3 Sep 2008

Z formal systems specification tool and CZT

I recently as part of a systems engineering course had to write a few system specification documents using the Z language. I now had to find a nice way to do this. The Community Z Tools at source forge provided the best and simplest way for me to get things done. They have integrated their tools in to jedit so that it would be very simple for them to get things working.

The instructions at source forge are not exactly straight forward. It seamed to me that I need to download the source and compile from source this is not the case. Just download the czt binary file form source forge and extract. The follow the instructions at http://czt.sourceforge.net/jedit/index.html ignoring the step to download and install the source. Every thing is include in the czt download.

The jedit tool also seams to be a quite useful tool worth a look.

2 Sep 2008

Jawug, wug, and wireless equipment

I recently decide to get involved with the South African Wireless Users Group. So I had to decide on what equipment to uses where and how I was going to connect. It was a really good learning experience. I now know a bit more about the wireless networks, the equipment and types of connections possible.

For equipment I found that Uniterm Direct had the best selection and devices. I will probably end up with an RB433, or RB411 device. The Mikrotik devices have a better routing software and are designed for extream conditions like out doors, or in relativly high heat. These mikrotik devices also allow for power of ethernet, so you can put in them in some really strange places, not have to worry to much about how to power them.

Most standarde wireless routres could do the same thing and a lot of people would use the linksys WRT54g series routers. Those are designed for indoor use and don't do well in your roof or out side in an antenna enclosure.

The only thing I was not sure about was signal quality, strength and my ability to connect to the high sites a round my house. The following articles helped me understand what was going on.
http://wireless.gumph.org/articles/longrangelink.html
and http://www.cisco.com/en/US/tech/tk722/tk809/technologies_tech_note09186a00801c12c2.shtml
and http://www.universalweb.com/CustomCablesUSA/Technical.html. This last one is particularly good at explaining the differences between the different low loss co-axial cables when using antenna.