May, 2010

Amateur Radio — No Comments
23
May 10

Buddistick™ Antenna and MFJ-269 HF/VHF/UHF SWR Analyzer

I recently purchased the MFJ-269 HF/VHF/UHF SWR Analyzer and I have owned a Buddistick™ from Buddipole Antennas for a while. My station does not have a 6M antenna so I wanted to use my new MFJ-269 to configure the Buddistick™ to be resonant (or at least have low SWR) in that band. Specifically I wanted a SWR low enough that I would not have to use an antenna tuner.

Through trial and error I was able to configure the Buddistick™ for SWR of 1.2 on 50.12 MHz. The base of the antenna was mounted at 6 feet from ground level, and antenna length was 68 inches. It was composed of two equal-sized solid pieces (11.25 inches each) and one telescoping piece extended to complete the 68 inches. Counterpoise wire was attached to the antenna base and extended approximately 12 feet and was about 5 feet from the ground at its lowest point.  All of these components are part of the Buddistick™ Deluxe package.

Computers / Unix/Linux Shell — No Comments
10
May 10

Hello World Shell Script

Using the directions from http://www.freeos.com/guides/lsst/ch02sec01.html you can easily put together a quick ‘Hello World’ shell script. What’s shell? It is software that allows interaction between users and the OS (read more at http://en.wikipedia.org/wiki/Shell_(computing)). In general the commands you run at the command line are available to use in a shell script.
#
#Filename: hello.sh
#Programmer: PFP
#Birthdate: 2010-05-10
#Notes: Hello world script.
#
clear
echo "Hello World"
You can enter these few lines by using vi or any other editor on your Linux machine. Be sure to set the file as executable by running chmod 755 hello.sh from the command line.  To execute the script you simply type ./hello.sh at the command line.

Computers / Perl — No Comments
9
May 10

Download a Web Page with Perl

This is a simple Perl script to download a Web page and display the downloaded text on the screen.
use LWP::Simple;
$URL=http://www.google.com;
$contents = get($URL);
print $contents;