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[aprssig] Solar Powered Digi's and Voice Alert.

Rick Green rtg at aapsc.com
Wed Dec 5 14:16:50 UTC 2007


On Wed, 5 Dec 2007, Robert Bruninga wrote:

> When a local net is activated, the call goes out on Voice alert
> asking everyone to QSY to the local APRS packet channel.
   WHAT???  You're suggesting running a voice Net on the APRS packet 
channel?  Mixing modes like that is bound to be deleterious for all users. 
I thought the idea of voice alert was for infrequent calls and immediate 
QSY.  Any more than that, or even that in a busy area, and you're asking 
for trouble.

>
> 1) The local channel does not have the QRM from out of area, so the 
> channel load drops to only 5% of what it normally is.  This improves 
> APRS reliability by a factor of 20 or more, even low power trackers can 
> Be operating there without being clobbered.
   At first look, that's patently ridiculous.  How can you say that the 
local packet channel will drop to 5% of it's normal activity???  Where's 
all the traffic going?  It'll still have all its normal APRS activity, 
PLUS the out-of-area QRM inserted by your wide-area x-band voice repeater! 
And I don't see a way to easily implement a carrier-sense and holdoff on 
the voice repeater, so it'll be the ultimate channel hog: a highly-placed 
high-powered transmit-only device!

   You'd be better off turning your project around 180 degrees.  144.39 
PL100 input, UHF output.  That way, the local APRS network(s) are 
unaffected, and just those who need and choose to hear the wide-area 
voice alerts can have the capability.

-- 
Rick Green N8BJX

"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."
                                   -Benjamin Franklin





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