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Unusual Behavior K3S / KPA500 Drive Power Greater Than 12 watts

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Tony-3

Unusual Behavior K3S / KPA500 Drive Power Greater Than 12 watts

All:

I've noticed an unusual thing happen with my K3S and KPA500 amplifier
while in SSB mode. When I increase the K3S drive beyond 12 watts, the
KPA500 power drops-off dramatically. This only happens in SSB mode.

The KPA500 functions fine with other transceivers as well so the
condition appears to be unique to the K3S. Any suggestions?

Tony

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Rick Bates, NK7I

Re: Unusual Behavior K3S / KPA500 Drive Power Greater Than 12 watts

Except that it only happens in SSB, it sounds suspiciously like the high
power amp (final) has failed in your K3S. But start with your audio.
Are the settings normal (comp, mic gain etc)?

Can you try another microphone and turn on the monitor function to hear
what your mic is producing? Is the two-tone function accidentally on?

What power output can you read when not using the amp and going above 12
watts? If more than 12 watts, a calibrate output would be in order for
for your confidence.

Is it confined to one band?

If you don't get direction of the cause from these tests, a phone call
to Elecraft service is in order.

73,
Rick NK7I

On 3/3/2020 10:48 PM, Tony wrote:

> All:
>
> I've noticed an unusual thing happen with my K3S and KPA500 amplifier
> while in SSB mode. When I increase the K3S drive beyond 12 watts, the
> KPA500 power drops-off dramatically. This only happens in SSB mode.
>
> The KPA500 functions fine with other transceivers as well so the
> condition appears to be unique to the K3S. Any suggestions?
>
> Tony
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
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>
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David Box-2

Re: Unusual Behavior K3S / KPA500 Drive Power Greater Than 12 watts

In reply to this post by Tony-3

Tony, Have you checked the K3s power out, at 12 W the K3s switches from the internal LPA to the HPA.
de Dave K5MWR

On March 4, 2020 12:48:09 AM CST, Tony <[hidden email]> wrote:

>All:
>
>I've noticed an unusual thing happen with my K3S and KPA500 amplifier
>while in SSB mode. When I increase the K3S drive beyond 12 watts, the
>KPA500 power drops-off dramatically. This only happens in SSB mode.
>
>The KPA500 functions fine with other transceivers as well so the
>condition appears to be unique to the K3S. Any suggestions?
>
>Tony
>
>______________________________________________________________
>Elecraft mailing list
>Home: http://mailman.qth.net/mailman/listinfo/elecraft
>Help: http://mailman.qth.net/mmfaq.htm
>Post: mailto:[hidden email]
>
>This list hosted by: http://www.qsl.net
>Please help support this email list: http://www.qsl.net/donate.html
>Message delivered to [hidden email]

--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
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Don Wilhelm

Re: Unusual Behavior K3S / KPA500 Drive Power Greater Than 12 watts

In reply to this post by Tony-3

Tony,

Try doing the TX Gain Calibration on the K3S. You only need a dummy
load that is flat (1:1 SWR) up through 6 meters along with K3 Utility.

73,
Don W3FPR

On 3/4/2020 1:48 AM, Tony wrote:
> All:
>
> I've noticed an unusual thing happen with my K3S and KPA500 amplifier
> while in SSB mode. When I increase the K3S drive beyond 12 watts, the
> KPA500 power drops-off dramatically. This only happens in SSB mode.
>
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Tony-3

Re: Unusual Behavior K3S / KPA500 Drive Power Greater Than 12 watts

In reply to this post by Rick Bates, NK7I

Rick Et al:

The K3S makes 110 watts measured so the rigs finals appear to be just
fine. Audio is also clean with no distortion. After further testing, I
found that the power drop is only momentary.

The RF output on the KPA500 does drop when the drive on the K3S is
increased from 12 to 13 watts, but it quickly rebounds to it's normal
output a few seconds later.

This happens on all bands and only takes place during the transition
from 12 to 13 watts. I can hear a relay click during the 12 to 13 watt
increase which happens to coincide with the momentary condition
described above.

Whatever it is, something changes the way the transmitter behaves
momentarily during that specific power change and my guess is that it's
not unique to my K3S.

I spend most of my time on CW and little on SSB so I never noticed this
before. Other than that, the K3S and KPA500 work flawlessly.

Tony

On 3/4/2020 6:09 AM, Rick Bates, NK7I wrote:

> Except that it only happens in SSB, it sounds suspiciously like the
> high power amp (final) has failed in your K3S. But start with your
> audio. Are the settings normal (comp, mic gain etc)?
>
> Can you try another microphone and turn on the monitor function to
> hear what your mic is producing? Is the two-tone function
> accidentally on?
>
> What power output can you read when not using the amp and going above
> 12 watts? If more than 12 watts, a calibrate output would be in order
> for for your confidence.
>
> Is it confined to one band?
>
> If you don't get direction of the cause from these tests, a phone call
> to Elecraft service is in order.
>
> 73,
> Rick NK7I
>
>
> On 3/3/2020 10:48 PM, Tony wrote:
>> All:
>>
>> I've noticed an unusual thing happen with my K3S and KPA500 amplifier
>> while in SSB mode. When I increase the K3S drive beyond 12 watts, the
>> KPA500 power drops-off dramatically. This only happens in SSB mode.
>>
>> The KPA500 functions fine with other transceivers as well so the
>> condition appears to be unique to the K3S. Any suggestions?
>>
>> Tony
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
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>
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Bob McGraw - K4TAX

Re: Unusual Behavior K3S / KPA500 Drive Power Greater Than 12 watts

This condition you describe is viewed as normal. It is the TX ALC and
power control circuit gathering up information so as not to cause an
overshoot.

73

Bob, K4TAX

On 3/4/2020 8:20 PM, Tony wrote:

> Rick Et al:
>
> The K3S makes 110 watts measured so the rigs finals appear to be just
> fine. Audio is also clean with no distortion. After further testing, I
> found that the power drop is only momentary.
>
> The RF output on the KPA500 does drop when the drive on the K3S is
> increased from 12 to 13 watts, but it quickly rebounds to it's normal
> output a few seconds later.
>
> This happens on all bands and only takes place during the transition
> from 12 to 13 watts. I can hear a relay click during the 12 to 13 watt
> increase which happens to coincide with the momentary condition
> described above.
>
> Whatever it is, something changes the way the transmitter behaves
> momentarily during that specific power change and my guess is that
> it's not unique to my K3S.
>
> I spend most of my time on CW and little on SSB so I never noticed
> this before. Other than that, the K3S and KPA500 work flawlessly.
>
> Tony
>
>
>
>
>
>
> On 3/4/2020 6:09 AM, Rick Bates, NK7I wrote:
>> Except that it only happens in SSB, it sounds suspiciously like the
>> high power amp (final) has failed in your K3S. But start with your
>> audio. Are the settings normal (comp, mic gain etc)?
>>
>> Can you try another microphone and turn on the monitor function to
>> hear what your mic is producing? Is the two-tone function
>> accidentally on?
>>
>> What power output can you read when not using the amp and going above
>> 12 watts? If more than 12 watts, a calibrate output would be in
>> order for for your confidence.
>>
>> Is it confined to one band?
>>
>> If you don't get direction of the cause from these tests, a phone
>> call to Elecraft service is in order.
>>
>> 73,
>> Rick NK7I
>>
>>
>> On 3/3/2020 10:48 PM, Tony wrote:
>>> All:
>>>
>>> I've noticed an unusual thing happen with my K3S and KPA500
>>> amplifier while in SSB mode. When I increase the K3S drive beyond 12
>>> watts, the KPA500 power drops-off dramatically. This only happens in
>>> SSB mode.
>>>
>>> The KPA500 functions fine with other transceivers as well so the
>>> condition appears to be unique to the K3S. Any suggestions?
>>>
>>> Tony
>>>
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:[hidden email]
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>> Message delivered to [hidden email]
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

Rick Bates, NK7I

Re: Unusual Behavior K3S / KPA500 Drive Power Greater Than 12 watts

In reply to this post by Tony-3

12 watts is the transition point for the high(er) power amp in the K3 to
engage, so it's feasible that as that happens, the LPA drops it's output
some to make the set power out (to not immediately put out 100 watts but
what the reading says it should be).

If the K3S has normal output when you're not adjusting the power out, I
wouldn't worry about it.

If the K3S in CW is set for the desired power output, phone will be also.

73,
Rick NK7I

On 3/4/2020 6:20 PM, Tony wrote:

Don Wilhelm

Re: Unusual Behavior K3S / KPA500 Drive Power Greater Than 12 watts

In reply to this post by Tony-3

Tony,

The other comments are correct, but I will add one more. Adjust the SSB
audio so that you have 5 to 7 bars on the ALC meter when talking into
the mic. If you have less than that, the K3/K3S will "Power Hunt"
trying to keep up with the requested power.

73,
Don W3FPR

On 3/4/2020 9:20 PM, Tony wrote:

Tony-3

Re: Unusual Behavior K3S / KPA500 Drive Power Greater Than 12 watts

Don:

> Adjust the SSB audio so that you have 5 to 7 bars on the ALC meter. If
> you have less than that, the K3/K3S will "Power Hunt" trying to keep
> up with the requested power.

I noticed that some time ago -- took a while to figure out what was
going on.

Thanks.

Tony

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Tony-3

Re: Unusual Behavior K3S / KPA500 Drive Power Greater Than 12 watts

In reply to this post by Rick Bates, NK7I

Rick:

I'm glad it's not an issue - can't do without my K3S!

Thanks, Tony

On 3/4/2020 10:42 PM, Rick Bates, NK7I wrote:

> 12 watts is the transition point for the high(er) power amp in the K3
> to engage, so it's feasible that as that happens, the LPA drops it's
> output some to make the set power out (to not immediately put out 100
> watts but what the reading says it should be).
>
> If the K3S has normal output when you're not adjusting the power out,
> I wouldn't worry about it.
>
> If the K3S in CW is set for the desired power output, phone will be also.
>
> 73,
> Rick NK7I
>
>
> On 3/4/2020 6:20 PM, Tony wrote:
>> Rick Et al:
>>
>> The K3S makes 110 watts measured so the rigs finals appear to be just
>> fine. Audio is also clean with no distortion. After further testing,
>> I found that the power drop is only momentary.
>>
>> The RF output on the KPA500 does drop when the drive on the K3S is
>> increased from 12 to 13 watts, but it quickly rebounds to it's normal
>> output a few seconds later.
>>
>> This happens on all bands and only takes place during the transition
>> from 12 to 13 watts. I can hear a relay click during the 12 to 13
>> watt increase which happens to coincide with the momentary condition
>> described above.
>>
>> Whatever it is, something changes the way the transmitter behaves
>> momentarily during that specific power change and my guess is that
>> it's not unique to my K3S.
>>
>> I spend most of my time on CW and little on SSB so I never noticed
>> this before. Other than that, the K3S and KPA500 work flawlessly.
>>
>> Tony
>>
>>
>>
>>
>>
>>
>> On 3/4/2020 6:09 AM, Rick Bates, NK7I wrote:
>>> Except that it only happens in SSB, it sounds suspiciously like the
>>> high power amp (final) has failed in your K3S. But start with your
>>> audio. Are the settings normal (comp, mic gain etc)?
>>>
>>> Can you try another microphone and turn on the monitor function to
>>> hear what your mic is producing? Is the two-tone function
>>> accidentally on?
>>>
>>> What power output can you read when not using the amp and going
>>> above 12 watts? If more than 12 watts, a calibrate output would be
>>> in order for for your confidence.
>>>
>>> Is it confined to one band?
>>>
>>> If you don't get direction of the cause from these tests, a phone
>>> call to Elecraft service is in order.
>>>
>>> 73,
>>> Rick NK7I
>>>
>>>
>>> On 3/3/2020 10:48 PM, Tony wrote:
>>>> All:
>>>>
>>>> I've noticed an unusual thing happen with my K3S and KPA500
>>>> amplifier while in SSB mode. When I increase the K3S drive beyond
>>>> 12 watts, the KPA500 power drops-off dramatically. This only
>>>> happens in SSB mode.
>>>>
>>>> The KPA500 functions fine with other transceivers as well so the
>>>> condition appears to be unique to the K3S. Any suggestions?
>>>>
>>>> Tony
>>>>
>>>> ______________________________________________________________
>>>> Elecraft mailing list
>>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>>> Help: http://mailman.qth.net/mmfaq.htm
>>>> Post: mailto:[hidden email]
>>>>
>>>> This list hosted by: http://www.qsl.net
>>>> Please help support this email list: http://www.qsl.net/donate.html
>>>> Message delivered to [hidden email]
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:[hidden email]
>>>
>>> This list hosted by: http://www.qsl.net
>>> Please help support this email list: http://www.qsl.net/donate.html
>>> Message delivered to [hidden email]
>>
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
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>
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