[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: STUPID DIGITAL QUESTION



>forth and tell us what working the digital birds do for them....perhaps
>Mike, James and I could be converted.  Perhaps there's something we're

I think the issue is not so much "digital vs analog" but "store and
forward vs real-time". It just so happens that most of the existing
amateur radio satellites that provide real-time service are analog
transponders, and those that provide store-and-forward service are
digital.

But I can conceive of an analog store-and-forword satellite (e.g., a
voice mailbox), and I can certainly conceive of a digital satellite
that provides real-time communications. (It's not like they don't
exist outside of ham radio, but many hams seem to have blinders on
when it comes to technologies not yet in amateur use.)

The RUDAK experiment on P3D is a good example. When it finally gets to
orbit, users will see for themselves just how little antenna it takes
to reliably receive a high speed data stream when halfway modern
digital modulation and coding is used. I expect a lot of eyes will
open to the possibilities.

Bob WB4APR makes a good point about the need to better support
portable and mobile users on our satellites if ham radio is to
continue to have any attraction. Digital modulation and coding, on
either digital or analog transponders, is key to making this happen.

We've reached the practical limits of what analog modulation through
analog transponders can do. The sheer size (some would say
"unwieldiness") of P3D shows that it's time to change. Just don't
assume "digital" can't mean "real time ragchewing", if that's what you
like to do.

Phil
----
Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org



AMSAT Top AMSAT Home