[FADCA] VHF/UHF PACKET RADIOS EVALUATED AT 9600 BAUD

[Aa4mi at aol.com]

RADIOS AND TNCS FOR USE IN WINLINK 2000 NETWORKING
 
VHF/UHF PACKET RADIOS EVALUATED AT 9600 BAUD
 

Many thanks to Mike Tracy, KC1SX, ARRL Lab, August 20. 2004
and bud  Thompson, N0IA from May 2005, QST.
 
The information provided is a valuable insight into 9.6kb-ready  radios.
 
However the information, though valuable, is not user-friendly.
 
The mathematical notation used to explain Bit Error Rate (BER) is expressed  
in 3 different scales. Thus the casual user cannot quickly evaluate their  
current 
equipment nor decide on the new/upgrade equipment they should  pursue.  This 
is an apples, oranges and grapefruit presentation of  numbers which must be 
converted to a "common base" to be fairly and quickly  used.  
 
I have made this effort on your behalf to quickly determine "common base"  
equipment parameters.
 
Also in my evaluation, I have used the poorest SINAD measurement to see  
"how best" the equipment performs under the "worst" (-12db.)  conditions.  
Anyone can 
easily see that under the optimum favorable  conditions, all equipment 
"performed well".  
 
However that is exactly "not" what we are looking for in quality  thruput.  
Seldom 
do we get "optimum conditions" under emergency  conditions.  On the contrary, 
they are, in reality, the worst of  conditions is the norm.
 
Finally I have used the RX BER instead of the TX BER information because of  
the 
commonly used adage that "if you can't hear them, you can't work  them".  
This 
established criteria has been proven over many years in  common 
communications 
practice.
 
Further, it is up to you, the user, to determine the cost of each piece of  
equipment.
The prices vary from different sources i.e. retailers, hamfests,  ebay, swap 
nets, etc.
 
The ultimate decision is based upon lowest RX BER per dollar.  That is  to 
say if a 
BER is 25 and the equipment is $400 versus a BER of 30 and $250,  you can 
readily see 
that the additional lower BER difference of 5 is not  worth the additional 
money.
 
If however your budget is unlimited, go for the best.
 
73,
Carl, AA4MI
email: _aa4mi at arrl.net_ (mailto:aa4mi at arrl.net)