On Fri, 28 Sep 2001, Brian wrote:
> First of all, I recommend anyone doing any sort of wireless to get your
> ham license or at least browse the material.  Start at www.qrz.com for
> good info.  Lots of EE's hang out on the bulletin boards and stuff too.

I actually studied up for my ham license years ago, but never actually
bothered getting it.  :)

> > I mean, I know that yagi's generally have a wider beam than parabolics,
> > etc, but that's all gleaned from product specifications, not actual
> > information about the antenna.
>
> Yagi has a wider beam and generally higher gain.  Good for hams, bad for
> keeping your wireless net private.

Most Yagi's I see have a generally lower gain than Parabolic Grid's..  but
the wider angle can come in very handy.  :)

> > But, for a specific question: what's the difference between vertical and
> > horizontal polarity on a parabolic?
>
> With a parbolic your antenna (I don't know your exact design) is is either
> a dish or a curved piece of rectangular material.  The driven element (the
> thingie in the center) is usually a piece of metal that's
> oblong (copper pipe works well).  Vertical polarization is if the driven
> element is higher than it is wide, horizontal is if it's wider than it is
> high.  There is also circular polarization, which you can use if you have
> a round coil as the driven element.  Basically for max performance, all
> your antennas should be polarized identically.  The most common is
> vertical since it takes up less "real estate".

I've got a 19dBi parabolic grid that I use for testing.. 'twas cheap.
That's what I figured polarity meant; just thought I'd make sure. :)
Thanks!

-- 
Nate Carlson <natecars at real-time.com>   | Phone : (952)943-8700
http://www.real-time.com                | Fax   : (952)943-8500