Hi Michael

Will be off newsgroups for about a month from tomorrow..

As I recall packet neds a very good signal to noise. I have found that
even a S3 copy on 2m FM will be noisy enough for retries. If your RIT
works on FM check if you are on the digis exact freq.

The original NOS docs (wherever they may be) had discussions on these
parameters I think.

Shortening the max packet length gives better results in flakey
conditions because there is less time for the packet to be corrupted in.
Ensuring that the TXDelay and TXtail is both long enough and short
enough is also important. I remember setting my TXD by changing the
number dynamically as a ping job was in progress, then adding about 10%
when errors occurred. My old IC2A use to run at around 30mS but an older
relay based XTAL clunker needed 400mS. If you think it maybe a problem
(and remember that the time also helpds the other guys squelch open) set
it to something ridiculous like 1 second and see if the throughput improves.

The other timers (and persist/slottime) are more of use in crowded
channels so initially it probably isnt worth fiddling with. As a general
rule of thumb you would use what the local group are using so you had a
fair chance as them. Biggest problem is to ensure that you can hear
every other TX on your channel and they can hear you. Not a good idea to
use a yagi and low power because your (and their) collision rate will
skyrocket, despite any settings you use.

I'd accept the default settings as they appear in the proc filesystem,
set TXD and TXT by experiment, use the persist/slot that the local group
uses (or leave it as default), MaxFrame/window at 1 and thats it. If you
specifically want to use point to point with another station, make
persist/slot more agressive, fine tune the TXD, Maxframe/window to 7 and
make the packet length as long as possible.

I thought the howto actually described the params well enough for me..

Cheers Bob VK2YQA


Michael Hofmann wrote:
Bob Bob wrote:

[snipped]


I seem to have the software tamed so that PR basically works, but I get
very low and flaky connection quality - tons of RR-/RR+ packets, but few
"payload" packets. I think I remember from my earlier packet days that
these are reject/acknowledge packets, indicating some sort of
misunderstanding between my station and the digi. Next thing I will
check at the weekend is the modulation deviation of my Kenwood transceiver.
Other than that, is there a document describing the ax25 parameters (Tn,
N2, idle, window) and useful values? Again the Ax25-HowTo is very
unprecise about those.

TIA,
Michael