[OZAPRS] Life's Red Face Moments

Ray Wells vk2tv at exemail.com.au
Sat Mar 20 18:18:34 EST 2010

Hi All,

vk2rmc-1 may not have had the deafness problem I thought existed, a 
discovery made on the bench at home.

There's a deprecated KISS function called "tail" that holds the tx up 
long enough to ensure that all data is sent, prior to PTT being dropped.

Tail is still an option for KISS TNC's in Linux and, I've always used it 
on HF because I found out a long time ago that it enhances connection 

I'm currently not using TNC's but instead use my Baycom USCC>4, four 
port card. The Baycom configuration includes a "tail" option but the 
docs don't pay much heed to it.

Based on my TNC experiences I've always set txtail with the USCC card. I 
had set 40mS for VHF and 80mS for HF.

I recently changed txtail on my gateway vhf port to 10mS and thought no 
more of it. My lack of time in the shack means I rarely monitor what's 
going on with the Igate or digi.

It wasn't until I had the digi radio in the shack that I was able to 
observe the Igate tx being ignored, except for radio busy and DCD on the 
TNC. Increasing TXD from 200mS to 250mS made no difference. That was 
when I took another look at txtail and reset it to 40mS - problem 
solved. TXD is now 180mS, tail 40mS, and all is working fine.

A lack of txtail with a TNC is probably fine but it certainly isn't with 
the USCC card, possibly because of timing issues with the SCC chips. 
Regardless of txtail issues the USCC is better than any TNC for 
performance, especially rx decode.

Even though the radio and TNC were ok, all is not lost, however, because 
I've been looking for an excuse to bring the radio down from the hill to 
interface the Site Alert unit that's been ready for at least eight months.

When the digi goes back Monday or Tuesday I'll also install a new power 
supply arrangement. I just wish I had time to change the mast and 
antennas. Maybe next trip.

Ray vk2tv

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