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From: retzner@ihlpg.UUCP (Retzner)
Newsgroups: net.ham-radio.packet
Subject: Re: General questions on packet
Message-ID: <1392@ihlpg.UUCP>
Date: Thu, 31-Oct-85 10:43:46 EST
Article-I.D.: ihlpg.1392
Posted: Thu Oct 31 10:43:46 1985
Date-Received: Sat, 2-Nov-85 04:37:57 EST
References: <1260@sphinx.UChicago.UUCP>
Organization: AT&T Bell Laboratories
Lines: 56

> 	1)  Where can I get lots of information about it?  The only
> 	      documentation I have so far is the November CQ magazine.  
There have been some "introductory" articles in recent issues of
QST.  Detailed information is available, just not in one place.
Here are some national organizations for possible sources:

	AMRAD
	P. O. Drawer 6148
	McLean, VA 22106-6148

	AMSAT
	850 Sligo #601
	Silver Spring MD 20910
	301-589-6062

	Tucson Amateur Packet Radio (TAPR)
	P. O. Box 22888
	Tucson, AZ 85734-2888

	ARRL
	Newington, CT 06111
> 
> 	2)  What is the maximum size of an AX.25 packet?
> 
AX.25 is limited to 128 bytes of data in a packet.

> 	3)  What plans are there for the next level of network software
> 	      to be add to the basic network layer of error checking 
> 	      packet communications that has been provided by AX.25.
> 
These plans are currently in the works.  There are small groups all
over the country looking into this, some are playing with their own
implementations.  This is one of the main concerns of TAPR now.

> 	4)  Why has the FCC limited H.F. data transmission rates to 300
>               baud?  I'm aware of the the limits on 2 meters and above.
> 
In a word, bandwidth.  Higher baud rates (frequency response) requires
more bandwidth.  More sophisticated modem techniques could cram more
data into the available bandwidth (i.e. 212a), but at higher costs.

> 	5)  I'm particularly interested in H.F. (D.X.) packet radio.  How 
> 	      much success has been made on the long distance bands?  
> 	      I'm aware of the digirepeater capabilities of most of the 
> 	      packet boxes, however I'm thinking more of long distance 
> 	      point to point transmission because of the sacrificed speed
> 	      that digirepeating inherently requires.
> 
There are people using it.  Some computer equipped sites have "gateways"
that connect a VHF TNC to an HF TNC.  Others have experimented with
OSCAR satellites.

Hope this is of some help to the net.

Bill Retzner WB9QXJ
ihnp4!ihlpg!retzner