[OZAPRS] Questions about tncs
mbainrot at gmail.com
Tue Jul 10 12:43:57 AEST 2018
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.
> 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
>> Max - VK2NMF
>> On Fri, 6 Jul 2018 at 9:40 am, Matthew Cook <vk5zm at bistre.net> wrote:
>>> 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.
>>> 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,
>>>> OZAPRS mailing list
>>>> OZAPRS at aprs.net.au
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