I have a question about the Antennas.  I have found several companies
offering 900 or 2.4 Spread spectrum  radios for under $100.  The problem I
have found is that any good Yagi or corner reflector antenns is $150 plus.

I have been told that at 900 and especialy at 2.4G, making your own antenna
is quite difficult because of the small wave lengths.

Any insight or comments about making your own antenna or a cost effective
source?

Shawn

-----Original Message-----
From: Jim [mailto:jvpoll@DALLAS.NET]
Sent: Thursday, September 20, 2001 2:30 PM
To: PICLIST@MITVMA.MIT.EDU
Subject: Re: [PIC]: Buffering/Bypassing RS232 handshaking


Some of these systems, properly engineered in a
point-to-point configuration using fixed, gain
antennas (Yagis) mounted on masts/building roof
tops are capable of appreciable range.

It is also a matter of terrain and man made obstacles
as well.

The bottom line is, you won't get 20 miles between
units with unity-gain back-of-the-set antennas - but
equipped with yagis at 50' at each end with no
mountains in between - 20 miles could be expected ...

Jim



----- Original Message -----
From: "Dave Vanee" <dvanee@MECH.UBC.CA>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Thursday, September 20, 2001 12:44 PM
Subject: Re: [PIC]: Buffering/Bypassing RS232 handshaking


> The (very little) documentation I have says the range depends on the type
> of antenna and terrain.  That much is quite obvious, but I agree that 35
> does seem a bit much.  The company's website (www.worldwireless.com) no
> longer mentions the 900 SS Direct (only the Hopper and uHopper).  The
> systems currently offered are rated at 40km(~24m) and 500m.  These numbers
> may be slightly more reasonable, but the 24 is still pretty far.
>
> Dave
>
> On Thu, 20 Sep 2001, Sean H. Breheny wrote:
>
> > Hi Dave,
> >
> > Wow, I wonder how they can claim 35+ miles, since that is way over the
> > horizon unless you have got some serious altitude.
> >
> > Sean
> >
> > At 08:32 PM 9/19/01 -0700, you wrote:
> > >I'm not sure if the modem uses the handshaking to determine R/Tx
changeover.
> > >The PC software will just be the datalogger client software.  I'm using
a
> > >World Wireless Communications 900 SS Direct system.  It is rated at 35+
> > >miles, 4800/9600 bps.
> > >
> > >Dave
> >
> > ---------------------------------------------------------------
> > NetZero Platinum
> > Only $9.95 per month!
> > Sign up in September to win one of 30 Hawaiian Vacations for 2!
> > http://my.netzero.net/s/signup?r=platinum&refcd=PT97
> >
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