[amsat-bb] Re: [APRS] Golden Packet 20 July gaps: NH, MA, NY, NC/TN

Robert Bruninga bruninga at usna.edu
Wed Jul 3 10:15:27 PDT 2013

> WHy only those 3 radios?
> Cannot any 2m rig with any [TNC] or one of their other devices, or even
a venerable kpc3+, digipeat?

Yes, but it is all about risk.  Generallly, 90% of all packet radio/TNC's
on the air are misconfigured in someway or another.  It has been this way
for the last 40 years of packet..., and although they "work" some suffer
as much as 20 dB or more loss of weak signal performance (but no one
notices because it "works").  Most are just plug-n-play till it "works"
with no attention to levels, deviation, clipping, compression, skew,
balance, bandwidth, pre-and de-emphasis, etc.

When trying to do a one-time long-chain national test, the risk of a
single station not meeting 100% optimum settings and causing the whole
test to fail is just too high.  The kenwoods may not be the perfect of any
of the above settings, but they are factory consistent and beyond the
owners abilty to screw up.  And they are very sensitive to each other,
able to decode each other's packets down to only 3 bars (about -116 dBm)
where as some TNC's and Trackers must have 60 dB over S9 full scale dead
full quieting signals before they are decoded.  Yet their owners claim
"the work"...

> All  you need is an APRS radio that can digipeat (D72, D700, D710) and
> a power source and antenna. (and Know how to operate it!)

And said another way, These radios all use a flat passband and most all
TNC/Radio combos use pre and de-emphasis.  I'm not saying one is better
than the other, but we must have consistency.  Many Many dB of weak signal
performance is lost when one tries to talk to the other.



Thanks! & 73, KD4E.com

David Colburn - Nevils, Georgia USA

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