[Elecraft] Winlink Express + K3S

[Nicklas Johnson]

FWIW, I did some more poking around.  Increasing the RF gain to present
Winlink with a louder signal helps to alleviate this problem.  Looking at
the meter in Winlink, when it switches from TX to RX, there's some ramp
time before it reflects the full amplitude of the incoming signal.

Curious about that, I recorded some audio using Audacity to see what the
recovery after the actual RX switch looks like: https://imgur.com/IPTabvm

There's about 10ms of ramp up, followed by about 10ms of signal, then a
40ms audio dropout, then the signal resumes and stays steady.  This same
pattern appeared for every TX/RX exchange, including the same 40ms dropout
in the same place.  Not a big deal with many modes, but it could be a
bigger problem with Winlink or other modes which rely on quick TX/RX
switching; the total latency between the end of the transmit and the end of
the dropout is 170ms; add to that sound driver latency and buffering
latency, and the total latency could be well over 200ms... 140ms would
certainly be more desirable if it could be achieved.  (See
https://imgur.com/a/C2McMby for the full switch cycle.)

I also tested this with an external sound card to determine whether these
artifacts are coming from the receiver or the internal sound card.  The
same artifacts are present from the external sound card connected to the
rig's line out as when using the internal sound card, which I suspect
indicates they're coming from the receiver, not the sound card.

This is happening in DATA-A mode with NR, NB and NTCH off and with AGC
off.  Using Windows 10 with all "enhancements" disabled on both cards.

What else should I check or try?  Can anyone else verify this same pattern?

   Nick


On Wed, 10 Oct 2018 at 22:42, Nicklas Johnson <nick at n6ol.us> wrote:

> Somewhat related to my other post, but sufficiently different that I
> figured it should be its own thread: I consistently get the "Timeout in T>R
> Latency Measurement" message from Winlink Express using the built-in
> software Winmor TNC.
>
> After some poking around and trying different things, I set up the K3S to
> do PTT on RTS, made sure the TX delay was as short as possible, configured
> Winlink to use RTS for PTT, and as far as I can tell, the switching is very
> fast... but Winlink is still not happy about it.  I tried VOX as well, but
> it seemed like latency should be less with RTS for PTT.
>
> I used to get the Timeout error on my KX3 on the first transmit, but
> subsequent transmissions always worked fine.
>
> Has anyone had more success with Winlink with the K3s and with avoiding
> this Timeout message?
>
>    Nick
>
> --
> *N6OL*
> Saying something doesn't make it true.  Belief in something doesn't make
> it real. And if you have to lie to support a position, that position is not
> worth supporting.
>


-- 
*N6OL*
Saying something doesn't make it true.  Belief in something doesn't make it
real. And if you have to lie to support a position, that position is not
worth supporting.