Re: [Elecraft] KX3 Bias Voltage

[Walter Underwood]

According to the Fred Cady book, the mic bias on the tip is +3.3 V. 

The ring has a different voltage, used for PTT and UP/DOWN. That voltage is not 
as clean as the mic bias. It is better tot split that out. You can do that with 
an off-the-shelf stereo to mono splitter. See this blog post for details.

https://observer.wunderwood.org/2015/08/16/yamaha-cm500-headset-with-ptt-on-elecraft-kx3/

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

> On Jun 22, 2022, at 7:23 PM, John Pierce via Elecraft 
>  wrote:
> 
> What is the bias voltage provided?  Is there a current limitation?
> 
> 
> 
> AD2F  John
> 
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Re: [Elecraft] I/Q details for the KX3.

[Alan Bloom]

But I think that SDRs that digitize at the VFO frequency itself (I believe
this is generally called "direct sampling" on RX and "direct digital
synthesis" on TX?) can get away with a single channel, since there's no
mixer to cause the "you mix A and B and get both A + B and A - B even
though you only wanted one of them" problem.


Yes, but...  You still need to reduce the sample rate to a lower value 
that the DSP can handle.  Either you need to mix down to a low-frequency 
IF or all the way down to an I/Q signal at a zero Hz center frequency.  
Either way, the mixer needs to be quadrature to avoid the image.


The output of the ADC goes to a quadrature digital downconverter (DDC), 
which consists of two digital mixers (that multiply the ADC signal times 
the digital local oscillator), with the local oscillator to each mixer 
90 degrees out of phase.  In this P3 this is done in an ASIC 
(application-specific IC) and in the K4 it is done in an FPGA.


Alan N1AL


On 6/22/22 20:45, Julia Tuttle wrote:

Mike,

I think you're right that SDRs that digitize at a zero IF (like the KX3)
need I and Q channels to distinguish the AF sidebands. That is, if the
radio mixes 7030.4 kHz down to a sidetone of 0.4 kHz, it also catches
signals at 7029.6 kHz.

And I think that SDRs that digitize at a non-zero and 'properly
intermediate' IF (that is, neither 0 nor the VFO frequency) also need I and
Q channels to distinguish the IF 'sidebands'. That is, if the radio mixes
7030 kHz down to an IF of 455 kHz, it also catches signals at 6120 kHz.

But I think that SDRs that digitize at the VFO frequency itself (I believe
this is generally called "direct sampling" on RX and "direct digital
synthesis" on TX?) can get away with a single channel, since there's no
mixer to cause the "you mix A and B and get both A + B and A - B even
though you only wanted one of them" problem.

Does this match your understanding?

Thanks,

Julie

On Wed, Jun 22, 2022 at 2:04 PM Mike Markowski  wrote:


Jerome,

This answer is for generic SDRs, since I don't have a KX3.

An SDR always must use both I and Q, even for CW.  I and Q are two
streams of samples of the same signal.  One of many advantages to i/q
sampling is the ADC's can run slower (cheaper).  In the extreme and
ignoring the intrusion of real life components on sampling, a 10 kHz
wide signal could be sampled with I and Q ADCs running at 10 kHz.
Nyquist is satisfied because you have 2 streams, or 20 kHz sampling in
this example.  Aliasing prevents you from using just I in that case.

The fact that Q is 90 deg from I, means we can plot them on axes 90 deg
apart.  That allows re-appropriating the entire field of complex
mathematics to work with the samples.  I and Q are both physical -
trying to avoid the word 'real'! - streams of samples, but I can be
called real and Q can be called imaginary.  Using Euler's Formula, they
can be bundled into a concise exp(j phi) formulation to work with.

I/Q imbalance is always a concern.  Maybe others can quantify it better
than me saying smaller is better.  :-)

73 es GL!
Mike ab3ap

On 6/21/22 11:08 PM, JEROME SODUS wrote:

Hello,

Although I have asked some of these questions on another forum, here I

have expanded on them a bit.

When the KX3 transmits a CW-signal, are both I and Q used?
If so, why would that be necessary?
(My guess is only the I is needed.)

Same questions too for a SSB-signal.

But, for any digital transmission like RTTY, FT8, or Olivia, wouldn't

both I and Q would be active?

The LO is used for the "In Phase" and is delayed by 90 degrees for the

"Quadrature"; how is that delay done?

How much can the delay deviate from 90 degrees and still be useful?

My reason for asking is that I'm to give a talk to the Radio Club in

August about how a KX3 works and want to mention these details.

TIA for any replies.
73 jerry km3kKX3#6088
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[Elecraft] Forsale - Pignology Pigknob

[ky7k]

I don’t think this went through the first time, apologies if it’s a dup.

I have an unused Pigknob that is excess to my needs. Includes the cables, 
interface board and even the pig eyes!
Basically new in box, but I think I may have tried it once to make sure it 
worked, but it’s been so long I can’t recall.
$100 including shipping to NA. I would ship elsewhere but would have to check 
shipping charges before committing to it.
 
Steve - KY7K
k...@arrl.net
Get OUT and play radio!

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Re: [Elecraft] I/Q details for the KX3.

[Julia Tuttle]

Mike,

I think you're right that SDRs that digitize at a zero IF (like the KX3)
need I and Q channels to distinguish the AF sidebands. That is, if the
radio mixes 7030.4 kHz down to a sidetone of 0.4 kHz, it also catches
signals at 7029.6 kHz.

And I think that SDRs that digitize at a non-zero and 'properly
intermediate' IF (that is, neither 0 nor the VFO frequency) also need I and
Q channels to distinguish the IF 'sidebands'. That is, if the radio mixes
7030 kHz down to an IF of 455 kHz, it also catches signals at 6120 kHz.

But I think that SDRs that digitize at the VFO frequency itself (I believe
this is generally called "direct sampling" on RX and "direct digital
synthesis" on TX?) can get away with a single channel, since there's no
mixer to cause the "you mix A and B and get both A + B and A - B even
though you only wanted one of them" problem.

Does this match your understanding?

Thanks,

Julie

On Wed, Jun 22, 2022 at 2:04 PM Mike Markowski  wrote:

> Jerome,
>
> This answer is for generic SDRs, since I don't have a KX3.
>
> An SDR always must use both I and Q, even for CW.  I and Q are two
> streams of samples of the same signal.  One of many advantages to i/q
> sampling is the ADC's can run slower (cheaper).  In the extreme and
> ignoring the intrusion of real life components on sampling, a 10 kHz
> wide signal could be sampled with I and Q ADCs running at 10 kHz.
> Nyquist is satisfied because you have 2 streams, or 20 kHz sampling in
> this example.  Aliasing prevents you from using just I in that case.
>
> The fact that Q is 90 deg from I, means we can plot them on axes 90 deg
> apart.  That allows re-appropriating the entire field of complex
> mathematics to work with the samples.  I and Q are both physical -
> trying to avoid the word 'real'! - streams of samples, but I can be
> called real and Q can be called imaginary.  Using Euler's Formula, they
> can be bundled into a concise exp(j phi) formulation to work with.
>
> I/Q imbalance is always a concern.  Maybe others can quantify it better
> than me saying smaller is better.  :-)
>
> 73 es GL!
> Mike ab3ap
>
> On 6/21/22 11:08 PM, JEROME SODUS wrote:
> > Hello,
> >
> > Although I have asked some of these questions on another forum, here I
> have expanded on them a bit.
> >
> > When the KX3 transmits a CW-signal, are both I and Q used?
> > If so, why would that be necessary?
> > (My guess is only the I is needed.)
> >
> > Same questions too for a SSB-signal.
> >
> > But, for any digital transmission like RTTY, FT8, or Olivia, wouldn't
> both I and Q would be active?
> >
> > The LO is used for the "In Phase" and is delayed by 90 degrees for the
> "Quadrature"; how is that delay done?
> > How much can the delay deviate from 90 degrees and still be useful?
> >
> > My reason for asking is that I'm to give a talk to the Radio Club in
> August about how a KX3 works and want to mention these details.
> >
> > TIA for any replies.
> > 73 jerry km3kKX3#6088
> > __
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[Elecraft] KX3 Bias Voltage

[John Pierce via Elecraft]

What is the bias voltage provided?  Is there a current limitation?

 

AD2F  John

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[Elecraft] KPA1500 segment SWR memory

[Jorge Diez (CX6VM-CW5W)]

Hello

I read that KPA1500 have a memory to recognize SWR of the antennas on different 
frequencies 

What happen if the antenna vary SWR periodically?

My warc dipole vary SWR, usually I have 1.5:1 on 18070, but today (raining day) 
SWR is 1.17:1

Is this a problem for KPA1500?

Thanks for the feedback!

73,
Jorge
CX6VM/CW5W


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Re: [Elecraft] [POSSIBLE SPAM] Common K3 failure modes???

[Wes]

Since buying a TS-890, my K3S is now a spare to it (although I doubt I'll ever 
need it) and my original K3, once a spare to the K3S (which I did need) is 
excess and I'm thinking of selling it.  But I'm wondering whether in today's 
climate, it might not bring more money as pieces than a whole.


Wes N7WS

On 6/22/2022 10:35 AM, David Gilbert wrote:


As I've said before, the advantage of a modular design is nonexistent if the 
modules don't exist.


Some people have suggested buying a complete spare rig for parts. I think 
that's ridiculous.  If I'm going to put out that much money for contingency 
purposes I'll buy a new rig from a company that didn't put me in that situation.


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Re: [Elecraft] I/Q details for the KX3.

[Mike Markowski]

Jerome,

This answer is for generic SDRs, since I don't have a KX3.

An SDR always must use both I and Q, even for CW.  I and Q are two 
streams of samples of the same signal.  One of many advantages to i/q 
sampling is the ADC's can run slower (cheaper).  In the extreme and 
ignoring the intrusion of real life components on sampling, a 10 kHz 
wide signal could be sampled with I and Q ADCs running at 10 kHz. 
Nyquist is satisfied because you have 2 streams, or 20 kHz sampling in 
this example.  Aliasing prevents you from using just I in that case.


The fact that Q is 90 deg from I, means we can plot them on axes 90 deg 
apart.  That allows re-appropriating the entire field of complex 
mathematics to work with the samples.  I and Q are both physical - 
trying to avoid the word 'real'! - streams of samples, but I can be 
called real and Q can be called imaginary.  Using Euler's Formula, they 
can be bundled into a concise exp(j phi) formulation to work with.


I/Q imbalance is always a concern.  Maybe others can quantify it better 
than me saying smaller is better.  :-)


73 es GL!
Mike ab3ap

On 6/21/22 11:08 PM, JEROME SODUS wrote:

Hello,

Although I have asked some of these questions on another forum, here I have 
expanded on them a bit.

When the KX3 transmits a CW-signal, are both I and Q used?
If so, why would that be necessary?
(My guess is only the I is needed.)

Same questions too for a SSB-signal.

But, for any digital transmission like RTTY, FT8, or Olivia, wouldn't both I 
and Q would be active?

The LO is used for the "In Phase" and is delayed by 90 degrees for the 
"Quadrature"; how is that delay done?
How much can the delay deviate from 90 degrees and still be useful?

My reason for asking is that I'm to give a talk to the Radio Club in August 
about how a KX3 works and want to mention these details.

TIA for any replies.
73 jerry km3kKX3#6088
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Re: [Elecraft] [POSSIBLE SPAM] Re: [POSSIBLE SPAM] Common K3 failure modes???

[Dr. William J. Schmidt]

The only opinion here that matters is Wayne's...

-Original Message-
From: elecraft-boun...@mailman.qth.net  On 
Behalf Of David Gilbert
Sent: Wednesday, June 22, 2022 12:35 PM
To: elecraft@mailman.qth.net
Subject: [POSSIBLE SPAM] Re: [Elecraft] [POSSIBLE SPAM] Common K3 failure 
modes???


Well, if Elecraft were to release the parts/specs/boards/gerber files to a 3rd 
party they would relieve themselves of the repair burden they clearly don't 
want, and any jeopardy for repair quality would fall on the 3rd party.  More 
importantly from Elecraft's perspective, it would address the image problem 
they have of leaving customers stranded without a repair path.  When I needed 
my K3IO repaired, Elecraft refused to do it and told me I should just buy the 
USB version ... and of course they no longer even offer that. None of which has 
anything to do with component obsolescence, by the way.  The key parts listed 
on the schematics are all still readily available, but of course replacing them 
can be problematic due to their small size.

As I've said before, the advantage of a modular design is nonexistent if the 
modules don't exist.

Some people have suggested buying a complete spare rig for parts.  I think 
that's ridiculous.  If I'm going to put out that much money for contingency 
purposes I'll buy a new rig from a company that didn't put me in that situation.

I hope you indeed consider offering a replacement K3IO board.  I'd probably buy 
one as a spare.

73,
Dave   AB7E



On 6/22/2022 9:40 AM, Dr. William J. Schmidt wrote:
> I actually designed and build a K3IO "ethernet" replacement KIO3 
> board...before the USB version was available.   I probably have the only 
> "ethernet" K3 on earth.   I may revive that card and replace the ethernet 
> stuff with USB parts so that I can fix some of these K3's laying around.  I 
> think there is ZERO chance that Elecraft will release parts/ boards/ gerbers 
> for these parts.  There is nothing in it for them to do so and may cause 
> maintenance headaches for them.  Some of us can pick up the slack though...
>
>
> -Original Message-
> From: elecraft-boun...@mailman.qth.net 
>  On Behalf Of David Gilbert
> Sent: Wednesday, June 22, 2022 10:47 AM
> To: elecraft@mailman.qth.net
> Subject: Re: [Elecraft] [POSSIBLE SPAM] Common K3 failure modes???
>
>
> I have also.  The K3IO module is pretty fragile, it seems.  Of all the 
> requests I've seen here on the reflector over the years for a replacement 
> item, the K3IO tops the list from my memory ... you can't just buy a 
> replacement from Mouser or Digi-Key like you can the input diodes.  And when 
> it goes bad, the K3 becomes essentially useless for contesting.
>
> I keep saying that Elecraft should pass on the PC board artwork and component 
> specs (I assume that not all of them are standard devices) for key 
> discontinued modules to someone who might be interested in offering 
> replacement as a 3rd party.  It's one of my key gripes with Elecraft that 
> they seem to have no interest in doing so.
>
> Dave   AB7E
>   

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Re: [Elecraft] [POSSIBLE SPAM] RE: Common K3 failure modes??? - K3 Ethernet

[Dr. William J. Schmidt]

It essentially packages the serial data and sends it over ethernet.
Anything you can do via the old RS232 cable connection, you can do over
ethernet.  Additional functionality (like audio) is currently not
supported... but it could be I suppose...



-Original Message-
From: Mike Cizek W0VTT  
Sent: Wednesday, June 22, 2022 12:20 PM
To: b...@wjschmidt.com; elecraft@mailman.qth.net
Subject: [POSSIBLE SPAM] RE: [Elecraft] Common K3 failure modes??? - K3
Ethernet

I wonder how much of a market there would be for a K3 Ethernet I/O board?
What would we need on the other end to control the radio though a built in
Ethernet line?


73,
Mike Cizek W0VTT

-Original Message-
From: elecraft-boun...@mailman.qth.net  On
Behalf Of Dr. William J. Schmidt
Sent: Wednesday, 22 June, 2022 11:40
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] [POSSIBLE SPAM] Common K3 failure modes???

I actually designed and build a K3IO "ethernet" replacement KIO3
board...before the USB version was available.   I probably have the only
"ethernet" K3 on earth.   I may revive that card and replace the ethernet
stuff with USB parts so that I can fix some of these K3's laying around.  I
think there is ZERO chance that Elecraft will release parts/ boards/ gerbers
for these parts.  There is nothing in it for them to do so and may cause
maintenance headaches for them.  Some of us can pick up the slack though...


-Original Message-
From: elecraft-boun...@mailman.qth.net  On
Behalf Of David Gilbert
Sent: Wednesday, June 22, 2022 10:47 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] [POSSIBLE SPAM] Common K3 failure modes???


I have also.  The K3IO module is pretty fragile, it seems.  Of all the
requests I've seen here on the reflector over the years for a replacement
item, the K3IO tops the list from my memory ... you can't just buy a
replacement from Mouser or Digi-Key like you can the input diodes.  And when
it goes bad, the K3 becomes essentially useless for contesting.

I keep saying that Elecraft should pass on the PC board artwork and
component specs (I assume that not all of them are standard devices) for key
discontinued modules to someone who might be interested in offering
replacement as a 3rd party.  It's one of my key gripes with Elecraft that
they seem to have no interest in doing so.

Dave   AB7E
 

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delivered to mgci...@gmail.com 

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Re: [Elecraft] [POSSIBLE SPAM] Common K3 failure modes???

[David Gilbert]

Well, if Elecraft were to release the parts/specs/boards/gerber files to 
a 3rd party they would relieve themselves of the repair burden they 
clearly don't want, and any jeopardy for repair quality would fall on 
the 3rd party.  More importantly from Elecraft's perspective, it would 
address the image problem they have of leaving customers stranded 
without a repair path.  When I needed my K3IO repaired, Elecraft refused 
to do it and told me I should just buy the USB version ... and of course 
they no longer even offer that. None of which has anything to do with 
component obsolescence, by the way.  The key parts listed on the 
schematics are all still readily available, but of course replacing them 
can be problematic due to their small size.


As I've said before, the advantage of a modular design is nonexistent if 
the modules don't exist.


Some people have suggested buying a complete spare rig for parts.  I 
think that's ridiculous.  If I'm going to put out that much money for 
contingency purposes I'll buy a new rig from a company that didn't put 
me in that situation.


I hope you indeed consider offering a replacement K3IO board.  I'd 
probably buy one as a spare.


73,
Dave   AB7E



On 6/22/2022 9:40 AM, Dr. William J. Schmidt wrote:

I actually designed and build a K3IO "ethernet" replacement KIO3 board...before the USB 
version was available.   I probably have the only "ethernet" K3 on earth.   I may revive 
that card and replace the ethernet stuff with USB parts so that I can fix some of these K3's laying 
around.  I think there is ZERO chance that Elecraft will release parts/ boards/ gerbers for these 
parts.  There is nothing in it for them to do so and may cause maintenance headaches for them.  
Some of us can pick up the slack though...


-Original Message-
From: elecraft-boun...@mailman.qth.net  On 
Behalf Of David Gilbert
Sent: Wednesday, June 22, 2022 10:47 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] [POSSIBLE SPAM] Common K3 failure modes???


I have also.  The K3IO module is pretty fragile, it seems.  Of all the requests 
I've seen here on the reflector over the years for a replacement item, the K3IO 
tops the list from my memory ... you can't just buy a replacement from Mouser 
or Digi-Key like you can the input diodes.  And when it goes bad, the K3 
becomes essentially useless for contesting.

I keep saying that Elecraft should pass on the PC board artwork and component 
specs (I assume that not all of them are standard devices) for key discontinued 
modules to someone who might be interested in offering replacement as a 3rd 
party.  It's one of my key gripes with Elecraft that they seem to have no 
interest in doing so.

Dave   AB7E
  


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Re: [Elecraft] Common K3 failure modes??? - K3 Ethernet

[Mike Cizek W0VTT]

I wonder how much of a market there would be for a K3 Ethernet I/O board?
What would we need on the other end to control the radio though a built in
Ethernet line?


73,
Mike Cizek W0VTT

-Original Message-
From: elecraft-boun...@mailman.qth.net  On
Behalf Of Dr. William J. Schmidt
Sent: Wednesday, 22 June, 2022 11:40
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] [POSSIBLE SPAM] Common K3 failure modes???

I actually designed and build a K3IO "ethernet" replacement KIO3
board...before the USB version was available.   I probably have the only
"ethernet" K3 on earth.   I may revive that card and replace the ethernet
stuff with USB parts so that I can fix some of these K3's laying around.  I
think there is ZERO chance that Elecraft will release parts/ boards/ gerbers
for these parts.  There is nothing in it for them to do so and may cause
maintenance headaches for them.  Some of us can pick up the slack though...


-Original Message-
From: elecraft-boun...@mailman.qth.net  On
Behalf Of David Gilbert
Sent: Wednesday, June 22, 2022 10:47 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] [POSSIBLE SPAM] Common K3 failure modes???


I have also.  The K3IO module is pretty fragile, it seems.  Of all the
requests I've seen here on the reflector over the years for a replacement
item, the K3IO tops the list from my memory ... you can't just buy a
replacement from Mouser or Digi-Key like you can the input diodes.  And when
it goes bad, the K3 becomes essentially useless for contesting.

I keep saying that Elecraft should pass on the PC board artwork and
component specs (I assume that not all of them are standard devices) for key
discontinued modules to someone who might be interested in offering
replacement as a 3rd party.  It's one of my key gripes with Elecraft that
they seem to have no interest in doing so.

Dave   AB7E
 

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Re: [Elecraft] I/Q details for the KX3.

[Julia Tuttle]

On receive, if you only mix the RF signal with only the I phase of the VFO,
you receive both sidebands, and you can't observe them separately. On
transmit, you have the same problem in reverse -- you transmit both
sidebands, and you can't control them separately.

For modes with a single sideband (SSB, DATA besides RTTY), the KX3 must
output the AF signal on both I and Q with the proper phase offset.

If it output the AF signal on I but left Q at 0 V, the TX mixer would
generate a mirror image (DSB-SC) signal.

(These are the "SSB and some data modes" covered by the TXSBNUL calibration
procedure on page 34.)

For modes that transmit a single frequency (CW, RTTY), the KX3 uses
*neither* I nor Q -- it leaves them at 0 V and controls the CW frequency
entirely with the VFO.

If it synthesized a constant sidetone frequency on I but left Q at 0 V, the
TX mixer would generate two CW signals, at the VFO frequency +/- the
sidetone frequency.

If it synthesized a constant sidetone frequency on I *and* Q with the
proper phase offset, it would also get a CW signal, but that would be
unnecessarily complex.

(These are the modes not covered by TXSBNUL.)

Digital modes like FT8 and Olivia (and RTTY if sent from a computer) are
handled just like SSB signals, just with some potentially distorting
features (compressor, equalizer, etc.) disabled.

The LO generates both the I and Q signals ("The synthesized, digitally
controlled local oscillator (LO) provides quadrature signals to the
transmit and receive mixers", page 49) -- there's no separate delay, so I
expect the phase difference would be quite accurate. I'm not sure how
accurate it actually is, nor how much it can deviate before it causes
problems.

If you haven't yet, I'd take a look at the Theory of Operation (pages
49-50) and KX3 Block Diagram (page 51) in the manual -- that's what I'm
basing my statements here on.

Related to how the KX3 handles RTTY internally, you might find the QRP Labs
QDX Digital Transceiver (https://qrp-labs.com/qdx.html) an interesting
architectural contrast. The KX3 handles CW and RTTY by simply leaving the
VFO output unmixed; the QDX handles *all* single-frequency digital modes
that way. It exposes an audio output over USB, but instead of running the
TX AF signal through a DAC and a mixer, it analyzes it in software to
determine which single frequency it contains, and adjusts the VFO to follow.

I hope this is helpful!

73,

Julie

On Wed, Jun 22, 2022 at 11:56 AM JEROME SODUS  wrote:

> Hello,
>
> Although I have asked some of these questions on another forum, here I
> have expanded on them a bit.
>
> When the KX3 transmits a CW-signal, are both I and Q used?
> If so, why would that be necessary?
> (My guess is only the I is needed.)
>
> Same questions too for a SSB-signal.
>
> But, for any digital transmission like RTTY, FT8, or Olivia, wouldn't both
> I and Q would be active?
>
> The LO is used for the "In Phase" and is delayed by 90 degrees for the
> "Quadrature"; how is that delay done?
> How much can the delay deviate from 90 degrees and still be useful?
>
> My reason for asking is that I'm to give a talk to the Radio Club in
> August about how a KX3 works and want to mention these details.
>
> TIA for any replies.
> 73 jerry km3kKX3#6088
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Re: [Elecraft] [POSSIBLE SPAM] Common K3 failure modes???

[Dr. William J. Schmidt]

I actually designed and build a K3IO "ethernet" replacement KIO3 board...before 
the USB version was available.   I probably have the only "ethernet" K3 on 
earth.   I may revive that card and replace the ethernet stuff with USB parts 
so that I can fix some of these K3's laying around.  I think there is ZERO 
chance that Elecraft will release parts/ boards/ gerbers for these parts.  
There is nothing in it for them to do so and may cause maintenance headaches 
for them.  Some of us can pick up the slack though...


-Original Message-
From: elecraft-boun...@mailman.qth.net  On 
Behalf Of David Gilbert
Sent: Wednesday, June 22, 2022 10:47 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] [POSSIBLE SPAM] Common K3 failure modes???


I have also.  The K3IO module is pretty fragile, it seems.  Of all the requests 
I've seen here on the reflector over the years for a replacement item, the K3IO 
tops the list from my memory ... you can't just buy a replacement from Mouser 
or Digi-Key like you can the input diodes.  And when it goes bad, the K3 
becomes essentially useless for contesting.

I keep saying that Elecraft should pass on the PC board artwork and component 
specs (I assume that not all of them are standard devices) for key discontinued 
modules to someone who might be interested in offering replacement as a 3rd 
party.  It's one of my key gripes with Elecraft that they seem to have no 
interest in doing so.

Dave   AB7E
 

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[Elecraft] I/Q details for the KX3.

[JEROME SODUS]

Hello,

Although I have asked some of these questions on another forum, here I have 
expanded on them a bit. 

When the KX3 transmits a CW-signal, are both I and Q used?
If so, why would that be necessary?
(My guess is only the I is needed.)

Same questions too for a SSB-signal.

But, for any digital transmission like RTTY, FT8, or Olivia, wouldn't both I 
and Q would be active?  

The LO is used for the "In Phase" and is delayed by 90 degrees for the 
"Quadrature"; how is that delay done?
How much can the delay deviate from 90 degrees and still be useful?

My reason for asking is that I'm to give a talk to the Radio Club in August 
about how a KX3 works and want to mention these details.

TIA for any replies.
73 jerry km3kKX3#6088
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Re: [Elecraft] [POSSIBLE SPAM] Common K3 failure modes???

[David Gilbert]

I have also.  The K3IO module is pretty fragile, it seems.  Of all the 
requests I've seen here on the reflector over the years for a 
replacement item, the K3IO tops the list from my memory ... you can't 
just buy a replacement from Mouser or Digi-Key like you can the input 
diodes.  And when it goes bad, the K3 becomes essentially useless for 
contesting.


I keep saying that Elecraft should pass on the PC board artwork and 
component specs (I assume that not all of them are standard devices) for 
key discontinued modules to someone who might be interested in offering 
replacement as a 3rd party.  It's one of my key gripes with Elecraft 
that they seem to have no interest in doing so.


Dave   AB7E


On 6/22/2022 5:13 AM, Robie Elms wrote:

I have K3IO failures as well.

Robie AJ4F

On Wed, Jun 22, 2022, 6:57 AM Dr. William J. Schmidt 
wrote:


My K3 failures always come in the form of either K3IOx failures (extremely
common) or the 10W module.  Everything else seems to hang together.

-Original Message-
From: elecraft-boun...@mailman.qth.net 
On
Behalf Of Geert Jan de Groot
Sent: Wednesday, June 22, 2022 3:30 AM
To: elecraft@mailman.qth.net
Subject: [POSSIBLE SPAM] [Elecraft] Common K3 failure modes???

On 22/06/2022 02:50, elecraft-requ...@mailman.qth.net wrote:

With more K3 radios broken on the bench than working at my contest
station
(J68HZ)  and NO spare modules to work with,

I am actually wondering about that. One of the magazines I read, the German
Funkamateur magazine, has a story each month about a group doing some
DXpedition and nearly every month they report about equipment getting
broken
during such an event. As these things often use Elecraft, there are reports
of K3's failing.

But I wonder the failure mode because the stories don't report anything
about that. I know of a few failure modes:
- Diodes at input blown up because of extremely strong signals
near-frequency. Bandfilters may help, as does careful frequency planning
and
some antenna distance. (ages ago I used a FT747 which uses a light bulb as
protection - after a heavy radio weekend I had the lightbulb open and one
of
the input coils fused!)
- PA kickback causing the low-power amplifier transistors to fail - there
has been discussion on the list to add transzorb diodes
- Encoders for filter settings etc may fail - easy to replace
- volume knob was bumped on, causing potmeter broken - just replaced it
- Plastic knobs cracked - partially solved by Elecraft warranty, partly
solved by buying new ones myself ( with shipping and customs)
- Audio amplifier dying because of a short circuit at the output. There is
a
mod kit for that.

I wonder about other failure modes. How does a K3 die at a contest station,
or a DXpedition, and what can be done to prevent?
What are the failures on the broken radios you are reporting about?

73,

Geert Jan PE1HZG


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Re: [Elecraft] Common K3 failure modes???

[Jerry Moore]

I get a PEBKAC error with my K3S all the time...

-Original Message-
From: elecraft-boun...@mailman.qth.net  On 
Behalf Of Udo Langenohl - DK5YA
Sent: Wednesday, June 22, 2022 6:10 AM
To: elecraft@mailman.qth.net
Subject: Re: [Elecraft] Common K3 failure modes???

> - Diodes at input blown up because of extremely strong signals 
> near-frequency. Bandfilters may help, as does careful frequency 
> planning and some antenna distance. (ages ago I used a FT747 which 
> uses a light bulb as protection - after a heavy radio weekend I had 
> the lightbulb open and one of the input coils fused!) 73,
> 
> Geert Jan PE1HZG

I own 3x K3, one a pure "S" and 2 which are pimped to be a "S" (almost..).

Blown diodes at the input (both Main and Sub RX) are the most common failures 
I'm struggling with for several years with each of my K3's. 
None of them blown by strong nearby signals but all of them by lightning in 
summer. I've never been faced by a direct hit - luckily - but a strike say some 
500 meters or even a kilometer away will send these diodes to the great 
Mannitou Of Radio. I have to admit that this is a hilltop QTH and sometimes I 
forget to disconnect the whole stuff when I'm in a QRL hurry or something 
similar (XYL hurry i.e..).
Fun fact: during our DU-DXpedition on Panglao Isl. we were in the very heart of 
all thunderstorms years ago when strong linghtning apperaed every evening and 
night for hours. We had two K3 with us and none of them struggled with dead 
diodes at the input. Just because I had a box with several spare with me? Only 
Murphy knows.

BTW, several broken knobs along the years too, thats another common failure.

73 Udo, DK5YA
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Re: [Elecraft] Common K3 failure modes???

[David Olean]

MY brother had his K3 fail. He turned it on and everything came up 
normally, but he could hear no signals or normal band noise on any band 
but there was slight noise on 80 meters. Turns out the 8 volt regulator 
had died. That is the one bolted to one of the side panels. If it quits, 
the synthesizer dies with it. I did write up some notes about the 
repair. (with pictures and arrows!) Changing out the regulator is 
simple, but finding out that the regulator is bad took some PC board 
sleuthing.


Dave K1WHS

On 6/22/2022 4:29 AM, Geert Jan de Groot wrote:

On 22/06/2022 02:50, elecraft-requ...@mailman.qth.net wrote:
With more K3 radios broken on the bench than working at my contest 
station

(J68HZ)  and NO spare modules to work with,


I am actually wondering about that. One of the magazines I read, the 
German Funkamateur magazine, has a story each month about a group 
doing some DXpedition and nearly every month they report about 
equipment getting broken during such an event. As these things often 
use Elecraft, there are reports of K3's failing.


But I wonder the failure mode because the stories don't report 
anything about that. I know of a few failure modes:
- Diodes at input blown up because of extremely strong signals 
near-frequency. Bandfilters may help, as does careful frequency 
planning and some antenna distance. (ages ago I used a FT747 which 
uses a light bulb as protection - after a heavy radio weekend I had 
the lightbulb open and one of the input coils fused!)
- PA kickback causing the low-power amplifier transistors to fail - 
there has been discussion on the list to add transzorb diodes

- Encoders for filter settings etc may fail - easy to replace
- volume knob was bumped on, causing potmeter broken - just replaced it
- Plastic knobs cracked - partially solved by Elecraft warranty, 
partly solved by buying new ones myself ( with shipping and customs)
- Audio amplifier dying because of a short circuit at the output. 
There is a mod kit for that.


I wonder about other failure modes. How does a K3 die at a contest 
station, or a DXpedition, and what can be done to prevent?

What are the failures on the broken radios you are reporting about?

73,

Geert Jan PE1HZG


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Re: [Elecraft] [off topic] Red Dogs

[Mark Goldberg]

I'm thinking Red Dog Bone Capacitors like these:

https://reverb.com/item/32640625-47pf-500v-lemco-dog-bone-capacitor-marshall-jmp-jcm800

https://www.surplussales.com/CAPACITORS/RF-TEMPDOGBONE.HTML

73,

Mark
W7MLG

On Wed, Jun 22, 2022 at 7:19 AM David Christ  wrote:

> A friend put a question to me this morning.  His dad was an Electrical
> Engineer and had a large number of the ubiquitous "parts drawers" full of
> various components.  One drawer (empty) is labelled "Red Dogs".  Any ideas
> what this might have been?
>
>
> David K0LUM
>
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Re: [Elecraft] [POSSIBLE SPAM] Common K3 failure modes???

[Pete Smith N4ZR]

The only hardware failure I've had over the long life of my K3 (SN 4275) 
was the driver MOSFET in the KEY OUT circuit.  No idea what happened, 
but the transistor exploded.  Got it repaired locally.


73, Pete N4ZR
Check out the new Reverse Beacon Network
web server at .
For spots, please use your favorite
"retail" DX cluster.


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[Elecraft] [off topic] Red Dogs

[David Christ]

A friend put a question to me this morning.  His dad was an Electrical Engineer 
and had a large number of the ubiquitous "parts drawers" full of various 
components.  One drawer (empty) is labelled "Red Dogs".  Any ideas what this 
might have been?


David K0LUM

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Re: [Elecraft] [POSSIBLE SPAM] Common K3 failure modes???

[Robie Elms]

I have K3IO failures as well.

Robie AJ4F

On Wed, Jun 22, 2022, 6:57 AM Dr. William J. Schmidt 
wrote:

>
> My K3 failures always come in the form of either K3IOx failures (extremely
> common) or the 10W module.  Everything else seems to hang together.
>
> -Original Message-
> From: elecraft-boun...@mailman.qth.net 
> On
> Behalf Of Geert Jan de Groot
> Sent: Wednesday, June 22, 2022 3:30 AM
> To: elecraft@mailman.qth.net
> Subject: [POSSIBLE SPAM] [Elecraft] Common K3 failure modes???
>
> On 22/06/2022 02:50, elecraft-requ...@mailman.qth.net wrote:
> > With more K3 radios broken on the bench than working at my contest
> > station
> > (J68HZ)  and NO spare modules to work with,
>
> I am actually wondering about that. One of the magazines I read, the German
> Funkamateur magazine, has a story each month about a group doing some
> DXpedition and nearly every month they report about equipment getting
> broken
> during such an event. As these things often use Elecraft, there are reports
> of K3's failing.
>
> But I wonder the failure mode because the stories don't report anything
> about that. I know of a few failure modes:
> - Diodes at input blown up because of extremely strong signals
> near-frequency. Bandfilters may help, as does careful frequency planning
> and
> some antenna distance. (ages ago I used a FT747 which uses a light bulb as
> protection - after a heavy radio weekend I had the lightbulb open and one
> of
> the input coils fused!)
> - PA kickback causing the low-power amplifier transistors to fail - there
> has been discussion on the list to add transzorb diodes
> - Encoders for filter settings etc may fail - easy to replace
> - volume knob was bumped on, causing potmeter broken - just replaced it
> - Plastic knobs cracked - partially solved by Elecraft warranty, partly
> solved by buying new ones myself ( with shipping and customs)
> - Audio amplifier dying because of a short circuit at the output. There is
> a
> mod kit for that.
>
> I wonder about other failure modes. How does a K3 die at a contest station,
> or a DXpedition, and what can be done to prevent?
> What are the failures on the broken radios you are reporting about?
>
> 73,
>
> Geert Jan PE1HZG
>
>
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Re: [Elecraft] [POSSIBLE SPAM] Common K3 failure modes???

[Dr. William J. Schmidt]

My K3 failures always come in the form of either K3IOx failures (extremely
common) or the 10W module.  Everything else seems to hang together.

-Original Message-
From: elecraft-boun...@mailman.qth.net  On
Behalf Of Geert Jan de Groot
Sent: Wednesday, June 22, 2022 3:30 AM
To: elecraft@mailman.qth.net
Subject: [POSSIBLE SPAM] [Elecraft] Common K3 failure modes???

On 22/06/2022 02:50, elecraft-requ...@mailman.qth.net wrote:
> With more K3 radios broken on the bench than working at my contest 
> station
> (J68HZ)  and NO spare modules to work with,

I am actually wondering about that. One of the magazines I read, the German
Funkamateur magazine, has a story each month about a group doing some
DXpedition and nearly every month they report about equipment getting broken
during such an event. As these things often use Elecraft, there are reports
of K3's failing.

But I wonder the failure mode because the stories don't report anything
about that. I know of a few failure modes:
- Diodes at input blown up because of extremely strong signals
near-frequency. Bandfilters may help, as does careful frequency planning and
some antenna distance. (ages ago I used a FT747 which uses a light bulb as
protection - after a heavy radio weekend I had the lightbulb open and one of
the input coils fused!)
- PA kickback causing the low-power amplifier transistors to fail - there
has been discussion on the list to add transzorb diodes
- Encoders for filter settings etc may fail - easy to replace
- volume knob was bumped on, causing potmeter broken - just replaced it
- Plastic knobs cracked - partially solved by Elecraft warranty, partly
solved by buying new ones myself ( with shipping and customs)
- Audio amplifier dying because of a short circuit at the output. There is a
mod kit for that.

I wonder about other failure modes. How does a K3 die at a contest station,
or a DXpedition, and what can be done to prevent?
What are the failures on the broken radios you are reporting about?

73,

Geert Jan PE1HZG


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Re: [Elecraft] Common K3 failure modes???

[Udo Langenohl - DK5YA]

- Diodes at input blown up because of extremely strong signals 
near-frequency. Bandfilters may help, as does careful frequency planning 
and some antenna distance. (ages ago I used a FT747 which uses a light 
bulb as protection - after a heavy radio weekend I had the lightbulb 
open and one of the input coils fused!)

73,

Geert Jan PE1HZG


I own 3x K3, one a pure "S" and 2 which are pimped to be a "S" (almost..).

Blown diodes at the input (both Main and Sub RX) are the most common 
failures I'm struggling with for several years with each of my K3's. 
None of them blown by strong nearby signals but all of them by lightning 
in summer. I've never been faced by a direct hit - luckily - but a 
strike say some 500 meters or even a kilometer away will send these 
diodes to the great Mannitou Of Radio. I have to admit that this is a 
hilltop QTH and sometimes I forget to disconnect the whole stuff when 
I'm in a QRL hurry or something similar (XYL hurry i.e..).
Fun fact: during our DU-DXpedition on Panglao Isl. we were in the very 
heart of all thunderstorms years ago when strong linghtning apperaed 
every evening and night for hours. We had two K3 with us and none of 
them struggled with dead diodes at the input. Just because I had a box 
with several spare with me? Only Murphy knows.


BTW, several broken knobs along the years too, thats another common 
failure.


73 Udo, DK5YA
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[Elecraft] Common K3 failure modes???

[Geert Jan de Groot]

On 22/06/2022 02:50, elecraft-requ...@mailman.qth.net wrote:

With more K3 radios broken on the bench than working at my contest station
(J68HZ)  and NO spare modules to work with,


I am actually wondering about that. One of the magazines I read, the 
German Funkamateur magazine, has a story each month about a group doing 
some DXpedition and nearly every month they report about equipment 
getting broken during such an event. As these things often use Elecraft, 
there are reports of K3's failing.


But I wonder the failure mode because the stories don't report anything 
about that. I know of a few failure modes:
- Diodes at input blown up because of extremely strong signals 
near-frequency. Bandfilters may help, as does careful frequency planning 
and some antenna distance. (ages ago I used a FT747 which uses a light 
bulb as protection - after a heavy radio weekend I had the lightbulb 
open and one of the input coils fused!)
- PA kickback causing the low-power amplifier transistors to fail - 
there has been discussion on the list to add transzorb diodes

- Encoders for filter settings etc may fail - easy to replace
- volume knob was bumped on, causing potmeter broken - just replaced it
- Plastic knobs cracked - partially solved by Elecraft warranty, partly 
solved by buying new ones myself ( with shipping and customs)
- Audio amplifier dying because of a short circuit at the output. There 
is a mod kit for that.


I wonder about other failure modes. How does a K3 die at a contest 
station, or a DXpedition, and what can be done to prevent?

What are the failures on the broken radios you are reporting about?

73,

Geert Jan PE1HZG


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