cantenna - Dish network dish ?

probably a foolish question.
would a regular Dish network or Direct TV satellite dish work as a cantenna
for wireless b or g ?

 

Of course it will. they showed some homemade antennas in TechTV using old
dishes about three weeks ago. It achieved impressive results.

 

Odd that you should ask that. I'm going to put a D-Link USB DWL-122 onto a
Dish-Dish tonight. Maybe I'll take pictures.

 

First a couple of observations:

"Cantenna" is the name of two distinct entities: Cantenna is the brand
name of a commercial product which sells for about twenty bucks. It is a
waveguide antenna which is designed for WiFi use.

"Cantenna" is also a generic name for homemade WiFi antennas of various RF
design specifications, which incorporate a metalic tin can, or other
cylindrical shaped packaging materials. The actual materials used in
these homemade designs have been limitted only by the user's ingenuity,
and have included Snack Chip cans, (pringles being the perrenial favorite),
Coffee cans, beef stew, etc.

Much ado has been made of the use of DSS type satellite dishes for WiFi
use. They can be made to work, but suffer from inherent drawbacks, like
wind loading factors, poor driver to reflector coupling, etc.

my personal feeling is that if a user wish to have a high gain, highly
directional antenna, they can be purchased for very affordable prices, and
the better designs don't suffer from the drawbacks mentioned.

The primnary difficulty for the do-it-yourselfer, when using these DSS
dishes is proper illumination of the dish, and RF coupling, from the
driven element onto the reflector. The best designs I've seen, which are
to be had from a judicious Googling, involve the "BiQuad" driver design.
If you're NOT going to be using a BiQuad driver, I wouldn't bother wasting
my time in this endeavor.



vg

 

Would ordinary co-axial cable work ?
Or should one use other types of cables ?
how would reception compare to a "cantenna" ?

 

I just don't get it. 2.4GHz antennas are so cheap and so well made, why
dick around with making your own? At the moment I have a 9dbi panel
antenna (about 4-5 inches in each direction, about 1 inch thick) out on
my porch connecting to an access point omni about a quarter mile away. I
have excellent signal strength and link quality. Do you know how cheap
these antennas are? If my time is worth $2/hr, then buying these panel
antennas is a really good deal.

 

Rôgêr ,

points well taken.
just that I've got a handy Dish sitting on a tripod.
what commercial antenna do you recommend ?
also some "experts" contend that a home made antenna often will
have better recepton than a commercial product.
also what type of access point are you receiving ? how much
strength is it putting out- i.e a commercial unit or just run of the
mill wireless router .


thanks

 

Taking a moment's reflection, Valentín Guillén mused:
|
| my personal feeling is that if a user wish to have a high gain, highly
| directional antenna, they can be purchased for very affordable prices, and
| the better designs don't suffer from the drawbacks mentioned.

Yeah, but the commercial stuff isn't as trick as the do-it-yourselfer
stuff. ;-)

 

Frank Dowling wrote: Rôgêr ,

      points well taken.
      just that I've got a handy Dish sitting on a tripod.
      what commercial antenna do you recommend ?


There are a whole slew of different antenna types which are available, depending upon your needs.   Directional types are good for higher gain needs, but have the disadvantage of needing precise aiming.  Omnis are good for wide-area coverage.  Flat panels are fairly directional, but have wider propagation  characteristics.  
      also some "experts" contend that a home made antenna often will
have better recepton than a commercial product.
      also what type of access point are you receiving ?


802.11b *cards* should connect with any brand of AP/router/etc. how much
strength is it putting out- i.e a commercial unit or just run of the
mill wireless router . Here are a couple of rinky-dink "dish-conversion" links, by people who didn't know better:

http://www5.cs.cornell.edu/~eckstrom/802.11a/primestar/
http://www.wwc.edu/~frohro/Airport/Primestar/Primestar.html

Here's a good shot from a page of a guy who knows what he's doing:

from this good "BiQuad" conversion page:  http://www.trevormarshall.com/biquad.htm

And here's another shot from another European dish conversion page: 
from here:  http://www.weijand.nl/wifi/

Here's the commercial Cantenna from this page:  http://www.cantenna.com


I'm partial to the Semi-Parabolic grid antennas, partially because of their extremely high gain characteristics, like this one:
    from this website:   http://www.wirelessinteractive.com

I can connect to many wifi spots from my home with one of these, and some of those are miles away.   I connect to a wide variety of brands with one of these!

And you're right......Many homemade antennas CAN often be very much better than commercial antennas, but invariably, these homemade jobs are constructed and designed by RF engineers, and they put a LOT of time and effort into them.   Don't be fooled!
 

Regards,

vg
 
 

 

.... and similar garbage.

Don't post HTML to newsgroups, and especially don't post broken html to
them. Set your newsreader to post in plain text only.

 

Frank Dowling wrote:

Rôgêr ,

points well taken.
just that I've got a handy Dish sitting on a tripod.
what commercial antenna do you recommend ?


There are a whole slew of different antenna types which are available,
depending upon your needs. Directional types are good for higher gain
needs, but have
the disadvantage of needing precise aiming. Omnis are good for
wide-area coverage. Flat panels are fairly directional, but have wider
propagation
characteristics.


also some "experts" contend that a home made antenna often will
have better recepton than a commercial product.
also what type of access point are you receiving ?


802.11b *cards* should connect with any brand of AP/router/etc.

how much
strength is it putting out- i.e a commercial unit or just run of the
mill wireless router .

Here are a couple of rinky-dink "dish-conversion" links, by people who
didn't know better:

http://www5.cs.cornell.edu/~eckstrom/802.11a/primestar/
http://www.wwc.edu/~frohro/Airport/Primestar/Primestar.html

Here's a good shot from a page of a guy who knows what he's doing:
http://www.trevormarshall.com/bq-soldering.jpg
from this good "BiQuad" conversion page:
http://www.trevormarshall.com/biquad.htm

And here's another shot from another European dish conversion page:
http://www.weijand.nl/wifi/index_files/image008.jpg
from here: http://www.weijand.nl/wifi/

Here's the commercial Cantenna from this page: http://www.cantenna.com
http://www.cantenna.com/cantenna_images/canandpigtail03.jpg

I'm partial to the Semi-Parabolic grid antennas, partially because of
their extremely high gain characteristics, like this one:
http://www.wirelessinteractive.com/images/Downloaded/WIDC24default_main.jpg
from this website: http://www.wirelessinteractive.com

I can connect to many wifi spots from my home with one of these, and
some of those are miles away. I connect to a wide variety of brands
with one of these!

And you're right......Many homemade antennas CAN often be very much
better than commercial antennas, but invariably, these homemade jobs are
constructed and designed by RF engineers, and they put a LOT of time and
effort into them. Don't be fooled!


Regards,

vg

 

My antenna is a Maxrad WISP24009XF, runs about $26 + shipping. I don't
mean that Maxrad is the only brand I'd use, it's just what I have at the
moment. I've also used a couple of other antennas on this same setup and
neither a 13dbi or a 19dbi performed any better.

The access point is a commercial unit if that means you can't just walk
into Walmart and buy one, and it's mounted outside. But it is unlicensed
802.11b and it's not even putting out the maximum allowed by the FCC in
terms of power - and it's on an 8 or 9dbi omni antenna. I *do* have
clear line of sight.

I also have another identical AP that's about a mile and half away that
I can associate with at roughly the same signal strength and link
quality as the one at a quarter mile. The only difference is it has a
120° sector antenna instead of an omni. One other important fact,
there's not much 2.4GHz pollution in my area, but that's changing month
by month.

 

Just out of interest at what distance could a regular home wireless
router be received by an antenna such as yours ?

 

You have to buid a new feed - the Dish LNB is a 900MHz <-- 11-12GHz
downconverter.

Don Woodward

 

That has a dealer cost of $25.95, but a list of $51.99. Most of their
other antennas are higher priced. Are you a dealer, or is the $26 a street
price?

My son threw away the Dish Network dish that I thought I was going to poach
for my antenna.
I was driving to work today with the DWL-122 usb-mini-wifi that I am going
to use for my hobbyist antenna on the dashboard, running NetStumbler. 89
APs in a 4 mile drive, 42 with WEP.

A year ago, that wasn't true. There were maybe 10 on the same route.

 

As for range on off the shelf products, I am using dlink 800+ access
point to a Dlink 810+ ethernet bridge from well over a mile away with
no problems, I also have several trees and bushes in the line of site
and it doesn't seem to affect my signal all that much. The antennas I
am using are 13dbi directional made by DB Performance (really just
some 3" pvc pipes) I only use this connection for my ADSL link and it
works great.

 

WiFi antenna, both commercial & DIY, may be "cheap " enough, but the
low loss connectors & microwave cable can be VERY costly. Losses of
1/2 dB a meter & 1dB a connector are typical even for US$5/m cable,&
connectors need specialised $$$ crimping tools. You may have a
tempting signal sweet spot say 10m (30') from your PC, but cabling to
cover even that distance may cost US$50 & be lossy. ARGH !

Off the shelf antenna in fact are often only modest performers for the
price, & DIY gives the satisfaction of rustling up superior designs -
especially if NetStumbler tuning/tweaking employed. Our 15-18 dB
parabolic dish cost US$4 & anything comparable commercially would have
been an order of magnitude more!

As you may guess, my WiFi cabling experiences have lead to
alternatives, such as POE (Power Over Ethernet).For DIY setups
"masthead" USB greatly appeals & even the WiFi adaptors are cheap. See
a "Poor Man's WiFi" educational project here in NZ =>
www.usbwifi.orcon.net.nz