in this case), but the added gain is incremental, and
I'm guessing they weren't talking about such.

Remember we're talking about microwaves here - not a 3 element beam,
more like 17! http://ebay.eu/1gLcJkp has a few - either their claims
have become wilder or I've remembered wrong; the _lowest_ claim there is
17 dB (though of course dBi; knock off a few to get dBd). I bought one
for a friend last Christmas, but unfortunately none of his wifi gear has
an external aerial socket, so we've never played with it: I have ones
that do, but asking for a Christmas present back isn't quite right!

I used to love playing around with them on the roof. I was too cheap to
ever own a tower, but the amateurs with a tower could always get distant
contacts that I had difficulty getting. But I gave up amateur radio a long
time ago, when it became filled with a bunch of "appliance operators". The
radio technology aspect of the hobby went out the window, like a lot of
things I miss these days.

I haven't keyed a transmitter (mic switch I mean - I don't think I ever
got into CW), apart from a fobile moan, for many years, though my
licence is still valid. I agree the practical side of the hobby is much
reduced now: IMO the decline, in UK anyway, started with the
introduction of the B licence (for those that hadn't passed the Morse
test) - not that the B licencees are to blame (I was/am one myself), but
they were restricted to above 100 MHz, which for most people meant
bought rigs only, as you need specialised equipment to build kit for up
there. So the new influx were dissuaded from practical work (_except_ on
aerials!), whereas IMO they could have brought new life into the hobby.
(The distinction was subsequently dropped - I can now use h. f., though
never have - but I think too late, the internet was well under way by
then.)
[]

 

[J. P. Gilliver (John)]

In message <[email protected]>, Paul <[email protected]>
writes:
[]

And if your house has metal door frames, metal 2x4 construction
instead of wood (metal 2x4s behind gypsum board), there can
be lots of reasons for a house to be completely attenuating
remote reception. But you'd probably have a hint of that,
if other kinds of radios do poorly.

[]
I don't think door frames, girders, etc. will make wifi unusable - I
think only continuous sheets (or mesh) would do that. They'll certainly
do strange things to the radiation patterns, reflections, and so on, but
I don't think they'll block it altogether - remember ordinary radio is
hundreds of metre wavelengths (AM) or about three (FM), whereas wifi is
125mm (2.4 GHz) or 80mm (5 GHz), which may well find a way round or
through such metalwork. As I mentioned in another post, my SatNav (which
is on a similar frequency, I think) works near to the floor of my car,
to my surprise.

 

[Paul]

And if your house has metal door frames, metal 2x4 construction
instead of wood (metal 2x4s behind gypsum board), there can
be lots of reasons for a house to be completely attenuating
remote reception. But you'd probably have a hint of that,
if other kinds of radios do poorly.

[]
I don't think door frames, girders, etc. will make wifi unusable - I
think only continuous sheets (or mesh) would do that. They'll certainly
do strange things to the radiation patterns, reflections, and so on, but
I don't think they'll block it altogether - remember ordinary radio is
hundreds of metre wavelengths (AM) or about three (FM), whereas wifi is
125mm (2.4 GHz) or 80mm (5 GHz), which may well find a way round or
through such metalwork. As I mentioned in another post, my SatNav (which
is on a similar frequency, I think) works near to the floor of my car,
to my surprise.[/QUOTE]

I've read second-hand accounts of metal door frames playing
a part. I haven't seen a web page where someone used test
instruments to investigate the patterns involved.

As well as direct reception, there is also the phenomenon of
multipath, which adds a bit of unpredictability to the whole
thing. In fact, in one testing lab, a tester discovered that
when his RF attenuator "mat" was present in the lab, the
Wifi gear was working better. (That would attenuate forward
signal as well as multipath reflections.)

(Some mats...)
http://www.mouser.com/catalog/specsheets/Laird_4024.pdf

So maybe the metal door frame is "reflecting".

If you want the ultimate RF environment, they make anechoic
chambers for RF. One of my buddies at work designed such
a room (that was his job), and it's too bad I was too
busy for a visit to see the thing. I gather it was visually
quite impressive.

("Looks quite absorbent... Careful where you walk")
http://en.wikipedia.org/wiki/File:Radio-frequency-anechoic-chamber-HDR-0a.jpg

Paul

 

[Paul]

Paul, did I misunderstand something here?
(Please let me know if I did - see below).


By "directional in the Z axis", I presume you mean the radiation pattern.
So I must be missing something in terms of orientation. ???

Use this one as an example.

http://www.antenna-theory.com/antennas/reflectors/dish4.php

If you're all the way to the right, there is a huge signal.

But if sitting on the floor below, and just a little bit to the right
of the origin, there's a null. No signal.

Paul

 

[Paul]

OK, so if we're talking about a dish (parabolic) antenna pointed straight
up, the signal would be maximum right above it (in the rooms above), but
drastically fall off as you move away from that Z axis (due to the very
narrow beamwidth of such an antenna)

Are these even sold and used for WiFi?

Yes. Using an image search engine, I can find 24dBi parabolic Wifi
antennas, with something like a 7 degree beam width. So you can
web surf in your barn Many of them don't use a solid dish, and
instead use a "wire frame" reflector.

Paul

 

[J. P. Gilliver (John)]

In message <[email protected]>, Paul <[email protected]>
writes:
[]

I've read second-hand accounts of metal door frames playing
a part. I haven't seen a web page where someone used test
instruments to investigate the patterns involved.

I'm sure they do affect the pattern; I was just saying I don't think
they'd block the signals completely, just cause its direction to vary.

As well as direct reception, there is also the phenomenon of
multipath, which adds a bit of unpredictability to the whole

About 10 or 20 years ago I was involved with a project to overcome the
effects of multipath on long-range h. f. paths; quite fascinating. This
was low rate signalling - 2400 baud, IIRR - but we managed to overcome
multipath that was several symbols long, which doesn't seem possible
when you first look at it. ("Channel estimating" was the method;
"channel equalising" is the alternative method. Both have their
advantages and disadvantages.)

thing. In fact, in one testing lab, a tester discovered that
when his RF attenuator "mat" was present in the lab, the
Wifi gear was working better. (That would attenuate forward
signal as well as multipath reflections.)

I could see that - if you're in a high-multipath environment, cancelling
the multipaths - provided you're left with at least one signal of usable
strength - will almost certainly help.
[]

If you want the ultimate RF environment, they make anechoic
chambers for RF. One of my buddies at work designed such
a room (that was his job), and it's too bad I was too
busy for a visit to see the thing. I gather it was visually
quite impressive.

I used to work at what was then Marconi Research Centre (became BAE
SYSTEMS Advanced Technology Centre by the time I left), and they had
one, mainly I think for testing antennas. Since the RF-absorbent "cones"
also worked reasonably well as acoustic absorbers, it had the same "dead
air" feel as the sort of anechoic chamber they use for testing
loudspeakers.

("Looks quite absorbent... Careful where you walk")
http://en.wikipedia.org/wiki/File:Radio-frequency-anechoic-chamber-HDR-0a.jpg

Paul

Actually, I think the Faraday centre where I work now has some such too.

 

[J. P. Gilliver (John)]

Paul wrote: []

Yes. Using an image search engine, I can find 24dBi parabolic Wifi
antennas, with something like a 7 degree beam width. So you can
web surf in your barn Many of them don't use a solid dish, and
instead use a "wire frame" reflector.

I guess that's what it's got to be for.
Or beaming it over to a distant room in a mansion, like the Hearst Castle.
Must be nice. Amazing.

Or, though of course the manufacturers don't actually push this in their
advertising!, clandestine activities, such as using a neighbour's (even
a distant one!) unsecured wifi, or eavesdropping with wireshark or
similar. I rather suspect such uses are responsible for more of the
sales of such things than just people with very big properties! (Though
some such - perhaps farms and the like, with widely-separated [and maybe
part-metal] outbuildings - I'm sure do exist.)

Here are a few http://ebay.eu/1jsgCww - though the little ones only
claim 8 dBi, so aren't too much better than the larger "rubber duck"
type; at these frequencies and for somethng reasonable in size, I think
yagi aerials http://ebay.eu/1gLcJkp still win (most of those are
claiming 25 dBi). Of course, the higher the gain, the narrower the beam,
so they're probably harder to point. Some of the bigger dishes on the
first link probably have comparable or even higher gains (and are even
harder to point).

 

[richard]

Paul wrote: []

Yes. Using an image search engine, I can find 24dBi parabolic Wifi
antennas, with something like a 7 degree beam width. So you can
web surf in your barn Many of them don't use a solid dish, and
instead use a "wire frame" reflector.

I guess that's what it's got to be for.
Or beaming it over to a distant room in a mansion, like the Hearst Castle.
Must be nice. Amazing.

Or, though of course the manufacturers don't actually push this in their
advertising!, clandestine activities, such as using a neighbour's (even
a distant one!) unsecured wifi, or eavesdropping with wireshark or
similar. I rather suspect such uses are responsible for more of the
sales of such things than just people with very big properties! (Though
some such - perhaps farms and the like, with widely-separated [and maybe
part-metal] outbuildings - I'm sure do exist.)

Here are a few http://ebay.eu/1jsgCww - though the little ones only
claim 8 dBi, so aren't too much better than the larger "rubber duck"
type; at these frequencies and for somethng reasonable in size, I think
yagi aerials http://ebay.eu/1gLcJkp still win (most of those are
claiming 25 dBi). Of course, the higher the gain, the narrower the beam,
so they're probably harder to point. Some of the bigger dishes on the
first link probably have comparable or even higher gains (and are even
harder to point).

IMO, a good yagi is the best.
At my borthers "ranch", he has a neighbor who uses a yagi to get a signal
because they live way off the grid.

One time as a trucker, I had a nice little experience with my littie
dongle.
I just toss the thing up on the dashboard for a good signal.
This particular night, I couldn't get a good enough signal to log on to
either of the two truckstops network.
But, there was a third signal and that one I logged on to.
That signal was coming from 25 mile up the road!
Albeit, it was a fluke due to the weather conditions.
Never got that luck again.

 

[Paul]

Paul wrote: []
Yes. Using an image search engine, I can find 24dBi parabolic Wifi
antennas, with something like a 7 degree beam width. So you can
web surf in your barn Many of them don't use a solid dish, and
instead use a "wire frame" reflector.
I guess that's what it's got to be for.
Or beaming it over to a distant room in a mansion, like the Hearst Castle.
Must be nice. Amazing.

Or, though of course the manufacturers don't actually push this in their
advertising!, clandestine activities, such as using a neighbour's (even
a distant one!) unsecured wifi, or eavesdropping with wireshark or
similar. I rather suspect such uses are responsible for more of the
sales of such things than just people with very big properties! (Though
some such - perhaps farms and the like, with widely-separated [and maybe
part-metal] outbuildings - I'm sure do exist.)

Here are a few http://ebay.eu/1jsgCww - though the little ones only
claim 8 dBi, so aren't too much better than the larger "rubber duck"
type; at these frequencies and for somethng reasonable in size, I think
yagi aerials http://ebay.eu/1gLcJkp still win (most of those are
claiming 25 dBi). Of course, the higher the gain, the narrower the beam,
so they're probably harder to point. Some of the bigger dishes on the
first link probably have comparable or even higher gains (and are even
harder to point).

IMO, a good yagi is the best.
At my borthers "ranch", he has a neighbor who uses a yagi to get a signal
because they live way off the grid.

One time as a trucker, I had a nice little experience with my littie
dongle.
I just toss the thing up on the dashboard for a good signal.
This particular night, I couldn't get a good enough signal to log on to
either of the two truckstops network.
But, there was a third signal and that one I logged on to.
That signal was coming from 25 mile up the road!
Albeit, it was a fluke due to the weather conditions.
Never got that luck again.

There's a protocol timeout limit, that prevents Wifi
at an infinite distance. When the South American
university students do their mountain top experiments
with Wifi, going hundreds of kilometers, they modify some code
somewhere, to change that time constant. Without that
change, the Wifi chip won't wait for some response to
come back. Or, will assume the packet was lost.

http://en.wikipedia.org/wiki/Long-range_Wi-Fi

"In addition to power levels it is also important to
know how the 802.11 protocol acknowledge each received frame.
If the acknowledgement is not received, the frame is re-transmitted.

By default, the maximum distance between transmitter and receiver
is 1-mile (1.6 km).

On longer distances the delay will force retransmissions. On
standard firmware for some professional equipment such as the
Cisco Aironet 1200, this parameter can be tuned for optimal
throughput. OpenWrt, DD-WRT and all derivatives of it also
enable such tweaking."

So you can go to longer distances, but it would require
having tweaked that parameter, to make it happen.

Perhaps a repeater device of some sort, was present
in the neighborhood.

Paul

 

[Jason]

In message <[email protected]>, Bill in Co
Paul wrote:
[]
Yes. Using an image search engine, I can find 24dBi parabolic Wifi
antennas, with something like a 7 degree beam width. So you can
web surf in your barn Many of them don't use a solid dish, and
instead use a "wire frame" reflector.
I guess that's what it's got to be for.
Or beaming it over to a distant room in a mansion, like the Hearst Castle.
Must be nice. Amazing.


Or, though of course the manufacturers don't actually push this in their
advertising!, clandestine activities, such as using a neighbour's (even
a distant one!) unsecured wifi, or eavesdropping with wireshark or
similar. I rather suspect such uses are responsible for more of the
sales of such things than just people with very big properties! (Though
some such - perhaps farms and the like, with widely-separated [and maybe
part-metal] outbuildings - I'm sure do exist.)

Here are a few http://ebay.eu/1jsgCww - though the little ones only
claim 8 dBi, so aren't too much better than the larger "rubber duck"
type; at these frequencies and for somethng reasonable in size, I think
yagi aerials http://ebay.eu/1gLcJkp still win (most of those are
claiming 25 dBi). Of course, the higher the gain, the narrower the beam,
so they're probably harder to point. Some of the bigger dishes on the
first link probably have comparable or even higher gains (and are even
harder to point).

IMO, a good yagi is the best.
At my borthers "ranch", he has a neighbor who uses a yagi to get a signal
because they live way off the grid.

One time as a trucker, I had a nice little experience with my littie
dongle.
I just toss the thing up on the dashboard for a good signal.
This particular night, I couldn't get a good enough signal to log on to
either of the two truckstops network.
But, there was a third signal and that one I logged on to.
That signal was coming from 25 mile up the road!
Albeit, it was a fluke due to the weather conditions.
Never got that luck again.

There's a protocol timeout limit, that prevents Wifi
at an infinite distance. When the South American
university students do their mountain top experiments
with Wifi, going hundreds of kilometers, they modify some code
somewhere, to change that time constant. Without that
change, the Wifi chip won't wait for some response to
come back. Or, will assume the packet was lost.

http://en.wikipedia.org/wiki/Long-range_Wi-Fi

"In addition to power levels it is also important to
know how the 802.11 protocol acknowledge each received frame.
If the acknowledgement is not received, the frame is re-transmitted.

By default, the maximum distance between transmitter and receiver
is 1-mile (1.6 km).

On longer distances the delay will force retransmissions. On
standard firmware for some professional equipment such as the
Cisco Aironet 1200, this parameter can be tuned for optimal
throughput. OpenWrt, DD-WRT and all derivatives of it also
enable such tweaking."

So you can go to longer distances, but it would require
having tweaked that parameter, to make it happen.

Perhaps a repeater device of some sort, was present
in the neighborhood.

Paul[/QUOTE]

A few years ago, Linksys opened up one of their routers to hacke...oops
experimenters. The 2.4GHz band is shared with an amateur radio
allocation, and hams began to modify the routers for all manner of
interesting uses. Hams are allowed to run much higher power than the puny
milliwatts the routers provide by default. And they did. High-gain
antennas and higher power allowed the routers to work over surprisingly
long distances. Some also modified the code to create automatic mesh
networks that were used for public service events like marathons.

Jason

 

[Stan Brown]

One time as a trucker, I had a nice little experience with my
littie dongle.

Shouldn't you be sending that story to Penthouse Forum?

 

[pjp]

Paul wrote: []
Yes. Using an image search engine, I can find 24dBi parabolic Wifi
antennas, with something like a 7 degree beam width. So you can
web surf in your barn Many of them don't use a solid dish, and
instead use a "wire frame" reflector.

I guess that's what it's got to be for.
Or beaming it over to a distant room in a mansion, like the Hearst Castle.
Must be nice. Amazing.

Or, though of course the manufacturers don't actually push this in their
advertising!, clandestine activities, such as using a neighbour's (even
a distant one!) unsecured wifi, or eavesdropping with wireshark or
similar. I rather suspect such uses are responsible for more of the
sales of such things than just people with very big properties! (Though
some such - perhaps farms and the like, with widely-separated [and maybe
part-metal] outbuildings - I'm sure do exist.)

Here are a few http://ebay.eu/1jsgCww - though the little ones only
claim 8 dBi, so aren't too much better than the larger "rubber duck"
type; at these frequencies and for somethng reasonable in size, I think
yagi aerials http://ebay.eu/1gLcJkp still win (most of those are
claiming 25 dBi). Of course, the higher the gain, the narrower the beam,
so they're probably harder to point. Some of the bigger dishes on the
first link probably have comparable or even higher gains (and are even
harder to point).

IMO, a good yagi is the best.
At my borthers "ranch", he has a neighbor who uses a yagi to get a signal
because they live way off the grid.

One time as a trucker, I had a nice little experience with my littie
dongle.
I just toss the thing up on the dashboard for a good signal.
This particular night, I couldn't get a good enough signal to log on to
either of the two truckstops network.
But, there was a third signal and that one I logged on to.
That signal was coming from 25 mile up the road!
Albeit, it was a fluke due to the weather conditions.
Never got that luck again.

I live in Nova Scotia, Canada and our provincial government sent out a
contract a few years ago in order to insure everyone in province got
decent speed. Most rural areas receive this thru a network of wireless
transmission towers with the house using a yaga style attena pointed at
the tower. Works fine for me but I'm less than 1Km away from tower but
otherwise very rural. Only other option is dialup (slow) or sat
(limitations and expensive).