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[K3] - Data mode TX problem from VK7JB

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VK7JB

[K3] - Data mode TX problem from VK7JB

Hi All,

I've just started using my K3 for data modes and have discovered a problem: prominent, irregular and short duration clicking/popping heard the monitored TX audio of the K3, also audible in the transmitted signal when I listen to my signal on another receiver. There is no clicking artefact on received signals, only on my transmitted signal.

Here's my set up:
I'm using direct connection from K3 to my laptop. No interface, but I have a soundcard in a USB dongle, which I need to connect the audio in and out to my computer.
I have Data mode A enabled and ALC set to 4 bars solid with the 5th flickering. Power output is set to 40W. Monitored IMD is good (-29 to-30) using KK7UQ device for off-air monitoring - the signal is otherwise clean.

I have checked and can confirm that the clicking/popping is independent of: Line in Gain/soundcard audio drive settings; data mode used (PSK31/RTTY/Olivia - all are affected); digimode software application used (same with Fldigi, Airlink Express, digipan and HRD) and finally, I have USB soundcard dongles of 2 different manufacturers and the problem is present using both.

Any ideas or advice gratefully received. I'd like to get rid of this TX clicking!

73 and thanks in advance,

John
VK7JB

Dave Perry N4QS

Re: [K3] - Data mode TX problem from VK7JB

Yes, I've always had those same pops on RTTY.

Dave, N4QS
Sent via BlackBerry by AT&T

-----Original Message-----
From: VK7JB <[hidden email]>
Sender: [hidden email]
Date: Tue, 13 Sep 2011 06:21:49
To: <[hidden email]>
Subject: [Elecraft] [K3] - Data mode TX problem from VK7JB

Hi All,

I've just started using my K3 for data modes and have discovered a problem:
prominent, irregular and short duration clicking/popping heard the
monitored TX audio of the K3, also audible in the transmitted signal when I
listen to my signal on another receiver. There is no clicking artefact on
received signals, only on my transmitted signal.

Here's my set up:
I'm using direct connection from K3 to my laptop. No interface, but I have
a soundcard in a USB dongle, which I need to connect the audio in and out to
my computer.
I have Data mode A enabled and ALC set to 4 bars solid with the 5th
flickering. Power output is set to 40W. Monitored IMD is good (-29 to-30)
using KK7UQ device for off-air monitoring - the signal is otherwise clean.

I have checked and can confirm that the clicking/popping is independent of:
Line in Gain/soundcard audio drive settings; data mode used
(PSK31/RTTY/Olivia - all are affected); digimode software application used
(same with Fldigi, Airlink Express, digipan and HRD) and finally, I have USB
soundcard dongles of 2 different manufacturers and the problem is present
using both.

Any ideas or advice gratefully received. I'd like to get rid of this TX
clicking!

73 and thanks in advance,

John
VK7JB

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KK7P

Re: [K3] - Data mode TX problem from VK7JB

Windows has a problem doing real-time things, and Delayed Procedure
Calls (DPCs) often produce huge latency spikes, resulting in audio
pops. Other OSes may have similar problems, and may or may not be
called the same thing.

If you are using a Windows computer to send Tx audio to your K3 (or any
other radio) and you hear occasional pops and crackles in the Tx (or Rx)
audio, do a web search on tuning your OS to minimize DPCs.

73,

Lyle kK7P

> Yes, I've always had those same pops on RTTY.

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Tony Estep

Re: [K3] - Data mode TX problem from VK7JB

On Tue, Sep 13, 2011 at 6:44 PM, Lyle Johnson <[hidden email]> wrote:

> ....Delayed Procedure Calls (DPCs) often produce huge latency spikes....
>
=============
To test for this problem on your system, download the DPC checker at:
http://www.thesycon.de/deu/latency_check.shtml

Note that it takes a lot of latency to cause an audio problem. Well-written
drivers and interrupt handlers may cause some latency, but not enough to
make an audible click. However, not every piece of software is well-written.
For an informative explanation, see the post by "aj" at:
http://forum.cakewalk.com/tm.aspx?&m=1935436&mpage=2

The instruction .pdf that comes with the latency checker has additional
useful info.

If you have problems due to DPCs, you can disable drivers, services and
programs one by one until you find the culprit.

It is a time-honored tradition to fault the operating system for problems
caused by non-OS software, and this topic is a rich lode of such misplaced
blame.

73,
Tony KT0NY

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Tony Estep

Re: [K3] - Data mode TX problem from VK7JB

In reply to this post by KK7P

Don Wilhelm-4

Re: [K3] - Data mode TX problem from VK7JB

Tony,

What you say is true, but the fact with many ham radio applications is
that they were designed to run on Windows 3.1 or Windows 98, and have
never been updated to run on later versions of Windows. WinXP *usually*
supports those applications, but the game was changed with Vista and
Win7. If the applications do not update to abide by the "rules" of
those newer operating systems, problems such as this can occur.

Is this an OS problem? or is it an application problem? Sort of a
"chicken and egg" answer. Business applications are quick to make the
changes required to keep up with the OS requirements, but many ham radio
applications are not upgraded - I guess the authors do not get enough
support contributions to make it worth their effort to change things.

This is one of the reasons I will stick with WinXP for as long as
possible. I have a number of applications, including my preferred
backup program that will not run on Vista of Win7.

73,
Don W3FPR

On 9/13/2011 7:46 PM, Tony Estep wrote:

> On Tue, Sep 13, 2011 at 6:44 PM, Lyle Johnson<[hidden email]> wrote:
>
>> ....Delayed Procedure Calls (DPCs) often produce huge latency spikes....
>>
> =============
> To test for this problem on your system, download the DPC checker at:
> http://www.thesycon.de/deu/latency_check.shtml
>
> Note that it takes a lot of latency to cause an audio problem. Well-written
> drivers and interrupt handlers may cause some latency, but not enough to
> make an audible click. However, not every piece of software is well-written.
> For an informative explanation, see the post by "aj" at:
> http://forum.cakewalk.com/tm.aspx?&m=1935436&mpage=2
>
> The instruction .pdf that comes with the latency checker has additional
> useful info.
>
> If you have problems due to DPCs, you can disable drivers, services and
> programs one by one until you find the culprit.
>
> It is a time-honored tradition to fault the operating system for problems
> caused by non-OS software, and this topic is a rich lode of such misplaced
> blame.
>
> 73,
> Tony KT0NY
>
>

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Tony Estep

Re: [K3] - Data mode TX problem from VK7JB

On Tue, Sep 13, 2011 at 8:02 PM, Don Wilhelm <[hidden email]> wrote:

> .... the fact with many ham radio applications is that they were designed
> to run on Windows 3.1 or Windows 98, and have
> never been updated ...

=============================
Sure, but DPCs may be caused by anything that is running on your machine.
The most common offender is a WiFi driver, which has nothing to do with ham
software.

The issue of weak coding standards in ham software is a different topic, one
that I've bemoaned before on this forum. To write real-time software with a
GUI requires coding skills that are beyond most hobbyist programmers. Even
among the pros there are those who have the requisite advanced knowledge and
skills, and those who don't. To experience this firsthand, just plunge
yourself into the whirlpool of PSDRs and their associated virtual serial
ports and virtual audio cables. Most of it works most of the time, but it's
a long way from being consumer-friendly.

However, as I said, ham software probably is not related to the pops and
clicks that were reported in earlier posts. If they are being caused by
DPCs, it's most likely due to something like the virus-checker, the
safe-site monitor, the WiFi driver, or other unexpected source.

73,
Tony KT0NY

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Don Wilhelm-4

Re: [K3] - Data mode TX problem from VK7JB

Tony,

I do not disagree with your statements, but as you have alluded to, many
ham applications are not written to deal with the requirements of later
OS versions - you cited some examples. User be aware! Yes, a properly
written application will "ride around" those interruptions caused by
virus checkers and other things going on with the computer maintenance,
but others do not, they expect to have full control of the computer if
their window is open - unfortunately, that is not within the realm of
reality with today's OS - background applications must exist and do
their function, whether that be virus checking or the ethernet
connection or any of the other computer services that run in the
background and we take for granted as "just being there".

User awareness of this situation is essential - the K3 is probably not
to blame for the clicks and pops, it is most likely that the computer
that is causing them. If the K3 creates the clicks and pops with no
input from the computer, then it is a K3 problem, but it the K3 output
is clean with no computer input and there is clicks and pops when the
computer is introduced, the clicks and pops are being generated in the
computer audio stream - nothing that the K3 (or any other transceiver)
can do about it..

73,
Don W3FPR

On 9/13/2011 8:14 PM, Tony Estep wrote:

> Sure, but DPCs may be caused by anything that is running on your
> machine. The most common offender is a WiFi driver, which has nothing
> to do with ham software. The issue of weak coding standards in ham
> software is a different topic, one that I've bemoaned before on this
> forum. To write real-time software with a GUI requires coding skills
> that are beyond most hobbyist programmers. Even among the pros there
> are those who have the requisite advanced knowledge and skills, and
> those who don't. To experience this firsthand, just plunge yourself
> into the whirlpool of PSDRs and their associated virtual serial ports
> and virtual audio cables. Most of it works most of the time, but it's
> a long way from being consumer-friendly. However, as I said, ham
> software probably is not related to the pops and clicks that were
> reported in earlier posts. If they are being caused by DPCs, it's most
> likely due to something like the virus-checker, the safe-site monitor,
> the WiFi driver, or other unexpected source.

Tony Estep

Re: [K3] - Data mode TX problem from VK7JB

On Tue, Sep 13, 2011 at 8:54 PM, Don Wilhelm <[hidden email]> wrote:

> ...a properly written application will "ride around" those interruptions
> caused by
> virus checkers and other things
> ===========

No, it won't. It can't. The DPC takes control and that's that. See the
explanation of what a DPC is and how it works on the link I posted.

Tony KT0NY

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VK7JB

Re: [K3] - Data mode TX problem from VK7JB - solved!

Hi All,

Thanks for your suggestions and for the interesting discussion. To close the loop, here's some information about the solution, which I discovered by accident:

More careful sleuthing showed that the issue was in the computer audio chain (as I suspected) and not with the K3. The artefact was present on the soundcard audio output. I tried another, older, laptop running XP, and with the same USB Soundcard dongle connected and all other parameters unchanged, and this time the problem was absent.

I then went back to the original laptop (running Win 7) and ran the latency checker application. All green bars, which didn't help me much. I'm not sure why, but I then decided to disable the computer's internal sound card through device manager. I had muted the mic input of the internal sound card earlier, but hadn't disabled it. Anyway, after that, the problem is fixed.

So, using the USB soundcard dongle with the internal soundcard disabled, the pops and clicks are gone.
I should explain that I need to use the dongle because this computer's own soundcard has no line or mic in jack - it has an inbuilt mic, but no way of routing an external audio source to the internal soundcard.

Thanks again to everyone for your suggestions, on and off the list.

73,

John
VK7JB