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[aprssig] Local Event using RELAY?

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Thu Mar 31 12:19:54 UTC 2005


	From: John Kraus
	Posted At: Wednesday, March 30, 2005 10:21 PM
	Subject: RE: [aprssig] Local Event using RELAY?
	At 09:00 PM 3/30/2005, you wrote:

		Ah ha!!!  The light came on for me!  Henk and I are
talking apples to Pete's
		oranges...   Apples and Oranges...

	This discussion is silly. 
	The key is to understand that the primary factor that influences
whether a station is CSMA or ALOHA is, at its most basic, simply a
matter of antenna height or more succinctly HAAT.  
	If a station is running near a unity gain antenna at less than
10 ft above ground it is almost always functionally ALOHA.  The
exception being when it is on a high site or is located in a station
dense area.
	Conversely if it is located at 300ft HAAT or on a mountain it is
mostly CSMA. 

I did not receive Wes's email via TAPR so I will respond to his email as
a SIG post in my next post.  As to your statements above, they are
incorrect.  Reread my original post.  That station with the low HAAT is
most definitely running CSMA to over 90% of the packets being generated.
Actually, it is running closer to CSMA for 99% of the packets on the
frequency when you take the time to do the math and take into
consideration what a station can _hear_ versus what a station can
_decode_.  This is a very important distinction which your statements do
not take into account.


Pete Loveall AE5PL
mailto:pete at ae5pl.net 

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