George Hardesty

Jul 152009


Re: ubiquiti SRX 300mW 802.11a/b/g MMCX card
reception issue in Linux. Both OS’s see the card fine. I bought the optional MMCX clip on antenna

For the Linux issue, here’s what our customer had to type in to get it to work (using the external antenna):

“sysctl -w dev.wifi0.diversity=0”

which sets the antenna diversity to 0 (that made all the difference, vast improvement).

From what I’ve been reading there still may be a small issue with some networks not showing up, I’m sure they will correct this with a driver update at some point. The card works quite nice now, and picks up nets with a good signal. Also, I disabled the built in wifi card in my laptop, as I’m sure this was causing interference.

Written by customer: “Brian”

Jul 152009

From customer:   I have used the same signal booster on wrt54gl with excellent results: However, you must use an antenna on the booster of higher-gain than the 2-dBi antenna that comes with the booster: It should be 5dBi or more. We have compatible antennas here:

—–Original Message—–
Sent: Friday, February 29, 2008 10:58 AM
To: George Hardesty

I currently have a Alfa 500mW from you… I’d like to find another solution so I can have multiple machines use it.

I’m looking at your signal boosters.

If I setup the wrt54gl in bridge mode to connect to another wrt will this signal booster provide the same power? Will the linksys wrt54gl be able to reach access points at a further distance like the alfa can?

wrt54gl connects to -> a access point 1/2 mile away to get it’s internet connection.

My local machines in the house will then connect to my wrt54gl that is in the house to get to the internet.

Please let me know if this will work.   Thank You, Justin

ANSWER:  Yes – this will extend the range just as you describe. 

Jul 152009

VERY RECENTLY issued patch for WinXP USB…Fixes problem and speeds USB up considerably…This must be the VISTA version of the drivers since it is still a HOTFIX. Rumour has it that they’ll be releasing a Service Pack for WinXP (SP3) with VISTA-like updates

Run the executable in the UNPACKED directory (only on Windows XP – Any variant: Home, Pro, etc)….reboot..

I suspect that the USB adapters will work better when they share the bus with other USB devices (like portable drives)…

Problem report to which the HotFIX was the answer…

The problems have been reported going back three years….A fairly deep look at it is here:

Generally, the problem has been known as the “delayed write” problem on USB and it causes an inordinate amount of pain and suffering such as corrupted disks….Not exactly what you have in mind as you try to use an external drive to backup your internal one…Microsoft did nothing about this for at least four years.

Jul 152009

[The following was compiled by a Data Alliance customer who approved of the posting of his writings here]:

DOWNLOAD DRIVERS FOR Realtek 8187L chipset (the chipset of the Alfa AWUS036H 1000mW USB adapter):

New drivers (dated 11/16-20) for the Alfa Networks (e.g. Realtek 8187L chipset) USB device have been posted on Realtek’s site (v1293) .

Download page for the older version Realtek 8185L chipset:


The new driver works very well with WinXP (at long last)…I am still using my tweaks (14 in Long and Short Retry Limits), and I am not using the associated client software ( I am still using XP’s “zero configuration utility” – “Use Windows to configure my wireless network settings” box checked)

Throughput has improved – especially in “burst” mode – and the “Site Survey” bug is fixed (thus far has not re-appeared). That bug required the adapter to “restarted” in order to have it find anything sometimes. It seems to be forming connections much quicker as well..

All-in-all – a big improvement over other recent versions – Although the 1207 version is just as stable…It appears that the many bugs which were introduced along the way to the Vista “port” of the driver have been fixed.

These comments are with respect to WinXP – No other OS was tested.

Be sure that you reference/download the 8187L driver and not the others.

Clearly Realtek has been doing quite a bit of work …From 1243 to now has been a real nightmare…or maybe a “Realtek” nightmare would be more accurate.  I think they only have one guy as a developer for the chip.  Fortunately the Vista stuff has caused him to look more carefully at a bunch of the other code.  A review of the comments tells you how serious the problems have been….disconnects, power-management…etc..

There have been quite a few corrections since the 1207 version…And it is clear that recent versions introduced as many bugs as they fixed.

Realtek does not keep older versions around, so it’s always good to stay on top of new versions.

 Posted by at 10:01 am Alfa AWUS036H No Responses »
Jul 152009

It’s difficult to give accurate estimates of range and signal strength, because every situation is different.  

As an example of the difficulty of estimating range:  In situations in which a lot of radio-frequency equipment is in use (such as hospitals, law enforcement, fire station), this RF gear will interfere with WiFi signals and reduce range.

Of course, obstacles of any kind will reduce range, and direct line of sight is the best situation to produce the longest range.   Obstacles adjacent to the line of sight will affect range, though less than obstacles in the line of sight.

Roofs, such as on a porch, pavilian, purgula etc. will also reduce range/signal strength even when you have a direct line of sight.  If you step out from under the roof or pavilian, you will probably see an increase in signal strength.

Jul 152009

 Alfa 1000mW client works on Fedora 7 Linux:

You have to add the line “alias wlan0 rtl8187” to the file /etc/modprobe.conf Then reboot. after booting into the GUI go to System | Administration | Network. New – Wireless – Follow it through.

Alfa compatible profile manager / site survey wizard for linux – Fedora 7.

Open a terminal and type in “yum install wlassistant”

this will then show up under system | preferences as Wireless Assistant.

This information provided by:  Brendon Prole

Jul 152009

 We’re over the moon that we can get one of your Alfas to work over such a wopping distance. If you’d like us to say anything or about any of the other products we have bought from you please let us know.

Sylvan Andrew  Oct. ’07


The 500mw Alfa card with the optional 9 dbi antenna brings in excellent internet connectivity to my sailboat.

Within the next couple of days, will take my laptop and Alfa card (with both the standard and the optional 9 dbi antenna) and see if I can pick up the internet from the furthest points in the Marina.

Roger Freedman – October ’07

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