Re: 2.4 Ghz 24dbi Grid Antenna No Signal!!

On Sat, 10 Nov 2007 18:24:19 -0500, kr3
<kr3.2zuvoj@no-mx.wirelessforums.org> wrote:

>Iv just bought a 24dbi grid antenna with 10 meters of LLC400 Coxial
>cable from here :'eBay Seller: wifilink uk: Networking, Computing items
>on eBay.co.uk'
>(http://search.ebay.co.uk/_W0QQfgtpZ1...ZwifilinkQ5fuk)

Does it look assembled like the one in the photograph? I've seen them
mis-assembled with the feed rotated 90 degrees with respect to the
reflector. That doesn't work.

>I am using a 200mw pci card to connect the antenna to bought from
>here:'Find 200mW Wireless WiFi G/B Desktop PCI Card Jack & Antenna on
>eBay within PC Cards, USB, Adapters, NICs, Wireless Networking, WiFi,
>Networking, Computers Networking (end time 17-Nov-07 00:00:00 GMT)'
>(http://tinyurl.com/2uaonw)

Ok, the card has an RP-SMA connector.

>The problem is that i am just about catching 2 or 3 networks even less
>than what I was catching with my USB cantenna which only cost me 20
>pounds whereas this ended up costing me 70 pounds. So why is my signal
>so low? What should the range really be the range of my antenna?

The range depends on where you point the antenna. You should get more
range but not to the side or back of the antenna. If you're just
pointing the antenna is some random direction, you'll only hear
stations that are perhaps within +/- 5 degrees of where you point the
antenna. If you want to check *AREA* coverage, you have to rotate the
antenna in a full circle, slowly.

>I am using a low loss cable which has a loss of 0.22db per meter so the
>10 meter cable shouldn't be a problem should it?

I'm suppose to guess the coax type. I probably could, but I'm lazy.
So, I'll guess. Is it LMR-400? Did you make this cable yourself, or
did you buy it from a reputeable vendor? Is there a pigtail involved?
You might want to check for construction errors on the coax, such as a
short to ground or a missing center pin. 2.2dB of loss will be
noticeable but far from fatal.

There should also be a pigtail involved to go from the LMR-400 to the
small RP-SMA connector. Have you checked it? If there's no pigtail,
and you built or bought an RP-SMA connector to go directly into your
PC card, there's your problem. Those connectors last about 30 seconds
after installation thanks to the extreme bending on the RP-SMA
connector. Inspect, and I would not be suprised if it were falling
apart.

>What am I doing wrong ? Please Help ME!! I really appreciatte any
>help!!
>
>Thanks
--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558 jeffl@comix.santa-cruz.ca.us
# http://802.11junk.com jeffl@cruzio.com
# http://www.LearnByDestroying.com AE6KS

Hi,
Thanks for your reply, I really appreciate it. The antenna was not assembled I had to assemble it myself and yes I have assembled properly like the one in the picture. Yes it LMR-400. The cable was bought with the antenna from the seller so that shouldn't really be a problem. yes there is a pigtail involved but from what I can see there are no real errors.
Sorry what is short to ground? No i did not make the RP-SMA connector so that can't be the problem.

????????

Thanks
KR3

On Thu, 15 Nov 2007 06:46:46 -0500, kr3
<kr3.3046e4@no-mx.wirelessforums.org> wrote:

>Thanks for your reply, I really appreciate it. The antenna was not
>assembled I had to assemble it myself and yes I have assembled properly
>like the one in the picture. Yes it LMR-400. The cable was bought with
>the antenna from the seller so that shouldn't really be a problem. yes
>there is a pigtail involved but from what I can see there are no real
>errors.
>Sorry what is short to ground? No i did not make the RP-SMA connector
>so that can't be the problem.

Well, it's a very simple test for continuity in both the coax cable
and the pigtail. Disconnect both ends of the coax cable. Find a
cheap (about $10) DVM (digital voltmeter) and use the continuity
tester to see if you have a connection from end to end for both the
center conductor and the shield. Also check if there is a short
circuit (unwanted connection) between the shield and the center
conductor. If you don't understand the terms, you'll probably need
some local help to show you how to use the DVM. It's not a perfect
test and there are plenty of things that it will not check, but it's a
good start. Anything more will require some expensive test equipment.

Also, visually check for something really dumb. Make sure that the
RP-SMA end actually has the correct polarity center pin installed. The
antenna will screw together with the wrong polarity center pins, but
it won't work.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558 jeffl@comix.santa-cruz.ca.us
# http://802.11junk.com jeffl@cruzio.com
# http://www.LearnByDestroying.com AE6KS