[nos-bbs] Collision avoidance

[George (Skip) VerDuin]

Greeting Jay and all others interested in collisions...

I wish to report that Jay's feedback was good "dog food".
This "dog" ate it up and solved the problem at hand.

On Thu, 2006-08-10 at 23:08 -0400, Jay Nugent wrote:

> Greetings Skip,
> 
> On Thu, 10 Aug 2006, George (Skip) VerDuin wrote:
> 
> > As I go deeper into jnos operation, I am now beginning to look in detail
> > at signals on vhf radio. Not by any means the best, but I find
> > "Baudline" fairly useful for that purpose.

Using the tool, I charted a segment of about 5 minutes of air time and
28 transmissions on my part at 1200B.
The other issue of the moment for me was that jnos was in "recovery"
mode on ax.25 and had a significant packet count in queue.
What I found is that my collision issue is gone after applying
parameters per: slottime=7, persist=85, fulldup=off, etc
100%-no collision / 60%-long wait / 40%-apply formula / 14%-shortest, /
14%-tier#2 / ...
Just like the text book - jnos and Kan 9612 are working together just
fine...
And I guess I'm no longer the "bad guy" in the neighborhood at least for
the signals I can hear...

Other things I found are:

      * Other stations do step on my signal (collide) as seen in the
        signal immediately after transmission and in lost packets.
      * Other stations do step on other stations - sometimes garbling &
        sometimes overriding signals.
      * Other stations do have a variety of drive levels.

None of this can be a surprise....
As for restoring "connected" mode from "recovery" mode - that is for
another thread.
>SNIP<

As a postscript, I find Baudline useful in measuring to about 1ms, plus
the signal analysis is pretty illuminating.
On the other hand the time scale is a bear, and so useful results do not
come easily.
There must be a better way?

There were also some other important points made in this thread - THANKS
TO EVERYONE.

73
de Skip k8rra k


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