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KXPA100 Intermittent VSWR Issues

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KXPA100 Intermittent VSWR Issues

I've run into several occasions where in mid-CW transmission my KXPA100
(with internal tuner) SWR takes a momentary jump from matched to maybe 3:1. I
see the SWR jump on both the KXPA front panel LEDs and on the KX3 VSWR
display. It lasts for maybe half a second, I hear several clicks of the
relays in the tuner, and them it's back to normal. When normal the SWR is pretty
much 1:1 on the KX3, and the second green LED lit on the KX3. I've not
seen it happen at the start of a transmission, but rather several characters
into a CQ or exchange..

In the ARRL 160 contest Saturday night this was happening perhaps once
every 2-3 minutes. I'm using a fairly well matched antenna - not random wires.
I also encountered this problem on 15 meters when operating from W1AW/8 in
WV in October. In both cases I was running a pretty high CW duty cycle
while running at a pretty good clip. The amp was warm, but the heat sink air
flow is not blocked.

Any thoughts?

73 - Jim K8MR

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vk2rq

Re: KXPA100 Intermittent VSWR Issues

I had a similar issue earlier in the year, and there was a firmware fix for it, so I suggest you upgrade your KXPA100 to the latest firmware.

73, Matt VK2RQ

> On 8 Dec 2014, at 2:07 pm, Jim Stahl via Elecraft <[hidden email]> wrote:
>
> I've run into several occasions where in mid-CW transmission my KXPA100
> (with internal tuner) SWR takes a momentary jump from matched to maybe 3:1. I
> see the SWR jump on both the KXPA front panel LEDs and on the KX3 VSWR
> display. It lasts for maybe half a second, I hear several clicks of the
> relays in the tuner, and them it's back to normal. When normal the SWR is pretty
> much 1:1 on the KX3, and the second green LED lit on the KX3. I've not
> seen it happen at the start of a transmission, but rather several characters
> into a CQ or exchange..
>
> In the ARRL 160 contest Saturday night this was happening perhaps once
> every 2-3 minutes. I'm using a fairly well matched antenna - not random wires.
> I also encountered this problem on 15 meters when operating from W1AW/8 in
> WV in October. In both cases I was running a pretty high CW duty cycle
> while running at a pretty good clip. The amp was warm, but the heat sink air
> flow is not blocked.
>
> Any thoughts?
>
>
> 73 - Jim K8MR
>
>
>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
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> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

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Jack Brindle-2

Re: KXPA100 Intermittent VSWR Issues

In reply to this post by Elecraft mailing list

Check for something arcing in the antenna system at higher power. This would be something that heats
up before the arcing starts, like maybe a grounding RF choke on a vertical or something similar. The
worst feedline component for this is the cheap right-angle UHF adapter. The center conductors are not
well made, and will bend and arc to the shell over time. This usually is a problem at powers higher than
the KXPA puts out, but it can still happen.

We see a lot of these, and it is rarely something in the ATU, although that is a possibility. This is also
_very_ difficult to track down since it is usually inside something in the antenna system and thus well
hidden. You would be looking for the tell-tale signs of slightly charred or smoked markings.

What are the antennas in use for both bands?

- Jack B, W6FB

> On Dec 7, 2014, at 7:07 PM, Jim Stahl via Elecraft <[hidden email]> wrote:
>
> I've run into several occasions where in mid-CW transmission my KXPA100
> (with internal tuner) SWR takes a momentary jump from matched to maybe 3:1. I
> see the SWR jump on both the KXPA front panel LEDs and on the KX3 VSWR
> display. It lasts for maybe half a second, I hear several clicks of the
> relays in the tuner, and them it's back to normal. When normal the SWR is pretty
> much 1:1 on the KX3, and the second green LED lit on the KX3. I've not
> seen it happen at the start of a transmission, but rather several characters
> into a CQ or exchange..
>
> In the ARRL 160 contest Saturday night this was happening perhaps once
> every 2-3 minutes. I'm using a fairly well matched antenna - not random wires.
> I also encountered this problem on 15 meters when operating from W1AW/8 in
> WV in October. In both cases I was running a pretty high CW duty cycle
> while running at a pretty good clip. The amp was warm, but the heat sink air
> flow is not blocked.
>
> Any thoughts?
>
>
> 73 - Jim K8MR
>
>
>
>
> ______________________________________________________________
> 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
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Jim Brown-10

Re: KXPA100 Intermittent VSWR Issues

On Sun,12/7/2014 9:19 PM, Jack Brindle wrote:
> Check for something arcing in the antenna system at higher power. This would be something that heats
> up before the arcing starts, like maybe a grounding RF choke on a vertical or something similar. The
> worst feedline component for this is the cheap right-angle UHF adapter. The center conductors are not
> well made, and will bend and arc to the shell over time. This usually is a problem at powers higher than
> the KXPA puts out, but it can still happen.

While I agree that these junk connectors can cause many problems that
are difficult to track down, I'd be surprised to that spring overheating
at 100W with a well matched antenna. 1kW, sure -- I had exactly that
happen an hour into a contest running legal limit and calling CQ a lot.

But I certainly agree about avoiding these junk connectors. If it
doesn't say Amphenol or have a MIL-spec number stamped into it, it's
junk, and has no place in our stations. It can only cause us grief. I
know that from direct personal experience -- when I got back on the air
in 2003 after a couple of decades off, I restocked my box of parts with
all sorts of these el cheapo adapters -- Tees, barrels, BNC to UHF, to
N, and so on. Over a period of three or four years, I experienced more
than a half dozen flaky failures that were hard to track down, all due
to those junk connectors.

73, Jim K9YC
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Jim Kutsch, KY2D-2

Re: KXPA100 Intermittent VSWR Issues

In reply to this post by Elecraft mailing list

I'm experiencing the same thing but mostly on 40 meters where the best match
with the ATU isn't as good as on other bands. It *SEEMS* to have started
Saturday when I installed the latest KX3 beta and set compression to 20. The
antenna is a Carolina Windham.

73, Jim, KY2D
.

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of Jim
Stahl via Elecraft
Sent: Sunday, December 07, 2014 10:08 PM
To: [hidden email]
Subject: [Elecraft] KXPA100 Intermittent VSWR Issues

I've run into several occasions where in mid-CW transmission my KXPA100
(with internal tuner) SWR takes a momentary jump from matched to maybe 3:1.
I see the SWR jump on both the KXPA front panel LEDs and on the KX3 VSWR
display. It lasts for maybe half a second, I hear several clicks of the
relays in the tuner, and them it's back to normal. When normal the SWR is
pretty much 1:1 on the KX3, and the second green LED lit on the KX3. I've
not seen it happen at the start of a transmission, but rather several
characters into a CQ or exchange..

In the ARRL 160 contest Saturday night this was happening perhaps once every
2-3 minutes. I'm using a fairly well matched antenna - not random wires.
I also encountered this problem on 15 meters when operating from W1AW/8 in
WV in October. In both cases I was running a pretty high CW duty cycle
while running at a pretty good clip. The amp was warm, but the heat sink
air flow is not blocked.

Any thoughts?

73 - Jim K8MR

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Cady, Fred

Re: KXPA100 Intermittent VSWR Issues

The SWR circuitry in the KXAT100 (and KAT500) measure the forward and reverse voltage values at different times. They cannot be measured simultaneously because they don't have dual A/D converters or sample-and-hold circuits. To be sure, there is only a short time between sampling the forward and reverse directions but if your output power is changing with time as it will with a high speed CW signals and more especially and more troublesomely with a SSB signal, the SWR metering may indicate an incorrect value. If you have the tuner in AUTO mode, this may trigger a retune. For this reason it is best to operate either of these tuners in MAN mode and train the tuner(s) to store good L-C values for different frequencies in each of your operational bands. The tuners store this information in "frequency buckets" and when they detect the frequency within that bucker they recall the L-C values and if they need to be changed they will be.

Summary:
Train the tuner so that it can remember the L-C values to use for a specific range of frequencies.
Don't use AUTO mode; use MAN mode.

Cheers and 73,
Fred KE7X
"The Elecraft K3: Design, Configuration and Operation 2nd ed"
"The Elecraft KX3 - Going for the summit"
"The Elecraft KPA500 and KAT500 - the K-Line Dream Station"
Printed, coil bound copies of these are all available at www.elecraft.com
KPA500 and KAT500 Quick Set Up Guide
http://www.ke7x.com/home/k-line-introduction-and-set-up-guide

> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of
> Jim Kutsch, KY2D
> Sent: Monday, December 08, 2014 9:18 AM
> To: [hidden email]
> Subject: Re: [Elecraft] KXPA100 Intermittent VSWR Issues
>
> I'm experiencing the same thing but mostly on 40 meters where the best
> match with the ATU isn't as good as on other bands. It *SEEMS* to have
> started Saturday when I installed the latest KX3 beta and set
> compression to 20. The antenna is a Carolina Windham.
>
> 73, Jim, KY2D
> .
>
>
> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of
> Jim Stahl via Elecraft
> Sent: Sunday, December 07, 2014 10:08 PM
> To: [hidden email]
> Subject: [Elecraft] KXPA100 Intermittent VSWR Issues
>
> I've run into several occasions where in mid-CW transmission my KXPA100
> (with internal tuner) SWR takes a momentary jump from matched to maybe
> 3:1.
> I see the SWR jump on both the KXPA front panel LEDs and on the KX3
> VSWR display. It lasts for maybe half a second, I hear several clicks
> of the relays in the tuner, and them it's back to normal. When normal
> the SWR is pretty much 1:1 on the KX3, and the second green LED lit on
> the KX3. I've not seen it happen at the start of a transmission, but
> rather several characters into a CQ or exchange..
>
> In the ARRL 160 contest Saturday night this was happening perhaps once
> every
> 2-3 minutes. I'm using a fairly well matched antenna - not random
> wires.
> I also encountered this problem on 15 meters when operating from
> W1AW/8 in WV in October. In both cases I was running a pretty high CW
> duty cycle while running at a pretty good clip. The amp was warm, but
> the heat sink air flow is not blocked.
>
> Any thoughts?
>
>
> 73 - Jim K8MR
>
>
>
>
> ______________________________________________________________
> 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]

David Ahrendts

Re: KXPA100 Intermittent VSWR Issues

Gentlemen, I will confirm Fred’s advice having just replaced an LDG AT-600Proll antenna tuner with the excellent Elecraft KAT500, assembled Friday. I’m running a KX3 into a KXPA100 into an Ameritron ALS-600S with lots of attention paid to SWR hygiene (since there is a tendency for one device to unbalance another device). On 20M, with nothing yet memorized on the KAT500, I methodically brought power up from 20 watts to 100 watts (barefoot), then backed off to 30 watts and engaged the ALS-600S, and all was good in a tune up to 600 watts. But, on SSB, at high power, those occasional voice spikes caused the KAT500 to trip an auto tune virtually every time. So, as Fred has suggested, allowing the KAT500 to memorize it’s best L and C values for those “frequency buckets” and then operating the KAT500 in manual solved the issue. Seeing that, I spent some time finding each “frequency bucket” on the 20M band, auto tuning each, memorizing that (you can cause setting to be memorized for any frequency using the KAT500 utility), and then operating with known values on the band. And I plan to do that for all other bands.
Also built and installed the little SW2 meter which has a fabulous utility showing, in real time, power output and SWR. Further, it gives you the matched VSWR value vs. the unmatched.

David A., KC0XT

> On Dec 8, 2014, at 12:01 PM, Cady, Fred <[hidden email]> wrote:
>
> The SWR circuitry in the KXAT100 (and KAT500) measure the forward and reverse voltage values at different times. They cannot be measured simultaneously because they don't have dual A/D converters or sample-and-hold circuits. To be sure, there is only a short time between sampling the forward and reverse directions but if your output power is changing with time as it will with a high speed CW signals and more especially and more troublesomely with a SSB signal, the SWR metering may indicate an incorrect value. If you have the tuner in AUTO mode, this may trigger a retune. For this reason it is best to operate either of these tuners in MAN mode and train the tuner(s) to store good L-C values for different frequencies in each of your operational bands. The tuners store this information in "frequency buckets" and when they detect the frequency within that bucker they recall the L-C values and if they need to be changed they will be.
>
> Summary:
> Train the tuner so that it can remember the L-C values to use for a specific range of frequencies.
> Don't use AUTO mode; use MAN mode.
>
> Cheers and 73,
> Fred KE7X
> "The Elecraft K3: Design, Configuration and Operation 2nd ed"
> "The Elecraft KX3 - Going for the summit"
> "The Elecraft KPA500 and KAT500 - the K-Line Dream Station"
> Printed, coil bound copies of these are all available at www.elecraft.com
> KPA500 and KAT500 Quick Set Up Guide
> http://www.ke7x.com/home/k-line-introduction-and-set-up-guide
>
>> -----Original Message-----
>> From: Elecraft [mailto:[hidden email]] On Behalf Of
>> Jim Kutsch, KY2D
>> Sent: Monday, December 08, 2014 9:18 AM
>> To: [hidden email]
>> Subject: Re: [Elecraft] KXPA100 Intermittent VSWR Issues
>>
>> I'm experiencing the same thing but mostly on 40 meters where the best
>> match with the ATU isn't as good as on other bands. It *SEEMS* to have
>> started Saturday when I installed the latest KX3 beta and set
>> compression to 20. The antenna is a Carolina Windham.
>>
>> 73, Jim, KY2D
>> .
>>
>>
>> -----Original Message-----
>> From: Elecraft [mailto:[hidden email]] On Behalf Of
>> Jim Stahl via Elecraft
>> Sent: Sunday, December 07, 2014 10:08 PM
>> To: [hidden email]
>> Subject: [Elecraft] KXPA100 Intermittent VSWR Issues
>>
>> I've run into several occasions where in mid-CW transmission my KXPA100
>> (with internal tuner) SWR takes a momentary jump from matched to maybe
>> 3:1.
>> I see the SWR jump on both the KXPA front panel LEDs and on the KX3
>> VSWR display. It lasts for maybe half a second, I hear several clicks
>> of the relays in the tuner, and them it's back to normal. When normal
>> the SWR is pretty much 1:1 on the KX3, and the second green LED lit on
>> the KX3. I've not seen it happen at the start of a transmission, but
>> rather several characters into a CQ or exchange..
>>
>> In the ARRL 160 contest Saturday night this was happening perhaps once
>> every
>> 2-3 minutes. I'm using a fairly well matched antenna - not random
>> wires.
>> I also encountered this problem on 15 meters when operating from
>> W1AW/8 in WV in October. In both cases I was running a pretty high CW
>> duty cycle while running at a pretty good clip. The amp was warm, but
>> the heat sink air flow is not blocked.
>>
>> Any thoughts?
>>
>>
>> 73 - Jim K8MR
>>
>>
>>
>>
>> ______________________________________________________________
>> 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]
>
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> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]

David Ahrendts [hidden email]

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vk2rq

Re: KXPA100 Intermittent VSWR Issues

In reply to this post by Cady, Fred

It's not just that, a varying signal can also cause the amp's internal frequency counter to misread your current frequency. If the amp thinks you moved frequency, it can tickle the ATU. The "frequency counter inertia" adjustment in the latest firmware addresses this issue very effectively, and my amp/ATU has been a rock-solid performer since loading that latest KXPA100 firmware release.

73,
Matt VK2RQ

> On 9 Dec 2014, at 7:01 am, Cady, Fred <[hidden email]> wrote:
>
> The SWR circuitry in the KXAT100 (and KAT500) measure the forward and reverse voltage values at different times. They cannot be measured simultaneously because they don't have dual A/D converters or sample-and-hold circuits. To be sure, there is only a short time between sampling the forward and reverse directions but if your output power is changing with time as it will with a high speed CW signals and more especially and more troublesomely with a SSB signal, the SWR metering may indicate an incorrect value. If you have the tuner in AUTO mode, this may trigger a retune. For this reason it is best to operate either of these tuners in MAN mode and train the tuner(s) to store good L-C values for different frequencies in each of your operational bands. The tuners store this information in "frequency buckets" and when they detect the frequency within that bucker they recall the L-C values and if they need to be changed they will be.
>
> Summary:
> Train the tuner so that it can remember the L-C values to use for a specific range of frequencies.
> Don't use AUTO mode; use MAN mode.
>
> Cheers and 73,
> Fred KE7X
> "The Elecraft K3: Design, Configuration and Operation 2nd ed"
> "The Elecraft KX3 - Going for the summit"
> "The Elecraft KPA500 and KAT500 - the K-Line Dream Station"
> Printed, coil bound copies of these are all available at www.elecraft.com
> KPA500 and KAT500 Quick Set Up Guide
> http://www.ke7x.com/home/k-line-introduction-and-set-up-guide
>
>> -----Original Message-----
>> From: Elecraft [mailto:[hidden email]] On Behalf Of
>> Jim Kutsch, KY2D
>> Sent: Monday, December 08, 2014 9:18 AM
>> To: [hidden email]
>> Subject: Re: [Elecraft] KXPA100 Intermittent VSWR Issues
>>
>> I'm experiencing the same thing but mostly on 40 meters where the best
>> match with the ATU isn't as good as on other bands. It *SEEMS* to have
>> started Saturday when I installed the latest KX3 beta and set
>> compression to 20. The antenna is a Carolina Windham.
>>
>> 73, Jim, KY2D
>> .
>>
>>
>> -----Original Message-----
>> From: Elecraft [mailto:[hidden email]] On Behalf Of
>> Jim Stahl via Elecraft
>> Sent: Sunday, December 07, 2014 10:08 PM
>> To: [hidden email]
>> Subject: [Elecraft] KXPA100 Intermittent VSWR Issues
>>
>> I've run into several occasions where in mid-CW transmission my KXPA100
>> (with internal tuner) SWR takes a momentary jump from matched to maybe
>> 3:1.
>> I see the SWR jump on both the KXPA front panel LEDs and on the KX3
>> VSWR display. It lasts for maybe half a second, I hear several clicks
>> of the relays in the tuner, and them it's back to normal. When normal
>> the SWR is pretty much 1:1 on the KX3, and the second green LED lit on
>> the KX3. I've not seen it happen at the start of a transmission, but
>> rather several characters into a CQ or exchange..
>>
>> In the ARRL 160 contest Saturday night this was happening perhaps once
>> every
>> 2-3 minutes. I'm using a fairly well matched antenna - not random
>> wires.
>> I also encountered this problem on 15 meters when operating from
>> W1AW/8 in WV in October. In both cases I was running a pretty high CW
>> duty cycle while running at a pretty good clip. The amp was warm, but
>> the heat sink air flow is not blocked.
>>
>> Any thoughts?
>>
>>
>> 73 - Jim K8MR
>>
>>
>>
>>
>> ______________________________________________________________
>> 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]

Dan Baker

Re: KXPA100 Intermittent VSWR Issues

In reply to this post by Elecraft mailing list

Mine does the same thing all the time, so much that I do not like to using
the tuner any longer.
I confirmed it was tuner in the amp by operating into a dummy load. Its
does it into the dummy load on CW and SSB. I have not said anything,
thinking an update will be pushed out and the problem will disappear. In
the meantime I use the KAT500. Its all to frustrating to be in a QSO and
have it act up. It kind of behaves like the KAT500 did before they upgraded
the firmware. I am sure they will get around to taking care of it.

73, Dan KM6CQ

I've run into several occasions where in mid-CW transmission my KXPA100
(with internal tuner) SWR takes a momentary jump from matched to maybe
3:1. I
see the SWR jump on both the KXPA front panel LEDs and on the KX3 VSWR
display. It lasts for maybe half a second, I hear several clicks of the
relays in the tuner, and them it's back to normal. When normal the SWR is
pretty
much 1:1 on the KX3, and the second green LED lit on the KX3. I've not
seen it happen at the start of a transmission, but rather several
characters
into a CQ or exchange..

In the ARRL 160 contest Saturday night this was happening perhaps once
every 2-3 minutes. I'm using a fairly well matched antenna - not random
wires.
I also encountered this problem on 15 meters when operating from W1AW/8 in
WV in October. In both cases I was running a pretty high CW duty cycle
while running at a pretty good clip. The amp was warm, but the heat sink
air
flow is not blocked.

Any thoughts?

73 - Jim K8MR

--
KM6CQ
Dan Baker
www.km6cq.com
@danielbaker
DM09dn
SKCC: 8260 NAQCC: 6817
QSL via LoTW, eQSL, & Direct.
D-Star REF014C
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vk2rq

Re: KXPA100 Intermittent VSWR Issues

Are you running the latest KXPA100 firmware (v1.32)? If so, and you are still experiencing problems, then contact the Elecraft support team. Even though those guys are very efficient, they can't fix problems they don't know about.

73,
Matt VK2RQ

> On 9 Dec 2014, at 10:35 am, Dan Baker <[hidden email]> wrote:
>
> Mine does the same thing all the time, so much that I do not like to using
> the tuner any longer.
> I confirmed it was tuner in the amp by operating into a dummy load. Its
> does it into the dummy load on CW and SSB. I have not said anything,
> thinking an update will be pushed out and the problem will disappear. In
> the meantime I use the KAT500. Its all to frustrating to be in a QSO and
> have it act up. It kind of behaves like the KAT500 did before they upgraded
> the firmware. I am sure they will get around to taking care of it.
>
> 73, Dan KM6CQ
>
>
> I've run into several occasions where in mid-CW transmission my KXPA100
> (with internal tuner) SWR takes a momentary jump from matched to maybe
> 3:1. I
> see the SWR jump on both the KXPA front panel LEDs and on the KX3 VSWR
> display. It lasts for maybe half a second, I hear several clicks of the
> relays in the tuner, and them it's back to normal. When normal the SWR is
> pretty
> much 1:1 on the KX3, and the second green LED lit on the KX3. I've not
> seen it happen at the start of a transmission, but rather several
> characters
> into a CQ or exchange..
>
> In the ARRL 160 contest Saturday night this was happening perhaps once
> every 2-3 minutes. I'm using a fairly well matched antenna - not random
> wires.
> I also encountered this problem on 15 meters when operating from W1AW/8 in
> WV in October. In both cases I was running a pretty high CW duty cycle
> while running at a pretty good clip. The amp was warm, but the heat sink
> air
> flow is not blocked.
>
> Any thoughts?
>
>
> 73 - Jim K8MR
>
>
> --
> KM6CQ
> Dan Baker
> www.km6cq.com
> @danielbaker
> DM09dn
> SKCC: 8260 NAQCC: 6817
> QSL via LoTW, eQSL, & Direct.
> D-Star REF014C
> ______________________________________________________________
> 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]

Cady, Fred

Re: KXPA100 Intermittent VSWR Issues

In reply to this post by Dan Baker

Are you using AUTO or MAN mode? You should be using MAN mode after training the tuner.
Cheers,
Fred KE7X

> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of
> Dan Baker
> Sent: Monday, December 08, 2014 4:36 PM
> To: [hidden email]
> Subject: Re: [Elecraft] KXPA100 Intermittent VSWR Issues
>
> Mine does the same thing all the time, so much that I do not like to
> using the tuner any longer.
> I confirmed it was tuner in the amp by operating into a dummy load. Its
> does it into the dummy load on CW and SSB. I have not said anything,
> thinking an update will be pushed out and the problem will disappear.
> In the meantime I use the KAT500. Its all to frustrating to be in a QSO
> and have it act up. It kind of behaves like the KAT500 did before they
> upgraded the firmware. I am sure they will get around to taking care of
> it.
>
> 73, Dan KM6CQ
>
>
> I've run into several occasions where in mid-CW transmission my KXPA100
> (with internal tuner) SWR takes a momentary jump from matched to maybe
> 3:1. I see the SWR jump on both the KXPA front panel LEDs and on the
> KX3 VSWR display. It lasts for maybe half a second, I hear several
> clicks of the relays in the tuner, and them it's back to normal. When
> normal the SWR is pretty much 1:1 on the KX3, and the second green LED
> lit on the KX3. I've not seen it happen at the start of a
> transmission, but rather several characters into a CQ or exchange..
>
> In the ARRL 160 contest Saturday night this was happening perhaps once
> every 2-3 minutes. I'm using a fairly well matched antenna - not random
> wires.
> I also encountered this problem on 15 meters when operating from
> W1AW/8 in WV in October. In both cases I was running a pretty high CW
> duty cycle while running at a pretty good clip. The amp was warm, but
> the heat sink air flow is not blocked.
>
> Any thoughts?
>
>
> 73 - Jim K8MR
>
>
> --
> KM6CQ
> Dan Baker
> www.km6cq.com
> @danielbaker
> DM09dn
> SKCC: 8260 NAQCC: 6817
> QSL via LoTW, eQSL, & Direct.
> D-Star REF014C
> ______________________________________________________________
> 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]

Dan Baker

Re: KXPA100 Intermittent VSWR Issues

I am running the latest firmware. And it does it in manual mode also. Maybe
Elecraft does need to see it.

Dan

On Monday, December 8, 2014, Cady, Fred <[hidden email]> wrote:

> Are you using AUTO or MAN mode? You should be using MAN mode after
> training the tuner.
> Cheers,
> Fred KE7X
>
>
> > -----Original Message-----
> > From: Elecraft [mailto:[hidden email] <javascript:;>]
> On Behalf Of
> > Dan Baker
> > Sent: Monday, December 08, 2014 4:36 PM
> > To: [hidden email] <javascript:;>
> > Subject: Re: [Elecraft] KXPA100 Intermittent VSWR Issues
> >
> > Mine does the same thing all the time, so much that I do not like to
> > using the tuner any longer.
> > I confirmed it was tuner in the amp by operating into a dummy load. Its
> > does it into the dummy load on CW and SSB. I have not said anything,
> > thinking an update will be pushed out and the problem will disappear.
> > In the meantime I use the KAT500. Its all to frustrating to be in a QSO
> > and have it act up. It kind of behaves like the KAT500 did before they
> > upgraded the firmware. I am sure they will get around to taking care of
> > it.
> >
> > 73, Dan KM6CQ
> >
> >
> > I've run into several occasions where in mid-CW transmission my KXPA100
> > (with internal tuner) SWR takes a momentary jump from matched to maybe
> > 3:1. I see the SWR jump on both the KXPA front panel LEDs and on the
> > KX3 VSWR display. It lasts for maybe half a second, I hear several
> > clicks of the relays in the tuner, and them it's back to normal. When
> > normal the SWR is pretty much 1:1 on the KX3, and the second green LED
> > lit on the KX3. I've not seen it happen at the start of a
> > transmission, but rather several characters into a CQ or exchange..
> >
> > In the ARRL 160 contest Saturday night this was happening perhaps once
> > every 2-3 minutes. I'm using a fairly well matched antenna - not random
> > wires.
> > I also encountered this problem on 15 meters when operating from
> > W1AW/8 in WV in October. In both cases I was running a pretty high CW
> > duty cycle while running at a pretty good clip. The amp was warm, but
> > the heat sink air flow is not blocked.
> >
> > Any thoughts?
> >
> >
> > 73 - Jim K8MR
> >
> >
> > --
> > KM6CQ
> > Dan Baker
> > www.km6cq.com
> > @danielbaker
> > DM09dn
> > SKCC: 8260 NAQCC: 6817
> > QSL via LoTW, eQSL, & Direct.
> > D-Star REF014C
> > ______________________________________________________________
> > Elecraft mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/elecraft
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:[hidden email] <javascript:;>
> >
> > 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] <javascript:;>
>

--
KM6CQ
Dan Baker
www.km6cq.com
@danielbaker
DM09dn
SKCC: 8260 NAQCC: 6817
QSL via LoTW, eQSL, & Direct.
D-Star REF014C
______________________________________________________________
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