Linux-Hams archive - October 1997: Re: some questions about 'listen'

Re: some questions about 'listen'

Terry Dawson (dqeri@kerailya.tunkki.fi)
Thu, 02 Oct 1997 16:22:29 +1000


Pete Rossi WA3NNA wrote:

> Yet, I actually HEARD my radio transmit only *one* packet. So.. what
> really happened? and what is 'listen' trying to tell me? Was one packet
> transmitted, 3 packets transmitted in one burst, or is "listen" confused?

Pete,
One _transmission_ isn't always one _packet_.

Chances are you are transmitting multiple packets per transmission,
which would be indicative of your rtt value being too low.

The irtt parameter is the initial rtt parameter, you should start
this at a high value. I use 5 seconds for 4800, but that is probably
an ok starting point for 1200 too.

> Also there seems to often be considerable delay between either hearing
> a packet and having 'listen' display it... or seeing outgoing packets
> displayed and hearing my radio transmit them.

Buffering in the tnc.

Listen displays raw AX.25 packets _when they are received/transmitted
by the kernel_

Terry