24+ Dbi antenna, does it work?

Hi everyone, i'm new here, i'm from Quebec(canada), so i'm french but i
can speak english. I do some mistakes so sorry for that...

I live in an appartement(8th floor) and there's a big neighborhood at
about 600meters of my windows. I know there are some wifi signals in
this neighborhood and i wanted to buy this antenna to receive some of
those signals... my question is really simple... does it really work?
will i be able to have a strong connection with that?
'eBay.ca: Wifi 802.11 g Router And Strong Yagi N Type Antenna (item
150176202865 end time 02-Nov-07 21:12:10 EDT)'
(http://tinyurl.com/2puc3y)

And do you think it's going to help if i also buy this:
'eBay.ca: Indoor WiFi WLAN Wireless LAN Booster Amplifier Router (item
270181444548 end time 03-Nov-07 11:00:00 EDT)'
(http://tinyurl.com/37275h)

so Thanks everyone !


------------------------------------------------------------------------
View this thread: http://www.wirelessforums.org/showthread.php?t=31292
http://www.wirelessforums.org

"BANGBANGMAX" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
>
> Hi everyone, i'm new here, i'm from Quebec(canada), so i'm french but i
> can speak english. I do some mistakes so sorry for that...
>
> I live in an appartement(8th floor) and there's a big neighborhood at
> about 600meters of my windows. I know there are some wifi signals in
> this neighborhood and i wanted to buy this antenna to receive some of
> those signals... my question is really simple... does it really work?
> will i be able to have a strong connection with that?
> 'eBay.ca: Wifi 802.11 g Router And Strong Yagi N Type Antenna (item
> 150176202865 end time 02-Nov-07 21:12:10 EDT)'
> (http://tinyurl.com/2puc3y)
>
> And do you think it's going to help if i also buy this:
> 'eBay.ca: Indoor WiFi WLAN Wireless LAN Booster Amplifier Router (item
> 270181444548 end time 03-Nov-07 11:00:00 EDT)'
> (http://tinyurl.com/37275h)
>
> so Thanks everyone !
>

I don't think any reasonable length Yagi will give you +24 dBi - - maybe
around +17 dBi for a 21 element Yagi, but you usually have to go to a dish
to get +24 dBi - - it provides a large capture area.

About the Router, "Booster Amplifier" may be someone's hype since power
output is hard to measure. If you have something to compare it to, then
results will tell if there's any boosting going on. Otherwise, I would
suggest just getting a new Router that you can return if not satisfied.

BANGBANGMAX <(E-Mail Removed)> hath wroth:

>I live in an appartement(8th floor) and there's a big neighborhood at
>about 600meters of my windows. I know there are some wifi signals in
>this neighborhood and i wanted to buy this antenna to receive some of
>those signals... my question is really simple... does it really work?
>will i be able to have a strong connection with that?
>'eBay.ca: Wifi 802.11 g Router And Strong Yagi N Type Antenna (item
>150176202865 end time 02-Nov-07 21:12:10 EDT)'
>(http://tinyurl.com/2puc3y)

I don't believe that thing has 24dBi gain. The picture is
intentionally distorted to prevent the average user from calculating
the length of the antenna. However, I can make a guess by counting
the number of elements (17) by approximately 1/4 wave at 2.4GHz
(3.13cm) to yield an overall length of about 55 cm. No way is an
antenna that short going to have 24dBi of gain. 14dBi is more
realistic. For example, see:
<http://www.mfjenterprises.com/products.php?prodid=MFJ-1800>
which is roughly the same length and number of elements but only
advertises 15dBi gain. They lie.

I just noticed that the antenna on eBay does not have a reflector
element behind the driven element. That will work, but not very well.

Incidentally, to get 3dB more gain out of a yagi, you need to *DOUBLE*
the length. Assuming the MFJ antenna is the advertised 15dBi gain and
is about 45 cm long, a 24dBi antenna would be approximately 360 cm
(141 inches) long.

>And do you think it's going to help if i also buy this:
>'eBay.ca: Indoor WiFi WLAN Wireless LAN Booster Amplifier Router (item
>270181444548 end time 03-Nov-07 11:00:00 EDT)'
>(http://tinyurl.com/37275h)

No. Amplifiers cause other problems. You end up with an improved
transmit range, but no improvement in receive range. Everyone can
hear you, but you can't hear anyone's replies. That's not a problem
with antennas, where the gain is (usually) symmetrical between
transmit and receive.

--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

BANGBANGMAX <(E-Mail Removed)> wrote in
news:(E-Mail Removed):

>
> Hi everyone, i'm new here, i'm from Quebec(canada), so i'm french but i
> can speak english. I do some mistakes so sorry for that...
>
> I live in an appartement(8th floor) and there's a big neighborhood at
> about 600meters of my windows. I know there are some wifi signals in
> this neighborhood and i wanted to buy this antenna to receive some of
> those signals... my question is really simple... does it really work?
> will i be able to have a strong connection with that?
> 'eBay.ca: Wifi 802.11 g Router And Strong Yagi N Type Antenna (item
> 150176202865 end time 02-Nov-07 21:12:10 EDT)'
> (http://tinyurl.com/2puc3y)
>
> And do you think it's going to help if i also buy this:
> 'eBay.ca: Indoor WiFi WLAN Wireless LAN Booster Amplifier Router (item
> 270181444548 end time 03-Nov-07 11:00:00 EDT)'
> (http://tinyurl.com/37275h)
>
> so Thanks everyone !

I tend to agree with Jeff Liebermann on this one.

Are you looking for a router & antenna, or just an antenna ?

You can get a 'real' 24dBi grid for $55 US. (Don't know what the
shipping/duty to Canada would be.)

http://www.hyperlinktech.com/web/ant...irectional.php

On Thu, 01 Nov 2007 19:14:36 -0700, Jeff Liebermann <(E-Mail Removed)>
wrote:

>I don't believe that thing has 24dBi gain.

Just for fun, I decided to run a simple simulation of a mythical 24dBi
yagi. See:
<http://www.k7mem.150m.com/Electronic_Notebook/antennas/yagi_vhf_quick.html>
The result was 4.2meters (14ft) long monster antenna with 101 elements
Yikes. No wonder nobody sells a real 24dBi yagi.

The beamwidth worked out to about 7.5" degrees in both axes which is
slightly wider than a dish with the same gain.

The parameters I used were:
Freq: 2400Mhz
Gain: 22dBd (same as 24dBi)
Reflector: Per DL6WU
Director: Per DL6WU
Metal Boom (bonded)
Boom Dia: 5mm
Driven: 1mm dia
Parasitic: 1mm dia

Drivel: I actually did build an ultra long 2meter (146MHz) antenna
that was about 25 ft long for a hidden transmitter hung. It was two
pieces of twisted polypropelene rope, with 1/2 wave (38") pieces of
electrical wires suspended between the two ropes. The ropes were then
hung between a tree and a telephone pole. It worked great. I suppose
someone could buld something similar, with 101 elements, and actually
build a 14ft long 2.4GHz rope ladder yagi.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558 (E-Mail Removed)
# http://802.11junk.com (E-Mail Removed)
# http://www.LearnByDestroying.com AE6KS

Hey guys, with these links to an ebay site I am pretty sure he is just
looking for your ebay account info. You better check to see if you can still
log in and change all your passwords for ebay and paypal

BANGBANGMAX wrote:
>Hi everyone, i'm new here, i'm from Quebec(canada), so i'm french but i
>can speak english. I do some mistakes so sorry for that...
>
>I live in an appartement(8th floor) and there's a big neighborhood at
>about 600meters of my windows. I know there are some wifi signals in
>this neighborhood and i wanted to buy this antenna to receive some of
>those signals... my question is really simple... does it really work?
>will i be able to have a strong connection with that?
>'eBay.ca: Wifi 802.11 g Router And Strong Yagi N Type Antenna (item
>150176202865 end time 02-Nov-07 21:12:10 EDT)'
>(http://tinyurl.com/2puc3y)
>
>And do you think it's going to help if i also buy this:
>'eBay.ca: Indoor WiFi WLAN Wireless LAN Booster Amplifier Router (item
>270181444548 end time 03-Nov-07 11:00:00 EDT)'
>(http://tinyurl.com/37275h)
>
>so Thanks everyone !
>
>------------------------------------------------------------------------
>View this thread: http://www.wirelessforums.org/showthread.php?t=31292
>http://www.wirelessforums.org

Then again maybe not...

Sorry about that, but I did hit one in the vista forum that was using the
same type tinyurl link that was an account info grabber. now that i viewed
the pages it looks legit. Sorry again.

flyercan wrote:
>Hey guys, with these links to an ebay site I am pretty sure he is just
>looking for your ebay account info. You better check to see if you can still
>log in and change all your passwords for ebay and paypal
>
>>Hi everyone, i'm new here, i'm from Quebec(canada), so i'm french but i
>>can speak english. I do some mistakes so sorry for that...
>[quoted text clipped - 18 lines]
>>View this thread: http://www.wirelessforums.org/showthread.php?t=31292
>>http://www.wirelessforums.org

"Jeff Liebermann" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> BANGBANGMAX <(E-Mail Removed)> hath wroth:
>
> >I live in an appartement(8th floor) and there's a big neighborhood at
> >about 600meters of my windows. I know there are some wifi signals in
> >this neighborhood and i wanted to buy this antenna to receive some of
> >those signals... my question is really simple... does it really work?
> >will i be able to have a strong connection with that?
> >'eBay.ca: Wifi 802.11 g Router And Strong Yagi N Type Antenna (item
> >150176202865 end time 02-Nov-07 21:12:10 EDT)'
> >(http://tinyurl.com/2puc3y)
>
> I don't believe that thing has 24dBi gain. The picture is
> intentionally distorted to prevent the average user from calculating
> the length of the antenna. However, I can make a guess by counting
> the number of elements (17) by approximately 1/4 wave at 2.4GHz
> (3.13cm) to yield an overall length of about 55 cm. No way is an
> antenna that short going to have 24dBi of gain. 14dBi is more
> realistic. For example, see:
> <http://www.mfjenterprises.com/products.php?prodid=MFJ-1800>
> which is roughly the same length and number of elements but only
> advertises 15dBi gain.

looking at the MFJ antenna -
it would be interesting to measure the length
of a couple of the elements,
and the inter-spacing of the elements...

and then compare that to the photo of the eBay antenna
to maybe get an idea of what freq that are using ??

physics is physics - the wavelengths don't change on eBay -