2.4 ghz range/erp/power prediction ??

I would like to be able to predict 2.4 ghz signal strength in terms of
range/antenna configuration and haven't been able to find an
appropriate formula. I'm trying to predict link strength before I
actually acquire equipment.

I'll assume "perfect" conditions (perfect LOS, perfect antenna
alignment, assume no atmospheric contributions --- yeah, I KNOW...)

For sake of argument, assume 15 dB transmitters, -60 dB receiver
sensitivity for link speed desired, "very" short coax with 3 dB loss,
and 24dB parabolic antennas. Same configuration at both ends of link.

Is my assumption of 6dB loss for each doubling of distance (in meters)
correct?? I'm again assuming that the initial erp is measured at 1
meter.

In this scenario, transmitter erp = approx. 36dB.

So, at 2048 meters, radiated power = approx. -30dB, (and after
receiving antenna's 24-3 dB) the receiver should see approx. -9 dB,
and at 4096 meters it should see -15 dB ?? (sounds a little too good
to be true).

Does this sound even remotely correct? If it sounds right, does
anyone know what the atmospheric "fudge-factor" should be?

If the above figures are even remotely in the ballpark, 802.11g speeds
should be possible at well over 4 miles with the above hardware. Has
anyone personally done this (with g, I mean) and had good success?

On 31/10/03 9:19 am, in article (E-Mail Removed),
"Bubba" <(E-Mail Removed)> wrote:

> I would like to be able to predict 2.4 ghz signal strength in terms of
> range/antenna configuration and haven't been able to find an
> appropriate formula. I'm trying to predict link strength before I
> actually acquire equipment.
>
Try here under the left hand tab called Predictions

http://www.ydi.com/