With the proliferation of RF consumer devices, the Industrial - Scientific - Medical (ISM) bands are becoming quite crowded. Devices including microwave ovens, cordless telephones, toys, wireless routers, and so on all have a presence in the ISM bands. Although many new devices are spread spectrum as opposed to narrow band and some use frequency hopping, there can still be interference issues due to the crowded nature of ISM.
When there is a problem, it is handy to have the ability to view the spectrum. For this you need a RF spectrum analyzer.Unfortunately, RF Spectrum Analyzers, such as those manufactured by Anritsu, are prohibitively expensive and beyond the means of many. However, there are low cost solutions available. This project uses Fitlet in conjunction with the Ubiquiti Airview Series of Spectrum Analyzer USB Dongles to form a budget priced ISM band spectrum analyzer. The Ubiquity devices give Fitlet capabilities in the 900 MHz and 2400 MHz bands.
Anritsu = $$$$$ = €€€€€
- ANR_MS2721A.jpg (13.41 KiB) Viewed 6991 times
Hardware
1. Fitlet
2. Ubiquiti Airview9 900 MHz USB Dongle
3. Ubiquitu Airview2 2400 MHz USB Dongle
- Airview Hardware.jpg (150.65 KiB) Viewed 6990 times
Software
For Linux, you will need a copy of Ubiquiti's AirView-Spectrum-Analyzer-v1.0.12.tar.gz package. Unfortunately, Ubiquiti no longer offers this software. Fortunately, it is available from Archive.org at the following link.
http://web.archive.org/web/201307031013 ... /downloads
Install all the required software as follows:
Openjdk-7-jre
Use the following commands:
1. $sudo apt-get install openjdk-7-jre
2. $java - version (if this returns java version "1.6.......", you will need to change to version 1.7 - use command 3, other wise if version is 1.7, skip command 3)
3. $sudo update-alternatives --config java
There are 2 choices for the alternative java (providing /usr/bin/java).
Selection Path Priority Status
------------------------------------------------------------
0 /usr/lib/jvm/java-6-openjdk-armel/jre/bin/java 1057 auto mode
1 /usr/lib/jvm/java-6-openjdk-armel/jre/bin/java 1057 manual mode
* 2 /usr/lib/jvm/java-7-openjdk-armel/jre/bin/java 1043 manual mode
Press enter to keep the current choice[*], or type selection number:
Select 2 for Java-7.
Airview Spectrum Analyzer
Use the following commands in the directory of your choice:
1. $tar xzf AirView-Spectrum-Analyzer-v1.0.12.tar.gz
2. $cd AirView-Spectrum-Analyzer-v1.0.12/
3. $dir
airview-3rdpartylibs.jar airview-o.jar airview.sh librxtxSerial.so log
Here is where things get just a little bit tricky. Make special note of the linux serial device shared library file librxtxSerial.so. As installed, it is specific to x86, 32 bit architecture, and it will not work with Fitlet's 64 bit Mint OS. Therefore, you must manually replace librxtxSerial.so with a 64 bit version. If you don't replace the file, the software endlessly searches for and never finds the Airview dongle. Fortunately, in my case, the required library file already exists on Fitlet. Replace the file as follows:
1. Navigate to: /usr/lib/jni
2. Locate the file: librxtxSerial-2.2pre1.so
3. Copy librxtxSerial-2.2pre1.so and paste it into the directory where you extracted/installed AirView-Spectrum-Analyzer
4. In your Airview directory/folder, delete the existing 32 bit librxtxSerial.so
5. Rename librxtxSerial-2.2pre1.so to librxtxSerial.so
Caution do not copy the librxtxSerial.so found in /usr/lib/jni. It is a symlink which points to librxtxSerial-2.2pre1.so. If you copy and paste the librxtxSerial.so, the symlink is broken and Airview will never find the Airview dongle. You must follow the procedure listed above.
Now you are ready to run AirView-Spectrum-Analyzer using the following script command:
$./airview.sh