[Namaste-dev] My reading of the latest Link Analysis

Bob McGwier rwmcgwier at gmail.com
Mon Jun 30 17:34:36 PDT 2008


 

On the desirability and need for FH-CDMA,  I am in some doubt.  When we left
San Diego in 2006,  we had decided that the spacecraft would announce
unoccupied channels and the user terminal would "pick one at random".
This relieves the major sources of interference does it not?   Since FH-CDMA
is designed to mitigate interference and the narrow band channels on the
uplink are almost surely noise and not interference limited the FH-CMDA
seems an unnecessary complication.  Do we have any evidence at all that we
actually need this interference mitigation?  

 

Even if we are worried about malicious interference,  it seems hard to
believe a malicious interferer can take out sufficient number of channels to
be more than an irritant without the expenditure of gobs of power.  I guess
I can be convinced but I am reluctant to entertain it without a serious
argument to support it.  Given that all of this is a software defined radio
as shown in the KB5MU block diagram,  we can change it later or add it so
long as the design of the transmitter on the ground will admit either
modulation.

 

Bob

 

 

ARRL SDR Working Group Chair, AMSAT VP Engineering.

Member: ARRL, AMSAT, AMSAT-DL, TAPR, Packrats,

NJQRP, QRP ARCI, QCWA, FRC.

"Trample the slow ....  Hurdle the dead"

 

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