Re: [Elecraft] K2 No Power Output

[VA1CQ]

I've discovered that my VPWR voltage is high (4.90 V). I don't see 
anything wrong with the RF Detector circuit. The signal on D9 is only 84 
mV when measured with the RF Probe. So I pressed forward with signal 
tracing. It appears I have an RF signal at the Transmit Mixer (0.274 V) 
and Buffer (1.45 V) outputs. But at W6 (Band-Pass Filter output) and T-R 
Switch #1 output, I have no measurable signal (0.5 mV). Further, DC 
voltages check out on diodes D1 to D7 on the RF Board and all diodes are 
oriented correctly on the board. I also noted that the Driver and PA 
transistors have correct voltages and seem to switch on keydown.


Tuning the Band-Pass filters had no effect no effect on improving output 
power.  Power remains at 0.1 to 0.2 watts. I was able to tune L8 and L9 
for the 30-metre filter to improve reception on that band to receive 
some RTTY, WWV and a CW signal.


During the build, I swapped location of the two 20-metre trimmer 
capacitors (C21, C23) with the location for the 10-metre trimmers (C44, 
C46). In reversing these, it's possible I damaged one or more of the 
trimmers. But, if I did, I don't think this would cause the no power 
output problem on any band that I'm experiencing.


Murray VA1CQ


On 6/26/2021 6:33 PM, Don Wilhelm wrote:

Murray,

Not only logical, but the only way to approach Transmit problems.
When you get to jumper W6, know that you can and should adjust the 
bandpass filters for maximum RF voltage there.


On a new build, be aware that the most common problems are soldering, 
misplaced or incorrect components and diode orientation.  If you 
suspect diode orientation problems, refer to the Parts Placement 
Diagrams in the back of the manual to check them.
Another common problem is inadequately stripped and tinned toroid 
leads.  You should be able to see a bit of tinned lead on the top of 
the board.


73,
Don W3FPR

On 6/26/2021 4:58 PM, VA1CQ wrote:

Don,

A logical suggestion. I already have made the RF Probe and it's ready 
to use. I was hoping the cause of no power might be something 
simpler. I will start troubleshooting in my next work session.


Murray VA1CQ

On 6/26/2021 5:34 PM, Don Wilhelm wrote:

Murray,

I suggest that you build the RF Probe that was included with the K2 
kit.  The schematic is shown on page 9 of Appendix E along with the 
assembly instructions.
After that, start on Appendix E page 12 - Preparation for 
Transmitter Signal Tracing and follow the steps shown there.


73,
Don W3FPR

On 6/26/2021 4:21 PM, VA1CQ wrote:
I am just completing the build of K2 Serial No. 6397. Everything 
was going perfectly with all receiver tests and adjustments. 
Everything is in spec.


Then I started the transmitter tests. I set the output power 
control for 2.0 watts. Beginning on 40 metres, I am supposed to be 
able to adjust L1 and L2 to measure 2 watts on the internal power 
meter. I measure 0.1 to 0.2 watts. Nothing I adjust or do changes 
this. My input voltage is 13.6V with 250 mA on receive and 600 mA 
on transmit. I've taken a quick read through the Troubleshooting 
section, but I'm wondering if I'm just doing something stupid and 
only think I have a problem when I don't. Being new to the K2, 
perhaps I'm not setting something correctly.


Any tips for what I should do next?

Murray VA1CQ










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Re: [Elecraft] K2 No Power Output

[Don Wilhelm]

Murray,

Not only logical, but the only way to approach Transmit problems.
When you get to jumper W6, know that you can and should adjust the 
bandpass filters for maximum RF voltage there.


On a new build, be aware that the most common problems are soldering, 
misplaced or incorrect components and diode orientation.  If you suspect 
diode orientation problems, refer to the Parts Placement Diagrams in the 
back of the manual to check them.
Another common problem is inadequately stripped and tinned toroid 
leads.  You should be able to see a bit of tinned lead on the top of the 
board.


73,
Don W3FPR

On 6/26/2021 4:58 PM, VA1CQ wrote:

Don,

A logical suggestion. I already have made the RF Probe and it's ready 
to use. I was hoping the cause of no power might be something simpler. 
I will start troubleshooting in my next work session.


Murray VA1CQ

On 6/26/2021 5:34 PM, Don Wilhelm wrote:

Murray,

I suggest that you build the RF Probe that was included with the K2 
kit.  The schematic is shown on page 9 of Appendix E along with the 
assembly instructions.
After that, start on Appendix E page 12 - Preparation for Transmitter 
Signal Tracing and follow the steps shown there.


73,
Don W3FPR

On 6/26/2021 4:21 PM, VA1CQ wrote:
I am just completing the build of K2 Serial No. 6397. Everything was 
going perfectly with all receiver tests and adjustments. Everything 
is in spec.


Then I started the transmitter tests. I set the output power control 
for 2.0 watts. Beginning on 40 metres, I am supposed to be able to 
adjust L1 and L2 to measure 2 watts on the internal power meter. I 
measure 0.1 to 0.2 watts. Nothing I adjust or do changes this. My 
input voltage is 13.6V with 250 mA on receive and 600 mA on 
transmit. I've taken a quick read through the Troubleshooting 
section, but I'm wondering if I'm just doing something stupid and 
only think I have a problem when I don't. Being new to the K2, 
perhaps I'm not setting something correctly.


Any tips for what I should do next?

Murray VA1CQ








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Re: [Elecraft] K2 No Power Output

[VA1CQ]

Don,

A logical suggestion. I already have made the RF Probe and it's ready to 
use. I was hoping the cause of no power might be something simpler. I 
will start troubleshooting in my next work session.


Murray VA1CQ

On 6/26/2021 5:34 PM, Don Wilhelm wrote:

Murray,

I suggest that you build the RF Probe that was included with the K2 
kit.  The schematic is shown on page 9 of Appendix E along with the 
assembly instructions.
After that, start on Appendix E page 12 - Preparation for Transmitter 
Signal Tracing and follow the steps shown there.


73,
Don W3FPR

On 6/26/2021 4:21 PM, VA1CQ wrote:
I am just completing the build of K2 Serial No. 6397. Everything was 
going perfectly with all receiver tests and adjustments. Everything 
is in spec.


Then I started the transmitter tests. I set the output power control 
for 2.0 watts. Beginning on 40 metres, I am supposed to be able to 
adjust L1 and L2 to measure 2 watts on the internal power meter. I 
measure 0.1 to 0.2 watts. Nothing I adjust or do changes this. My 
input voltage is 13.6V with 250 mA on receive and 600 mA on transmit. 
I've taken a quick read through the Troubleshooting section, but I'm 
wondering if I'm just doing something stupid and only think I have a 
problem when I don't. Being new to the K2, perhaps I'm not setting 
something correctly.


Any tips for what I should do next?

Murray VA1CQ






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Re: [Elecraft] K2 No Power Output

[Don Wilhelm]

Murray,

I suggest that you build the RF Probe that was included with the K2 
kit.  The schematic is shown on page 9 of Appendix E along with the 
assembly instructions.
After that, start on Appendix E page 12 - Preparation for Transmitter 
Signal Tracing and follow the steps shown there.


73,
Don W3FPR

On 6/26/2021 4:21 PM, VA1CQ wrote:
I am just completing the build of K2 Serial No. 6397. Everything was 
going perfectly with all receiver tests and adjustments. Everything is 
in spec.


Then I started the transmitter tests. I set the output power control 
for 2.0 watts. Beginning on 40 metres, I am supposed to be able to 
adjust L1 and L2 to measure 2 watts on the internal power meter. I 
measure 0.1 to 0.2 watts. Nothing I adjust or do changes this. My 
input voltage is 13.6V with 250 mA on receive and 600 mA on transmit. 
I've taken a quick read through the Troubleshooting section, but I'm 
wondering if I'm just doing something stupid and only think I have a 
problem when I don't. Being new to the K2, perhaps I'm not setting 
something correctly.


Any tips for what I should do next?

Murray VA1CQ




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[Elecraft] K2 No Power Output

[VA1CQ]

I am just completing the build of K2 Serial No. 6397. Everything was 
going perfectly with all receiver tests and adjustments. Everything is 
in spec.


Then I started the transmitter tests. I set the output power control for 
2.0 watts. Beginning on 40 metres, I am supposed to be able to adjust L1 
and L2 to measure 2 watts on the internal power meter. I measure 0.1 to 
0.2 watts. Nothing I adjust or do changes this. My input voltage is 
13.6V with 250 mA on receive and 600 mA on transmit. I've taken a quick 
read through the Troubleshooting section, but I'm wondering if I'm just 
doing something stupid and only think I have a problem when I don't. 
Being new to the K2, perhaps I'm not setting something correctly.


Any tips for what I should do next?

Murray VA1CQ


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Re: [Elecraft] [K2] Low power output

[Petr Ourednik]

Hi Don,

many thanks for all kind help and ideas.
I will try to call him in order to explain all of these steps to be checked.
Most important is to double check what the real power is from his K2 as
I do not know if he measured the output power correctly with his external 
equipment.

Again Don thanks for your kind help and time!

btw: if you remember our son's K1 is still waiting on the shelf to be finished 
the
alignment...:)

best 73 - Petr, OK1RP



On Wed, Sep 4, 2019, at 4:29 PM, Don Wilhelm wrote:
> Petr,
> 
> The specification for the K2 is for 10 watts or greater.  Most will go 
> to 12 watts on 40 and 30 meters with an adequate power supply voltage 
> while few can achieve 15 watts on all bands.
> 
> There is nothing specific to the KPA100 option that would cause low 
> power output from the base K2.
> However, there are a few things to check.
> 
> First check the value of R98 on the bottom of the board.  The normal 
> value is 270 ohms, but after the addition of the KPA100, some 
> experienced power oscillation due to the added RF Gain, and that value 
> may have been increased to damp the oscillation.
> 
> Then check to make certain T4 was not wound for "greater efficiency at 5 
> watts" with a 2:2:1:1 ratio instead of the normal 2:3:1:1 ratio - count 
> the number of white turns on T4.  That 'more efficient' T4 is actually 
> less efficient above 5 watts and should never be used with the KSB2 
> option or the KPA100.
> 
> If there is also HiCur as well as low power then the problem is either 
> with T4 or the Low Pass Filter.
> 
> Make certain the power supply leads are tight and large enough to keep 
> the voltage drop low - a power source with at least 13.8 volts should be 
> used and the voltage should not drop below 12.5 during transmit.  15 
> watts is not possible with a lower voltage, and the output on 12 and 10 
> meters may be less.  10 watts or more meets specification.
> 
> If those checks do not provide the answer, then he will have to do the 
> "Transmit Signal Tracing" in Appendix A of the manual to identify the 
> first stage with less than the expected RF voltage output.
> 
> 73,
> Don W3FPR
> 
> On 9/4/2019 6:47 AM, Petr, OK1RP/M0SIS wrote:
> > Hi folks,
> > 
> > my colleque got as birthday gift from family the K2. All seems ok, receiver
> > works excellent.
> > The only issue he found is the low power output thru all bands. He can not
> > get 15W but something
> > below 10W... He mentioned in last email that preview owner had installed
> > KPA100 option which
> > has been removed probably before selling.
> > Is there something related to KPA100 which could be modified and need to be
> > now set back to get
> > 15W from his K2 please?
> > 
>

-- 
73 - Petr, OK1RP
--
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MeWe: https://bit.ly/2HGPoDx
MeWe: https://bit.ly/2FmwvDt
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Re: [Elecraft] [K2] Low power output

[Don Wilhelm]

Petr,

The specification for the K2 is for 10 watts or greater.  Most will go 
to 12 watts on 40 and 30 meters with an adequate power supply voltage 
while few can achieve 15 watts on all bands.


There is nothing specific to the KPA100 option that would cause low 
power output from the base K2.

However, there are a few things to check.

First check the value of R98 on the bottom of the board.  The normal 
value is 270 ohms, but after the addition of the KPA100, some 
experienced power oscillation due to the added RF Gain, and that value 
may have been increased to damp the oscillation.


Then check to make certain T4 was not wound for "greater efficiency at 5 
watts" with a 2:2:1:1 ratio instead of the normal 2:3:1:1 ratio - count 
the number of white turns on T4.  That 'more efficient' T4 is actually 
less efficient above 5 watts and should never be used with the KSB2 
option or the KPA100.


If there is also HiCur as well as low power then the problem is either 
with T4 or the Low Pass Filter.


Make certain the power supply leads are tight and large enough to keep 
the voltage drop low - a power source with at least 13.8 volts should be 
used and the voltage should not drop below 12.5 during transmit.  15 
watts is not possible with a lower voltage, and the output on 12 and 10 
meters may be less.  10 watts or more meets specification.


If those checks do not provide the answer, then he will have to do the 
"Transmit Signal Tracing" in Appendix A of the manual to identify the 
first stage with less than the expected RF voltage output.


73,
Don W3FPR

On 9/4/2019 6:47 AM, Petr, OK1RP/M0SIS wrote:

Hi folks,

my colleque got as birthday gift from family the K2. All seems ok, receiver
works excellent.
The only issue he found is the low power output thru all bands. He can not
get 15W but something
below 10W... He mentioned in last email that preview owner had installed
KPA100 option which
has been removed probably before selling.
Is there something related to KPA100 which could be modified and need to be
now set back to get
15W from his K2 please?


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[Elecraft] [K2] Low power output

[Petr, OK1RP/M0SIS]

Hi folks,

my colleque got as birthday gift from family the K2. All seems ok, receiver
works excellent.
The only issue he found is the low power output thru all bands. He can not
get 15W but something
below 10W... He mentioned in last email that preview owner had installed
KPA100 option which
has been removed probably before selling. 
Is there something related to KPA100 which could be modified and need to be
now set back to get
15W from his K2 please?

Thanks, 



-
73 - Petr, OK1RP 
"Apple & Elecraft freak"
B:http://ok1rp.blogspot.com
MeWe: https://bit.ly/2HGPoDx
MeWe: https://bit.ly/2FmwvDt
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Re: [Elecraft] K2 - Unstable power output on 40m (digital modes)

[Don Wilhelm]

Brian,

Do things settle down if you drive a dummy load instead of the antenna?  
If so, that would nail it as an RF Feedback.  If that is the case, use a 
good quality common mode choke at the junction of the coax with the 
ladderline.  See K9YC's RFI information at 
http://audiosystemsgroup.com/RFI-Ham.pdf - chapters 6 and 7 cover making 
effective feedline chokes.


Also investigate your KPA100 to see if it has the latest upgrade. The 
T/R switch was changed to eliminate instability on 40 meters.
Remove the right side panel of the K2 and peer between the KPA100 shield 
and board.  If you see blue toroid cores at RFC1 and L16, you have the 
updated version.  If you see red cores, update with KPA100UPKT.
You may also have to update the shield.  If you do not have shield clips 
to connect the shield to the sides of the base K2 and a shield over the 
speaker magnet, add the KPA100SHLDKT.


73,
Don W3FPR


On 10/25/2015 1:45 AM, Brian - N5BCN via Elecraft wrote:

I'm having an issue with unstable power output using digital modes on 40m
above about 20 watts.  All other bands seem to be ok.

My antenna setup is as follows: a loop consisting of about 245 feet of wire,
feed line consists of about 21 feet of 450 ohm ladderline to an Elecraft BL2
balun, then about 3 feet of coax to KAT100/KPA100/K2.  I've tried the balun
in 1:1 and 4:1 configs with no apparent change.  The feed point of the loop
is in the attic above the shack, but the majority of the wire is outside
running along a wood fence.

No problems tuning any band including 40m.  When using digital modes, power
output and ALC action (no bars) appears normal on 10 through 30m, and even
works ok on 80m.  Haven't tried 160m.




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Re: [Elecraft] K2 - Unstable power output on 40m (digital modes)

[David Anderson]

Brian,

The Elecraft K series requires a different way of setting power out on digital. 

You increase the audio drive from the SignaLink until the "ALC" meter is 
showing 4 to 5 bars and then adjust the power control to set the required power 
out, do not use the audio level to adjust the power.

The "ALC" meter is actually just an audio level meter until the 6th bar when 
actual power reducing ALC starts. 

I know this apparently goes against normal advice to not have any ALC showing, 
but in effect you are not because of the way the "ALC" meter on the K series is 
configured. There is no ALC action until the 6th bar of "ALC".

If you don't have sufficient audio (4 to 5 bars of "ALC" ) then the radio power 
output will be unstable as you have described.


73

David Anderson GM4JJJ 

> On 25 Oct 2015, at 05:45, Brian - N5BCN via Elecraft 
>  wrote:
> 
> No problems tuning any band including 40m.  When using digital modes, power
> output and ALC action (no bars) appears normal on 10 through 30m, and even
> works ok on 80m.  Haven't tried 160m.
> 
> However, when attempting digital modes (using a Signalink) on 40m, power
> output and ALC action is "all over the place" and generally folds back to a
> couple of watts.  The output also seems to be extremely "touchy" and
> sensitive to the TX drive setting on the Signalink that's not apparent on
> other bands.  I don't see this craziness using a dummy load, so I'm
> suspecting maybe I'm getting RF feedback only on 40m for some reason.
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Re: [Elecraft] K2 - Unstable power output on 40m (digital modes)

[David Anderson]

Brian,

Too early in the morning with me, I just noticed the fact you have a K2 not a 
K3 or KX3.

In that case the ALC meter is different, but perhaps you may find something 
that is helpful on the late G4ILO's site:

http://www.g4ilo.com/k2psk31.html


73

David Anderson GM4JJJ 

> On 25 Oct 2015, at 09:19, David Anderson  wrote:
> 
> Brian,
> 
> The Elecraft K series requires a different way of setting power out on 
> digital. 
> 
> Snip..


> 
>> On 25 Oct 2015, at 05:45, Brian - N5BCN via Elecraft 
>>  wrote:
>> 
>> No problems tuning any band including 40m.  When using digital modes, power
>> output and ALC action (no bars) appears normal on 10 through 30m, and even
>> works ok on 80m.  Haven't tried 160m.
>> 
>> How
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Re: [Elecraft] K2 - Unstable power output on 40m (digital modes)

[Brian - N5BCN via Elecraft]

Don,

Yes, things settle down with a dummy load, so it looks like I'm dealing with
RF feedback.

Per the original post, I'm using an Elecraft BL2 balun at the
coax/ladderline junction.  Shouldn't this act as the common mode choke that
you suggest or are you suggesting to place a common mode choke in addition
to the balun?

Interesting idea regarding the KPA100 latest version since 40m is the
troublesome band.  I purchased the KPA100 around 2011-2012, so I would think
it has the latest hardware but I'll double check when I get a chance.

73 Brian, N5BCN



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Re: [Elecraft] K2 - Unstable power output on 40m (digital modes)

[Bob McGraw - K4TAX]

My take on this is baluns are baluns and common mode chokes are common 
mode chokes.  In many cases baluns do not provide adequate common mode 
choking requirements.  Thus both may be needed. Usually, the balun is 
located physically at the load and the common mode choke is located at 
the source.In certain antenna configurations, a balun is used at the 
feed point along with a common mode choke and then a 2nd common mode 
choke at the source is required as well.


73
Bob, K4TAX
K3S s/n 10163
 


On 10/25/2015 10:09 AM, Brian - N5BCN via Elecraft wrote:

Don,

Yes, things settle down with a dummy load, so it looks like I'm dealing with
RF feedback.

Per the original post, I'm using an Elecraft BL2 balun at the
coax/ladderline junction.  Shouldn't this act as the common mode choke that
you suggest or are you suggesting to place a common mode choke in addition
to the balun?

Interesting idea regarding the KPA100 latest version since 40m is the
troublesome band.  I purchased the KPA100 around 2011-2012, so I would think
it has the latest hardware but I'll double check when I get a chance.

73 Brian, N5BCN



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Re: [Elecraft] K2 - Unstable power output on 40m (digital modes)

[Fred Jensen]

Yep, almost.  The word "balun" is a portmanteau of "balanced" and 
"unbalanced."  They are transformers or auto-transformers and their job 
is to keep a balanced feed to the antenna balanced when transitioning to 
unbalanced coax.  Since they're transformers, they can also transform 
the impedance.


Common mode chokes act as a series high impedance to current on the 
outside of the coax shield.  For RF, coaxial cable is really a 
3-conductor circuit because of the so-called "skin effect" ... inner 
conductor and inside of shield form one path are is unaffected by a CM 
choke.  Current can also be induced on the outside of the shield and is 
the common-mode current.  When transmitting, they can radiate close to 
the shack and get into places that don't like RF.  They can also distort 
the radiation pattern of the antenna.  When receiving, the outside of 
the shield acts as a vertical antenna and can pick up noise.


CM chokes are often a string of ferrite toroids taped together with the 
coax going through them.  Sometimes, the coax is wound several times 
through a larger toroid.  First place to put them is at the antenna-end 
of the coax.  In some cases, a CM choke at the station entrance will 
help as well, but it's not the first choice.


Jim, K9YC, has prepared "Common Mode Chokes [and other things] For 
Dummies" at http://audiosystemsgroup.com/RFI-Ham.pdf  It's full of 
information, including some charts demonstrating that all ferrites are 
not created equal.


73,

Fred K6DGW
- Northern California Contest Club
- CU in the Cal QSO Party 1-2 Oct 2016
- www.cqp.org


On 10/25/2015 12:32 PM, Bob McGraw - K4TAX wrote:

My take on this is baluns are baluns and common mode chokes are common
mode chokes.  In many cases baluns do not provide adequate common mode
choking requirements.  Thus both may be needed. Usually, the balun is
located physically at the load and the common mode choke is located at
the source.In certain antenna configurations, a balun is used at the
feed point along with a common mode choke and then a 2nd common mode
choke at the source is required as well.


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Re: [Elecraft] K2 - Unstable power output on 40m (digital modes)

[Don Wilhelm]

Brian,

The Elecraft BL2 is a good common mode choke.  It is rated at 250 watts 
into a *matched* load.
Your load certainly is not matched, and I do not know how to de-rate the 
power for any given load.
Check to see if the balun core heats - if so, you could be operating the 
BL2 outside its range of capability.

Note that I am only making a guess here.

One thing that you could do is to remove the coax from the tuner and 
measure the impedance of the entire antenna system with an antenna 
analyzer.  That will give you a better idea of whether to use the 1:1 or 
4:1 position on the balun.


Another thing to consider is the position on the antenna feedline in 
relationship to the radiator - the feedline should come away from the 
radiator at right angles for as far as possible.  If it does not, energy 
from the radiator can couple onto the feedline and create common mode 
current that is difficult to choke off - in that case, the choking 
impedance of the BL2 may not be sufficient and you may have to add 
additional common mode chokes.


As a quick test for common mode current on 40 meters, yes try tying a 33 
foot counterpoise wire to the ground post on the BL2 - keep the far end 
isolated and insulated because it will have a high RF voltage on it.  If 
it makes a difference, then you will have to get rid of the common mode 
current on the feedline.


73,
Don W3FPR

On 10/25/2015 11:09 AM, Brian - N5BCN via Elecraft wrote:

Don,

Yes, things settle down with a dummy load, so it looks like I'm dealing with
RF feedback.

Per the original post, I'm using an Elecraft BL2 balun at the
coax/ladderline junction.  Shouldn't this act as the common mode choke that
you suggest or are you suggesting to place a common mode choke in addition
to the balun?

Interesting idea regarding the KPA100 latest version since 40m is the
troublesome band.  I purchased the KPA100 around 2011-2012, so I would think
it has the latest hardware but I'll double check when I get a chance.

73 Brian, N5BCN



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Re: [Elecraft] K2 - Unstable power output on 40m (digital modes)

[Jim Brown]

Yes. And even more important -- the word "balun" is used to describe so 
many (at least) ten different very kinds of components that the word 
itself should be banned from our language.  ONE of those components is a 
common mode choke. Another is an array of common mode chokes. Another is 
a simple transformer. Another is a simple autotransformer. Another is a 
section of transmission line. Another is an array of sections of 
transmission line. Another is an active device to put broadband video on 
twisted pair. And so on.


73, Jim K9YC

On Sun,10/25/2015 12:32 PM, Bob McGraw - K4TAX wrote:
My take on this is baluns are baluns and common mode chokes are common 
mode chokes.  In many cases baluns do not provide adequate common mode 
choking requirements.  Thus both may be needed. Usually, the balun is 
located physically at the load and the common mode choke is located at 
the source.In certain antenna configurations, a balun is used at 
the feed point along with a common mode choke and then a 2nd common 
mode choke at the source is required as well.


73 


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[Elecraft] K2 - Unstable power output on 40m (digital modes)

[Brian - N5BCN via Elecraft]

I'm having an issue with unstable power output using digital modes on 40m
above about 20 watts.  All other bands seem to be ok.

My antenna setup is as follows: a loop consisting of about 245 feet of wire,
feed line consists of about 21 feet of 450 ohm ladderline to an Elecraft BL2
balun, then about 3 feet of coax to KAT100/KPA100/K2.  I've tried the balun
in 1:1 and 4:1 configs with no apparent change.  The feed point of the loop
is in the attic above the shack, but the majority of the wire is outside
running along a wood fence.

No problems tuning any band including 40m.  When using digital modes, power
output and ALC action (no bars) appears normal on 10 through 30m, and even
works ok on 80m.  Haven't tried 160m.

However, when attempting digital modes (using a Signalink) on 40m, power
output and ALC action is "all over the place" and generally folds back to a
couple of watts.  The output also seems to be extremely "touchy" and
sensitive to the TX drive setting on the Signalink that's not apparent on
other bands.  I don't see this craziness using a dummy load, so I'm
suspecting maybe I'm getting RF feedback only on 40m for some reason.

I'm not sure what to try to mitigate this.  The variables I could change
would be to increase/decrease the ladderline length, try a more robust
balun, or maybe try a counterpoise wire tied to the balun's ground lug?  Any
ideas and suggestions would be most appreciated, I sure would like to be
able to use 40m!

73 Brian, N5BCN



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[Elecraft] K2 Low power output

[W8OV]

I recently acquired a very clean K2/100 with external KAT100 ATU.  I 
have a K3/100 and its power output agrees closely with the readings of 
both Bird and Elecraft W2 watt meters. According to these watt meters 
the K2, set to full power of 110W, puts out about 80 - 85 W into a dummy 
load (SWR reads 1.1 on KAT100).  Everything else seems to work very 
well, and manuals came with the radio.


Any suggestions as to steps I should take to get full power output from 
the K2 (S/N 4000+), or is that close enough?


Dave, W8OV

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Re: [Elecraft] K2 Low power output

[Don Wilhelm]

Dave,

It may be that the wattmeter in the KPA100 needs calibration - and is 
the most likely reason.

Dig out the KPA100 manual and look at page 48.
Do the SWR Bridge Null Adjustment first.
Then do the Power Calibration.

There may be some variability in the calibration from band to band 
because the diode response is not entirely  linear with respect to 
frequency, but if you do the calibration on 40 meters or 30 meters, it 
should be quite reasonable for all bands.


73,
Don W3FPR

On 11/25/2014 12:55 PM, W8OV wrote:
I recently acquired a very clean K2/100 with external KAT100 ATU.  I 
have a K3/100 and its power output agrees closely with the readings of 
both Bird and Elecraft W2 watt meters. According to these watt meters 
the K2, set to full power of 110W, puts out about 80 - 85 W into a 
dummy load (SWR reads 1.1 on KAT100). Everything else seems to work 
very well, and manuals came with the radio.


Any suggestions as to steps I should take to get full power output 
from the K2 (S/N 4000+), or is that close enough?


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[Elecraft] K2/100 power output

[wsm]

Hello

My K2/100 just recently started going to 100 watts output
as soon as I set the output to 11 watts or greater.
I disconnected the amp, and am back to the qrp version and
everything works fine. So I asume the problem is with the
amp. Am I correct?
Thanks
Scott N5SM 


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Re: [Elecraft] K2/100 power output

[Don Wilhelm]

Scott,

Yes, the problem is with the KPA100.  The most likely thing is that 
diodes D16 and D17 are damaged which results in the KPA100 not being 
able to tell the K2 that power output is being developed, so the K2 just 
increases the power to the max in an effort to obtain a power output 
indication.  At setting less than 11 watts, the base K2 is probably 
producing its maximum power output as well which will be in the 10 to 15 
watt range.


The most probable cause for D16, D17 failure is a lightning surge - it 
is always a good idea to disconnect the antennas when not in use.  I 
switch all my equipment to a dummy load unless I am actively operating.


73,
Don W3FPR

[EMAIL PROTECTED] wrote:

Hello

My K2/100 just recently started going to 100 watts output
as soon as I set the output to 11 watts or greater.
I disconnected the amp, and am back to the qrp version and
everything works fine. So I asume the problem is with the
amp. Am I correct?
Thanks
Scott N5SM 



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Re: [Elecraft] K2-no power output

[Gary Marks]

Don,
   I can't find any problems with the KAT2 cables. I removed the KAT2 from 
the rig by disconnecting the coax at P6 and the 10-pin connector. Using the 
BNC connector marked ANTENNA, I've connected my dummy load.I set the power 
level at 5 watts and pressed TUNE and only see an output of 0.2 watts.
I've read the prep for signal tracing and am not exactly sure about the 
jumpers at J9  J10. I'm guessing the two jumpers go from pin 1 to pin 3 ? 
Correct ?  Also, I no longer have C167 (.001 or 102) and would have to get 
one next week. I do have a .001 disc cap available. Would that work ?

Gary


Gary,

This problem has nothing to do directly with the installation of the 
KDSP2.
Think of whatever else you may have accidently touched - the KAT2 cables 
are

a relevant example.

Remove the KAT2 and feed the K2 directly into a 50 ohm dummy load - when 
you

press TUNE you should see the output power displayed (and it will be
accurate if you have a good 50 ohm dummy load).  That will tell you if the
K2 is capable of producing the required power output.

If you do see the proper power output with the ATU disconnected, look for
the problem with the ATU.  Check your K2 to KAT2 coaxial cable carefully 
to

be certain the pins are properly seated and the wires for the coax are not
broken at either end - sometimes they will break with a bit of flexing if
they are not properly soldered.

If you get no output with the ATU disconnected, then prepare yourself for
the Transmit Signal Tracing that is detailed in the Troubleshooting 
section

of the manual.  You will need the RF Probe assembled (or an oscilloscope
with a 10X probe) for that testing.

73,
Don W3FPR



-Original Message-

I just finished installing the KDPS2 boards and they check out
OK. I also have the KAT2 installed and it was working.

I was going to operate today for the first time but when
pressing TUNE, I'm not getting any power out. I have an external
watt meter too. When I press TUNE, I see Atu on the right side of
the LCD then it quickly flashes to 1.0-1 on the left side , then
displays Lo  P. I've changed bands and frequency's up  down but
do not here the relays in the antenna tuner clicking as before.
I went through the various relays through the MENU and I can here
each individual relay click just as I did when first testing
the KAT2 option. Nothing on CW or SSB. I switched to ANT2 which
is my Elecraft Dummy Load with the same thing happening so it
isn't a problem with the antenna.

The KAT2 manual says that when this happens to increase the power
which I did in steps up to 15 watts with no change.   Am
I missing a setting or does the KDSP2 board have something to do
with this. I believe I installed the top cover correctly and have
all the wires connected after installing the DSP boards.

Any suggestions ?

THANKS.Gary  WD8ICX





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[Elecraft] K2-no power output

[Gary Marks]

I just finished installing the KDPS2 boards and they check out OK. I also have 
the KAT2 installed and it was working.

I was going to operate today for the first time but when pressing TUNE, I'm 
not getting any power out. I have an external watt meter too. When I press 
TUNE, I see Atu on the right side of the LCD then it quickly flashes to 1.0-1 
on the left side , then displays Lo  P. I've changed bands and frequency's up  
down but do not here the relays in the antenna tuner clicking as before. I 
went through the various relays through the MENU and I can here each individual 
relay click just as I did when first testing the KAT2 option. Nothing on CW 
or SSB. I switched to ANT2 which is my Elecraft Dummy Load with the same thing 
happening so it isn't a problem with the antenna.

The KAT2 manual says that when this happens to increase the power which I did 
in steps up to 15 watts with no change.   Am I missing a setting or 
does the KDSP2 board have something to do with this. I believe I installed the 
top cover correctly and have all the wires connected after installing the DSP 
boards.

Any suggestions ?

THANKS.Gary  WD8ICX
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RE: [Elecraft] K2-no power output

[Ron D'Eau Claire]

Are you by any chance in TEST mode??

If so the c and the underline on the display will be blinking and you'll
get no power output. 

Hold the MODE button to return to normal operation. 

Ron AC7AC

-Original Message-
I just finished installing the KDPS2 boards and they check out OK. I also
have the KAT2 installed and it was working.

I was going to operate today for the first time but when pressing TUNE,
I'm not getting any power out. I have an external watt meter too. When I
press TUNE, I see Atu on the right side of the LCD then it quickly flashes
to 1.0-1 on the left side , then displays Lo  P. I've changed bands and
frequency's up  down but do not here the relays in the antenna tuner
clicking as before. I went through the various relays through the MENU and
I can here each individual relay click just as I did when first testing
the KAT2 option. Nothing on CW or SSB. I switched to ANT2 which is my
Elecraft Dummy Load with the same thing happening so it isn't a problem with
the antenna.

The KAT2 manual says that when this happens to increase the power which I
did in steps up to 15 watts with no change.   Am I missing a setting
or does the KDSP2 board have something to do with this. I believe I
installed the top cover correctly and have all the wires connected after
installing the DSP boards.

Any suggestions ?

THANKS.Gary  WD8ICX ___

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RE: [Elecraft] K2-no power output

[Don Wilhelm]

Gary,

This problem has nothing to do directly with the installation of the KDSP2.
Think of whatever else you may have accidently touched - the KAT2 cables are
a relevant example.

Remove the KAT2 and feed the K2 directly into a 50 ohm dummy load - when you
press TUNE you should see the output power displayed (and it will be
accurate if you have a good 50 ohm dummy load).  That will tell you if the
K2 is capable of producing the required power output.

If you do see the proper power output with the ATU disconnected, look for
the problem with the ATU.  Check your K2 to KAT2 coaxial cable carefully to
be certain the pins are properly seated and the wires for the coax are not
broken at either end - sometimes they will break with a bit of flexing if
they are not properly soldered.

If you get no output with the ATU disconnected, then prepare yourself for
the Transmit Signal Tracing that is detailed in the Troubleshooting section
of the manual.  You will need the RF Probe assembled (or an oscilloscope
with a 10X probe) for that testing.

73,
Don W3FPR


 -Original Message-

 I just finished installing the KDPS2 boards and they check out
 OK. I also have the KAT2 installed and it was working.

 I was going to operate today for the first time but when
 pressing TUNE, I'm not getting any power out. I have an external
 watt meter too. When I press TUNE, I see Atu on the right side of
 the LCD then it quickly flashes to 1.0-1 on the left side , then
 displays Lo  P. I've changed bands and frequency's up  down but
 do not here the relays in the antenna tuner clicking as before.
 I went through the various relays through the MENU and I can here
 each individual relay click just as I did when first testing
 the KAT2 option. Nothing on CW or SSB. I switched to ANT2 which
 is my Elecraft Dummy Load with the same thing happening so it
 isn't a problem with the antenna.

 The KAT2 manual says that when this happens to increase the power
 which I did in steps up to 15 watts with no change.   Am
 I missing a setting or does the KDSP2 board have something to do
 with this. I believe I installed the top cover correctly and have
 all the wires connected after installing the DSP boards.

 Any suggestions ?

 THANKS.Gary  WD8ICX


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[Elecraft] K2 lowest power output

[Siu Johnny]

Hi Don,

I do not have any power meter which can measure any RF power output less 
than 1 watt.  Could you please advise the minimum output power level of K2 
with the power knot fully CCW?


BTW, under the SEC menu of K2, the transverter output (without the 
installation of KV60) can be lowered to 0.1 watt.  Would this be the lowest 
level output of K2?


I encounter some problems in building my XV144 and am in communication with 
Gary.  He is very responsive and helpful.  Upon solving the problem, I 
shall come back to this reflector again and let other members know my 
experience.


TNX  73

Johnny Siu VR2XMC


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[Elecraft] K2 indicated power output funnies

[bobatbay]

Hi 
I have owned K2 #3914 for a few years now, but just recently 
it has developed a rather strange fault. 

On all bands, whatever the requested power level using the 
front Panel power knob, the bargraph display and power 
indication from the  Pout display from the onboard atu 
indicate no higher than about 6 watts. At requested power 
below 6 watts all appears OK.

Upon checking with a Bird thruline into dummy load the power 
requested tallies with the power out on the thruline. 

Has anyone experienced similar problems 

Bob G4DBW  
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RE: [Elecraft] K2 indicated power output funnies

[Don Wilhelm]

Bob,

I would have to have a lot more data for a more definite analysis, but one
thing that can cause 'funny' power readings is the diodes in the ATU
wattmeter.  They are sitting right out there on the antenna line where they
can be easily subjected to static discharges.  You may want to arbitrarily
replace them and see if the situation improves.  Re-calibrate the wattmeter
after replacing them.

73,
Don W3FPR


 -Original Message-

 Hi
 I have owned K2 #3914 for a few years now, but just recently
 it has developed a rather strange fault.

 On all bands, whatever the requested power level using the
 front Panel power knob, the bargraph display and power
 indication from the  Pout display from the onboard atu
 indicate no higher than about 6 watts. At requested power
 below 6 watts all appears OK.

 Upon checking with a Bird thruline into dummy load the power
 requested tallies with the power out on the thruline.

 Has anyone experienced similar problems

 Bob G4DBW


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[Elecraft] K2 10m Power Output

[Ben Hofmann KB1AHR]

Hello all,
 
I completed the transmitter alignment on K2 #4429 recently.  In checking the 
power output on all the bands I found that I can indeed get just over 10w on 
10m at 28.2 MHz (the frequency used to peak the bandpass filters) as long as I 
am using a power supply.  Using a battery, I had too much voltage drop, and 
less power output.  When I tune up to 28.8 MHz, I can only get less than 9w 
output (using the power supply.)  Why does the manual instruct to use 28.2 MHz 
to peak the filters rather than 28.4 MHz which would be the center of the K2 
band specification for 10m?  I would think using 28.4 MHz would give me higher 
output at the high end of the band probably at the expense of lower power at 
the lower end of the band.  Since the bandpass filter is shared between 10m and 
12m, I don't know if doing the peak at 28.4 MHz would adversely affect 12m or 
not.  Any thoughts?  I'd like to get 10w minumum over the whole band if I can.  
Should I try and get the power to be more even across t
 he band,
 or am I being too picky here?
 
By the way, I was very careful with T2 during construction.  Red winding 
occupies about 85% of core, and green winding about 50%.  It is spaced between 
3/32 and 1/8 off the PC board.  I did not however interleave the windings on 
T4, I wound it as instructed in the manual.
 
-Ben  KB1AHR
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RE: [Elecraft] K2 10m Power Output

[W3FPR - Don Wilhelm]

Ben,

The place where one aligns the bandpass filter on 10 meters must depend on
the 10 meter operating that is anticipated.  If the interest is mainly CW,
the bandpass filter would be peaked at 28.2 MHz as stated in the manual --
OTOH, if more phone operation (or CW higher in the band) is more desirable,
then by all means peak the Bandpass at a higher frequency.  I often peak the
bandpass filter at 28.4 or 28.5 to provide more coverage over the band with
10 watts or more.  You will note that the output drops off more quickly (per
kHz) on the high end than at the low end, so I just balance things so I have
10 watts or more at both 28.0 and 28.8 - whatever the peaking frequency may
be to achieve that goal.

Yes, you will have to re-peak 12 meters after peaking 10 -- there is no
danger of running out of adjustment range on 12 meters.

73,
Don W3FPR

 -Original Message-

 I completed the transmitter alignment on K2 #4429 recently.  In
 checking the power output on all the bands I found that I can
 indeed get just over 10w on 10m at 28.2 MHz (the frequency used
 to peak the bandpass filters) as long as I am using a power
 supply.  Using a battery, I had too much voltage drop, and less
 power output.  When I tune up to 28.8 MHz, I can only get less
 than 9w output (using the power supply.)  Why does the manual
 instruct to use 28.2 MHz to peak the filters rather than 28.4 MHz
 which would be the center of the K2 band specification for 10m?
 I would think using 28.4 MHz would give me higher output at the
 high end of the band probably at the expense of lower power at
 the lower end of the band.  Since the bandpass filter is shared
 between 10m and 12m, I don't know if doing the peak at 28.4 MHz
 would adversely affect 12m or not.  Any thoughts?  I'd like to
 get 10w minumum over the whole band if I can.  Should I try and
 get the power to be more even across t
  he band,
  or am I being too picky here?




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Re: [Elecraft] K2 #4130 power output result

[Don Brown]

Hi

This looks good to me. The basic K2 power sensing circuit will not be exact. If 
you have the KAT2, KAT100 OR KPA100 the power calibration can be set almost 
perfect because of the better directional coupler type power meter circuit. The 
basic K2 uses a peak detector using a diode and a couple of precision resistors 
and some filtering. There are no adjustments with this circuit so it can vary a 
little from K2 to K2 mostly due to differences in the diode

Don Brown
KD5NDB


  - Original Message - 
  From: JEAN-FRANCOIS MENARDmailto:[EMAIL PROTECTED] 
  To: elecraft@mailman.qth.netmailto:elecraft@mailman.qth.net 
  Sent: Friday, July 16, 2004 11:07 AM
  Subject: [Elecraft] K2 #4130 power output result


  Now, after a little technical briefing by Tom N0SS and Gary AB7MY 
  (thanks),

  There are my K2 power output results using the DL1 dummy load when 
  applying the formula written in the build sheet of the DL1 and my VMM 
  set to DC.

BAND Power set on K2 @ 5W Power set on K2 @ 10W

  160M (1.9 Mhz) 5.2W 10.9W

  80M (3.750 Mhz) 5.3W 10.8W

  40M (7.070 Mhz) 5.5W 11.0W

  20M (14.100 Mhz) 4.5W 9.5W

  15M (21.200 Mhz) 4.9W 9.3W

  10M (28.500 Mhz) 4.3W 8.6W


  Is it these values are in the average with most builders ???


  ===
  Jean-François Ménard / VA2VYZ
  [EMAIL PROTECTED]mailto:[EMAIL PROTECTED]
  Elecraft K2 #4130

  Amateur Radio Club of Sherbrooke, Quebec, Canada

  Web site: http://homepage.mac.com/jfmenardhttp://homepage.mac.com/jfmenard
  ===
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[Elecraft] K2 #4293 power output problem solved

[Jukka Tarvainen (OH4MFA)]

Good morning Elecrafters!

My K2 power output problem solved, first QSO done. Everything seems to be
OK now.

Yesterday my friend Sami, OH4KLU, came over and we looked together into
K2 problem. There was no indication of TX nowhere. 8R voltage went down
to 0.6 V, not below 0.3 V. We started to look reason for that and didn't
find any. Then checked D7 and voltage was missing from there when in TUNE.
Then we looked for 8T and found out that U6 P27 on control board did not
go to 5 V when in TUNE. P28 RX was OK and changed from 5 to 0 V when in
TUNE. Then we look into Q1-Q4 (ctrl-board) and found that there was something
wrong around Q3. There was only 100 ohms between gate and ground. We took
another 2N7000 from amp keying kit and replaced Q3. Then tested again and
got 1+ watts from 40 m. TX worked! I installed heat sink back in place and
started to align BPF. All bands went easily to 2 watts and got 10 watts
in 40 m with 2.2 A using 12 V SLA-battery as power supply. It was late after
midnight, so we didn't test other bands power output. But we had to make
short test and put a wire on the balcony and went looking for stations in
40 m. With 5 watts I worked HF650D (SP) and asked about my tone. The answer
was that tone is FB and clear. Then I shut down K2 and went to sleep with
big smile on my face.

Today I will check output on other bands too and go to test the rig with
better antennas.

Thank you Gary at Elecraft, Don W3FPR and others for help. I still have
many options to go ahead, so I believe I will need some assistance later
on too.

73 de Jukka, OH4MFA
K2 #4293

p.s. I found PTTL in T6 :( I will make toroids in the future more carefully.


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