[amsat-bb] APRS on AO27

[Assi Friedman <assib@xxxxxxxxxxxxxxx>]

Hi,
I saw a note suggesting 1200 packet on AO27.
Without talking about the politics of such an experiment,
here are some notes about the technical aspects of it.

The FM repeater on AO27 is a simple audio FM repeater.
It does not have any digital regenerative capability in the mode.
This means that the signal that goes up will hit the bird and bounce back.
The downlink signal resulting will be=signal+noise_up.
This does not take into acount the frequency response of the 
audio path on the bird. In addition to this, the downlink antenna 
is mounted on the side of the bird. This causes the downlink to have
spin modulation too. I think that all of this together will result in 
a very bad success ratio. 
It sounds to me like what an experiment like APRS needs is a buffer on a 
bird that save the last n posits and spits them down upon request by a
gateway or such. Just my 0.02 shekel worth :-)
assi 4x1kx/kk7kx

--------------------------------------------------------------
 Assi Friedman, Deputy Program Manager - ASUSat Program
 Tel: 480-844-1458 (home)
 Tel: 480-965-2474 (ASUSat lab)
 Tel: 480-965-2859 (ASUSat office)
 Fax: 480-965-0277 (ASUSat lab)
 Email: assib@asu.edu
 Home Page: http://www.public.asu.edu/~assib
 ASUSat Page: http://www.eas.asu.edu/~nasasg/asusat/asusat.html
---------------------------------------------------------------
*** NOTE AREA CODE CHANGE FROM 602 -> 480 ***
----
Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org