George Hardesty

Jul 212012
 

dBi  dB(isotropic):  The forward gain of an antenna compared with the hypothetical isotropic antenna, which uniformly distributes energy in all directions. Linear polarization of the EM field is assumed unless noted otherwise.

dBm  dB(mW): Power relative to 1 milliwatt. When used in audio work the milliwatt is referenced to a 600 ohm load, with the resultant voltage being 0.775 volts. When used in the 2-way radio field, the dB is referenced to a 50 ohm load, with the resultant voltage being 0.224 volts. There are times when spec sheets may show the voltage & power level e.g. -120 dBm = 0.224 microvolts.

“dBm” is used to compare against watts.  There is no direct correlation between watts and dBi.  dbm is logarithmic and mw is linear.

The term “dB” is not a reference but is rather a method and a measurement standard.  dB must be used against a standard, hence “dBm” is used to compare against watts…

 Posted by at 12:40 pm Frequency Bands: LTE, GSM, WiMax & WiFi 802.11 standards Tagged with: , ,  Comments Off on dBi dB, dBm dB(mW): Defined & explained
Jul 202012
 

Comment from customer:

As a side note I purchased an ALFA AWUS036NH a couple of years ago from your folks and I still use it on my laptop today. I am amazed at how far it will pull in networks and connect to them. Great little unit. Thanks for your time and attention.    -Mike Hall / Ontario Canada

 Posted by at 4:36 pm Alfa AWUS036NH Tagged with:  Comments Off on Alfa AWUS036NH performance over years
Mar 082012
 

R36 cannot be properly configured on Macs (at least not on Mac OS 10.7 using Safari which is the only Mac we tried). On this Mac, the R36/AWUS036H combo will detect no networks in the Site Survey area even after rescan. On a Windows PC, it will detect just fine. Oddly, the older firmware version of R36 from last fall can be set up just fine on the same Mac so their latest firmware must have some kind of a compatibility issue with the Apple web browser which prevents it from displaying properly.

 Posted by at 3:24 pm Alfa R36, Mac compatibility Tagged with: ,  Comments Off on Alfa R36 & Mac: Not compatible
Feb 292012
 
Please note that the following is old information – referring to old versions of the R36 firmware:
After about 80 minutes of testing on different configurations the results are:
1.2.0.7 is Only compatible with the AWUS036H
1.3.0.0 is Only compatible with the AWUS036NH & AWUS036NHR – NOT AWUs036h
with the 1.3.0.0 on it, the AWUS036H will not even power up, so we wouldn’t recommend upgrading to it cause it is irreversible .
 Posted by at 12:35 pm Alfa R36 Tagged with:  4 Responses »
Jan 172012
 

Install AWUS036H onto Mac OS 10.7

1) Starting your Mac with 32-bit
Option 1: Start up key combination (for current startup only)
You can start up with the 32-bit kernel by holding the keys 2 and 3 simultaneously during startup.Option 2: On-disk setting (persistent)
To select the 32-bit kernel for the current startup disk, use the following command in Terminal:
sudo systemsetup -setkernelbootarchitecture i386
Restart your computer.2) Download the AWUS036H driver from Alfa’s website:
If you are downloading from another link be sure you are downloading 8187L, NOT 8187B since it will not work in this case.
3) Unpack the ZIP file using a program like Zipeg. Once unpacked, double-click the install.pkg file to begin the installation and proceed through the installation as you normally would.
Restart your computer.4) Once rebooted, open up the Terminal window. Then type in the commands listed below in that order (leave out the #, they are simply indicators of commands). When using sudo you will be prompted for your password, so be prepared to enter it.
# cd /System/Library/Extensions
# sudo chmod -R 755 rtl8187l.kext
# sudo chown -R 0:0 rtl8187l.kext
# exit
Close the Terminal window and once again reboot your computer.5) Plug in your device via the USB connector. Then open up the Terminal once more and type:
# sudo kextutil -t -v /System/Library/Extensions/rtl8187l.kext
# exit
Close Terminal.6) At this point the Mac Network window will open and ask if you want to accept a new interface. Select accept, DO NOT ADJUST ANY SETTINGS JUST YET. Realtek should then open and assign an IP address to your Alfa device.That’s it! You’re done. Go over to the “Available Network” tab and choose the network you want, and then click connect. Input the password if necessary. And you’re connected! You can shutdown the Apple AirPort service (optional) and make your Alfa device your primary wireless interface.
TROUBLESHOOTING
– Check to make sure the chipset is RTL8187L, NOT RTL8187B, as this chipset requires a different driver and is not covered in this guide although the same basic steps should in fact work.
– Check your spelling. After typing RTL8187L over and over all of the letters and numbers seems to jumble together. Make sure you have the correct spelling.
– In Terminal, type:
# sudo rm /System/Library/Extensions.mktext
This will reset all of the kept caching done by OS X. Reboot your computer.
 Posted by at 5:54 pm Mac compatibility Tagged with:  Comments Off on Alfa AWUS036H (CU5) now supports MAC OS 10.7 version
Nov 152011
 

We’ve had two cases in which Linux users told us that their OS or WiFi device management software indicated that the chipset was Both of the users who told us that their OS or software told them that their AWUS036H was a RTL8187B chipset. We feel all but certain that this is a bug of the Linux OS or software that they are using: RTL8187B and RTL8187L are similar chipsets and the OS or software probably was not updated to distinguish between the two.

 Posted by at 5:20 pm Chipsets, Compatibility, Linux compatibility Tagged with:  Comments Off on Alfa AWUS036H Linux users’ confusion re. chipset
Sep 252011
 

Realtek has announced that they are discontinuing their support for RT8187L chipset: There will not be any driver updates for future operating systems for RT8187L:

WINDOWS 7 will be the last Windows version that is compatible.

MACINTOSH:  Alfa AWUS036H and AWUS036EW are not compatible with Mac OS 10.6.7 and later version. Alfa has verified that AWUS036NH, AWUS051NH, AWUS036NHR and AWUS036NEH are compatible with Mac OS 10.6.7 and later versions.

 Posted by at 6:03 pm Alfa AWUS036H, Alfa AWUS036NH, Chipsets, Linux compatibility, Mac compatibility, USB WiFi adapters: Alfa, WiFi card specs Tagged with: , ,  Comments Off on Alfa USB adapters based on RealTek RT8187 chipset: Driver not available for any future operating systems
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