[aprssig] Draft Copy of Thesis on APRS

Kenneth Finnegan kennethfinnegan2007 at gmail.com
Mon Dec 8 16:23:59 CST 2014

An amazing response so far from all of you on and off the APRSsig. I
could not have hoped for half of the detailed feedback I've gotten

To address/repeat a myriad of issues pointed out so far:

* Bell 202 adoption likely had more to do with the availability of
Bell 202 chipsets than second-hand modems. I should make that clear.

* I know that AX.25 has been traditionally tied to HDLC, but I grouped
HDLC with Bell 202 to encourage anyone designing new modems under
AX.25 to possibly select bit stuffing / framing protocols with better
characteristics than HDLC.

* The 10 minute FCC ID is only required during an exchange, not
continuously. The largest issue with depending on the AX.25 frame is
that many stations don't use FCC callsigns for their AX.25 address. I
don't have a strong feeling on whether stations should be regularly
using tactical callsigns, but they do need to somehow stay legal.

* Amateur radio has been around much longer than three decades.
Amateur PACKET radio has only been around since 1980.

* The correct term for what APRS is often used for is Automatic
Vehicle Location (AVL)

* I should make it more clear what I mean when I discuss a TNC or Tracker
 - TNCs are embedded devices providing a radio interface. TNCs
developed before APRS obviously don't support APRS, but I group
devices like the Argent Data OT3m in the category of "TNCs," so I
don't think my use of the term is invalid.
 - Many of you consider Trackers to mean TX-only. I'm aware that deaf
Trackers are popular in APRS, but I consider Trackers to include any
mobile APRS nodes. I personally do not condone deaf trackers, and
won't revise my figures to indicate that I do. I hope that you forgive
me for pushing that as part of my agenda in writing this document.

* This document is FAR from comprehensive. I am aware that there are
many variants of APRS using UHF backhauls, 30m HF, IP multicast, etc.
If I tried to mention all of these, my thesis would be ever more
scattered and disjointed than it already is. I'm painting the most
popular modes of APRS with broad strokes here. The job of fully
documenting APRS is sadly beyond the scope of me earning my masters

* The block diagrams for trackers / digis / igates clearly need some more work.

* I only mentioned the KPC3 dedup bug because it directly impacted the
evolution of APRS. I'm aware of MANY other common bugs involving the
KPC3 and other TNCs/radios. None of them have had as notable of an
impact on the definition of APRS, and I've steered clear of attempting
(and inevitably failing) at collecting a comprehensive list of TNC
errata. Trust me, I'm as tired of writing "beyond the scope of this
work" as you are of reading it.

* Thank you thank you thank you for all the small
grammar/spelling/English fixes.

I will be revising this document before submitting a final draft to
the Cal Poly library for my degree, so look for an eventual
replacement to what you currently have.
Kenneth Finnegan, W6KWF

On Sat, Dec 6, 2014 at 3:43 PM, Kenneth Finnegan
<kennethfinnegan2007 at gmail.com> wrote:
> Ladies and Gentlemen,
> I am preparing to defend my thesis at Cal Poly SLO next week, and
> thought some readers of this list might enjoy seeing a draft copy of
> my thesis. I'd appreciate feedback on any glaring quantifiable errors
> in the document.
> http://thelifeofkenneth.com/files/draft_finnegan_aprs_thesis.pdf
> I'd like to say once again thanks for all the help offered by many of
> you as I've worked on my thesis for the last year.
> If you happen to be in the SLO area, my defence will be on Friday Dec
> 12 at 9am in the EE department conference room, and you are welcome to
> attend.
> --
> Kenneth Finnegan
> http://blog.thelifeofkenneth.com/

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