Re: [Elecraft] KPA100 Power Surge Advice

[Michael Carter]

Thanks, Geert Jan, for recounting the 'origin story'
of the K2 'twins', the outboard combination of the
KPA100 and KAT100.  I had not previously heard
of the origin and Lyle's (KK7P) role in that process.

I hope Larry can provide more detail about
the actual configuration of his outboard
KPA100.

73,
Mike, K8CN
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com 

Re: [Elecraft] KPA100 Power Surge Advice

[Geert Jan de Groot]

Hi,

In addition to Mike's response (always happy to read his comments!), I 
think it is useful to give some additional hints as you may need a 
better understanding of the configuration you have.


The Elecraft K2 is a 15W QRP transceiver, with the optional QRP 
antennatuner and the battary option in the top lid.


When Elecraft introduced the 100W KPA option, the basic idea was that 
the top lid could be replaced with the KPA100 to get 100W output. When 
the KAT100 antenna tuner was introduced, it would add another (lower) 
box that was supposed to sit under the K2/100 radio. Switching between 
QRP portable mode (with battary) and 100W version meant switching the 
top lid.


The KPA100 doesn't have any indicators. The KAT100 tuner does: ANT1/ANT2 
selection, LOW/HIGH power (enabling or disabling the KPA100 amplifier, 
which could be switched to be bypassed for QRP power levels) and a LED 
bar to indicate SWR.


I think it was Lyle KK6P (of KDSP2 fame) who conceived a different 
approach: the frontpanel of the KAT100 tuner was available in two 
versions, one for the low KAT100 box, but also a bigger frontpanel that 
would be the same size as a K2 radio. You would buy a "K2 empty box" and 
in this second box, one would install the KAT100 tuner (bottom) and the 
KPA100 amplifier (top).
The QRP antenna tuner / battary would be in the original top, that stays 
on the K2. Connecting the boxes together would give a 100W radio with 
PA, 100W antenna tuner; disconnecting the two would give a the K2 
portable radio with builtin battary. I built this configuration.


Since you mention "separate enclosure" I suspect this is the config you 
built too.


It seems that information about this configuration has gotten a bit lost 
over the years. The KAT100 module design was made to allow for this; for 
instance, it had a BNC connector so that the input of the KPA100 
amplifier could be connected to the K2 this way. Power to the twin boxes 
would be via the 20A powerpole connector on the KPA100 module; the 
KPA100 module has a low-power power connector that would normally supply 
the K2, but in this configuration would power the KAT100 module. The 
KAT100 module, as well as the K2 radio itself, has a 2.1mm barrel jack 
that if you would use interconnect powercables, would power the K2 (from 
the KPA100 and the KAT100 module). And the AUX connector (DE9) on K2 and 
KPA100 on the twin box would be connected via a short jumper cable. 
There are a number of options here, depending on how this was built 
(hence 'information a bit lost').


I need *three* cables between the two twin boxes: a coax jumpercable to 
interconnect the BNC antenna ports, a powercable to power the K2 from 
the twin box, and a DE9 jumpercable to bring AUXbus, 12VCNTL, ALC, 8R 
and ground between the two boxes. Please verify you connected al three 
cables; I have my suspicions about the DE9 cable.


Now,to your question. First, the KPA100 module (again / still) does not 
have a power indicator. The KAT100 module *does* have indicators. And 
they only light if the KAT100 module senses power from the K2 radio 
(that is now it "switches off" if the K2 is switched off).


So, the first question is whether the K2 and the twin box is connected 
correctly. The twin box has 2 AUX DE9 connectors (one on the KPA100, one 
on the KAT100); please verify it is connected to the right one.
(In my case, I did not place the KAT100 DE9 connector because it didn't 
serve a purpose in my my radio config, the twinbox is made to use the 
DE9 of the KPA100 module!).


Another question is whether the KIO2 module, that provides the DE9 
connector on the K2 radio, actually still supplies +12V on pin 8 of the 
DE9 connector. The voltage is only used as "sense voltage" on the 
KAT100, not to power the tuner.


The K2 senses if it has the twin box connected during powerup. You can 
do a few checks: pressing the ANT1/2 button will flip the relays in the 
KAT100 if it was found during powerup, but will flip the relays in the 
KAT2 QRP antenna tuner if not (the relays in the KAT100 are LOUD!). The 
POWER knob will go to 110 if the KPA100 is found, bit only to 15 (or 10) 
if the KPA100 is not found.
If the K2 radio has the builtin battery, then you should be able to see 
the power supply voltage if you select it using the DISPLAY knob and 
then switch the power supply on and off (the K2 doesn't handle this very 
gracefully, kindly powercycle the K2 after this test).


In short, the problem description is a bit terse but I hope this message 
gives some more background about a config that is partially forgotten in 
past years and not very well documented.


And whatever you do, NEVER CONNECT A NORMAL RS232 SERIAL CABLE IN THE 
DE9 of a K2 OR KPA100 MODULE. A "serial device" only connects pin 2, 3 
and 5, NOTHING ELSE.


73, Geert Jan PE1HZG

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: 

Re: [Elecraft] KPA100 Power Surge Advice

[Michael Carter]

Hi Larry,

You mention in the title '...Power Surge Advice.'
I presume your KPA100 was working properly
prior to not powering up?

You also describe the connection from your power supply to
the KPA100 and then to the K2 - does this
imply a Y-connection from the power supply
to both the K2 and KPA100 since the units
use different power connectors?

Do you have an external fuse inline from the
the power supply to the KPA100 and separately
the K2?

The KPA100 has no visual indication of
power-up status unless you added some
indicator in its external enclosure - how
do you know it is not powering up?

I would disconnect the power supply from
both units, measure the open-circuit terminal
voltage, then connect only the K2 to the power
supply and your antenna (bypass the KPA100).
Verify that the base K2/10 works as before.

Check your cables from the power supply
to the KPA100 and K2 for low resistance - and
be sure that the Anderson PowerPoles are
fully seated in the KPA100 connector.

I would measure the resistance at the
KPA100 power connector - in the normal
polarity it should read a high resistance,
in the other polarity it should read a
low resistance due to the reverse polarity
protection diode.

Please let us know your findings.

73,
Mike, K8CN
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com 

Re: [Elecraft] KPA100/KAT100 EC2 Combo to ICOM 705

[kd4iz]

Robin,

I second Don's comments. To add, have been using my KXPA100AT with the 705 and 
have found it simple and trouble free. I know of quite a few other who do the 
same. Good discussions of that on ic-...@groups.io list.

Jack - KD4IZ

-Original Message-
From: elecraft-boun...@mailman.qth.net  On 
Behalf Of Don Wilhelm
Sent: Wednesday, September 29, 2021 11:48
To: Robin Tew ; elecraft@mailman.qth.net
Subject: Re: [Elecraft] KPA100/KAT100 EC2 Combo to ICOM 705

Robin,

That will not work.  The KPA100 depends on internal signals from the base K2 
such as AUXBUS and several other signals to operate and control power output.  
In other words, it is an amplifier dedicated to the K2 and not a general 
purpose amplifier.

The KXPA100 and KXAT100 would serve you better than cobbling up an interface 
that would be quite complex.

he signals needed are those in the 9 pin AUX IO connector.  AUXBUS allows the 
base K2 firmware to 'talk' to the KPA100 firmware IC as well as the KAT100 
firmware.

73,
Don W3FPR

On 9/29/2021 10:59 AM, Robin Tew wrote:
> Hi All
> Just thinking about using the KPA100/KAT100 EC2 Combo with the Icom 705.
>
> Any pointers,ideas,tips etc. To achieve this?.
> Many thanks
> Robin G4JDO
>
>

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message 
delivered to kd...@frawg.org 

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com 

Re: [Elecraft] KPA100/KAT100 EC2 Combo to ICOM 705

[Don Wilhelm]

Robin,

That will not work.  The KPA100 depends on internal signals from the 
base K2 such as AUXBUS and several other signals to operate and control 
power output.  In other words, it is an amplifier dedicated to the K2 
and not a general purpose amplifier.


The KXPA100 and KXAT100 would serve you better than cobbling up an 
interface that would be quite complex.


he signals needed are those in the 9 pin AUX IO connector.  AUXBUS 
allows the base K2 firmware to 'talk' to the KPA100 firmware IC as well 
as the KAT100 firmware.


73,
Don W3FPR

On 9/29/2021 10:59 AM, Robin Tew wrote:

Hi All
Just thinking about using the KPA100/KAT100 EC2 Combo with the Icom 705.

Any pointers,ideas,tips etc. To achieve this?.
Many thanks
Robin G4JDO




__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com 

Re: [Elecraft] KPA100 and Audio Issue

[Bill Steffey NY9H]

Rich really meant WATTs.

On 4/6/2020 5:54 PM, Adrian wrote:

I always use 15.6v and with double heavy cable to minimise VD,


On 7/4/20 4:08 am, Bob McGraw K4TAX wrote:
I’d say that 10 - 12 volts is too low. The supply should be 13.8 to 
14.8.


Bob, K4TAX


Sent from my iPhone


On Apr 6, 2020, at 10:52 AM, Rich  wrote:

I am having an issue with distorted audio once the KPA100 kicks in 
at about 10-12v.


The KPA100 is putting out 100 watts

I have re-calibrated the radio with no change.

I am testing with the hand mic and a dummy load.   Which should 
eliminate any external devices causing it


Any suggestions as to what can be causing this issue?

Thanks

Rich

K3RWN

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to rmcg...@blomand.net


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to vk4...@gmail.com

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to n...@arrl.net 


--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com 

Re: [Elecraft] KPA100 and Audio Issue

[Adrian]

I always use 15.6v and with double heavy cable to minimise VD,


On 7/4/20 4:08 am, Bob McGraw K4TAX wrote:

I’d say that 10 - 12 volts is too low. The supply should be 13.8 to 14.8.

Bob, K4TAX


Sent from my iPhone


On Apr 6, 2020, at 10:52 AM, Rich  wrote:

I am having an issue with distorted audio once the KPA100 kicks in at about 
10-12v.

The KPA100 is putting out 100 watts

I have re-calibrated the radio with no change.

I am testing with the hand mic and a dummy load.   Which should eliminate any 
external devices causing it

Any suggestions as to what can be causing this issue?

Thanks

Rich

K3RWN

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to rmcg...@blomand.net


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to vk4...@gmail.com

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com 

Re: [Elecraft] KPA100 and Audio Issue

[Ed Pflueger]

That's where the problem was in my 2 K3S's.

Ed.. AB4IQ

-Original Message-
From: elecraft-boun...@mailman.qth.net 
[mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Don Wilhelm
Sent: Monday, April 6, 2020 1:09 PM
To: Rich ; Elecraft 
Subject: Re: [Elecraft] KPA100 and Audio Issue

Rich,

Well, since the KPA100 is an option for the K2 (and not for any other 
transceiver), I did not make a typo.
Since you have the K3S, the 100 watt amplifier is the KPA3.
That is why one has to be careful when specifying designations of options.

As I recall, that distorted audio on the K3S is a symptom of a failure in the 
LPA on the RF Board.  Contact supp...@elecraft.com to get some points to check.

73,
Don W3FPR

On 4/6/2020 1:43 PM, Rich wrote:
> Just to make sure that was a typo you said K2??
>
> I did your test on my K3S and I am getting about 55 watts on the meter
>
> Any other ideas?
>
> Thank you so much
>


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message 
delivered to ab...@comcast.net 

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com 

Re: [Elecraft] KPA100 and Audio Issue

[Bob McGraw K4TAX]

From my experience Don is correct that a failure of the KPA3A will cause 
distortion.  Mine failed twice and was replaced by Elecraft. 

The best description of the failure is “fuzzy audio”.   I don’t recall the 
output was showing less than 100 watts. 


Bob, K4TAX


Sent from my iPhone

> On Apr 6, 2020, at 1:25 PM, Don Wilhelm  wrote:
> 
> Rich,
> 
> Well, since the KPA100 is an option for the K2 (and not for any other 
> transceiver), I did not make a typo.
> Since you have the K3S, the 100 watt amplifier is the KPA3.
> That is why one has to be careful when specifying designations of options.
> 
> As I recall, that distorted audio on the K3S is a symptom of a failure in the 
> LPA on the RF Board.  Contact supp...@elecraft.com to get some points to 
> check.
> 
> 73,
> Don W3FPR
> 
>> On 4/6/2020 1:43 PM, Rich wrote:
>> Just to make sure that was a typo you said K2??
>> 
>> I did your test on my K3S and I am getting about 55 watts on the meter
>> 
>> Any other ideas?
>> 
>> Thank you so much
>> 
> 
> 
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to rmcg...@blomand.net


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com 

Re: [Elecraft] KPA100 and Audio Issue

[Rich]

Thanks for your help as always.   Well frankly I have been calling it 
the wrong thing forever.


Rich

On 4/6/2020 14:09 PM, Don Wilhelm wrote:

Rich,

Well, since the KPA100 is an option for the K2 (and not for any other 
transceiver), I did not make a typo.

Since you have the K3S, the 100 watt amplifier is the KPA3.
That is why one has to be careful when specifying designations of 
options.


As I recall, that distorted audio on the K3S is a symptom of a failure 
in the LPA on the RF Board.  Contact supp...@elecraft.com to get some 
points to check.


73,
Don W3FPR

On 4/6/2020 1:43 PM, Rich wrote:

Just to make sure that was a typo you said K2??

I did your test on my K3S and I am getting about 55 watts on the meter

Any other ideas?

Thank you so much





__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com 

Re: [Elecraft] KPA100 and Audio Issue

[Don Wilhelm]

Rich,

Well, since the KPA100 is an option for the K2 (and not for any other 
transceiver), I did not make a typo.

Since you have the K3S, the 100 watt amplifier is the KPA3.
That is why one has to be careful when specifying designations of options.

As I recall, that distorted audio on the K3S is a symptom of a failure 
in the LPA on the RF Board.  Contact supp...@elecraft.com to get some 
points to check.


73,
Don W3FPR

On 4/6/2020 1:43 PM, Rich wrote:

Just to make sure that was a typo you said K2??

I did your test on my K3S and I am getting about 55 watts on the meter

Any other ideas?

Thank you so much




__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com 

Re: [Elecraft] KPA100 and Audio Issue

[Bob McGraw K4TAX]

I’d say that 10 - 12 volts is too low. The supply should be 13.8 to 14.8.  

Bob, K4TAX


Sent from my iPhone

> On Apr 6, 2020, at 10:52 AM, Rich  wrote:
> 
> I am having an issue with distorted audio once the KPA100 kicks in at about 
> 10-12v.
> 
> The KPA100 is putting out 100 watts
> 
> I have re-calibrated the radio with no change.
> 
> I am testing with the hand mic and a dummy load.   Which should eliminate any 
> external devices causing it
> 
> Any suggestions as to what can be causing this issue?
> 
> Thanks
> 
> Rich
> 
> K3RWN
> 
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to rmcg...@blomand.net


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com 

Re: [Elecraft] KPA100 and Audio Issue

[Rich]

Just to make sure that was a typo you said K2??

I did your test on my K3S and I am getting about 55 watts on the meter

Any other ideas?

Thank you so much

Rich

On 4/6/2020 13:01 PM, Don Wilhelm wrote:

Rich,

Connect an external wattmeter and a dummy load.
Then set the K2 power to 50 watts and do a TUNE.
What is the actual power output?  If it is much greater than 100 watts 
(as I suspect), then you do not have power control and that says that 
the wattmeter in the KPA100 has been damaged - likely from static 
coming in on the feedline.

Replace D16 and D17 in the KPA100 and the problem should go away.

73,
Don W3FPR

On 4/6/2020 11:36 AM, Rich wrote:
I am having an issue with distorted audio once the KPA100 kicks in at 
about 10-12v.


The KPA100 is putting out 100 watts

I have re-calibrated the radio with no change.

I am testing with the hand mic and a dummy load.   Which should 
eliminate any external devices causing it


Any suggestions as to what can be causing this issue?


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com 

Re: [Elecraft] KPA100 and Audio Issue

[Don Wilhelm]

Rich,

Connect an external wattmeter and a dummy load.
Then set the K2 power to 50 watts and do a TUNE.
What is the actual power output?  If it is much greater than 100 watts 
(as I suspect), then you do not have power control and that says that 
the wattmeter in the KPA100 has been damaged - likely from static coming 
in on the feedline.

Replace D16 and D17 in the KPA100 and the problem should go away.

73,
Don W3FPR

On 4/6/2020 11:36 AM, Rich wrote:
I am having an issue with distorted audio once the KPA100 kicks in at 
about 10-12v.


The KPA100 is putting out 100 watts

I have re-calibrated the radio with no change.

I am testing with the hand mic and a dummy load.   Which should 
eliminate any external devices causing it


Any suggestions as to what can be causing this issue?


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com 

Re: [Elecraft] KPA100 Hi Cur

[Don Wilhelm]

Johnathan and all,

Actually it is not negative feedback for power control, but it is a 
closed circuit control loop providing positive control of the power level.
The actual power is measured at the KPA100 output and the result is sent 
to the MCU (via the VRFDET signal line) where it is compared with the 
requested power setting.  The result of that comparison is used to 
control the level of BFO injection in order to regulate the power output.


When the KPA100 wattmeter diodes are faulty, the MCU thinks there is low 
or no power output, and ramps up the drive to maximum.  The result is 
uncontrolled maximum power output.  If operated in that condition for 
some time, the base K2 PA transistors will be stressed and will 
eventually fail.  That condition also causes distortion, especially 
noted in SSB transmissions, but also increased IMD on the transmitted 
signal because the base K2 PA transistors are no longer being operated 
in a linear fashion.


With the KPA100 in the circuit, the KAT100 power sensing is not used, 
and the KAT100 wattmeter is used only to light the SWR indicators.
The KAT100 wattmeter is used if the KPA100 is not present.  The KAT2 
wattmeter is used if neither the KPA100 or KAT100 wattmeters are not 
present.  In the basic K2 (without the KAT2 or KPA100 or KAT100), there 
is an RF Detector to measure the power output, but that detector is 
dependent on the load - a 50 ohm resistivity load is assumed by the MCU 
calculation of power so it will not be correct if the load is other than 
50 ohms non-reactive.


So that is the story of how the K2 controls the power output.  The K1 
and K3/K3S use a similar system.  As far as I know, this system of power 
control is only used by some commercial transceivers and most other 
amateur transceivers simply let the operator control the drive level or 
provide only a fixed drive level.


73,
Don W3FPR

On 1/3/2020 10:15 PM, Jonathan Taylor, K1RFD wrote:

Don,

Thanks for the tip -- that was exactly it. I checked and replaced D16
and D17 and all is well now.  (Both were showing the same voltage drop
in both directions.)  I gather from your description that the built-in
wattmeter forms a negative feedback loop with the power adjustment.

My diodes and I are definitely static-challenged -- I have had a
similar problem at least twice in the KAT100 despite my best efforts
to remember to disconnect the antenna after operating.




__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com 

Re: [Elecraft] KPA100 Hi Cur

[Jonathan Taylor, K1RFD]

Don,

Thanks for the tip -- that was exactly it. I checked and replaced D16
and D17 and all is well now.  (Both were showing the same voltage drop
in both directions.)  I gather from your description that the built-in
wattmeter forms a negative feedback loop with the power adjustment.

My diodes and I are definitely static-challenged -- I have had a
similar problem at least twice in the KAT100 despite my best efforts
to remember to disconnect the antenna after operating.

73
Jonathan K1RFD

On Fri, Jan 3, 2020 at 10:44 AM Don Wilhelm  wrote:
>
> Jonathan,
>
> The normal cause of that HiCur message is a failure in the wattmeter of
> the KPA100.  Re-alignment will not help.
>
> To test for that possibility set the power knob for about 50 watts,
> connect an external wattmeter and a dummy load.  Then go Keydown and see
> what the actual power output is.  If it is in excess of 100 watts, then
> that is proof that the KPA100 wattmeter has a problem.
>
> The most common cause is that the diodes D16 and D17 have been damaged
> by static from the feedline, so replacing D16 and D17 is the first step
> in attempting to correct the problem.  Check again for actual power
> output with the power set for 50 watts after replacing those diodes.
>
> If you still have a problem after replacing those diodes, I can help
> with further troubleshooting.
>
> 73,
> Don W3FPR
>
> On 1/3/2020 9:15 AM, Jonathan Taylor, K1RFD wrote:
> > K2 #2462
> >
> > I just upgraded the KPA100 from Rev A to Rev D, and installed the
> > upgraded shield, under the philosophy of "better late than never" :)
> >
> > I am noticing two problems, when connected to a 50-ohm dummy load:
> >
> > 1) In TUNE, the display briefly shows "Hi Cur", followed by a strange
> > power/SWR indication such as "7 5.0-1"
> > 2) At any setting above 10W, the Power knob seems to have no effect --
> > the wattmeter always reads approximately 100W output.  This is true
> > both in TUNE and in CW.
> >
> > The actual power output appears to be about 100W, when measured with
> > an external wattmeter (although a bit low on 10M).
> >
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com 

Re: [Elecraft] KPA100 Hi Cur

[Don Wilhelm]

Jonathan,

The normal cause of that HiCur message is a failure in the wattmeter of 
the KPA100.  Re-alignment will not help.


To test for that possibility set the power knob for about 50 watts, 
connect an external wattmeter and a dummy load.  Then go Keydown and see 
what the actual power output is.  If it is in excess of 100 watts, then 
that is proof that the KPA100 wattmeter has a problem.


The most common cause is that the diodes D16 and D17 have been damaged 
by static from the feedline, so replacing D16 and D17 is the first step 
in attempting to correct the problem.  Check again for actual power 
output with the power set for 50 watts after replacing those diodes.


If you still have a problem after replacing those diodes, I can help 
with further troubleshooting.


73,
Don W3FPR

On 1/3/2020 9:15 AM, Jonathan Taylor, K1RFD wrote:

K2 #2462

I just upgraded the KPA100 from Rev A to Rev D, and installed the
upgraded shield, under the philosophy of "better late than never" :)

I am noticing two problems, when connected to a 50-ohm dummy load:

1) In TUNE, the display briefly shows "Hi Cur", followed by a strange
power/SWR indication such as "7 5.0-1"
2) At any setting above 10W, the Power knob seems to have no effect --
the wattmeter always reads approximately 100W output.  This is true
both in TUNE and in CW.

The actual power output appears to be about 100W, when measured with
an external wattmeter (although a bit low on 10M).


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com 

Re: [Elecraft] KPA100 for sale

[Zbigniew Lipecki]

Hi, All
The kpa100 has been sold
Thanks to All.
Zbigniew, 73
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 Rev C errata Rev. C-5, correct version?

[Don Wilhelm]

Casey,

You need only the latest errata sheet.  Earlier errata is included in 
the latest one.


73,
Don W3FPR

On 1/29/2019 4:28 PM, TI2/NA7U wrote:

I have a new KPA100 kit, everything still in the box, with assembly manual
Appendix G, Rev C, Feb. 11, 2004 and a single errata sheet for that with
notation Rev. C-5, July 20, 2005.

Is that the only errata sheet I need or are there intervening/subsequent
ones too? I ran through the errata and they certainly match up to the manual
...

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 failure

[N2TK, Tony]

Don,
You are correct about Schottky diodes such as the 1N5711. Don't just trust 
using an ohmmeter. They are not typical PN bipolar devices like diodes such as 
the 1N5811. We actually do some tests as if they are a FET. They are so cheap, 
that if you suspect an issue, just replace them.
73,
N2TK, Tony

-Original Message-
From: elecraft-boun...@mailman.qth.net  On 
Behalf Of Don Wilhelm
Sent: Saturday, January 05, 2019 4:12 PM
To: Paul Wilton 
Cc: Elecraft Discussion List 
Subject: Re: [Elecraft] KPA100 failure

Paul,

Sometimes it is just better to replace D16 and D17 than to trust them to an 
ohmmeter reading.
They can be "half bad" - OK at DC, but not at RF.  They are 1N5711 diodes.

If you have the latest updates, the oscillation is not a concern unless you 
have a T/R switch problem.

If your thermal pads look OK, reuse them.  they already have conformed to the 
slight contours of the heatsink and PA transistor surfaces.  Just be sure to 
put then back the same way they were - they usually stick to the heatsink, so 
re=positioning them is not a problem.

Measure those 22 ohm resistors to make certain they have not changed value due 
to overheating.

73,
Don W3FPR

On 1/5/2019 3:55 PM, Paul Wilton wrote:
> Don
> Thanks for the helpful pointers.
>
> Although I didn’t build the KPA100, I did have to fix a few items 
> before it worked.  It has got all the updates.
>
> I have checked D16 and D17 - they are OK.
>
> I’ll check for oscillations - should be easy to spot at 8MHz on an SDR
>
> The PA transistors do appear to be tight.  However, I have a spare 
> pair of pads so I’ll replace them since I’ll take to undo the heatsink 
> to put the resistors back.  I’ll also check out the T/R switch when I 
> recommission everything - I was aware of the changes to the manual thanks.
>
> Hopefully I will be able to do these over the next couple of evenings. 
>  And I’ll pay attention to the 10s max power spec!
>
> Thanks again
>
> 73
>
> Paul
> M1CNK
>
>
>
>
>
>> On 5 Jan 2019, at 20:12, Don Wilhelm > <mailto:donw...@embarqmail.com>> wrote:
>>
>> Paul,
>>
>> I have three possible guesses.
>> First is that the KPA100 was developing the full power output that it 
>> is capable of (often 180 watts) because the wattmeter diodes D16 and
>> D17 have been damaged by static (wind, rain, snow, or nearby lightning).
>> If those diodes are damaged the MCU thinks there is no power output 
>> and drives to it full power capability.  If left to continue, the PA 
>> transistors in the base K2 will eventually destroy themselves.  The 
>> PA transistors in the KPA100 are quite hardy and seldom need to be 
>> replaced (I have only replaced 1 set in the last 14 years of 
>> repairing K2s).
>>
>> The 2nd possibility is that there is some oscillation.  That can 
>> happen more frequently on 40 meters, and the KPA100 tries to transmit 
>> at about 8 MHz.  Be certain your KPA100 is at the latest level.  If 
>> you have blue toroid cores at RFC1 and L16 it is the latest.  If not 
>> the latest, upgrade it with the KPA100UPKT.
>>
>> Thirdly, were the PA transistors tight?  If not, the PA transistors 
>> will heat the board around the transistors and not be thermally
>>  coupled to the heatsink.  Are the thermal pads properly in place?
>> After initial assembly (and anytime afterwards if the thermal pads 
>> are changed) you must re-tighten the screws after about 10 hours of 
>> operation at high power.
>>
>> A 4th possibility is that you have a problem in the T/R switch. 
>>  After you get it up and running, do the Diode Voltage checks in the 
>> manual. If you have an older manual but have the latest upgrade 
>> installed, use the chart in the KPA100UPKT instructions rather than 
>> what is in your manual.
>>
>> Note well, the KPA100 is rated for only 10 seconds of keydown power 
>> at 100 watts, so you did exceed its maximum rating.
>>
>> If you melted the fuseholder without blowing the fuse, you may have 
>> had bad contact from the wire to the fuse.  That would also result in 
>> a low voltage to the KPA100 and cause it to draw greater than the 
>> normal amount of current because the K2 controls try to keep the 
>> power constant - less voltage requires more current for the same power.
>>
>> Hopefully some of that information will answer your question.
>> Do all initial testing into a dummy load and not an antenna and 
>> bypass the KAT100 by connecting the dummy load (and perhaps a
>> wattmeter) directly to the KPA100 - remove the coax between the
>> KPA100 RF out and the KAT100 RF IN jacks.
>>
>> 73,,
>> D

Re: [Elecraft] KPA100 in EC2 Enclosure?

[Francis Belliveau]

Eric,

Don tells you what you need to do to make it possible, I want to expand on the 
utility of the result.
Many of us like our QRP K2 setup.  My K2 has the KAT installed for seamless QRP 
operations when that is what I want.
I also have the KPA and KAT 100 pair installed in an EC2 so that when I want to 
operate QRO I reconnect cables, power up the amp and use the two boxes like 
they are one rig.

Elecraft did a wonderful job and you will be very pleased with the result if 
you can get hold of that front panel like Don said.

Fran

> On Jan 4, 2019, at 23:15, Don Wilhelm  wrote:
> 
> Eric,
> 
> Yes, it is possible to mount the KPA100 in an EC2 enclosure - If you already 
> have the enclosure.  Just mount it instead of the EC2 enclosure top cover.
> 
> You will need to add a BNC connector to the lower rear panel of the EC2 so 
> you can attach the coax from the K2 to the input coax of the KPA100.
> 
> If you also want to add the KAT100, you will have to contact Elecraft sales 
> to see if they have any of the E100142 - KAT100-2 Front panel and the E100143 
> - KAT100-2 rear panels left.  If they have them, order those panels and the 
> KAT100-1.  You will also need E620012, x2 - 2 pin male, 0.156" spacing Male 
> headers and E620040 - connector 10 pin (5x2) male connector 0.1" spacing.
> 
> Make up the control cable shown in the KAT100 manual and you will be good to 
> go.  You need that control cable whether or not you have the KAT100.
> 
> 73,
> Don W3FPR
> 
> On 1/4/2019 10:42 PM, Eric Norris wrote:
>> Is it possible to build a KPA100 into an EC2 enclosure (I have one), and
>> use all external connections between the K2 and the KPA100/EC2?  In other
>> words, make it plug and play?  My K2 is serial #6000+, and has all the
>> options including KDSP2 and KIO2.  I removed the KBT2 just as it started to
>> leak. :-)
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to f.belliv...@comcast.net

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 failure

[Don Wilhelm]

Paul,

Sometimes it is just better to replace D16 and D17 than to trust them to 
an ohmmeter reading.

They can be "half bad" - OK at DC, but not at RF.  They are 1N5711 diodes.

If you have the latest updates, the oscillation is not a concern unless 
you have a T/R switch problem.


If your thermal pads look OK, reuse them.  they already have conformed 
to the slight contours of the heatsink and PA transistor surfaces.  Just 
be sure to put then back the same way they were - they usually stick to 
the heatsink, so re=positioning them is not a problem.


Measure those 22 ohm resistors to make certain they have not changed 
value due to overheating.


73,
Don W3FPR

On 1/5/2019 3:55 PM, Paul Wilton wrote:

Don
Thanks for the helpful pointers.

Although I didn’t build the KPA100, I did have to fix a few items 
before it worked.  It has got all the updates.


I have checked D16 and D17 - they are OK.

I’ll check for oscillations - should be easy to spot at 8MHz on an SDR

The PA transistors do appear to be tight.  However, I have a spare 
pair of pads so I’ll replace them since I’ll take to undo the heatsink 
to put the resistors back.  I’ll also check out the T/R switch when I 
recommission everything - I was aware of the changes to the manual thanks.


Hopefully I will be able to do these over the next couple of evenings. 
 And I’ll pay attention to the 10s max power spec!


Thanks again

73

Paul
M1CNK





On 5 Jan 2019, at 20:12, Don Wilhelm > wrote:


Paul,

I have three possible guesses.
First is that the KPA100 was developing the full power output that it 
is capable of (often 180 watts) because the wattmeter diodes D16 and 
D17 have been damaged by static (wind, rain, snow, or nearby lightning).
If those diodes are damaged the MCU thinks there is no power output 
and drives to it full power capability.  If left to continue, the PA 
transistors in the base K2 will eventually destroy themselves.  The 
PA transistors in the KPA100 are quite hardy and seldom need to be 
replaced (I have only replaced 1 set in the last 14 years of 
repairing K2s).


The 2nd possibility is that there is some oscillation.  That can 
happen more frequently on 40 meters, and the KPA100 tries to transmit 
at about 8 MHz.  Be certain your KPA100 is at the latest level.  If 
you have blue toroid cores at RFC1 and L16 it is the latest.  If not 
the latest, upgrade it with the KPA100UPKT.


Thirdly, were the PA transistors tight?  If not, the PA transistors 
will heat the board around the transistors and not be thermally 
 coupled to the heatsink.  Are the thermal pads properly in place?
After initial assembly (and anytime afterwards if the thermal pads 
are changed) you must re-tighten the screws after about 10 hours of 
operation at high power.


A 4th possibility is that you have a problem in the T/R switch. 
 After you get it up and running, do the Diode Voltage checks in the 
manual. If you have an older manual but have the latest upgrade 
installed, use the chart in the KPA100UPKT instructions rather than 
what is in your manual.


Note well, the KPA100 is rated for only 10 seconds of keydown power 
at 100 watts, so you did exceed its maximum rating.


If you melted the fuseholder without blowing the fuse, you may have 
had bad contact from the wire to the fuse.  That would also result in 
a low voltage to the KPA100 and cause it to draw greater than the 
normal amount of current because the K2 controls try to keep the 
power constant - less voltage requires more current for the same power.


Hopefully some of that information will answer your question.
Do all initial testing into a dummy load and not an antenna and 
bypass the KAT100 by connecting the dummy load (and perhaps a 
wattmeter) directly to the KPA100 - remove the coax between the 
KPA100 RF out and the KAT100 RF IN jacks.


73,,
Don W3FPR



On 1/5/2019 2:34 PM, Paul Wilton wrote:
I was using my KPA100/KAT100 combination today to check out some 
changes to my OCFD antenna.  Previously I have had problems with the 
balun heating up and the SWR increasing over an extended transmit on 
7MHz (eg 50w on an FT8 over).   I have made an improvement to my 
OCFD antenna by adding another choke to reduce the common mode 
current.  So in order to test it out, I planned to run 100w CW for 
15-30seconds watching the SWR meter on the KAT100 to see if I was 
going to get the SWR increase.  This was done with a “cold” PA.
So I started the test and unlikely previously, the SWR remained 
good.  However at about the 30s mark, I saw some smoke coming from 
the KPA100 and then it went dead.  It also melted my fuseholder in 
the PA supply (although didn’t actually blow the fuse).
I have opened up the KPA100 only to find that the two 22R power 
resistors around the two final transistors (R38 and R39) have both 
unsoldered themselves from the board and were lying in the bottom of 
the case!
Clearly it is an easy job just to put them in again but before 

Re: [Elecraft] KPA100 failure

[Paul Wilton]

Don
Thanks for the helpful pointers.

Although I didn’t build the KPA100, I did have to fix a few items before it 
worked.  It has got all the updates.

I have checked D16 and D17 - they are OK.  

I’ll check for oscillations - should be easy to spot at 8MHz on an SDR

The PA transistors do appear to be tight.  However, I have a spare pair of pads 
so I’ll replace them since I’ll take to undo the heatsink to put the resistors 
back.  I’ll also check out the T/R switch when I recommission everything - I 
was aware of the changes to the manual thanks.

Hopefully I will be able to do these over the next couple of evenings.  And 
I’ll pay attention to the 10s max power spec!

Thanks again

73

Paul
M1CNK





> On 5 Jan 2019, at 20:12, Don Wilhelm  wrote:
> 
> Paul,
> 
> I have three possible guesses.
> First is that the KPA100 was developing the full power output that it is 
> capable of (often 180 watts) because the wattmeter diodes D16 and D17 have 
> been damaged by static (wind, rain, snow, or nearby lightning).
> If those diodes are damaged the MCU thinks there is no power output and 
> drives to it full power capability.  If left to continue, the PA transistors 
> in the base K2 will eventually destroy themselves.  The PA transistors in the 
> KPA100 are quite hardy and seldom need to be replaced (I have only replaced 1 
> set in the last 14 years of repairing K2s).
> 
> The 2nd possibility is that there is some oscillation.  That can happen more 
> frequently on 40 meters, and the KPA100 tries to transmit at about 8 MHz.  Be 
> certain your KPA100 is at the latest level.  If you have blue toroid cores at 
> RFC1 and L16 it is the latest.  If not the latest, upgrade it with the 
> KPA100UPKT.
> 
> Thirdly, were the PA transistors tight?  If not, the PA transistors will heat 
> the board around the transistors and not be thermally  coupled to the 
> heatsink.  Are the thermal pads properly in place?
> After initial assembly (and anytime afterwards if the thermal pads are 
> changed) you must re-tighten the screws after about 10 hours of operation at 
> high power.
> 
> A 4th possibility is that you have a problem in the T/R switch.  After you 
> get it up and running, do the Diode Voltage checks in the manual. If you have 
> an older manual but have the latest upgrade installed, use the chart in the 
> KPA100UPKT instructions rather than what is in your manual.
> 
> Note well, the KPA100 is rated for only 10 seconds of keydown power at 100 
> watts, so you did exceed its maximum rating.
> 
> If you melted the fuseholder without blowing the fuse, you may have had bad 
> contact from the wire to the fuse.  That would also result in a low voltage 
> to the KPA100 and cause it to draw greater than the normal amount of current 
> because the K2 controls try to keep the power constant - less voltage 
> requires more current for the same power.
> 
> Hopefully some of that information will answer your question.
> Do all initial testing into a dummy load and not an antenna and bypass the 
> KAT100 by connecting the dummy load (and perhaps a wattmeter) directly to the 
> KPA100 - remove the coax between the KPA100 RF out and the KAT100 RF IN jacks.
> 
> 73,,
> Don W3FPR
> 
> 
> 
> On 1/5/2019 2:34 PM, Paul Wilton wrote:
>> I was using my KPA100/KAT100 combination today to check out some changes to 
>> my OCFD antenna.  Previously I have had problems with the balun heating up 
>> and the SWR increasing over an extended transmit on 7MHz (eg 50w on an FT8 
>> over).   I have made an improvement to my OCFD antenna by adding another 
>> choke to reduce the common mode current.  So in order to test it out, I 
>> planned to run 100w CW for 15-30seconds watching the SWR meter on the KAT100 
>> to see if I was going to get the SWR increase.  This was done with a “cold” 
>> PA.
>> So I started the test and unlikely previously, the SWR remained good.  
>> However at about the 30s mark, I saw some smoke coming from the KPA100 and 
>> then it went dead.  It also melted my fuseholder in the PA supply (although 
>> didn’t actually blow the fuse).
>> I have opened up the KPA100 only to find that the two 22R power resistors 
>> around the two final transistors (R38 and R39) have both unsoldered 
>> themselves from the board and were lying in the bottom of the case!
>> Clearly it is an easy job just to put them in again but before doing so I 
>> want to try and understand what is happening
>> So a few questions:
>> a) I am hoping that my two finals are still OK.  Is there a simple test I 
>> can do perform applying power?  Using a DMM in resistance mode, I measure 
>> approx 2M between collector and emitter and 11.2R between base and emitter 
>> (other than the missing 22R resistors I haven’t disconnected anything else).
>> b) Any idea what could have caused that much heat that the two resistors 
>> unsoldered themselves?  It can’t be a DC failure since there is a capacitor 
>> blocking the path in the event of a PA transistor 

Re: [Elecraft] KPA100 failure

[Don Wilhelm]

Paul,

I have three possible guesses.
First is that the KPA100 was developing the full power output that it is 
capable of (often 180 watts) because the wattmeter diodes D16 and D17 
have been damaged by static (wind, rain, snow, or nearby lightning).
If those diodes are damaged the MCU thinks there is no power output and 
drives to it full power capability.  If left to continue, the PA 
transistors in the base K2 will eventually destroy themselves.  The PA 
transistors in the KPA100 are quite hardy and seldom need to be replaced 
(I have only replaced 1 set in the last 14 years of repairing K2s).


The 2nd possibility is that there is some oscillation.  That can happen 
more frequently on 40 meters, and the KPA100 tries to transmit at about 
8 MHz.  Be certain your KPA100 is at the latest level.  If you have blue 
toroid cores at RFC1 and L16 it is the latest.  If not the latest, 
upgrade it with the KPA100UPKT.


Thirdly, were the PA transistors tight?  If not, the PA transistors will 
heat the board around the transistors and not be thermally  coupled to 
the heatsink.  Are the thermal pads properly in place?
After initial assembly (and anytime afterwards if the thermal pads are 
changed) you must re-tighten the screws after about 10 hours of 
operation at high power.


A 4th possibility is that you have a problem in the T/R switch.  After 
you get it up and running, do the Diode Voltage checks in the manual. 
If you have an older manual but have the latest upgrade installed, use 
the chart in the KPA100UPKT instructions rather than what is in your manual.


Note well, the KPA100 is rated for only 10 seconds of keydown power at 
100 watts, so you did exceed its maximum rating.


If you melted the fuseholder without blowing the fuse, you may have had 
bad contact from the wire to the fuse.  That would also result in a low 
voltage to the KPA100 and cause it to draw greater than the normal 
amount of current because the K2 controls try to keep the power constant 
- less voltage requires more current for the same power.


Hopefully some of that information will answer your question.
Do all initial testing into a dummy load and not an antenna and bypass 
the KAT100 by connecting the dummy load (and perhaps a wattmeter) 
directly to the KPA100 - remove the coax between the KPA100 RF out and 
the KAT100 RF IN jacks.


73,,
Don W3FPR



On 1/5/2019 2:34 PM, Paul Wilton wrote:

I was using my KPA100/KAT100 combination today to check out some changes to my 
OCFD antenna.  Previously I have had problems with the balun heating up and the 
SWR increasing over an extended transmit on 7MHz (eg 50w on an FT8 over).   I 
have made an improvement to my OCFD antenna by adding another choke to reduce 
the common mode current.  So in order to test it out, I planned to run 100w CW 
for 15-30seconds watching the SWR meter on the KAT100 to see if I was going to 
get the SWR increase.  This was done with a “cold” PA.

So I started the test and unlikely previously, the SWR remained good.  However 
at about the 30s mark, I saw some smoke coming from the KPA100 and then it went 
dead.  It also melted my fuseholder in the PA supply (although didn’t actually 
blow the fuse).

I have opened up the KPA100 only to find that the two 22R power resistors 
around the two final transistors (R38 and R39) have both unsoldered themselves 
from the board and were lying in the bottom of the case!

Clearly it is an easy job just to put them in again but before doing so I want 
to try and understand what is happening

So a few questions:
a) I am hoping that my two finals are still OK.  Is there a simple test I can 
do perform applying power?  Using a DMM in resistance mode, I measure approx 2M 
between collector and emitter and 11.2R between base and emitter (other than 
the missing 22R resistors I haven’t disconnected anything else).
b) Any idea what could have caused that much heat that the two resistors 
unsoldered themselves?  It can’t be a DC failure since there is a capacitor 
blocking the path in the event of a PA transistor shorting to ground.  I am 
concerned that there is some sort of oscillation going on ie the PA is starting 
to hoot.
c) Any advice on how to proceed?



__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 in EC2 Enclosure?

[Don Wilhelm]

Eric,

Yes, it is possible to mount the KPA100 in an EC2 enclosure - If you 
already have the enclosure.  Just mount it instead of the EC2 enclosure 
top cover.


You will need to add a BNC connector to the lower rear panel of the EC2 
so you can attach the coax from the K2 to the input coax of the KPA100.


If you also want to add the KAT100, you will have to contact Elecraft 
sales to see if they have any of the E100142 - KAT100-2 Front panel and 
the E100143 - KAT100-2 rear panels left.  If they have them, order those 
panels and the KAT100-1.  You will also need E620012, x2 - 2 pin male, 
0.156" spacing Male headers and E620040 - connector 10 pin (5x2) male 
connector 0.1" spacing.


Make up the control cable shown in the KAT100 manual and you will be 
good to go.  You need that control cable whether or not you have the KAT100.


73,
Don W3FPR

On 1/4/2019 10:42 PM, Eric Norris wrote:

Is it possible to build a KPA100 into an EC2 enclosure (I have one), and
use all external connections between the K2 and the KPA100/EC2?  In other
words, make it plug and play?  My K2 is serial #6000+, and has all the
options including KDSP2 and KIO2.  I removed the KBT2 just as it started to
leak. :-)

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 no PA Key Out

[Martin]

Sorry for the bandwidth, we found it ourselves. The 8r Hold parameter 
was set to 0.01 .


--

Ohne CW ist es nur CB..

73, Martin DM4iM
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 no PA Key Out

[Don Wilhelm]

Martin,

It could be a solder failure, a failure of Q12, an open R1, or a bad 
output from firmware U1 pin 16.


73,
Don W3FPR

On 9/15/2018 9:28 AM, Martin wrote:

Elecrafters,
a friend is trying to connect his K2/100 to his external amp. I own a 
K2/10 only , so have no expirience with it.


He performed measurements and found the PA Key Out on the rear panel of 
the KPA100 will not go low on transmit.

What could be the cause?
Thanks.

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 post-assembly voltage test abnormal.

[Don Wilhelm]

David,

J3+ is the power supply voltage.  Make certain the APP connectors (both 
on the KPA100 and the Power cable) are correct.
Look at the end of the connector - you should see only the contact 
blade.  If you can see the spring finger that is under the contact 
blade, the contact blade is not inserted far enough.


Measure the voltage at the end of your power cable - it should be 13.8 
volts or higher (up to 15 volts is OK).  If not, check your power supply 
or the power cable.  Make sure all connections to the power supply are 
tight, and that the fuseholder on the power cable is assembled 
correctly.  The free side of the fuseholder should slide freely along 
the red wire.  If not, there may be a lack of contact with the fuse.


You can also check with your ohmmeter to be certain the J3+ line is not 
shorted to ground.


73,
Don W3FPR

On 7/12/2018 9:13 PM, David Dawson wrote:

Hi to all,
Just put together the KPA100, and did the initial voltage tests while connected 
to the K2. The preceeding resistance tests were within specs. The voltages were 
okay too, except for the J3+ which read 6V.
I haven't come across any mention of this in the mail archives, could the 
ribbon cable be mis-wired. (I have normal colour vision, by the way.)
thanks.


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 100% Duty Cycle - Operating Temperature

[aj4tf]

Bruce, 
I had the same problem a while ago,  but instead of just replacing the
diodes, I installed some machined IC socket pins in the PWB (i.e.  pins from
a Mill-Max IC socket), then put the diodes in those.   That way, if they
have to be replaced again, it's a "no-solder" job that can be performed in
the field with some needle-nose pliers.

David AJ4TF 
K2, K3S



--
Sent from: http://elecraft.365791.n2.nabble.com/
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 100% Duty Cycle - Operating Temperature

[Don Wilhelm]

Bruce,

To do the job properly, you will have to remove the board from the heatsink.
Remove the shield and the standoffs - note that the 2 standoffs toward 
the front are shorter.

Then remove the 6 screws holding the PA transistor and Q3 and Q4.
There are 3 more screws on the rear panel to remove.
You can then remove the board from the heatsink.  You may want to 
unsolder the wires from the speaker, but that is your choice.


Locate D16 and D17 near the SO-239 jack.  Remove them and replace with 
new 1N5711 diodes.
If you do not have good desoldering equipment, don't fret - if you can't 
unsolder the diodes one end at a time, crush the diodes and remove the 
leads one at a time.  Clean up with solder wick and if solder remains in 
the holes, heat the pad and push it out with a wooden toothpick.
Normally, just replacing the diodes is sufficient, but you can check 
your work by powering only the base K2 with the external wattmeter/dummy 
load (you can do that before mounting the KPA100 board onto the 
heatsink).  If you have proper power control in the low power range, all 
is well.  If not, there may be another problem with the KPA100 wattmeter 
circuit.


BTW, examine the KPA100 board.  If it has blue toroid cores (other than 
the Low Pass Filter), then it is the most recent.  If instead you see a 
red toroid core at L16 and L15, it would be a good time to upgrade it 
with KPA100UPKT.
Also examine the shield - if it has a notch over the SO-239 that is only 
3/16 inch or less, it is the new one, and you should also have a shield 
over the speaker magnet.  If both those conditions are not true, add the 
KPA100SHLDKT.


73,
Don W3FPR

On 11/5/2017 1:37 PM, K1FFX wrote:

Don,

You were right on the money with your diagnosis.

I have the Elecraft W1 wattmeter.  At 10 watts or below, the "14 watt" range
LED was illuminated.  As I rotated the Power knob past 10 watts to just
about 12 watts, the "14 watt" LED went out and the "140 watt" LED was then
illuminated!

So, I've got to replace D16 and D17.  Any hints on that replacement job will
be appreciated.  I found
an old forum posting from someone who apparently had a difficult time
disassembling the KPA100 to get to the two diodes.

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 100% Duty Cycle - Operating Temperature

[K1FFX]

Don, 

You were right on the money with your diagnosis.

I have the Elecraft W1 wattmeter.  At 10 watts or below, the "14 watt" range
LED was illuminated.  As I rotated the Power knob past 10 watts to just
about 12 watts, the "14 watt" LED went out and the "140 watt" LED was then
illuminated!

So, I've got to replace D16 and D17.  Any hints on that replacement job will
be appreciated.  I found
an old forum posting from someone who apparently had a difficult time
disassembling the KPA100 to get to the two diodes.

Meanwhile, I've to go back and find your e-mail (I saved it somewhere) on
bleeding off static
charges on the antenna to protect D16 and D17.

Thanks!

- Bruce K1FFX







-
Bruce Rosen
K1FFX
K2/100 6982 KSB2 KAT100-1

--
Sent from: http://elecraft.365791.n2.nabble.com/
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 100% Duty Cycle - Operating Temperature

[Bob McGraw K4TAX]

Digital modes lend themselves to lower power contacts successfully.  It gets 
messy for all when a station jumps in with excessive power.  I'm seeing more 
and more stations with poor to very poor quality signals.  It takes very little 
effort to be loud, but requires more effort and skill to be good. 

Bob, K4TAX


Sent from my iPhone

> On Nov 4, 2017, at 7:04 PM, Rick Bates (WA6NHC)  wrote:
> 
> Pffft.
> 
> Use only enough power to allow the completion of the contact.  Even if it’s 
> legal limit. 
> 
> It’s a common misconception.   
> 
> Rick WA6NHC
> 
> Smell Czech happens
> 
>> On Nov 4, 2017, at 4:59 PM, Lynn W. Taylor, WB6UUT 
>>  wrote:
>> 
>> 20 watts is a lot of power on PSK-31.
>> 
>> 10 watts is a lot of power on PSK-31.
>> 
>> 73 -- Lynn
>> 
>>> On 11/4/2017 3:55 PM, K1FFX wrote:
>>> I started running some 100% duty cycle operation with my KPA100 (PSK31 and
>>> Olivia).  I was running 20 watts ..
>> __
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft@mailman.qth.net
>> 
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to wa6...@gmail.com
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to rmcg...@blomand.net


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 100% Duty Cycle - Operating Temperature

[Rick Bates (WA6NHC)]

Pffft.

Use only enough power to allow the completion of the contact.  Even if it’s 
legal limit. 

It’s a common misconception.   

Rick WA6NHC

Smell Czech happens

> On Nov 4, 2017, at 4:59 PM, Lynn W. Taylor, WB6UUT 
>  wrote:
> 
> 20 watts is a lot of power on PSK-31.
> 
> 10 watts is a lot of power on PSK-31.
> 
> 73 -- Lynn
> 
>> On 11/4/2017 3:55 PM, K1FFX wrote:
>> I started running some 100% duty cycle operation with my KPA100 (PSK31 and
>> Olivia).  I was running 20 watts ..
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to wa6...@gmail.com
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 100% Duty Cycle - Operating Temperature

[Lynn W. Taylor, WB6UUT]

20 watts is a lot of power on PSK-31.

10 watts is a lot of power on PSK-31.

73 -- Lynn

On 11/4/2017 3:55 PM, K1FFX wrote:

I started running some 100% duty cycle operation with my KPA100 (PSK31 and
Olivia).  I was running 20 watts ..

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 100% Duty Cycle - Operating Temperature

[Don Wilhelm]

Bruce,

If you had the fan turn on at 20 watts, there is likely a problem.
Get an external wattmeter and check the actual power output.
I suspect the actual power is not controlled, and can exceed 150 watts.

The usual cause of that problem is damaged diodes D16 and D17 in the KPA100.

There will usually be no harm to the KPA100 PA transistors, but the PA 
transistors in the base K2 can be damaged because they are being 
stressed to produce their maximum output.


Also that condition is likely to give you a distorted signal, and with 
Data Modes that usually means a high IMD.


73,
Don W3FPR

On 11/4/2017 6:55 PM, K1FFX wrote:

I started running some 100% duty cycle operation with my KPA100 (PSK31 and
Olivia).  I was running 20 watts ... I'm not sure what power folks normally
run in these modes (I'd be happy to get feedback on that), but, in any case,
I was running well below the KPA100's 100 watt maximum.  After around 90
seconds, the little fan on the KPA100 kicked in and really rev'ed up.  The
heat sink was, not surprisingly, quite warm to the touch.

So, considering I was running at 20 watts, would that level of heat be
normal, i.e., was it actually no surprise that the fan kicked in?  And is
there any danger to the output transistors running key-down at the 20 watt
level?

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 damaged by open circuit output

[Don Wilhelm]

Harry,

I would replace those components that look damaged.
When you begin testing it again, first set the bias.
Then unplug the power cable to the KPA100 and power only the base K2.
Run the base K2 at 10 watts while nulling and adjusting the wattmeter 
potentiometers R26 and R27.
Once you have done the above, power the KPA100 once again and touch up 
the wattmeter reading at 80 or 100 watts.


73,
Don W3FPR

On 8/9/2017 9:53 AM, harry weston wrote:

Hello
A while ago I built a KPA100 to go with my K2, but unfortunately was careless 
while testing it and accidentally fed its output at a high power into a cable 
with a bad, open circuit PL259 connection. Whiff of magic smoke, panic, and I 
found several components in the TR switch badly scorched. The obviously damaged 
items are: R21, R13 and C71, and the 1K resistor across RFC3 is black and open 
circuit. RFC3 itself appears undamaged, and its inductance measures 88 
micro-Henries.
My question is, please: is it ok just to replace these burnt components, or is 
there likely to be further unseen damage that I should also allow for? If so 
what else should I replace, or are there any special tests I can do to find out?

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 SWR Bridge Issue

[Don Wilhelm]

Curt,

You do have a wattmeter problem, and likely if you fix that, all will 
settle down.


You can work on the wattmeter problem at low power only - at low power, 
you do not have to mount the board to the heatsink.  Just power the base 
K2 and do not plug any power into the KPA100 board.


First set the two trimpots R26 and R27 close to mid-range.  Then measure 
the resistance to ground from U5 pin 3 and U5 pin 5.  You should read 
something between 40k and 50k ohms.
If vastly other than that, first check diodes D16 and D17.  Make sure 
the diodes are oriented correctly - look at the parts placement diagram 
near the back of the manual.
The next thing is T4 - it must be wound *exactly* as shown in the 
diagram in the manual - including the direction of the winding - and the 
leads must be in the proper holes.
The "1 turn link" provided by the red wire and the bare wire soldered to 
the SO-239 center must also be in the right places and well soldered.


Did you put the correct trimmer capacitor at C1?  If this is a new kit, 
the proper trimmer has a white body (not the yellow one).


I have a suspicion that you may have wound T4 in the wrong direction or 
have the leads not in the right holes.


73,
Don W3FPR

On 6/22/2016 9:18 PM, Curt Milton via Elecraft wrote:

Before I dismantle this thing one more time, curious if any sage info is 
available --
I noticed that with a dummy load plugged in, and operating at 5 watts -- I get 
a reasonable power reading but SWR is around 10:1.  It does not change at all 
as I tweak C1.  both outputs from the op amp are reading around 1 volt more or 
less.  both diodes are reading okay with my DVM.  both pots have been adjusted 
for 43k ohms per the instruction.

maybe I damaged C1 is disassembly, or I don't have the windings connected to 
the PC board - but DVM affirms conductivity so at least one is attached.  yes I 
realize not much in this network, yet something is astray.  (no surprise that 
sensing a high SWR that the KPA won't do high power?)

73 Curt
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to donw...@embarqmail.com


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 tools

[lstavenhagen]

Ah, gotcha, thanks Don. I'll see if I can borrow an accurate one for that
part...

Thank you,
LS
W5QD



--
View this message in context: 
http://elecraft.365791.n2.nabble.com/KPA100-tools-tp7615415p7615436.html
Sent from the Elecraft mailing list archive at Nabble.com.
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 tools

[Don Wilhelm]

LS,

The KPA100 wattmeter calibration will be as accurate as the accuracy of 
the external wattmeter used.
The real question is -- How much can you trust your wattmeter at the 20 
watt and 100 watt levels?


73,
Don W3FPR

On 3/21/2016 5:03 PM, lstavenhagen wrote:

Ok thanks Don. That reminds me, my dummy load is eons old, so I should check
and see if it's still 50 ohms. And I believe my DMM has a 10amp setting that
may work for the bias setting, but I'll check. Also I have a very old MFJ
manual ant. tuner with an analogue wattmeter in it (assuming it still
works). Will that be sufficient for the items requiring a wattmeter or will
I need something more precise than that?

Thank you,
LS
W5QD.



--
View this message in context: 
http://elecraft.365791.n2.nabble.com/KPA100-tools-tp7615415p7615422.html
Sent from the Elecraft mailing list archive at Nabble.com.
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to w3...@embarqmail.com



__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 tools

[lstavenhagen]

Ok thanks Don. That reminds me, my dummy load is eons old, so I should check
and see if it's still 50 ohms. And I believe my DMM has a 10amp setting that
may work for the bias setting, but I'll check. Also I have a very old MFJ
manual ant. tuner with an analogue wattmeter in it (assuming it still
works). Will that be sufficient for the items requiring a wattmeter or will
I need something more precise than that?

Thank you,
LS
W5QD.



--
View this message in context: 
http://elecraft.365791.n2.nabble.com/KPA100-tools-tp7615415p7615422.html
Sent from the Elecraft mailing list archive at Nabble.com.
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 tools

[Don Wilhelm]

LS,

The tools listed in the KPA100 manual are quite sufficient.
To set the PA bias, you do need a means of measuring the current rise 
for the PA idle current, and most DMMs will suffice - you will have to 
measure a current rise of 400mA.  I use a dedicated DMM on the workbench 
set on the 10 Amp scale for that purpose.  Since you are doing only one, 
a dedicated DMM for that purpose is not economical.  Use your existing 
DMM connected to measure current.


The only other things I use are a precision 25 ohm and precision 100 ohm 
dummy load.  Those 2 dummy loads allow me to more accurately set C1 than 
I am able to do by measuring the DC voltage null as instructed in the 
manual.  When the wattmeter bridge is correctly balanced, the SWR shown 
by both those loads will be the same.  After adjusting C1 so the SWR 
reading for both loads is the same, I can easily set the REFL pot 
exactly for a 2.0 SWR.


If you do not have the capability to produce a 25 ohm and a 100 ohm 
dummy load, then simply follow the instructions in the manual, and it 
will be close enough for proper operation.  The KPA100 throttles power 
back if it detects an SWR in excess of 2.0, so this is not a critical 
setting and those tools are not required - this is just a refinement 
that I do on my repairs.


73,
Don W3FPR


On 3/21/2016 4:06 PM, lstavenhagen wrote:

Hi all,
And speaking of the K2... I can't recall if I asked this several years ago
on my first K2 build when I was contemplating this exact same question the
first time, :),  and I couldn't find this specifically in the reflector
archives either.

Are there any specific tools for building/aligning/testing the KPA100
_other_ than the ones listed in the manual that are either required or very
strongly suggested?




__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 has 0.1 w indicated, SWR 1.0 during tune test

[Ron D'Eau Claire]

Good point. I would think so.

 

73, Ron AC7AC

 

From: Catherine James [mailto:catherine.ja...@att.net] 
Sent: Sunday, January 3, 2016 11:19 AM
To: Ron D'Eau Claire; elecraft@mailman.qth.net
Subject: Re: RE: [Elecraft] KPA100 has 0.1 w indicated, SWR 1.0 during tune
test

 


Wouldn't that (failure in coax confection to K2) prevent the receive from
working? I have good reception, but no TX.

Sent from Yahoo Mail on Android
<https://overview.mail.yahoo.com/mobile/?.src=Android> 


From:"Ron D'Eau Claire" <r...@cobi.biz>
Date:Sun, Jan 3, 2016 at 2:06 PM
Subject:RE: [Elecraft] KPA100 has 0.1 w indicated, SWR 1.0 during tune test

Did you dislodge the connector on the coax between the KPA100 and the K2
main board? If in place, is it oriented correctly? While keyed, it can be
reversed by a clever person, Hi! 

You can see that connector by simply removing the K2 side panel. Usually
take if off when replacing the KPA100 just so I can see the cables and
connectors clearly. It's easier to plug the power and RF cables in AFTER
putting the KPA100 on than trying to do it holding the KPA100 up enough to
see in from the top. 

73 Ron AC7AC 


-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net 
] On Behalf Of
Catherine James
Sent: Sunday, January 3, 2016 10:41 AM
To: elecraft@mailman.qth.net  ; Don Wilhelm
Subject: [Elecraft] KPA100 has 0.1 w indicated, SWR 1.0 during tune test

I am attempting the C1 adjustment to get correct SWR. Unfortunately, with a
dummy load on the SO239 port and the power knob set to 5w, pressing TUNE
just gives a beep followed by 0.1 1.0-1. Adjusting C1 has no effect at all.
The receive audio does cut out while tune mode is on, then reappears when
off.

I get the same behavior whether 8r is set to norm or hold.

I'm guessing there a break in the transmit RF path somewhere.  *sigh*

Cathy
N5WVR

Sent from Yahoo Mail on Android



__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net  

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
<http://www.qsl.net/donate.html%20> Message
delivered to r...@cobi.biz  

 

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 has 0.1 w indicated, SWR 1.0 during tune test

[Dale Putnam]

HI Cathy,  Let's slip back to basics for just a sec, can you get QRP levels 
from the K2 by itself? with the coax/dummy load connected to the back of the 
qrp K2? With the power connected to the qrp K2 also, does the qrp power appear 
as expected on the SO239 of the KPA100?One if these fail, that would provide a 
direction to look.Keep in touch.. these should be fun, not frustration.. 

Have a great day, 
 
 
--...   ...--
Dale - WC7S in Wy
 
 


> From: r...@cobi.biz
> To: catherine.ja...@att.net; elecraft@mailman.qth.net
> Date: Sun, 3 Jan 2016 13:57:01 -0800
> Subject: Re: [Elecraft] KPA100 has 0.1 w indicated, SWR 1.0 during tune test
> 
> Good point. I would think so.
> 
>  
> 
> 73, Ron AC7AC
> 
>  
> 
> From: Catherine James [mailto:catherine.ja...@att.net] 
> Sent: Sunday, January 3, 2016 11:19 AM
> To: Ron D'Eau Claire; elecraft@mailman.qth.net
> Subject: Re: RE: [Elecraft] KPA100 has 0.1 w indicated, SWR 1.0 during tune
> test
> 
>  
> 
> 
> Wouldn't that (failure in coax confection to K2) prevent the receive from
> working? I have good reception, but no TX.
> 
> Sent from Yahoo Mail on Android
> <https://overview.mail.yahoo.com/mobile/?.src=Android> 
> 
> 
> From:"Ron D'Eau Claire" <r...@cobi.biz>
> Date:Sun, Jan 3, 2016 at 2:06 PM
> Subject:RE: [Elecraft] KPA100 has 0.1 w indicated, SWR 1.0 during tune test
> 
> Did you dislodge the connector on the coax between the KPA100 and the K2
> main board? If in place, is it oriented correctly? While keyed, it can be
> reversed by a clever person, Hi! 
> 
> You can see that connector by simply removing the K2 side panel. Usually
> take if off when replacing the KPA100 just so I can see the cables and
> connectors clearly. It's easier to plug the power and RF cables in AFTER
> putting the KPA100 on than trying to do it holding the KPA100 up enough to
> see in from the top. 
> 
> 73 Ron AC7AC 
> 
> 
> -Original Message-
> From: Elecraft [mailto:elecraft-boun...@mailman.qth.net 
> ] On Behalf Of
> Catherine James
> Sent: Sunday, January 3, 2016 10:41 AM
> To: elecraft@mailman.qth.net  ; Don Wilhelm
> Subject: [Elecraft] KPA100 has 0.1 w indicated, SWR 1.0 during tune test
> 
> I am attempting the C1 adjustment to get correct SWR. Unfortunately, with a
> dummy load on the SO239 port and the power knob set to 5w, pressing TUNE
> just gives a beep followed by 0.1 1.0-1. Adjusting C1 has no effect at all.
> The receive audio does cut out while tune mode is on, then reappears when
> off.
> 
> I get the same behavior whether 8r is set to norm or hold.
> 
> I'm guessing there a break in the transmit RF path somewhere.  *sigh*
> 
> Cathy
> N5WVR
> 
> Sent from Yahoo Mail on Android
> 
> 
> 
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net  
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> <http://www.qsl.net/donate.html%20> Message
> delivered to r...@cobi.biz  
> 
>  
> 
> __
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft@mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to daleput...@hotmail.com
  
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 has 0.1 w indicated, SWR 1.0 during tune test

[Ron D'Eau Claire]

Did you dislodge the connector on the coax between the KPA100 and the K2
main board? If in place, is it oriented correctly? While keyed, it can be
reversed by a clever person, Hi! 

You can see that connector by simply removing the K2 side panel. Usually
take if off when replacing the KPA100 just so I can see the cables and
connectors clearly. It's easier to plug the power and RF cables in AFTER
putting the KPA100 on than trying to do it holding the KPA100 up enough to
see in from the top. 

73 Ron AC7AC 

-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of
Catherine James
Sent: Sunday, January 3, 2016 10:41 AM
To: elecraft@mailman.qth.net; Don Wilhelm
Subject: [Elecraft] KPA100 has 0.1 w indicated, SWR 1.0 during tune test

I am attempting the C1 adjustment to get correct SWR. Unfortunately, with a
dummy load on the SO239 port and the power knob set to 5w, pressing TUNE
just gives a beep followed by 0.1 1.0-1. Adjusting C1 has no effect at all.
The receive audio does cut out while tune mode is on, then reappears when
off.

I get the same behavior whether 8r is set to norm or hold.

I'm guessing there a break in the transmit RF path somewhere.  *sigh*

Cathy
N5WVR

Sent from Yahoo Mail on Android

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html Message
delivered to r...@cobi.biz

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 has 0.1 w indicated, SWR 1.0 during tune test

[Catherine James]

Wouldn't that (failure in coax confection to K2) prevent the receive from 
working? I have good reception, but no TX.

Sent from Yahoo Mail on Android

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 U6 voltage issue

[John Lemay]

Cathy

With several observed voltages being an order of magnitude wrong, I would
suspect the meter - or, dare I suggest,  the user !

John G4ZTR

-Original Message-
From: Elecraft [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of
Catherine James
Sent: 27 June 2015 19:11
To: elecraft@mailman.qth.net
Subject: [Elecraft] KPA100 U6 voltage issue

I recently began building a just-purchased KPA100 kit for my K2 #5191.  All
was well until I reached the voltage checkpoints on page 26.

U5 pin 1 is 0.8 volts (not 0 to 0.1)

U5 pin 7 is 0.9 V (not 0 to 0.1)

U6 pin 6 is 17 volts (not 0 to 0.5)


I am much more concerned about U6, but perhaps the U5 voltages give you more
information.


The no pa pa message comes up as expected, and the current indicated on the
k2 display is less than 400 ma.


The keys are in the correct places on the ribbon cable. Nothing has ever
been plugged into the DB9 port, so this is not the issue where a standard
serial cable damages the kpa100 through the aux port non-standard wiring.


The K2 appears to work fine with the partially built KPA100 disconnected.
Voltages on D9 of the K2 RF board (my proxy for V RFDET) are much lower than
17 volts (kpa100 not connected) so the high voltage appears to come from the
KPA100, not the K2.


I have the KSB2 installed, but haven't explored that its voltages, and
haven't tested whether it still works following the 17 volt incident.


I don't see any obvious solder bridges on the KPA100.


Where would voltages near 17 volts normally be found on the KPA100 board?


Thoughts on next steps?


Cathy

N5WVR

Sent from Yahoo Mail on Android

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to j...@carltonhouse.eclipse.co.uk

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 U6 voltage issue

[Don Wilhelm]

Cathy,

Are you saying that with the KPA100 connected to the base K2, you have 
17 volts on U6 pin 6, but with it still connected to the base K2, you 
have a lower voltage at RF board D9?  Check the voltage at both ends of 
RF board R66 -  If the highest voltage there does not match the reading 
at KPA100 U6 pin 6, there is a discontinuity somewhere.
I can't think of any way you could actually have 17 volts on U6 pin 6 - 
maybe 12 volts or even up to 15, but that is a strange voltage.

During receive that voltage should be very close to zero.
First make certain all the pins on U6 are soldered.
Then measure U6 pin 7 and pin 8.  Both should be at 5 volts.
If you really have 17 volts (actually anything more than 5 volts) at U6 
pin 6, there is no way that U6 could be generating that voltage. It has 
to be coming from a source outside U6 (although the 17 volts may have 
damaged U6).


Check the KPA100 carefully with a magnifier for solder bridges, 
especially on the pins of P1 (12CTRL is adjacent to VRFDET).
Check the orientation of diodes D1 thru D8 - especially D6 - all the 
cathodes should point in the same direction.


Do you have the ribbon cable oriented in the proper direction - from P1, 
the cable should extend over the front edge of the KPA100 - it it is the 
other way around, swap the ends of the cable with each other.


If you have the KSB2 option or the K60XV option installed, try removing 
both those options and check again.  Other than the MCU and D9 in the 
base K2, those are the only places you will find the VRFDET line.


73,
Don W3FPR

On 6/27/2015 2:10 PM, Catherine James wrote:

I recently began building a just-purchased KPA100 kit for my K2 #5191.  All was 
well until I reached the voltage checkpoints on page 26.

U5 pin 1 is 0.8 volts (not 0 to 0.1)
U5 pin 7 is 0.9 V (not 0 to 0.1)
U6 pin 6 is 17 volts (not 0 to 0.5)
I am much more concerned about U6, but perhaps the U5 voltages give you more 
information.

The K2 appears to work fine with the partially built KPA100 disconnected. 
Voltages on D9 of the K2 RF board (my proxy for V RFDET) are much lower than 17 
volts (kpa100 not connected) so the high voltage appears to come from the 
KPA100, not the K2.

I have the KSB2 installed, but haven't explored that its voltages, and haven't tested 
whether it still works following the 17 volt incident.

I don't see any obvious solder bridges on the KPA100.

Where would voltages near 17 volts normally be found on the KPA100 board?



__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 final test.

[Michael Eberle]

Have you double checked that the W2 is on the 200 or 2000 watt scale as 
opposed to 20 watts?


Mike
KI0HA

On 5/22/2015 6:42 PM, Brian Denley wrote:

Don et al:
I am doing the final test on a KPA100 kit that I have assembled.  Every test 
has been nominal but my W2 peaks out at 20 watts.  I do get 5 watts when set at 
5, etc. but for any setting above 20, I just get 20 watts out.  If I go into 
tune mode for 10 sec or so, the KPA100 transistors do get hot.  Every 
resistance test, etc. has been perfect, my bias is set at .97 amps.  T-R is set 
to 8R- HOLD.

Any ideas would be appreciated.

Brian
KB1VBF
Sent from my iPad



__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 and KAT100 in EC2 - is replacement of L1 on AUX2 necessary?

[Don Wilhelm]

Brian,

If the toroid cores have a painted color on them, they are *not* ferrite 
cores.
The ferrite cores are a dull gray.  The more common ferrite cores are 
type 43 Mix, but could also be a 61 mix.  The 61 mix is a lighter shade 
of grey than the 43 mix.
For reference, the tiny cores used for winding the KSB2 RFC1 and RFC2 
are FT25-43.

The FT designates a ferrite material,
The 25 or 37 (or any other number) is the outer diameter in inches x 
100 - i.e .25 inch diameter is 25.

The number after the dash is the ferrite mixture type.

I hope that helps.

73,
Don W3FPR

On 3/26/2015 11:15 PM, Brian Denley wrote:

Ken and Don:
I am interested in this as well.  My KAT100 is complete in the EC-2 and I just 
started the KPA100 build today.  I'm sure I have a few spare toroid cores 
around here.  How do I tell if they are the ones specified by Don?

Brian
KB1VBF
Sent from my iPad


On Mar 26, 2015, at 7:57 AM, Don Wilhelm w3...@embarqmail.com wrote:

Ken,

Although *supposedly* the inductor should be able to supply the needed current, 
I recommend replacing it with a toroid.
Especially if the inductor is of the older miniature type.
12 turns on a FT25-43 or FT37-43 core will work nicely.



__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 and KAT100 in EC2 - is replacement of L1 on AUX2 necessary?

[Don Wilhelm]

Ken,

Although *supposedly* the inductor should be able to supply the needed 
current, I recommend replacing it with a toroid.

Especially if the inductor is of the older miniature type.
12 turns on a FT25-43 or FT37-43 core will work nicely.

73,
Don W3FPR

On 3/26/2015 1:41 AM, Kenneth Talbott wrote:

I just completed moving my KPA100 and KAT100 into the EC2 enclosure.  I am
really pleased with the result!  Spring is here!  All I have to do is
disconnect 2 cables from my K2/10 with KAT2 and hook up the camper for QRP
fun in the woods of Virginia.  Can someone advise me whether or not it is
necessary to replace L1 (the 15-mH inductor on AUX2 board)?  Some posts
suggest that its current capacity is inadequate to power the digital
subsystem of the KPA100/KAT100.  I do provide DC power to the K2/10 and
KAT100 through their coaxial DC connectors.  Thanks!

Ken - ke4rg

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to w3...@embarqmail.com



__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 and KAT100 in EC2 - is replacement of L1 on AUX2 necessary?

[Brian Denley]

Ken and Don:
I am interested in this as well.  My KAT100 is complete in the EC-2 and I just 
started the KPA100 build today.  I'm sure I have a few spare toroid cores 
around here.  How do I tell if they are the ones specified by Don?

Brian 
KB1VBF
Sent from my iPad

 On Mar 26, 2015, at 7:57 AM, Don Wilhelm w3...@embarqmail.com wrote:
 
 Ken,
 
 Although *supposedly* the inductor should be able to supply the needed 
 current, I recommend replacing it with a toroid.
 Especially if the inductor is of the older miniature type.
 12 turns on a FT25-43 or FT37-43 core will work nicely.
 
 73,
 Don W3FPR
 
 On 3/26/2015 1:41 AM, Kenneth Talbott wrote:
 I just completed moving my KPA100 and KAT100 into the EC2 enclosure.  I am
 really pleased with the result!  Spring is here!  All I have to do is
 disconnect 2 cables from my K2/10 with KAT2 and hook up the camper for QRP
 fun in the woods of Virginia.  Can someone advise me whether or not it is
 necessary to replace L1 (the 15-mH inductor on AUX2 board)?  Some posts
 suggest that its current capacity is inadequate to power the digital
 subsystem of the KPA100/KAT100.  I do provide DC power to the K2/10 and
 KAT100 through their coaxial DC connectors.  Thanks!
 
 Ken - ke4rg
 
 __
 Elecraft mailing list
 Home: http://mailman.qth.net/mailman/listinfo/elecraft
 Help: http://mailman.qth.net/mmfaq.htm
 Post: mailto:Elecraft@mailman.qth.net
 
 This list hosted by: http://www.qsl.net
 Please help support this email list: http://www.qsl.net/donate.html
 Message delivered to w3...@embarqmail.com
 
 __
 Elecraft mailing list
 Home: http://mailman.qth.net/mailman/listinfo/elecraft
 Help: http://mailman.qth.net/mmfaq.htm
 Post: mailto:Elecraft@mailman.qth.net
 
 This list hosted by: http://www.qsl.net
 Please help support this email list: http://www.qsl.net/donate.html
 Message delivered to b.den...@comcast.net
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 unable to get a low null for SWR cal

[Don Wilhelm]

Michael,

With all the holiday stuff, I think your question did not yet receive a 
response.


Yes, you should be able to obtain a very good null when you adjust the 
capacitor.


Pre-set the trimmer pots R26 and R27 to measure 43k from the wiper to 
ground - you can easily measure that resistance from pins 3 and 5 of U5.


If you transmit into an open 'load' you will have the same voltage on 
the forward and reflected - that part is normal.


Is this a newly built KPA100?  If so, what is the color of the C1 body?  
If it is blue, no problem, also if it is white, again no problem, but if 
it is brown, that capacitor will not work in the C1 location - email 
parts at elecraft dot com and request a PN E540012 capacitor to use at 
the C1 location.
If this is an older KPA100 with either a blue or ceramic capacitor at 
C1, there is a possibility that C1 has failed.  Order PN E540012 to use 
as a replacement (the blue trimmer caps are no longer available).


73,
Don W3FPR


On 12/28/2014 7:45 PM, Michael via Elecraft wrote:

Usually I can get a SWR null around 10 - 15 mV with the power level at  2W.
  
For some reason I can only adjust it down to around 200 mV into a 50 Ohm

dummy load. I have tried changing the diodes and U5 but they did not make a
difference. Also rewound T4 using another toroid.
  
Also noticed that when I disconnect the dummy load and transmit at the 2W

adj level both FOR and REFL voltages are about the same (TP4 = 1.1Vdc, IC5
pin  7=1.1Vdc)!  Shouldn't the VREFL be much higher then the VFWD?
  
Both pots are adj to 27.8 kOhms for power calibration at 2W using a

LP-100A.
  
When transmitting 2W into 50 Ohm load (K2 display shows 2.1W   1.4:1)

LP-100A shows approx. 2W  SWR- 1.05:1
  
VFWD = 0.822 Vdc  (IC5 pin 7)

VREFL= 0.173 Vdc  (IC5 TP4 )
  
Why is the K2 showing a much higher SWR then it should be showing?   Could

there be a problem with U6?
  
I did not build this K2/100 and have found mistakes along the way then

trying to get it working properly I can't seem to find any in this area yet
  though!
  



__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 unable to get a low null for SWR cal

[Michael via Elecraft]

Thank you to Don W3FPR who solved my problem!
 
I could not get the swr null lower than 200 mV.
 
Provided trim cap C1 was brown and did not have the minimum  capacitance
required.  I used a Murata green trimmer cap which now allows me to go  
down to 
7.5 mV and the SWR shown on all bands into a dummy load it 1.0:1.
 
The replacement cap from Elecraft is part number E540012 (5 pF to 15 pF  
white body) which should be used at C1.
 
Michael n2zdb
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 Acoustic Noise

[Don Wilhelm]

Ray,

How old is this KPA100?  If it is the older design with red toroid cores 
at L15 and L16, I suggest that you update it with the KPA100UPKT.   In 
addition, the shield may have to be upgraded as well.  If the slot above 
the SO-239 jack is much greater than 3 mm, and you do not have the 
solder lugs to connect the outside of the shield directly to the SO-239 
jack and clips to ground the shield to the sides of the K2, then you 
need the updated shield KPA100SHLDKT.


I suspect you are experiencing some type of spurious oscillation that 
was present on some KPA100s with the older design - the newer design 
cures that problem.


If you have the updated shield and blue toroid cores at L16 and RFC1, 
then you  have the updated KPA100.


73,
Don W3FPR

On 3/25/2014 6:09 PM, raycollins wrote:
  
When my K2/100 is keyed in SSB mode (connected to a dummy load) and the

microphone is gently tapped, I can hear a faint noise coming from somewhere
on the KPA100 printed circuit board.  It is a low level buzzing/rattling
noise similar to a small metal object vibrating against a loudspeaker cone
but I have disconnected the loudspeaker to eliminate this possibility.

It is only noticeable in high power mode (at levels above about 20 Watts) on
40 metres which points to relays K5 and K6 in the KPA low pass filter but as
these relays are shared with the 30 metre band, I can't understand why the
problem isn't present on 30 metres.




__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to arch...@mail-archive.com

Re: [Elecraft] KPA100 recommended max power for digital modes?

[Lynn W. Taylor, WB6UUT]

... and I would have asked why are you running more?

PSK-31 is not a QRO mode.

It's also not necessarily a weak-signal mode, so comments about the 
various JT modes do not apply to PSK-31.


73 -- Lynn

On 2/22/2014 2:26 PM, Don Wilhelm wrote:
While low power may have been the recommendation, I started in PSK31 
in 2000 when I had only a K2/10.  I ran it in the 5 to 10 watt range.  
When I revealed my power level, many ops asked why I was running only 
that much power.

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 recommended max power for digital modes?

[Edward R Cole]

Glenn,

My guess is most figured you were referring to the KXPA100, but your 
question even has more general reach.


Since full output for the KXPA-100 is cited with 10w drive, it is a 
good guess that 3w = 30w, 4w= 40w, etc.  In reality the gain curve 
for amplifiers is not that flat and often you get a little more gain 
at lower inputs.  One advantage is that linearity is usually much 
better when an amp is driven below its max specs, so that is good for 
running psk-31 and other digital modes.  The K3 and KX3 are much 
better transmitters than most so maybe that is not as much of a concern.


Just a general comment about digital modes:  psk-31 was something I 
tried when it was fairly new and I generally ran at 15-25w with my 
FT-847.  I did well with a 20m dipole running at that level.  There 
were no locals to cause me grief so power level was not an issue.  I 
recall most contacts as nice chats and not certificate chasing.  I am 
looking forward to returning to psk-31 or its variants with 10w from 
my K3 or 3-5w from my KX3.  On 20-10m bands I use a three element 
yagi at 50-feet so that gives gain advantage of more ERP and 
selective reception if a neighbor is operating (I now have a 
multi-multi class station located about 12mi north of me).  But then 
I am not on for the contests so we have no issues (not even heard 
him).  He is big on RTTY and CW.


WSJT suite of digital modes was primarily developed for super 
weak-signal operation such as meteor scatter or eme.  They have 
evolved to weak-signal proponents on HF and LF, and up to mw, so I 
agree that a plain-text version is needed for chat style 
operating.  There are so many different digital modes these days so 
one has more to chose (eg: FLdigi).


73, Ed - KL7UW
17 bands: 600m - 3cm

--
From: WA7SPY wa7...@comcast.net
To: elecraft@mailman.qth.net elecraft@mailman.qth.net
Subject: Re: [Elecraft] KPA100 recommended max power for digital
modes?
Message-ID: 4144055f-7458-437a-a581-459369add...@comcast.net
Content-Type: text/plain;   charset=us-ascii

Thank you for all the replies they were very informative. In my 
original post I stated KPA100. It should have been KXPA100 my bad on 
my part. Most of you figured out what I meant.


I agree about the hi and bye PSK31 QSO's these days. That being said 
I will say I have had some really nice rag chew QSO's lately on 
PSK31. I typically start turning my power down during a QSO to see 
how low I can go and still have a good copy.


I do have my KX3 connected to a Hard Rock 50, 50 watt amplifier. I 
run the Hard Rock at 20 watts or less on PSK31.


In regard to the KXPA100 my original question was to find out what 
the max output power would be safe to go to without causing damage to 
the amp. If I am correct the answer is the amp will protect itself 
and automatically throttle itself back if the temp to the finals gets too hot.


Now in regard to the KX3 without the amp 2-3 watts is recommended for 
PSK31. What does 2 -3 watts driving the KXPA100 equate to for output 
power from the amp. I will be using the Elecraft cable set to 
integrate the amp. So from what I have read that means the PA menu is 
selected to on on the KX3. That means the power control on the KX3 is 
re-indexed. So does that mean it is safe to run in the 20-30 watt 
range with the amp without over driving the KX3 for PSK31?


Thank you
Glenn Maclean WA7SPY



73, Ed - KL7UW
http://www.kl7uw.com
Kits made by KL7UW
Dubus Mag business:
dubus...@gmail.com

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 recommended max power for digital modes?

[Walter Underwood]

Well-protected is not quite the same thing as continuous service or maximum 
linearity. The KX3 is fine at 10-12W for CW or SSB, but people generally run it 
at 3-5W for FM or digital modes.

Of course, when you need the juice, you need it, regardless of mode.

wunder
K6WRU

On Feb 21, 2014, at 11:04 PM, Jim Brown j...@audiosystemsgroup.com wrote:

 On 2/21/2014 7:43 PM, WA7SPY wrote:
 I was looking at the operating manual online and did not see any recommended 
 power setting for operating the amp with digital modes.
 
 Elecraft output stages are very well protected. In general, I feel 
 comfortable running them balls to the wall with keydown modes, with all the 
 lights lit. With well matched antennas, I run keydown modes at full power. If 
 the output stage gets warm, the fan will run faster, and if that isn't 
 enough, the rig will back off the drive.
 
 Remember that the WSJT modes are weak signal modes, NOT low power modes. 
 There is a big difference. We may get lots of distance per watt and be happy 
 with QRP for easy paths, but for the most difficult paths (EME, 
 transcontinental 160M), great digital ops pile on the watts and use their 
 best antennas. I do a lot of QRP, but I also know when to turn on the big 
 amp. :)
 
 73, Jim K9YC
 __
 Elecraft mailing list
 Home: http://mailman.qth.net/mailman/listinfo/elecraft
 Help: http://mailman.qth.net/mmfaq.htm
 Post: mailto:Elecraft@mailman.qth.net
 
 This list hosted by: http://www.qsl.net
 Please help support this email list: http://www.qsl.net/donate.html

--
Walter Underwood
wun...@wunderwood.org



__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 recommended max power for digital modes?

[Richard Ferch]

On 2/21/2014 7:43 PM, WA7SPY wrote:
 What is the recommended max power setting for the amp using PSK31 
with a KX3?


In the K3, the limiting factor in some digital modes (notably PSK) is 
not thermal capability of the radio or amplifier, it is linearity. The 
linearity limit depends on the particular digital mode in use, and it 
may also vary depending on the mode used in the radio. For PSK31 and its 
higher-speed brethren, using the radio's DATA A mode, power settings no 
higher than half the maximum power rating of the transmitter should be 
used. This will ensure that the maximum instantaneous peaks of the 
transmitted signal are not clipped (in PSK these peaks can be up to 
twice as high as the average transmitted power). I can't speak from 
personal experience for the KX3, but given the similarity in the way the 
transmitter power is controlled, I would expect it to be the same as the 
K3. Using the KXPA100, keeping the power setting below 50 watts should 
avoid non-linearity.


73,
Rich VE3KI
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 recommended max power for digital modes?

[WILLIS COOKE]

I don't think that Elecraft recommends any particular power.  The amplifier 
will put out full power with acceptable distortion, but the lower quality 
receivers of others will easily overload and if you use more than a few watts 
it will prevent the use of the pass band by your neighbors and you will not be 
popular with them.  They will tell you as they all want to be in the same SSB 
pass band so that they can see everybody at one time.  Elecraft can't do 
anything about the quality of their competitors receivers.
 
Willis 'Cookie' Cooke, TDXS DX Chairman
K5EWJ  Trustee N5BPS, USS Cavalla, USS Stewart



 From: WA7SPY wa7...@comcast.net
To: elecraft@mailman.qth.net elecraft@mailman.qth.net 
Sent: Friday, February 21, 2014 9:43 PM
Subject: [Elecraft] KPA100 recommended max power for digital modes?
 

I just ordered a KPA100 with the auto tuner for my KX3. In anticipation of the 
arrival of the amp  I was looking at the operating manual online and did not 
see any recommended power setting for operating the amp with digital modes. I 
plan to use the amp for PSK31. What is the recommended max power setting for 
the amp using PSK31 with a KX3?

Thanks,
Glenn Maclean WA7SPY
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 recommended max power for digital modes?

[Lynn W. Taylor, WB6UUT]

For PSK-31, you really want to run the minimal amount of power necessary.

Remember that the entire PSK-31 subband fits in your receiver filters -- 
you don't tune the VFO at all.


If you transmit a strong signal, and propagation is good, I'll be able 
to work you, but when my receiver AGC cuts in all the rest of the PSK-31 
stations on the band will go away.


If I happened to be working one of those other stations, my QSO is over.

As a rule of thumb, you don't want to exceed half the output power, 
unless the amp is rated for 100% key down.  Monitor the temperature.


50 watts is a lot of power on PSK-31.

73 -- Lynn

On 2/21/2014 7:43 PM, WA7SPY wrote:

I just ordered a KPA100 with the auto tuner for my KX3. In anticipation of the 
arrival of the amp  I was looking at the operating manual online and did not 
see any recommended power setting for operating the amp with digital modes. I 
plan to use the amp for PSK31. What is the recommended max power setting for 
the amp using PSK31 with a KX3?

Thanks,
Glenn Maclean WA7SPY
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html



__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 recommended max power for digital modes?

[Gerald Manthey]

I run 25 watts on my K3. I adjusted it by watching my peaks on a scope. At
25 watts and my alc set I have a clean signal. There are those that splat
more power and we all see them in the waterfall. 25 watts will work the
world on PSK.
Just my observations and my .02 cents.
73 Gerald
 On Feb 22, 2014 9:40 AM, Lynn W. Taylor, WB6UUT 
k...@coldrockshotbrooms.com wrote:

 For PSK-31, you really want to run the minimal amount of power necessary.

 Remember that the entire PSK-31 subband fits in your receiver filters --
 you don't tune the VFO at all.

 If you transmit a strong signal, and propagation is good, I'll be able to
 work you, but when my receiver AGC cuts in all the rest of the PSK-31
 stations on the band will go away.

 If I happened to be working one of those other stations, my QSO is over.

 As a rule of thumb, you don't want to exceed half the output power, unless
 the amp is rated for 100% key down.  Monitor the temperature.

 50 watts is a lot of power on PSK-31.

 73 -- Lynn

 On 2/21/2014 7:43 PM, WA7SPY wrote:

 I just ordered a KPA100 with the auto tuner for my KX3. In anticipation
 of the arrival of the amp  I was looking at the operating manual online and
 did not see any recommended power setting for operating the amp with
 digital modes. I plan to use the amp for PSK31. What is the recommended max
 power setting for the amp using PSK31 with a KX3?

 Thanks,
 Glenn Maclean WA7SPY
 __
 Elecraft mailing list
 Home: http://mailman.qth.net/mailman/listinfo/elecraft
 Help: http://mailman.qth.net/mmfaq.htm
 Post: mailto:Elecraft@mailman.qth.net

 This list hosted by: http://www.qsl.net
 Please help support this email list: http://www.qsl.net/donate.html


 __
 Elecraft mailing list
 Home: http://mailman.qth.net/mailman/listinfo/elecraft
 Help: http://mailman.qth.net/mmfaq.htm
 Post: mailto:Elecraft@mailman.qth.net

 This list hosted by: http://www.qsl.net
 Please help support this email list: http://www.qsl.net/donate.html

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 recommended max power for digital modes?

[Doug VE3VS]

Hi Glenn,
I started using PSK31 many, many years ago, when it was first introduced by
a ham in the UK. It was made very clear to operators that minimum power
should always be used for a QSO.  It was suggested that more than 10 watts
was excessive. As mentioned in one of the other replies, many transmissions
can fall within the receiver passband when using this mode. If you, or
anyone else uses much higher power, that strongest signal will take over
the passband on most receivers, spoiling other QSOs that are going on at the
time.

I have noticed over the past five years or more there has been a steady
increase in the power being used by thoughtless or unknowing operators. As a
result of this power creep, I have drifted away from a mode that I once
thoroughly enjoyed.

With your KX3, you should not normally need an amp to use PSK31.

Doug, VE3VS




--
View this message in context: 
http://elecraft.365791.n2.nabble.com/KPA100-recommended-max-power-for-digital-modes-tp7584537p7584569.html
Sent from the Elecraft mailing list archive at Nabble.com.
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 recommended max power for digital modes?

[Don Wilhelm]

Doug,

While low power may have been the recommendation, I started in PSK31 in 
2000 when I had only a K2/10.  I ran it in the 5 to 10 watt range.  When 
I revealed my power level, many ops asked why I was running only that 
much power.


So the push for higher power has been going on since shortly after the 
beginning of PSK31.


While I do use it occasionally, that factor and the preponderance of 
hello, brag sheet, goodbye QSOs has soured me on the mode.  It used to 
be a lot of keyboard to keyboard ragchew QSOs, but that is rare these 
days.  No opportunity to get to know something about the ham you are in 
QSO with.


73,
Don W3FPR

On 2/22/2014 5:05 PM, Doug VE3VS wrote:

Hi Glenn,
I started using PSK31 many, many years ago, when it was first introduced by
a ham in the UK. It was made very clear to operators that minimum power
should always be used for a QSO.  It was suggested that more than 10 watts
was excessive. As mentioned in one of the other replies, many transmissions
can fall within the receiver passband when using this mode. If you, or
anyone else uses much higher power, that strongest signal will take over
the passband on most receivers, spoiling other QSOs that are going on at the
time.

I have noticed over the past five years or more there has been a steady
increase in the power being used by thoughtless or unknowing operators. As a
result of this power creep, I have drifted away from a mode that I once
thoroughly enjoyed.

With your KX3, you should not normally need an amp to use PSK31.



__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 recommended max power for digital modes?

[Gerald Manthey]

I agree with Don! I like to chat, learn about the op or Qth. It is a major
draw back to Jt 65 or Jt9.
 On Feb 22, 2014 4:26 PM, Don Wilhelm w3...@embarqmail.com wrote:

 Doug,

 While low power may have been the recommendation, I started in PSK31 in
 2000 when I had only a K2/10.  I ran it in the 5 to 10 watt range.  When I
 revealed my power level, many ops asked why I was running only that much
 power.

 So the push for higher power has been going on since shortly after the
 beginning of PSK31.

 While I do use it occasionally, that factor and the preponderance of
 hello, brag sheet, goodbye QSOs has soured me on the mode.  It used to be
 a lot of keyboard to keyboard ragchew QSOs, but that is rare these days.
  No opportunity to get to know something about the ham you are in QSO with.

 73,
 Don W3FPR

 On 2/22/2014 5:05 PM, Doug VE3VS wrote:

 Hi Glenn,
 I started using PSK31 many, many years ago, when it was first introduced
 by
 a ham in the UK. It was made very clear to operators that minimum power
 should always be used for a QSO.  It was suggested that more than 10 watts
 was excessive. As mentioned in one of the other replies, many
 transmissions
 can fall within the receiver passband when using this mode. If you, or
 anyone else uses much higher power, that strongest signal will take over
 the passband on most receivers, spoiling other QSOs that are going on at
 the
 time.

 I have noticed over the past five years or more there has been a steady
 increase in the power being used by thoughtless or unknowing operators.
 As a
 result of this power creep, I have drifted away from a mode that I once
 thoroughly enjoyed.

 With your KX3, you should not normally need an amp to use PSK31.


 __
 Elecraft mailing list
 Home: http://mailman.qth.net/mailman/listinfo/elecraft
 Help: http://mailman.qth.net/mmfaq.htm
 Post: mailto:Elecraft@mailman.qth.net

 This list hosted by: http://www.qsl.net
 Please help support this email list: http://www.qsl.net/donate.html

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 recommended max power for digital modes?

[Jack Chomley]

Don,

I go hide on the WARC bands for PSK31 these days :-) Too many big guns on the 
other bands,  I have a hard time trying to filter them out, my receiver always 
gets swamped!

73,

Jack VK4JRC

Club.www.cqara.org.au
Member WIA SARL ARRL 
GQRP   #14392
QRPARCI #15068
VKQRP.#833

 On 23 Feb 2014, at 8:26 am, Don Wilhelm w3...@embarqmail.com wrote:
 
 Doug,
 
 While low power may have been the recommendation, I started in PSK31 in 2000 
 when I had only a K2/10.  I ran it in the 5 to 10 watt range.  When I 
 revealed my power level, many ops asked why I was running only that much 
 power.
 
 So the push for higher power has been going on since shortly after the 
 beginning of PSK31.
 
 While I do use it occasionally, that factor and the preponderance of hello, 
 brag sheet, goodbye QSOs has soured me on the mode.  It used to be a lot of 
 keyboard to keyboard ragchew QSOs, but that is rare these days.  No 
 opportunity to get to know something about the ham you are in QSO with.
 
 73,
 Don W3FPR
 
 On 2/22/2014 5:05 PM, Doug VE3VS wrote:
 Hi Glenn,
 I started using PSK31 many, many years ago, when it was first introduced by
 a ham in the UK. It was made very clear to operators that minimum power
 should always be used for a QSO.  It was suggested that more than 10 watts
 was excessive. As mentioned in one of the other replies, many transmissions
 can fall within the receiver passband when using this mode. If you, or
 anyone else uses much higher power, that strongest signal will take over
 the passband on most receivers, spoiling other QSOs that are going on at the
 time.
 
 I have noticed over the past five years or more there has been a steady
 increase in the power being used by thoughtless or unknowing operators. As a
 result of this power creep, I have drifted away from a mode that I once
 thoroughly enjoyed.
 
 With your KX3, you should not normally need an amp to use PSK31.
 
 __
 Elecraft mailing list
 Home: http://mailman.qth.net/mailman/listinfo/elecraft
 Help: http://mailman.qth.net/mmfaq.htm
 Post: mailto:Elecraft@mailman.qth.net
 
 This list hosted by: http://www.qsl.net
 Please help support this email list: http://www.qsl.net/donate.html
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 recommended max power for digital modes?

[Bill Frantz]

When I went back to New Hampshire last Christmas, I decided that 
the trip would be a rag chew trip. Since the only radio I had 
was the Small Wonder Labs PSK-20 -- The K3 is too big to carry 
and I don't yet have a KX3 -- it had to be rag chewing on 20M 
PSK. I found a number of people to chat with and had a good time 
on the radio.


I have a few thoughts on how to encourage rag chewing. Since 
people are used to the 5NN QRZ type of interchange, start 
chatting early in the QSO. I use macros for the boiler plate -- 
name, QTH, and call signs and use the keyboard for everything 
else. I'm lucky that after 40+ years as a computer programmer, I 
can type quite rapidly. Don't worry about typing slowly however. 
Rag chewing isn't a contest or a DX pileup.


In my first exchange after exchanging call signs, I try to give 
meaningful signal reports, I'll start with:


Hi OM, you are 569 569 569
and then run my QTH macro. If the other OP has already sent a 
name I'll use it in place of OM. Later in the QSO, if the 
other OP has already described the station, I'll try to include 
something about his station when I describe mine. By then we 
should be ready to branch out and talk about ARES/RACES, 
contesting, DX, WX, family, Christmas dinner -- anything that 
might come up.


It doesn't always work, but then just move on and do/answer 
another CQ.


As to being overpowered by strong stations, the K3 with a 250 Hz 
filter works wonders. However, for me, the real problem stations 
have been local running well under 50 watts. When you're in the 
target of a beam 1/4 mile away, it doesn't take much power to 
overload the A/D converter driving the computer.


The PSK-20 doesn't have any narrow filters like the K3 does, but 
in New Hampshire there aren't any close by PSK operators either. 
I rarely see any New England stations on my waterfall. (20 
meters is that way. I had a devil of a time working Nevada from 
the Los Gatos too.)


Now there are times and places for rag chewing. Contests, DX 
pileups, and rare opening aren't them. At times when it is 
appropriate, try to encourage it.


Cheers - Bill, AE6JV

On 2/23/14 at 2:46 PM, vk4...@gmail.com (Jack Chomley) wrote:

I go hide on the WARC bands for PSK31 these days :-) Too many 
big guns on the other bands,  I have a hard time trying to 
filter them out, my receiver always gets swamped!


On 2/22/14 at 2:41 PM, kc6...@gmail.com (Gerald Manthey) wrote:


I agree with Don! I like to chat, learn about the op or Qth. It is a major
draw back to Jt 65 or Jt9.

On Feb 22, 2014 4:26 PM, Don Wilhelm w3...@embarqmail.com wrote:


Doug,

...

While I do use [PSK] occasionally, that factor and the preponderance of
hello, brag sheet, goodbye QSOs has soured me on the mode.  It used to be
a lot of keyboard to keyboard ragchew QSOs, but that is rare these days.
No opportunity to get to know something about the ham you are in QSO with.


---
Bill Frantz| I like the farmers' market   | Periwinkle
(408)356-8506  | because I can get fruits and | 16345 
Englewood Ave
www.pwpconsult.com | vegetables without stickers. | Los Gatos, 
CA 95032


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 recommended max power for digital modes?

[Bill Turner]

ORIGINAL MESSAGE:  (may be snipped)

On 2/22/2014 2:05 PM, Doug VE3VS wrote:

If you, or
anyone else uses much higher power, that strongest signal will take over
the passband on most receivers, spoiling other QSOs that are going on at the
time.


REPLY:

This has been true forever, not just with PSK31, and this is why 
narrowband receivers were invented in the first place. PSK31 is a very 
narrowband mode so why not receive accordingly? Narrow your RX bandwidth 
down to 100 Hz or so and the problem goes away and everyone can run 
whatever power they like.


73, Bill W6WRT

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 recommended max power for digital modes?

[WA7SPY]

Thank you for all the replies they were very informative. In my original post I 
stated KPA100. It should have been KXPA100 my bad on my part. Most of you 
figured out what I meant. 

I agree about the hi and bye PSK31 QSO's these days. That being said I will say 
I have had some really nice rag chew QSO's lately on PSK31. I typically start 
turning my power down during a QSO to see how low I can go and still have a 
good copy. 

I do have my KX3 connected to a Hard Rock 50, 50 watt amplifier. I run the Hard 
Rock at 20 watts or less on PSK31.

In regard to the KXPA100 my original question was to find out what the max 
output power would be safe to go to without causing damage to the amp. If I am 
correct the answer is the amp will protect itself and automatically throttle 
itself back if the temp to the finals gets too hot.

Now in regard to the KX3 without the amp 2-3 watts is recommended for PSK31. 
What does 2 -3 watts driving the KXPA100 equate to for output power from the 
amp. I will be using the Elecraft cable set to integrate the amp. So from what 
I have read that means the PA menu is selected to on on the KX3. That means the 
power control on the KX3 is re-indexed. So does that mean it is safe to run in 
the 20-30 watt range with the amp without over driving the KX3 for PSK31?

Thank you
Glenn Maclean WA7SPY

 On Feb 22, 2014, at 4:07 PM, Bill Frantz fra...@pwpconsult.com wrote:
 
 When I went back to New Hampshire last Christmas, I decided that the trip 
 would be a rag chew trip. Since the only radio I had was the Small Wonder 
 Labs PSK-20 -- The K3 is too big to carry and I don't yet have a KX3 -- it 
 had to be rag chewing on 20M PSK. I found a number of people to chat with and 
 had a good time on the radio.
 
 I have a few thoughts on how to encourage rag chewing. Since people are used 
 to the 5NN QRZ type of interchange, start chatting early in the QSO. I use 
 macros for the boiler plate -- name, QTH, and call signs and use the keyboard 
 for everything else. I'm lucky that after 40+ years as a computer programmer, 
 I can type quite rapidly. Don't worry about typing slowly however. Rag 
 chewing isn't a contest or a DX pileup.
 
 In my first exchange after exchanging call signs, I try to give meaningful 
 signal reports, I'll start with:
 
 Hi OM, you are 569 569 569
 and then run my QTH macro. If the other OP has already sent a name I'll use 
 it in place of OM. Later in the QSO, if the other OP has already described 
 the station, I'll try to include something about his station when I describe 
 mine. By then we should be ready to branch out and talk about ARES/RACES, 
 contesting, DX, WX, family, Christmas dinner -- anything that might come up.
 
 It doesn't always work, but then just move on and do/answer another CQ.
 
 As to being overpowered by strong stations, the K3 with a 250 Hz filter works 
 wonders. However, for me, the real problem stations have been local running 
 well under 50 watts. When you're in the target of a beam 1/4 mile away, it 
 doesn't take much power to overload the A/D converter driving the computer.
 
 The PSK-20 doesn't have any narrow filters like the K3 does, but in New 
 Hampshire there aren't any close by PSK operators either. I rarely see any 
 New England stations on my waterfall. (20 meters is that way. I had a devil 
 of a time working Nevada from the Los Gatos too.)
 
 Now there are times and places for rag chewing. Contests, DX pileups, and 
 rare opening aren't them. At times when it is appropriate, try to encourage 
 it.
 
 Cheers - Bill, AE6JV
 
 On 2/23/14 at 2:46 PM, vk4...@gmail.com (Jack Chomley) wrote:
 
 I go hide on the WARC bands for PSK31 these days :-) Too many big guns on 
 the other bands,  I have a hard time trying to filter them out, my receiver 
 always gets swamped!
 
 On 2/22/14 at 2:41 PM, kc6...@gmail.com (Gerald Manthey) wrote:
 
 I agree with Don! I like to chat, learn about the op or Qth. It is a major
 draw back to Jt 65 or Jt9.
 
 On Feb 22, 2014 4:26 PM, Don Wilhelm w3...@embarqmail.com wrote:
 
 Doug,
 
 ...
 
 While I do use [PSK] occasionally, that factor and the preponderance of
 hello, brag sheet, goodbye QSOs has soured me on the mode.  It used to be
 a lot of keyboard to keyboard ragchew QSOs, but that is rare these days.
 No opportunity to get to know something about the ham you are in QSO with.
 
 ---
 Bill Frantz| I like the farmers' market   | Periwinkle
 (408)356-8506  | because I can get fruits and | 16345 Englewood Ave
 www.pwpconsult.com | vegetables without stickers. | Los Gatos, CA 95032
 
 __
 Elecraft mailing list
 Home: http://mailman.qth.net/mailman/listinfo/elecraft
 Help: http://mailman.qth.net/mmfaq.htm
 Post: mailto:Elecraft@mailman.qth.net
 
 This list hosted by: http://www.qsl.net
 Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 recommended max power for digital modes?

[Jack]

Minimum power to accomplish your communication goals, Bill. That still 
*is* part of the FCC regulations, is it not?


Jack, W6NF/VE4SNA

On 2/22/2014 5:45 PM, Bill Turner wrote:

ORIGINAL MESSAGE:  (may be snipped)

On 2/22/2014 2:05 PM, Doug VE3VS wrote:

If you, or
anyone else uses much higher power, that strongest signal will take 
over
the passband on most receivers, spoiling other QSOs that are going on 
at the

time.


REPLY:

This has been true forever, not just with PSK31, and this is why 
narrowband receivers were invented in the first place. PSK31 is a very 
narrowband mode so why not receive accordingly? Narrow your RX 
bandwidth down to 100 Hz or so and the problem goes away and everyone 
can run whatever power they like.


73, Bill W6WRT

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html




---
This email is free from viruses and malware because avast! Antivirus protection 
is active.
http://www.avast.com

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 recommended max power for digital modes?

[Matt Zilmer]

Hi Glenn,

Typically, the KX3 runs 5W to get 100W output from the KXPA100 (13 dB
gain).  There are minor varations due to calibration, but that's the
gist of it.

73,
matt

Now in regard to the KX3 without the amp 2-3 watts is recommended for PSK31. 
What does 2 -3 watts driving the KXPA100 equate to for output power from the 
amp. I will be using the Elecraft cable set to integrate the amp. So from what 
I have read that means the PA menu is selected to on on the KX3. That means 
the power control on the KX3 is re-indexed. So does that mean it is safe to 
run in the 20-30 watt range with the amp without over driving the KX3 for 
PSK31?

Glenn Maclean WA7SPY

Matt Zilmer, W6NIA
www.elecraft.com
831-763-4211  x129
Skype: matt.zilmer

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 recommended max power for digital modes?

[Bill Turner]

ORIGINAL MESSAGE:  (may be snipped)

On 2/22/2014 6:20 PM, Jack wrote:
Minimum power to accomplish your communication goals, Bill. That still 
*is* part of the FCC regulations, is it not?


Jack, W6NF/VE4SNA 


REPLY:

Of course it is. Nothing I said contradicts that.

73, Bill W6WRT

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 recommended max power for digital modes?

[Matt Zilmer]

In Navy-Marine Corps MARS, we use a *lot* of digital modes, including
PSK31 and a double handful of others.  On this KX3/KXPA100, I normally
use no more than 25W for PSK and a little more for some of the others.
On MT63, I use 30W.  Most data modes don't need a lot of SNR to
decode.  It also depends on transmission length.  If I'm going to
transmit MT63 for five minutes straight, I run the power down to 20W.

I'm not sure there is a recommended output power setting for data
modes using the KX3/KXPA100, but you can find out yourself by
monitoring the PA.X temp on the VFO B display (your room temperature
is different from others').  If you see the temp rise to more than
you're comfortable with, back down on the power.  Using the settings
stated above keeps the KXPA temp at comfortable levels at this
station, usually  50C, but sometimes a bit over.  The amp will
protect itself by lowering output power if the temp runs too hot. Like
everything Elecraft makes, the hardware and software are very robust.

73,
matt W6NIA


On Fri, 21 Feb 2014 19:43:42 -0800, you wrote:

I just ordered a KPA100 with the auto tuner for my KX3. In anticipation of the 
arrival of the amp  I was looking at the operating manual online and did not 
see any recommended power setting for operating the amp with digital modes. I 
plan to use the amp for PSK31. What is the recommended max power setting for 
the amp using PSK31 with a KX3?

Thanks,
Glenn Maclean WA7SPY
Matt Zilmer, W6NIA
--
Give me six hours to chop down a tree and I will
spend the first four sharpening the axe. -A. Lincoln
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 recommended max power for digital modes?

[Jim Brown]

On 2/21/2014 7:43 PM, WA7SPY wrote:

I was looking at the operating manual online and did not see any recommended 
power setting for operating the amp with digital modes.


Elecraft output stages are very well protected. In general, I feel 
comfortable running them balls to the wall with keydown modes, with 
all the lights lit. With well matched antennas, I run keydown modes at 
full power. If the output stage gets warm, the fan will run faster, and 
if that isn't enough, the rig will back off the drive.


Remember that the WSJT modes are weak signal modes, NOT low power 
modes. There is a big difference. We may get lots of distance per watt 
and be happy with QRP for easy paths, but for the most difficult paths 
(EME, transcontinental 160M), great digital ops pile on the watts and 
use their best antennas. I do a lot of QRP, but I also know when to turn 
on the big amp. :)


73, Jim K9YC
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] kpa100 toroid changes

[Don Wilhelm]

John,

The toroids have changed because of the KPA100UPKT.
If you have ordered that kit to update your older kit, you will have two 
blue toroid cores.  The red cores for use at L15 and L16 will not be 
used.  No, you cannot use those cores, you must have 15 uHy of 
inductance at L16 and RFC1 and it would take more turns on the red cores 
than you would want to wind.


Make certain you also have the updated shield kit.  If it is current you 
will have a shield for the speaker magnet and 3 grounding clips as well 
as 2 solder lugs to ground the SO-239 jack directly to the outer side of 
the shield.


73,
Don W3FPR

On 2/12/2014 2:11 PM, John Cooper wrote:

Over the years the type of toroids in the kpa100 have changed.  Is this because 
of availability or other reasons?  I have a prewound set of toroids for the 
kpa100 but its old enough to not have rfc1.  Plus the the ones I have don’t 
match descriptions from the latest manual Im working off of.  I don’t have the 
originals either since I never ordered the kit.  Can I modify the L18 I don’t 
need anymore to work in rfc1 spot?




__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] Kpa100 xtals

[Don Wilhelm]

John,

The 18 MHz crystal is low profile but the 4 MHz crystal is not in the 
standard KPA100 kit.
Yes, a low profile 4 MHz crystal should work OK in the KPA100, it is 
only used for the clock to the MCU.


73,
Don W3FPR

On 1/25/2014 3:50 PM, John Cooper wrote:


Are both the 4mhz and 18mhz crystals low profile in kpa100?  If not is low 
profile ok for 4mhz.




__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 First tests (p 22)

[Don Wilhelm]

Joe,

It is entirely possible that your ohmmeter is using polarity that is 
different than normal for DMMs.
You *are* using a DMM are you not?  If you are using a VOM or VTVM, stop 
- the voltage used in those meters (ohmmeter function) may be high 
enough to saturate semiconductor junctions and possibly cause damage.


If you do have a DMM, try the U1 pin 2 resistance with reversed leads.

73,
Don W3FPR

On 1/23/2014 11:23 AM, MARY HAYS CARNEY wrote:

Time to add some extra kick to my K2-10; but, of course, problems arise along 
the way:
  
I find that U1 pin 2 to ground is only 5 kohms rather than  10K.  I can find no  solder bridges or misplaced components.

   Resistors R24 and RP1 show the correct values.  Should I suspect that Q10 is 
shorted?  Other pins on U1 give correct resistances.
  
U4, pin 8 shows a resistance of only about 2.8K rather than the expected 10K.  (As directed, the +ve lead of the meter is on pin 8, -ve lead to ground.)  The circuit diagram suggests that this is to be expected since the measurement is made through two forward-biased diodes (D7 and D8) to ground.  Reversing the meter leads gives the expected high value of resistance.
  
Voltage tests as indicated on p 26 of the manual give expected voltages with only 300 ma total current (20 ma increase over the K2 alone).
  
Joe Carney, KB3FBR


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html



__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 problem with SWR bridge - High SWR

[Stan AE7UT]

Thanks for all the help.
Got it working FB and made my first contact tonight.

73
Stan AE7UT



--
View this message in context: 
http://elecraft.365791.n2.nabble.com/KPA100-problem-with-SWR-bridge-High-SWR-tp7580050p7580069.html
Sent from the Elecraft mailing list archive at Nabble.com.
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 and 100W ATU in separate EC2

[Don Wilhelm]

Dom,

I do not have the website information, but I think I can describe it on 
words - it is not that difficult.
If you are adding the KAT100 as well as the KPA100, order the KAT100-2 
as well as the KPA100. (If you already have a KAT100-1, there is a 
conversion kit available from Elecraft - or at least used to be)


The KAT100-2 contains all the connectors for plugging in the KPA100 
(except for the speaker cable), connect the base K2 RF (the ANT1 jack if 
the KAT2 is included) to the RF IN jack on the KAT100 and connect the 
KAT100 control cable between the KIO2 option in the base K2 and the DB-9 
jack on either the KAT100 or the KAT100.


If you do not wish to use the KAT100, it is just as easy.  Drill a hole 
in the bottom of of the EC2 enclosure (right rear area) to mount a BNC 
connector.  Solder an E620012 header to the back of the BNC jack to 
provide a connector to plug the KPA100 input coax into - you will have 2 
of those parts with the KPA100 kit - they are normally used at K2 RF P3 
and P6.  Make certain the orientation is correct, the center conductor 
of the input coax must connect to the BNC jack center conductor.


Download the KAT100 manual from Elecraft and build the control cable 
that is shown in that manual.


Connect the base K2 RF output to the BNC jack on the EC2 enclosure and 
the control cable to the DB-9 connector on the KPA100.  The connector 
with 2 cables must be plugged into the KIO2 if you use the connection to 
the computer.


Just one additional caution - do all the KPA100 alignment and 
calibration and checkout while connected directly to the base K2 (no QRP 
top cover), and check out the KAT100 using that same configuration.  
Once everything works in that configuration, move the KPA100 to the EC2 
and put the QRP top cover on the K2 - connect the 2 cables between the 
K2 and EC2 and it should work OK.


73,
Don W3FPR

On 5/5/2013 5:37 AM, dombai...@yahoo.com wrote:

Hi,

Been done by a few before...

Has anyone got the whole of the website and all the diagrams and 
images *http://www.kk7p.com/k2kpa100.html

*
I have the web archive pages but some of the diagrams and images are 
missing and original site has gone.


Also have http://home.pacbell.net/johngreb/k2_100_in_ec2.pdf

Or anyone got something else?



__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] kpa100

[Joel Curneal]

When you hold your leads up in the air,  your meter is reading infinity.
Infinity is 10K (greater than 10K).

Your resistance test passes.

Joel  --  N1JEO


On 5/14/12, leo kg6...@yahoo.com wrote:
On page 44 resistance test all good except J2(antenna jack)center pin
10K
 My meter reads nothing the same as if I hold the leads up in the air.What
 should I do.?

Leo kg6wni
  kg6...@yahoo.com





 --
 View this message in context:
 http://elecraft.365791.n2.nabble.com/kpa100-tp7555822.html
 Sent from the Elecraft mailing list archive at Nabble.com.
 __
 Elecraft mailing list
 Home: http://mailman.qth.net/mailman/listinfo/elecraft
 Help: http://mailman.qth.net/mmfaq.htm
 Post: mailto:Elecraft@mailman.qth.net

 This list hosted by: http://www.qsl.net
 Please help support this email list: http://www.qsl.net/donate.html

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] kpa100

[Don Wilhelm]

Leo,

If you shade the PA transistors from the light, that voltage will reduce 
- shine a brighter light on them and the voltage will rise.  All is OK

73,
Don W3FPR

On 5/14/2012 2:25 PM, leo wrote:
   Thanks for the help about the antenna jack one more thing on page 47 DC volt
 test J3 + lead
 it is supposed to be 0v I'm getting -019.0 It is less than 0 but I want to
 be safe.Thanks

   Leo kg6wni
   kg6...@yahoo.com


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 Rev D

[Don Wilhelm]

Syd,

If your KPA100 has red toroid cores at L15 and L16, install KPA100UPKT. 
  That kit will upgrade any level KPA100 to the latest.  If you do not 
have a shield over the speaker magnet, add the KPA100SHLDKT as well to 
upgrade your shield.

Those mods will add significantly to the stability of the amplifier, and 
I highly recommend them.
Those mods were specifically created to address a tendency to oscillate 
a little above the 40 meter ham band under some conditions.  If you 
operate with an autotuner  that tendency to oscillate is quite high.

73,
Don W3FPR

On 3/31/2012 4:17 PM, Syd Smith wrote:
 I recently became aware of the Rev D upgrade kit for the KPA100 at
 Elecraft.  Where can I find a description of the changes and a
 recommendation of why I would want to install this kit in my Rev A
 amplifier which works FB.

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 Rev D

[Don Wilhelm]

Folks,

Before I get more questions indicating confusion, let me clarify in 
detail --

In my response below, I ignored the poster's reference to a Rev D 
Upgrade kit.  There is no Rev D KPA100 - the closest I can imagine to 
Rev D is the manual revision, which is now Rev E.

The manual's rev letter is not linked to the board version (either 
populated or bare).
In this case, there have been only 2 versions of the raw KPA100 board - 
the Field Test level, and all others.  There have been 4 versions of the 
KPA100 - the Field Test version, then the first released version, and 
then the version which incorporated KPA100MODKT, and lastly, the version 
which incorporates KPA100UPKT.  This last mod kit has all the parts for 
upgrading any level KPA100 to the latest.  If your KPA100 has blue 
toroid cores at L16 and RFC1, you have the latest level.

The shield is a different matter.  There are 3 levels of the shield - 
the initial one with a wide notch at the SO-239 jack (about 1.4 inch 
wide), then one with a more narrow (about 1/8 inch (3mm)) notch at the 
jack, and lastly the addition of 2 solder lugs between the SO-239 jack 
and the outside surface of the shield - this last shield also added a 
shield for the speaker magnet since the magnet was sometimes responsible 
for interfering with the operation of relays K13, K14 and K15 on the RF 
board - some do it while others are just fine without the speaker shield.

73,
Don W3FPR

--- 


Syd,

If your KPA100 has red toroid cores at L15 and L16, install KPA100UPKT. 
  That kit will upgrade any level KPA100 to the latest.  If you do not 
have a shield over the speaker magnet, add the KPA100SHLDKT as well to 
upgrade your shield.

Those mods will add significantly to the stability of the amplifier, and 
I highly recommend them.
Those mods were specifically created to address a tendency to oscillate 
a little above the 40 meter ham band under some conditions.  If you 
operate with an autotuner  that tendency to oscillate is quite high.

73,
Don W3FPR

On 3/31/2012 4:17 PM, Syd Smith wrote:
 I recently became aware of the Rev D upgrade kit for the KPA100 at
 Elecraft.  Where can I find a description of the changes and a
 recommendation of why I would want to install this kit in my Rev A
 amplifier which works FB.

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 Rev D

[Hisashi T Fujinaka]

I was just scolded for using the original poster's terminology (it's a
KPA100UPKT, not a Rev D upgrade) but I'm glad Don finally answered my
question about the shields.

It's hard for regular people (i.e. everyone except Elecraft) to know
about rev levels and which mod kits to order (I'd bet things work fine
with none of the upgrades) so I'm sorry that I annoyed the people who
know.

Personally, my rig resets itself on 15M sometimes if I run  90W so I
had a real reason for asking about the shield kit. I seem to have the
latest shield so that's not the answer for my problems.

On Sat, 31 Mar 2012, Don Wilhelm wrote:

 Folks,

 Before I get more questions indicating confusion, let me clarify in
 detail --

 In my response below, I ignored the poster's reference to a Rev D
 Upgrade kit.  There is no Rev D KPA100 - the closest I can imagine to
 Rev D is the manual revision, which is now Rev E.

 The manual's rev letter is not linked to the board version (either
 populated or bare).
 In this case, there have been only 2 versions of the raw KPA100 board -
 the Field Test level, and all others.  There have been 4 versions of the
 KPA100 - the Field Test version, then the first released version, and
 then the version which incorporated KPA100MODKT, and lastly, the version
 which incorporates KPA100UPKT.  This last mod kit has all the parts for
 upgrading any level KPA100 to the latest.  If your KPA100 has blue
 toroid cores at L16 and RFC1, you have the latest level.

 The shield is a different matter.  There are 3 levels of the shield -
 the initial one with a wide notch at the SO-239 jack (about 1.4 inch
 wide), then one with a more narrow (about 1/8 inch (3mm)) notch at the
 jack, and lastly the addition of 2 solder lugs between the SO-239 jack
 and the outside surface of the shield - this last shield also added a
 shield for the speaker magnet since the magnet was sometimes responsible
 for interfering with the operation of relays K13, K14 and K15 on the RF
 board - some do it while others are just fine without the speaker shield.

 73,
 Don W3FPR

 ---


 Syd,

 If your KPA100 has red toroid cores at L15 and L16, install KPA100UPKT.
  That kit will upgrade any level KPA100 to the latest.  If you do not
 have a shield over the speaker magnet, add the KPA100SHLDKT as well to
 upgrade your shield.

 Those mods will add significantly to the stability of the amplifier, and
 I highly recommend them.
 Those mods were specifically created to address a tendency to oscillate
 a little above the 40 meter ham band under some conditions.  If you
 operate with an autotuner  that tendency to oscillate is quite high.

 73,
 Don W3FPR

 On 3/31/2012 4:17 PM, Syd Smith wrote:
 I recently became aware of the Rev D upgrade kit for the KPA100 at
 Elecraft.  Where can I find a description of the changes and a
 recommendation of why I would want to install this kit in my Rev A
 amplifier which works FB.

 __
 Elecraft mailing list
 Home: http://mailman.qth.net/mailman/listinfo/elecraft
 Help: http://mailman.qth.net/mmfaq.htm
 Post: mailto:Elecraft@mailman.qth.net

 This list hosted by: http://www.qsl.net
 Please help support this email list: http://www.qsl.net/donate.html


-- 
Hisashi T Fujinaka - ht...@twofifty.com
BSEE(6/86) + BSChem(3/95) + BAEnglish(8/95) + MSCS(8/03) + $2.50 = latte
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 Rev D

[Don Wilhelm]

I was not annoyed, but wanted to produce clarity for everyone.  Sorry if 
I was harsh, I didn't mean it that way.
I do realize that the level of Elecraft gear can be confusing for those 
who do not work with it regularly.
I am here to help, not criticize, but to be clear we all have to refer 
to things by clear and unambiguous terms.

That is the price we pay for being able to upgrade our Elecraft gear to 
the latest level rather than buying an upgraded radio.

73,
Don W3FPR

On 3/31/2012 7:36 PM, Hisashi T Fujinaka wrote:
 I was just scolded for using the original poster's terminology (it's a
 KPA100UPKT, not a Rev D upgrade) but I'm glad Don finally answered my
 question about the shields.

 It's hard for regular people (i.e. everyone except Elecraft) to know
 about rev levels and which mod kits to order (I'd bet things work fine
 with none of the upgrades) so I'm sorry that I annoyed the people who
 know.

 Personally, my rig resets itself on 15M sometimes if I run  90W so I
 had a real reason for asking about the shield kit. I seem to have the
 latest shield so that's not the answer for my problems.

 On Sat, 31 Mar 2012, Don Wilhelm wrote:

 Folks,

 Before I get more questions indicating confusion, let me clarify in
 detail --

 In my response below, I ignored the poster's reference to a Rev D
 Upgrade kit.  There is no Rev D KPA100 - the closest I can imagine to
 Rev D is the manual revision, which is now Rev E.

 The manual's rev letter is not linked to the board version (either
 populated or bare).
 In this case, there have been only 2 versions of the raw KPA100 board -
 the Field Test level, and all others.  There have been 4 versions of the
 KPA100 - the Field Test version, then the first released version, and
 then the version which incorporated KPA100MODKT, and lastly, the version
 which incorporates KPA100UPKT.  This last mod kit has all the parts for
 upgrading any level KPA100 to the latest.  If your KPA100 has blue
 toroid cores at L16 and RFC1, you have the latest level.

 The shield is a different matter.  There are 3 levels of the shield -
 the initial one with a wide notch at the SO-239 jack (about 1.4 inch
 wide), then one with a more narrow (about 1/8 inch (3mm)) notch at the
 jack, and lastly the addition of 2 solder lugs between the SO-239 jack
 and the outside surface of the shield - this last shield also added a
 shield for the speaker magnet since the magnet was sometimes responsible
 for interfering with the operation of relays K13, K14 and K15 on the RF
 board - some do it while others are just fine without the speaker shield.

 73,
 Don W3FPR

 ---


 Syd,

 If your KPA100 has red toroid cores at L15 and L16, install KPA100UPKT.
   That kit will upgrade any level KPA100 to the latest.  If you do not
 have a shield over the speaker magnet, add the KPA100SHLDKT as well to
 upgrade your shield.

 Those mods will add significantly to the stability of the amplifier, and
 I highly recommend them.
 Those mods were specifically created to address a tendency to oscillate
 a little above the 40 meter ham band under some conditions.  If you
 operate with an autotuner  that tendency to oscillate is quite high.

 73,
 Don W3FPR

 On 3/31/2012 4:17 PM, Syd Smith wrote:
 I recently became aware of the Rev D upgrade kit for the KPA100 at
 Elecraft.  Where can I find a description of the changes and a
 recommendation of why I would want to install this kit in my Rev A
 amplifier which works FB.

 __
 Elecraft mailing list
 Home: http://mailman.qth.net/mailman/listinfo/elecraft
 Help: http://mailman.qth.net/mmfaq.htm
 Post: mailto:Elecraft@mailman.qth.net

 This list hosted by: http://www.qsl.net
 Please help support this email list: http://www.qsl.net/donate.html

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 amplifier for sale.

[andyatd]

SOLD.



--
View this message in context: 
http://elecraft.365791.n2.nabble.com/KPA100-amplifier-for-sale-tp7368541p7370859.html
Sent from the Elecraft mailing list archive at Nabble.com.
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 used with other non elecraft QRP rigs

[Patrick Bourgeois]

Hello Jacob, In short no you can not, the pic in the KPA100 requires direct 
communication with the pic in the K2 for it to operate.  The KPA 100 will not 
work without being connected to the K2. Regards, KE5EBS 

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 Problem

[Don Wilhelm]

Mark,

Have you checked the setting of the K2 CAL TPA menu?  It should read the 
same as the actual temperature of the PA transistor cases.

Let everything acclimate to the ambient room temperature (power off for 
30 minutes should do it), then turn power on and set CAL TPA to the room 
temperature in degC.

73,
Don W3FPR

On 11/26/2011 11:44 AM, Mark Flavin wrote:



 Well, I wanted to change the bridge diodes in the KPA 100 cause I was getting 
 some wierd readings and hi swr readings so I decided to upgrade it while I 
 had it apart.  I did the whole upgrade and now as soon as I put it in high 
 power, even at only 15 watts, I get PA HOT readings.  I have checked all the 
 parts values twice and did the calibration again including the C6 adjust, the 
 r26 and 27 adjusts and even pulled the finals to make sure they weren't 
 shorted or anything.  Q3 and Q4 seem fine and are not cracked.  The voltages 
 seem to be fine and I readjusted R6 bias as per book.  Whats wierd is as soon 
 as I hit the key, even at 15 watts the fan comes on with the keying.  A dot 
 gives a short fan wiggle and an dash gives a loneger fan activation.  
 Eventually it comes on and then I get the PA HOT.  The fan even responds to 
 my voice on SSB.  I mean it comes on almost instantly.  I have checked the 
 archives and am starting to suspect the finals.  I put on new pads on the 
 transis
 to
   rs and checked it all twice.  Resoldered all connections.  All works fine 
 at 10 watts.  Im sure Im missing something but I dont seem to be able to find 
 it.  Any ideas where I can check before I order new finals and go through 
 that work again.  Thanks  MarkN5MF


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 Problem

[Mark Flavin]

Yeah. I did that too.  Im dreading changing the finals lol

T-Mobile. America's First Nationwide 4G Network.

-Original message-
From: Don Wilhelm w3...@embarqmail.com
To: Mark Flavin markf1...@hotmail.com
Cc: elecraft@mailman.qth.net
Sent: Sat, Nov 26, 2011 17:45:04 GMT+00:00
Subject: Re: [Elecraft] KPA100 Problem

Mark,

Have you checked the setting of the K2 CAL TPA menu?  It should read the  
same as the actual temperature of the PA transistor cases.

Let everything acclimate to the ambient room temperature (power off for 30  
minutes should do it), then turn power on and set CAL TPA to the room  
temperature in degC.

73,
Don W3FPR

On 11/26/2011 11:44 AM, Mark Flavin wrote:



 Well, I wanted to change the bridge diodes in the KPA 100 cause I was  
getting some wierd readings and hi swr readings so I decided to upgrade it  
while I had it apart.  I did the whole upgrade and now as soon as I put it  
in high power, even at only 15 watts, I get PA HOT readings.  I have checked  
all the parts values twice and did the calibration again including the C6  
adjust, the r26 and 27 adjusts and even pulled the finals to make sure they  
weren't shorted or anything.  Q3 and Q4 seem fine and are not cracked.  The  
voltages seem to be fine and I readjusted R6 bias as per book.  Whats wierd  
is as soon as I hit the key, even at 15 watts the fan comes on with the  
keying.  A dot gives a short fan wiggle and an dash gives a loneger fan  
activation.  Eventually it comes on and then I get the PA HOT.  The fan even  
responds to my voice on SSB.  I mean it comes on almost instantly.  I have  
checked the archives and am starting to suspect the finals.  I put on new  
pads on the transisto
   rs and checked it all twice.  Resoldered all connections.  All works  
fine at 10 watts.  Im sure Im missing something but I dont seem to be able  
to find it.  Any ideas where I can check before I order new finals and go  
through that work again.  Thanks  MarkN5MF  



__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 Problem

[Don Wilhelm]

Mark,

I don't think the finals are the problem.  I would check Q3 for good 
soldering and the value and soldering of R5 - make certain you used the 
1k trimmer at R6 rather than the 100k trimmers for R26 and R27.
The soldering at U1 pin 5 should also be checked, and be certain U1 pin 
5 is not bent under the socket or sticking out the side.  Make certain 
there is 5 volts on one end of R5 - if not, find out why.

The temperature of the heatsink is sensed by the conduction through Q3 
from the base to the emitter (and collector),  that resulting voltage is 
sent to U1 pin 5 for calculation by the firmware  - it has nothing to do 
with the actual PA transistors, just the temperature of the heatsink at 
the Q3 location.

73,
Don W3FPR

On 11/26/2011 1:04 PM, Mark Flavin wrote:
 Yeah. I did that too.  Im dreading changing the finals lol

 T-Mobile. America's First Nationwide 4G Network.

 -Original message-
 From: Don Wilhelmw3...@embarqmail.com
 To: Mark Flavinmarkf1...@hotmail.com
 Cc: elecraft@mailman.qth.net
 Sent: Sat, Nov 26, 2011 17:45:04 GMT+00:00
 Subject: Re: [Elecraft] KPA100 Problem

 Mark,

 Have you checked the setting of the K2 CAL TPA menu?  It should read the
 same as the actual temperature of the PA transistor cases.

 Let everything acclimate to the ambient room temperature (power off for 30
 minutes should do it), then turn power on and set CAL TPA to the room
 temperature in degC.

 73,
 Don W3FPR

 On 11/26/2011 11:44 AM, Mark Flavin wrote:


 Well, I wanted to change the bridge diodes in the KPA 100 cause I was
 getting some wierd readings and hi swr readings so I decided to upgrade it
 while I had it apart.  I did the whole upgrade and now as soon as I put it
 in high power, even at only 15 watts, I get PA HOT readings.  I have checked
 all the parts values twice and did the calibration again including the C6
 adjust, the r26 and 27 adjusts and even pulled the finals to make sure they
 weren't shorted or anything.  Q3 and Q4 seem fine and are not cracked.  The
 voltages seem to be fine and I readjusted R6 bias as per book.  Whats wierd
 is as soon as I hit the key, even at 15 watts the fan comes on with the
 keying.  A dot gives a short fan wiggle and an dash gives a loneger fan
 activation.  Eventually it comes on and then I get the PA HOT.  The fan even
 responds to my voice on SSB.  I mean it comes on almost instantly.  I have
 checked the archives and am starting to suspect the finals.  I put on new
 pads on the transisto
rs and checked it all twice.  Resoldered all connections.  All works
 fine at 10 watts.  Im sure Im missing something but I dont seem to be able
 to find it.  Any ideas where I can check before I order new finals and go
 through that work again.  Thanks  MarkN5MF
 


 __
 Elecraft mailing list
 Home: http://mailman.qth.net/mailman/listinfo/elecraft
 Help: http://mailman.qth.net/mmfaq.htm
 Post: mailto:Elecraft@mailman.qth.net

 This list hosted by: http://www.qsl.net
 Please help support this email list: http://www.qsl.net/donate.html

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 Problem

[Mark Flavin]

Thanks Don.  This thing worked before I did the upg kit.  I will check that  
again but I didn't really touch those.  Perhaps I will remove the   Q3 and  
check that area.  Best I can tell the upgrade didn't really address any of  
that but I don't know.  The finals don't get hot at all.  I even took the  
heatsink off to make sure there were no shorts or anything and its the same.  
  The weird thing is how the fan starts and stops as I key even at low (11  
to 15 watts) power.  I just hope its not the finals.  I don't think so  
either but I want to try everything else first.  Could Q3 just be too  
sensitive due to something.  I could try changing it I suppose.

T-Mobile. America's First Nationwide 4G Network.

-Original message-
From: Don Wilhelm w3...@embarqmail.com
To: Mark Flavin markf1...@hotmail.com
Cc: elecraft@mailman.qth.net
Sent: Sat, Nov 26, 2011 19:00:07 GMT+00:00
Subject: Re: [Elecraft] KPA100 Problem

Mark,

I don't think the finals are the problem.  I would check Q3 for good  
soldering and the value and soldering of R5 - make certain you used the 1k  
trimmer at R6 rather than the 100k trimmers for R26 and R27.
The soldering at U1 pin 5 should also be checked, and be certain U1 pin 5 is  
not bent under the socket or sticking out the side.  Make certain there is 5  
volts on one end of R5 - if not, find out why.

The temperature of the heatsink is sensed by the conduction through Q3 from  
the base to the emitter (and collector),  that resulting voltage is sent to  
U1 pin 5 for calculation by the firmware  - it has nothing to do with the  
actual PA transistors, just the temperature of the heatsink at the Q3  
location.

73,
Don W3FPR

On 11/26/2011 1:04 PM, Mark Flavin wrote:
 Yeah. I did that too.  Im dreading changing the finals lol

 T-Mobile. America's First Nationwide 4G Network.

 -Original message-
 From: Don Wilhelmw3...@embarqmail.com
 To: Mark Flavinmarkf1...@hotmail.com
 Cc: elecraft@mailman.qth.net
 Sent: Sat, Nov 26, 2011 17:45:04 GMT+00:00
 Subject: Re: [Elecraft] KPA100 Problem

 Mark,

 Have you checked the setting of the K2 CAL TPA menu?  It should read the
 same as the actual temperature of the PA transistor cases.

 Let everything acclimate to the ambient room temperature (power off for 30
 minutes should do it), then turn power on and set CAL TPA to the room
 temperature in degC.

 73,
 Don W3FPR

 On 11/26/2011 11:44 AM, Mark Flavin wrote:


 Well, I wanted to change the bridge diodes in the KPA 100 cause I was
 getting some wierd readings and hi swr readings so I decided to upgrade it
 while I had it apart.  I did the whole upgrade and now as soon as I put it
 in high power, even at only 15 watts, I get PA HOT readings.  I have  
checked
 all the parts values twice and did the calibration again including the C6
 adjust, the r26 and 27 adjusts and even pulled the finals to make sure  
they
 weren't shorted or anything.  Q3 and Q4 seem fine and are not cracked.   
The
 voltages seem to be fine and I readjusted R6 bias as per book.  Whats  
wierd
 is as soon as I hit the key, even at 15 watts the fan comes on with the
 keying.  A dot gives a short fan wiggle and an dash gives a loneger fan
 activation.  Eventually it comes on and then I get the PA HOT.  The fan  
even
 responds to my voice on SSB.  I mean it comes on almost instantly.  I have
 checked the archives and am starting to suspect the finals.  I put on new
 pads on the transisto
rs and checked it all twice.  Resoldered all connections.  All works
 fine at 10 watts.  Im sure Im missing something but I dont seem to be able
 to find it.  Any ideas where I can check before I order new finals and go
 through that work again.  Thanks  MarkN5MF
 


 __
 Elecraft mailing list
 Home: http://mailman.qth.net/mailman/listinfo/elecraft
 Help: http://mailman.qth.net/mmfaq.htm
 Post: mailto:Elecraft@mailman.qth.net

 This list hosted by: http://www.qsl.net
 Please help support this email list: http://www.qsl.net/donate.html


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 Problem

[Don Wilhelm]

Mark,

If there was a marginal solder connection, it may have worked but with 
the movement involved with the upgrade, it may have finally failed.

Yes, investigate those components that I mentioned.  If the temperature 
is not being sensed, the fan will be turned on and off by the firmware 
because the firmware is not getting correct information about the actual 
temperature.

Are the thermal pads under Q3 and Q4 in good shape?  It may be worth 
replacing them if there is any question.

73,
Don W3FPR

On 11/26/2011 2:24 PM, Mark Flavin wrote:
 Thanks Don.  This thing worked before I did the upg kit.  I will check that
 again but I didn't really touch those.  Perhaps I will remove the   Q3 and
 check that area.  Best I can tell the upgrade didn't really address any of
 that but I don't know.  The finals don't get hot at all.  I even took the
 heatsink off to make sure there were no shorts or anything and its the same.
The weird thing is how the fan starts and stops as I key even at low (11
 to 15 watts) power.  I just hope its not the finals.  I don't think so
 either but I want to try everything else first.  Could Q3 just be too
 sensitive due to something.  I could try changing it I suppose.

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 Problem

[Mark Flavin]

Ok. I will do that.  Anything is worth a try

T-Mobile. America's First Nationwide 4G Network.

-Original message-
From: Don Wilhelm w3...@embarqmail.com
To: Mark Flavin markf1...@hotmail.com
Cc: elecraft@mailman.qth.net
Sent: Sat, Nov 26, 2011 20:05:50 GMT+00:00
Subject: Re: [Elecraft] KPA100 Problem

Mark,

If there was a marginal solder connection, it may have worked but with the  
movement involved with the upgrade, it may have finally failed.

Yes, investigate those components that I mentioned.  If the temperature is  
not being sensed, the fan will be turned on and off by the firmware because  
the firmware is not getting correct information about the actual  
temperature.

Are the thermal pads under Q3 and Q4 in good shape?  It may be worth  
replacing them if there is any question.

73,
Don W3FPR

On 11/26/2011 2:24 PM, Mark Flavin wrote:
 Thanks Don.  This thing worked before I did the upg kit.  I will check  
that
 again but I didn't really touch those.  Perhaps I will remove the   Q3 and
 check that area.  Best I can tell the upgrade didn't really address any of
 that but I don't know.  The finals don't get hot at all.  I even took the
 heatsink off to make sure there were no shorts or anything and its the  
same.
The weird thing is how the fan starts and stops as I key even at low  
(11
 to 15 watts) power.  I just hope its not the finals.  I don't think so
 either but I want to try everything else first.  Could Q3 just be too
 sensitive due to something.  I could try changing it I suppose.


__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 question

[Don Wilhelm]

Mark,

The real answer is YES.

Measure your actual power when the power request is set to 5 watts - if 
it is really 12 watts or more, then that is an indication that the power 
control is not working, and the KPA100 wattmeter diodes are the first 
suspects.

380 ohms is much lower than normal, but that depends a lot on your 
ohmmeter.  They should measure low in one direction (normally about 3K) 
and quite high (about 43k) in the other direction.

73,
Don W3FPR

On 11/13/2011 9:52 PM, Mark Flavin wrote:
 I know its possible but just to verify could the d16 and 17 chem ok and be
 bad?  Im getting high power and current which from the archives suggests
 them but they chk about 380 ohms.  The q1 and q2 are ok.  Works fine below
 10 watts.  Thanks

 Mark

 T-Mobile. America's First Nationwide 4G Network.

 __
 Elecraft mailing list
 Home: http://mailman.qth.net/mailman/listinfo/elecraft
 Help: http://mailman.qth.net/mmfaq.htm
 Post: mailto:Elecraft@mailman.qth.net

 This list hosted by: http://www.qsl.net
 Please help support this email list: http://www.qsl.net/donate.html

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 Initial Test Problem

[Eugene Worth]

Resolved after much hair pulling.

Thanks to Don and Gary Surrency for all of the suggestions and most of their 
day answering emails as to troubleshooting! Here is the setup: K2 with KIO2. I 
have built the KAT100 in the EC-2 and am building the KPA100 as an outboard 
amplifier in the EC-2 enclosure. This is so I can still use the K2 as a 
QRP/Portable rig whenever wanted but have 100 watts at home location.

There is a website describing splitting the K2100 into the configuration 
above, but it doesn't cover what we found to be a problem. (You can Google 
KK7P) The 8R line from the K2 through the KIO2 has a 3.9 kOhm resistor in line. 
It turns out that the KAT100 has the same value resistor in line as well. When 
you take the cable from the KIO2 then pass the signal through the KAT100, the 
8R line is no longer 8 volts, but 4 volts. 

So, if you are building the configuration above, be aware that (Rev H KPA100) 
page 26 initial checks, you will find the U1 (KPA100 MCU) pin 27 value to be 
3.99 volts. This is the nominal value and not an error in building.

Thanks again!

gene
WG7GW

 Gene,
 
 Check RP1 pin 7.  If you do not find close to 8 volts there, you will 
 need to track down the source of the problem in the 8R input to the KPA100.
 
 If you find the voltage at RP1 pin 7 is not anywhere near 8 volts, check 
 the source - what is the voltage on the K2 Control Board Q2 collector - 
 that is the source for 8R.  If the two points have significantly 
 different voltages, you will have to find the discontinuity in the 
 wires, connectors and PC traces between those two points.
 
 If RP1 pin 7 is OK, but U1 pin 27 is lower than normal, that may be OK - 
 pin 27 of U1 is simply drawing a bit more power than usual - as long as 
 the 5R and 5T outputs from U1 at pins 13 and 14 work OK, you will not 
 have a problem.
 
 73,
 Don W3FPR
 
 On 10/25/2011 11:26 AM, Eugene Worth wrote:
 Hello all:
 
 I am building a remote KPA100 in an EC-2 enclosure. The KAT100-2 has already 
 been built and tested correctly.
 
 My K2 is S/N 5717 with firmware 2.04P.
 
 Problem: All the test point voltages are nominal (+/-10%) except U1 pin 27. 
 The voltage listed is 5.8 ? I got 3.99 volts. Everything else in the section 
 of initial tests is flawless.
 U1 pin 20 = 5.04
 U1 pin 28 = 5.56
 U2 pin 10 = 13.65
 U4 pin 1 = 13.65
 U4 pin 11 = 5.04
 All of the other values are 0 as noted in the checklist.
 On initial power up, the K2 power supply voltage was 13.8 and current 0.36.
 
 Any hints on where to look for the problem?
 
 Thanks.
 
 gene
 WG7GW
 

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 Initial Test Problem

[Don Wilhelm]

Gene,

Check RP1 pin 7.  If you do not find close to 8 volts there, you will 
need to track down the source of the problem in the 8R input to the KPA100.

If you find the voltage at RP1 pin 7 is not anywhere near 8 volts, check 
the source - what is the voltage on the K2 Control Board Q2 collector - 
that is the source for 8R.  If the two points have significantly 
different voltages, you will have to find the discontinuity in the 
wires, connectors and PC traces between those two points.

If RP1 pin 7 is OK, but U1 pin 27 is lower than normal, that may be OK - 
pin 27 of U1 is simply drawing a bit more power than usual - as long as 
the 5R and 5T outputs from U1 at pins 13 and 14 work OK, you will not 
have a problem.

73,
Don W3FPR

On 10/25/2011 11:26 AM, Eugene Worth wrote:
 Hello all:

 I am building a remote KPA100 in an EC-2 enclosure. The KAT100-2 has already 
 been built and tested correctly.

 My K2 is S/N 5717 with firmware 2.04P.

 Problem: All the test point voltages are nominal (+/-10%) except U1 pin 27. 
 The voltage listed is 5.8 … I got 3.99 volts. Everything else in the section 
 of initial tests is flawless.
 U1 pin 20 = 5.04
 U1 pin 28 = 5.56
 U2 pin 10 = 13.65
 U4 pin 1 = 13.65
 U4 pin 11 = 5.04
 All of the other values are 0 as noted in the checklist.
 On initial power up, the K2 power supply voltage was 13.8 and current 0.36.

 Any hints on where to look for the problem?

 Thanks.

 gene
 WG7GW

 __
 Elecraft mailing list
 Home: http://mailman.qth.net/mailman/listinfo/elecraft
 Help: http://mailman.qth.net/mmfaq.htm
 Post: mailto:Elecraft@mailman.qth.net

 This list hosted by: http://www.qsl.net
 Please help support this email list: http://www.qsl.net/donate.html

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 and KAT100 remote mounting

[Don Wilhelm]

Mike,

The tiny 15 uHy inductor on the older KIO2 AUX board is marginal in 
current handling capability when both the KPA100 and KAT100 are remote 
mounted.  It will likely work for a while just fine, but I would 
recommend changing it to a higher current inductor.  If you have a spare 
FT43-25 or FT43-37 toroid core around somewhere, wind 12 turns on it and 
install it.

The early KIO2 AUX boards used an inductor that was quite small and the 
tiny RFC body fit nicely into the holes in the board.  Those tiny RFCs 
are the ones which are marginal.  If the body of the RFC that you have 
installed is too large to fit the holes and still lay flat on the board, 
your existing RFC should have adequate current capacity.

Elecraft does not provide it as a part for that purpose, but if you want 
to order one, I would suggest the 15 uHy RF chokes normally used in the 
KPA100 T/R switch - PN E690006.

73,
Don W3FPR

On 9/17/2011 7:48 PM, Mike Weir wrote:
 I have read when you remote mount the KAT100 and KPA100 the KIO2 that is used 
 in the remote unit has to have a larger inductor? Is this still the case, if 
 so what size and does elecraft provide it?
 Mike
 VE3WDM
   
 __
 Elecraft mailing list
 Home: http://mailman.qth.net/mailman/listinfo/elecraft
 Help: http://mailman.qth.net/mmfaq.htm
 Post: mailto:Elecraft@mailman.qth.net

 This list hosted by: http://www.qsl.net
 Please help support this email list: http://www.qsl.net/donate.html

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 and KAT100 remote mounting

[VE3WDM]

Don thanks very much for the information. I was wondering  if the part number
you supplied was an Elecraft number? If so I will request that when I put my
next order into elecraft. If I decide to go with winding my own toroid what
gauge of wire do you suggest to use?
Mike
VE3WDM

--
View this message in context: 
http://elecraft.365791.n2.nabble.com/KPA100-and-KAT100-remote-mounting-tp6804851p6806823.html
Sent from the Elecraft mailing list archive at Nabble.com.
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 and KAT100 remote mounting

[Don Wilhelm]

Mike,

That part number is an Elecraft part number - otherwise I would have 
specified the distributor.
If you wind your own toroid, the wire size is not critical.  If you have 
some left over #26 or #28 wire from prior Elecraft kits, that will work 
just fine.

73,
Don W3FPR

On 9/18/2011 7:08 PM, VE3WDM wrote:
 Don thanks very much for the information. I was wondering  if the part number
 you supplied was an Elecraft number? If so I will request that when I put my
 next order into elecraft. If I decide to go with winding my own toroid what
 gauge of wire do you suggest to use?
 Mike
 VE3WDM

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 Installation Q:

[andyatd]

Don,

Reading the KPA100 manual I anticipated re-alignment and setup would be a
good idea.  The procedure looks straightforward and I do have adequate
equipment for the process.  The KPA100 will be installed on a 48xx series
serial number K2 and I am not sure whether the KPA100UPKT has been installed
or not, but I will do so if it is not.

Thank you for your recommendations.

Andy
N3LCW


--
View this message in context: 
http://elecraft.365791.n2.nabble.com/KPA100-Installation-Q-tp6707741p6707897.html
Sent from the Elecraft mailing list archive at Nabble.com.
__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Re: [Elecraft] KPA100 Installation Q:

[Don Wilhelm]

Andy,

If the KPA100 has red core toroids at L15 and L16, it is the old level 
and the KPA100UPKT should be installed.  If there are blue core toroids 
at RFC1 and L16, it has already been installed.

73,
Don W3FPR

On 8/21/2011 2:30 AM, andyatd wrote:
 Don,

 Reading the KPA100 manual I anticipated re-alignment and setup would be a
 good idea.  The procedure looks straightforward and I do have adequate
 equipment for the process.  The KPA100 will be installed on a 48xx series
 serial number K2 and I am not sure whether the KPA100UPKT has been installed
 or not, but I will do so if it is not.

 Thank you for your recommendations.

 Andy
 N3LCW


 --
 View this message in context: 
 http://elecraft.365791.n2.nabble.com/KPA100-Installation-Q-tp6707741p6707897.html
 Sent from the Elecraft mailing list archive at Nabble.com.
 __
 Elecraft mailing list
 Home: http://mailman.qth.net/mailman/listinfo/elecraft
 Help: http://mailman.qth.net/mmfaq.htm
 Post: mailto:Elecraft@mailman.qth.net

 This list hosted by: http://www.qsl.net
 Please help support this email list: http://www.qsl.net/donate.html

__
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft@mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html