[UFO Chicago] Wirelessness in Chicago

[Nate Riffe]

Just now Neil R. Ormos made 15 LEDs in my apartment flash with this:
> On Mon, 25 Mar 2002, Nate Riffe wrote:
> 
> > Just now Neil R. Ormos made 15 LEDs in my apartment flash
> > with this:
> > > Also, the
> > > models for these types of links, and the link budget
> > > analyses based on them, have several fudge factors built in,
> > > which I'm not sure Nate has taken into account.
>  
> > such as...
>  
> > Fade Margin?
> 
> Some models include an "atmosphere factor" and account for a
> number of link impairments; some include factors to account
> for temperature and age related degradation of antenna,
> transmission-line, and RF equipment, etc.  Some models
> include estimates of interference from other similar users
> and from other services.  I'm sure I'm missed a zillion of
> these; I'm not an expert.

Yeah, I've seen those models and played with the numbers a little bit.
However, I've come away from them with the distinct feeling that it's
not worth the hassle, and that for practical purposes there are better
methodologies.  The methodology I'm going to use is to just plan on
having a wide fade margin and if that doesn't cover it, boost the signal
until I'm either at the FCC limit or have a connection.  Failing that,
I'll start tweaking the hardware setup (better cable, fewer obstructions,
etc).

I'm NOT a professional, and I don't care if it shows.

> 
> I don't mean to pick on your analysis, and there's nothing
> wrong IMO with running the numbers.  But RF systems
> engineering is as much an art as it is a science, and unless
> you do extensive experimentation or otherwise acquire an
> understanding of the meaning of the numbers in the
> underlying models, I believe the numbers provide an
> extremely coarse prediction of real-world performance, no
> matter how many significant figures the models may spit out.

Well, I know what a decibel is, and I know that when you gain more of
them and lose less of them, the signal can go further.  And that is all
I need to know at this point.

Now, are you going to continue HECKLING, or are going to build some
goddamn antennas?

-- 
--< ((\))< >----< inkblot@movealong.org >----< http://www.movealong.org/ >--
pub  1024D/05A058E0 2002-03-07 Nate Riffe (06-Mar-2002) <inkblot@movealong.org>
     Key fingerprint = 0DAC F5CB D182 3165 D757  C466 CD42 12A8 05A0 58E0