[OZAPRS] Questions about tncs

Matthew Cook vk5zm at bistre.net
Tue Jul 10 13:24:31 AEST 2018

Hi Max,

Sounds like you have found your smoking gun.  Hope you get it sorted !



On 10 July 2018 at 12:13, Max Bainrot <mbainrot at gmail.com> wrote:

> Looking at the source briefly there does appear to be dcd but might appear
> to always be on.
> I had a bit more of a play and it appears to be some kind of interference
> maybe from the wuoxeon as it works great with vhf but not on uhf. Like on
> uhf the wuoxeon is deaf as a post but if I QSY to vhf without touching
> anything else it immediately starts receiving like nothing happened.
> I’m going to do up an adapter for one of my mobile rigs so I can confirm
> it as the tyt handheld only does uhf and it works fine
> Many thanks again for all the help and I’ll try to be a bit more active in
> getting back to y’all as I really appreciate the help
> 73s - Max, VK2NMF
> On Tue, 10 Jul 2018 at 11:23 am, Matthew Cook <vk5zm at bistre.net> wrote:
>> Hi Max,
>> Check your TNC code for Software DCD detection or similar, you need some
>> form of DCD to do CSMA properly.
>> 73
>> Matthew
>> VK5ZM
>> On 6 July 2018 at 11:50, Max Bainrot <mbainrot at gmail.com> wrote:
>>> Hi Matt
>>> I will definitely check that out, I have both the radios on open
>>> squealch because it seemed like the squealch control on the wuexon handheld
>>> was a bit slow to open.
>>> I haven’t implemented the leds as they weren’t in the schematic I used
>>> but looking in the source there was allocation for some indicator leds (one
>>> of the tncs uses a different ptt pin because of the non 0.1” header offset
>>> so had to tweak the pin allocations as initially I had stuck ptt issues)
>>> I’ll check tonight
>>> It is sending the acknowledgment though, I had a rtlsdr setup with basic
>>> decoder and I can see the two way traffic but the open squelch might be
>>> what’s slowing it down enough to miss the fast ACK
>>> 73s
>>> Max - VK2NMF
>>> On Fri, 6 Jul 2018 at 9:40 am, Matthew Cook <vk5zm at bistre.net> wrote:
>>>> Max,
>>>> Check how your TNC is detecting if the channel is busy.
>>>> Not many TNC's worked well in the day with open mute, in fact we used
>>>> to retrofit a small board to TNC's that would detect the AFSK tones and
>>>> drive the carrier SQ input on our TNC's.    What you describe is classic
>>>> CSMA "hold off" due to a busy channel.  I think you'll find that your TNC
>>>> thinks that the channel is busy, so it's not transmitting.  Since there is
>>>> no way for Xastir or Yaac to know if the packet has left, it retries.
>>>> Does your TNC have a carrier squelch input or software DCD (data
>>>> carrier detect), it may even have a DCD (or RX decoded) LED  if so what is
>>>> it telling you ?
>>>> I'm not familiar with your TNC per se, but can remember back to the
>>>> time where small fury creatures from alpha centari were real small furry
>>>> creatures from alpha centari.
>>>> 73
>>>> Matthew
>>>> VK5ZM
>>>> On 6 July 2018 at 08:02, Max Bainrot <mbainrot at gmail.com> wrote:
>>>>> Hi all,
>>>>> I’m fairly new to the whole packet radio shenanigans and been
>>>>> tinkering away for the past couple of days and have been running into
>>>>> gremlins
>>>>> I’m currently using a mobilinkd tnc2 firmware on a home brew shield on
>>>>> a 16mhz Arduino which works o.k. but it seems like it has a really long
>>>>> delay between transmitting and receiving, like long enough for default
>>>>> settings xastir (more on that later) to get impatient and retransmit like 6
>>>>> times before entropy has it that the acknowledgement makes it through.
>>>>> Is this just because the firmware is asking too much of the poor
>>>>> little atmega328p or is it something else? Doesn’t appear to be the
>>>>> radio(s) as I have two radios, wuxeon handheld and a tyt md380 (working
>>>>> 439.100 as there is no local digipeter) and switched radios between the
>>>>> sender and receiver, updated firmware on both Arduinos, the tncs where
>>>>> crashing before I attached ferrites to the cables but that appears to have
>>>>> fixed the issue.
>>>>> I haven’t confirmed beyond all doubt if the tnc is still randomly
>>>>> rebooting or not, going to hook the bus pirate (it has high z serial mode)
>>>>> up to the tnc’s serial lines to see if it’s singing it’s song of it’s
>>>>> people every time it transmits.
>>>>> The reset on connect jumper is enabled btw, is it xastir closing and
>>>>> reopening the serial port?
>>>>> I’m also using default settings in xastir for kiss tnc which could be
>>>>> another mistake I’ve made?
>>>>> Now onto the topic of xastir :) does anyone know where I can find the
>>>>> setting to slow it right down??? It resends wayyyyy too quickly which is
>>>>> both bad form and severely aggrevates the problem. I’m also thinking of
>>>>> rocking YAAC as it’s java based so I can use the latest version on all
>>>>> operating systems and I can slow it right down.
>>>>> Reason I am running down the open hardware and/or diy route is I am
>>>>> intending on cooking up a raspberry pi zero hat/cape, so want to leave
>>>>> options open for my future shenanigans.
>>>>> Many thanks in advance,
>>>>> VK2NMF
>>>>> _______________________________________________
>>>>> OZAPRS mailing list
>>>>> OZAPRS at aprs.net.au
>>>>> http://lists.aprs.net.au/mailman/listinfo/ozaprs
>>>>> _______________________________________________
>>>> OZAPRS mailing list
>>>> OZAPRS at aprs.net.au
>>>> http://lists.aprs.net.au/mailman/listinfo/ozaprs
>>> _______________________________________________
>>> OZAPRS mailing list
>>> OZAPRS at aprs.net.au
>>> http://lists.aprs.net.au/mailman/listinfo/ozaprs
>> _______________________________________________
>> OZAPRS mailing list
>> OZAPRS at aprs.net.au
>> http://lists.aprs.net.au/mailman/listinfo/ozaprs
> _______________________________________________
> OZAPRS mailing list
> OZAPRS at aprs.net.au
> http://lists.aprs.net.au/mailman/listinfo/ozaprs
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.aprs.net.au/pipermail/ozaprs/attachments/20180710/23b423dc/attachment-0001.html>

More information about the OZAPRS mailing list