[TowerTalk] Please help me with these questions?

[Jim Lux]

At 08:05 AM 3/10/2005, AHMED, Yaseen wrote:
>Hi Folks!
>I have some queries on some terms pretty simple for you all:
>1.  What is a "Cut off Frequency"?

Depends on the context, but usually refers to the frequency response of a 
filter, specifically, where the response is 3dB down.  Also used a lot in 
waveguide, where there's a "waveguide cutoff frequency", below which energy 
doesn't propagate down the waveguide.

>2. Can anyone explain Direct Sequence Spread Spectrum (DSSS) in detail?

A very good textbook on spread spectrum, not requiring extensive analytical 
skills or math knowledge, is R.C.Dixon, "Spread Spectrum Systems", 
published by Wiley.  I think the latest version is 1994, which covers a lot 
of commercial applications.  Earlier versions were focussed more on 
military systems.

>3.  Can any one mail me or show me the link for a ebook on HAM Radio's, 
>Please...?
A good place to start is http://www.arrl.org/

here's some online video presentations:
http://library.thinkquest.org/27887/gather/application/ham_radio.htm

Here's a power point presentation going over the questions on the test (but 
it's not a good "intro to ham radio" )
http://people.smu.edu/arc/tech/tech.ppt

Googling for "Introduction ham radio" turns up a lot of links, some good, 
some bad.

>4. Any one certified as a CWNA here?
>
>Thanks a Lot,
>AHMED