ScreenOS Firewalls (NOT SRX)
ScreenOS Firewalls (NOT SRX)

SSG20 WLAN - Weak Wireless Signal Issue

09.02.09   |  
‎09-02-2009 09:05 AM


I'm trying to solve a wireless signal issue with our SSG20 WLAN.  We have a relatively small open-spaced office and our servers and Juniper firewall are in a closet.  Because of an initial weak signal when we first set it up, I purchased a Juniper omnidirectional antenna and 30" Juniper Low Loss RF CABLE RP, TNC CONNECTOR, plugged the cable/antenna into port B and stretched the cable/antenna from the server room out to the main reception area.  Also, from the Web Console I changed the antenna for both WLAN0 and WLAN1 to Antenna B.  This worked great until about 2 months ago.  Suddenly, the signal is very weak and the connection drops when you move more than 20 feet away from the antenna.  In fact, if I change the Antenna in the web console to Antenna A (the antenna that is on the firewall box), the connection is slightly stronger than Antenna B.  Overall, the connection is just as weak as before I installed the cable extension and omnidirectional antenna. 


Juniper has replaced the firewall and we've updated the firmware but the connection is still weak.


Not sure what else to do.  Juniper won't replace the antenna and cable even though it is their product, and we really don't want to spend another $500 on a new cable/antenna not knowing if that will fix the issue.  I'm thinking of buying some sort of wireless amplifier or booster but I'm not sure what is compatible with the SSG20. 


If anyone has some suggestions on what to do I'm all ears.  Thank you!

ScreenOS Firewalls (NOT SRX)

Re: SSG20 WLAN - Weak Wireless Signal Issue

09.02.09   |  
‎09-02-2009 01:30 PM

Hi David,


I think you've got a damaged antenna. The connectors are extremely fragile in all of those things and the center pins especially have a tendency to break. 


Don't tell anyone I told you this* but any of the consumer grade external antennas will work - should be $100 or less. I also find that small patch (directional) antennas almost always work better than omnis because - even when you need an omni, the coverage envelope is never a perfect sphere. Directional antennas aren't nearly as directional as you might think, esp the less expensive ones.


You also probably want to turn off the extra antenna:


(WebUI) Wireless > General Settings: Select A or B from the Antenna Diversity drop-down list, and
then click Apply.
(CLI) set wlan antenna { a | b }





*Smiley Happy