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K3/KPA500/KAT500 SWR problem

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Ray Coles

K3/KPA500/KAT500 SWR problem

I do hope someone out there can give me a hand in solving a 2 month old
problem with my Elecraft station, even though the problem may not be due to
my Elecraft rig at all. I had been happily operating my K3/KPA500/KAT500 rig
for about 10 months with my simple wire doublet antenna, about 25 metres
long and 5m high. I work mainly digital modes, especially JT65 so I rarely
switch the KPA500 to Operate, using it mainly as a Wattmeter. I have used it
on SSB on my local Inter-G club net on 40m however, and everything used to
be fine and dandy at all power settings from 40W to 400W with the KAT500 set
to Auto.

THEN one evening operating at about 60W JT65 on 20m the Kat500 started
hunting and the SWR shot up into the red. Since that event the problem has
dogged me continuously. Of course, I immediately suspected a short (or open)
in my antenna system. My antenna feed used RG58 out to a 4:1 balun outside
in a convenient hawthorn bush. 300 ohm ladder line went from the balun to
the doublet T piece. Which was offset 1/3-2/3. This antenna matched, and had
bagged QSOs on all bands from 80m to 6m. The RG58 was suspect number one. I
replaced it with UR8 and used a new route to the balun which obviated the
need for any burial. THE PROBLEM REMAINED. The 300W rated balun was the next
suspect, and I already had a replacement 1kW unit to hand. I changed it. THE
PROBLEM REMAINED, but by now I had learned that if I ran the KAT500 on
Manual and kept power below 40W I could operate, and so I continued to add
DX QSOs to my log. All that was left were the aerial components, so I
dropped the antenna and changed the ladder line, the T piece the antenna
wire and the end insulators. THE PROBLEM REMAINED and it seemed that I would
be forever limited to 40W. I had an alternative antenna, an MFJ Magloop
which could be happily driven to 100+W connected either to K3 Ant2 or KAT500
Ant3 and I worked surprising DX with it, but I really wanted my lovely
Doublet back. (Forgot to mention that I also changed rig connecting leads).
Since then I have played with my rig to try and understand things better and
I am beginning to wonder whether there COULD be a rig problem. I also note
that when I start transmitting, power is always less than I have selected
and it climbs steadily to the demanded value over time. I have set up ALC as
documented. If I set power greater than 40W (this varies a little band to
band) the power climbs until....BAM!.... The SWR of 1 to 1.4 suddenly shoots
up into the Red with the KAT500 utility recording values of 5-25!

This is a weird set of observations I know, but I would be grateful for any
further suggestions from the trusty Elecraft Reflector Brains Trust.

HNY and 73,

Ray Coles, C.Eng. M0XDL

10 Littlemoor Road,

Weymouth DT3 6AA

Tel: +44 (0) 1305 833699

Mob: 07831 516517

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John Bastin

Re: K3/KPA500/KAT500 SWR problem

On 29 Dec 2013, at 5:46 PM, Ray Coles <[hidden email]> wrote:

> I also note
> that when I start transmitting, power is always less than I have selected
> and it climbs steadily to the demanded value over time. I have set up ALC as
> documented. If I set power greater than 40W (this varies a little band to
> band) the power climbs until....BAM!.... The SWR of 1 to 1.4 suddenly shoots
> up into the Red with the KAT500 utility recording values of 5-25!

I agree that first you should connect your output directly into a 50 ohm dummy load and see if you see the same symptoms or if everything looks normal. If it's normal there...

Your symptoms of SWR jumping up as the power is increased seem very indicative of a bad coax shield connection on your RG58 or RG8 feedline. I would carefully inspect your PL-259s and any barrel connectors that may be involved in the feedline path to the antenna, for looseness in the shield connection to the PL-259. Probably best would be to make up a new coax feedline with new connectors and make sure the solder connections to the shield side are very solid.

Hope this helps.

73,

John K8AJS
[hidden email]

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Bill-3

Re: K3/KPA500/KAT500 SWR problem

In reply to this post by Ray Coles

An interesting topic and - hopefully - will be fully discussed here and
not via direct emails. We cannot learn from what we do not see.

Thanks,

Bill W2BLC K-Line

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Brian J. Linn

Re: K3/KPA500/KAT500 SWR problem

In reply to this post by Ray Coles

All:

This issue sounds familiar. I'll be operating along in the middle of an SSB
QSO and suddenly the KAT500 goes wild. The SWR displayed on the meter is
HIGHER than the antenna WITHOUT a tuner. The sad part is that it will go on
for maybe 10 seconds and no match is found (odd when considering the nearly
resonant antenna). The amp then goes into fault and so on. It seems that if
I stop the QSO and retune manually all can again be well, but a serious
problem indeed.

Because it's so inconsistent and unexpected, I've been unable to try it
against a dummy load; however, I did rebuild both 10 meter antennas (just
before the recent contest) thinking they might be at fault. No joy ...
problem continued and is showing up on other bands too.

Brian KD0HII

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Ray Coles
Sent: Sunday, December 29, 2013 2:46 PM
To: [hidden email]
Subject: [Elecraft] K3/KPA500/KAT500 SWR problem

I do hope someone out there can give me a hand in solving a 2 month old
problem with my Elecraft station, even though the problem may not be due to
my Elecraft rig at all. I had been happily operating my K3/KPA500/KAT500 rig
for about 10 months with my simple wire doublet antenna, about 25 metres
long and 5m high. I work mainly digital modes, especially JT65 so I rarely
switch the KPA500 to Operate, using it mainly as a Wattmeter. I have used it
on SSB on my local Inter-G club net on 40m however, and everything used to
be fine and dandy at all power settings from 40W to 400W with the KAT500 set
to Auto.

THEN one evening operating at about 60W JT65 on 20m the Kat500 started
hunting and the SWR shot up into the red. Since that event the problem has
dogged me continuously. Of course, I immediately suspected a short (or open)
in my antenna system. My antenna feed used RG58 out to a 4:1 balun outside
in a convenient hawthorn bush. 300 ohm ladder line went from the balun to
the doublet T piece. Which was offset 1/3-2/3. This antenna matched, and had
bagged QSOs on all bands from 80m to 6m. The RG58 was suspect number one. I
replaced it with UR8 and used a new route to the balun which obviated the
need for any burial. THE PROBLEM REMAINED. The 300W rated balun was the next
suspect, and I already had a replacement 1kW unit to hand. I changed it. THE
PROBLEM REMAINED, but by now I had learned that if I ran the KAT500 on
Manual and kept power below 40W I could operate, and so I continued to add
DX QSOs to my log. All that was left were the aerial components, so I
dropped the antenna and changed the ladder line, the T piece the antenna
wire and the end insulators. THE PROBLEM REMAINED and it seemed that I would
be forever limited to 40W. I had an alternative antenna, an MFJ Magloop
which could be happily driven to 100+W connected either to K3 Ant2 or KAT500
Ant3 and I worked surprising DX with it, but I really wanted my lovely
Doublet back. (Forgot to mention that I also changed rig connecting leads).
Since then I have played with my rig to try and understand things better and
I am beginning to wonder whether there COULD be a rig problem. I also note
that when I start transmitting, power is always less than I have selected
and it climbs steadily to the demanded value over time. I have set up ALC as
documented. If I set power greater than 40W (this varies a little band to
band) the power climbs until....BAM!.... The SWR of 1 to 1.4 suddenly shoots
up into the Red with the KAT500 utility recording values of 5-25!

This is a weird set of observations I know, but I would be grateful for any
further suggestions from the trusty Elecraft Reflector Brains Trust.

HNY and 73,

Ray Coles, C.Eng. M0XDL

10 Littlemoor Road,

Weymouth DT3 6AA

Tel: +44 (0) 1305 833699

Mob: 07831 516517

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Bill-3

Re: K3/KPA500/KAT500 SWR problem

This is exactly why I want to see this complete discussion in full view.
It is a problem here also - occurring often and without any obvious
cause. Putting the tuner in AUTO or in MANUAL does not stop it from
happening. The tuner does not seem to understand the term MANUAL.

My experience is from 75 meters - with no change in antennas - and will
occur on oft used frequencies in the middle of a transmission. The tuner
just suddenly decides it is time to make noises. I do not use other
bands and the antenna is a dipole that present no problems to other rigs
and tuners (read as nothing wrong with the antenna or feedlines, which
have all been completely checked).

AT the very least, I now know I am not alone with this problem.

Thanks,

Bill W2BLC K-Line

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Cady, Fred

Re: K3/KPA500/KAT500 SWR problem

In reply to this post by Brian J. Linn

Hi all,
While it may not solve the problem that the original rp posted, here are some things I've learned while putting together the K-Line book (out soon).

It is best to operate in MAN mode after you have trained your tuner to your antennas. The reason is the KAT is continually measuring VSWR as you transmit and it takes a little time to do that. If it measures the forward voltage at one point in a SSB waveform and the reverse in another, you can see that the VSWR calculation will be off. If you are in AUTO mode, it will then try to go into a tune. There isn't much of a downside to operating in MAN mode. It basically ignores the transient wrong VSWR and if there is a really bad antenna (it fell down or something) the tuner will fault and take the amp off line and you will then be able to correct the problem.

You can also set the Key Interrupt VSWR threshold to something other than 99. This kind of acts as a back up to the KPA's innate ability to protect itself. I have mine set at 4:1 (I'm kind of a belt and braces kind of guy),

The other thing to do is to make sure you have the Amplifier Key Interrupt Power optimized for the KPA500. The factory default is about 30 watts which means the tuner won't interrupt the amp keying when it sees > 30 watts.

Cheers and Happy New Year all,
Fred KE7X

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf Of Brian Linn
Sent: Monday, December 30, 2013 5:36 AM
To: [hidden email]
Subject: Re: [Elecraft] K3/KPA500/KAT500 SWR problem

All:

This issue sounds familiar. I'll be operating along in the middle of an SSB QSO and suddenly the KAT500 goes wild. The SWR displayed on the meter is HIGHER than the antenna WITHOUT a tuner. The sad part is that it will go on for maybe 10 seconds and no match is found (odd when considering the nearly resonant antenna). The amp then goes into fault and so on. It seems that if I stop the QSO and retune manually all can again be well, but a serious problem indeed.

Because it's so inconsistent and unexpected, I've been unable to try it against a dummy load; however, I did rebuild both 10 meter antennas (just before the recent contest) thinking they might be at fault. No joy ...
problem continued and is showing up on other bands too.

Brian KD0HII

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Ray Coles
Sent: Sunday, December 29, 2013 2:46 PM
To: [hidden email]
Subject: [Elecraft] K3/KPA500/KAT500 SWR problem

I do hope someone out there can give me a hand in solving a 2 month old problem with my Elecraft station, even though the problem may not be due to my Elecraft rig at all. I had been happily operating my K3/KPA500/KAT500 rig for about 10 months with my simple wire doublet antenna, about 25 metres long and 5m high. I work mainly digital modes, especially JT65 so I rarely switch the KPA500 to Operate, using it mainly as a Wattmeter. I have used it on SSB on my local Inter-G club net on 40m however, and everything used to be fine and dandy at all power settings from 40W to 400W with the KAT500 set to Auto.

THEN one evening operating at about 60W JT65 on 20m the Kat500 started hunting and the SWR shot up into the red. Since that event the problem has dogged me continuously. Of course, I immediately suspected a short (or open) in my antenna system. My antenna feed used RG58 out to a 4:1 balun outside in a convenient hawthorn bush. 300 ohm ladder line went from the balun to the doublet T piece. Which was offset 1/3-2/3. This antenna matched, and had bagged QSOs on all bands from 80m to 6m. The RG58 was suspect number one. I replaced it with UR8 and used a new route to the balun which obviated the need for any burial. THE PROBLEM REMAINED. The 300W rated balun was the next suspect, and I already had a replacement 1kW unit to hand. I changed it. THE PROBLEM REMAINED, but by now I had learned that if I ran the KAT500 on Manual and kept power below 40W I could operate, and so I continued to add DX QSOs to my log. All that was left were the aerial components, so I dropped the antenna a
nd changed the ladder line, the T piece the antenna wire and the end insulators. THE PROBLEM REMAINED and it seemed that I would be forever limited to 40W. I had an alternative antenna, an MFJ Magloop which could be happily driven to 100+W connected either to K3 Ant2 or KAT500
Ant3 and I worked surprising DX with it, but I really wanted my lovely Doublet back. (Forgot to mention that I also changed rig connecting leads).
Since then I have played with my rig to try and understand things better and I am beginning to wonder whether there COULD be a rig problem. I also note that when I start transmitting, power is always less than I have selected and it climbs steadily to the demanded value over time. I have set up ALC as documented. If I set power greater than 40W (this varies a little band to
band) the power climbs until....BAM!.... The SWR of 1 to 1.4 suddenly shoots up into the Red with the KAT500 utility recording values of 5-25!

This is a weird set of observations I know, but I would be grateful for any further suggestions from the trusty Elecraft Reflector Brains Trust.

HNY and 73,

Ray Coles, C.Eng. M0XDL

10 Littlemoor Road,

Weymouth DT3 6AA

Tel: +44 (0) 1305 833699

Mob: 07831 516517

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KD0Q

Re: K3/KPA500/KAT500 SWR problem

In reply to this post by Bill-3

I experience this as well, only on 80 meters with the KPA500 in
operate. Always thought that it was RF getting into the KAT500 sensing
as I can usually back off to 300 Watts, force a KAT500 re-tune and continue.

Glenn - KD0Q

On 12/30/2013 07:59, Bill W2BLC wrote:

> This is exactly why I want to see this complete discussion in full
> view. It is a problem here also - occurring often and without any
> obvious cause. Putting the tuner in AUTO or in MANUAL does not stop it
> from happening. The tuner does not seem to understand the term MANUAL.
>
> My experience is from 75 meters - with no change in antennas - and
> will occur on oft used frequencies in the middle of a transmission.
> The tuner just suddenly decides it is time to make noises. I do not
> use other bands and the antenna is a dipole that present no problems
> to other rigs and tuners (read as nothing wrong with the antenna or
> feedlines, which have all been completely checked).
>
> AT the very least, I now know I am not alone with this problem.
>
> Thanks,
>
> Bill W2BLC K-Line
>
> ______________________________________________________________
> 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
>
>

Dr. William J. Schmidt, II

FW: K3/KPA500/KAT500 SWR problem

I take it everyone has good station RF ground systems in the shack (or where
ever the tuner is located)?

Dr. William J. Schmidt - K9HZ / J68HZ/ 8P6HK/ ZF2HZ

Owner - Operator
Big Signal Ranch
Staunton, Illinois

email: [hidden email]

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of KD0Q-Glenn
Sent: Monday, December 30, 2013 10:24 AM
To: [hidden email]
Subject: Re: [Elecraft] K3/KPA500/KAT500 SWR problem

I experience this as well, only on 80 meters with the KPA500 in
operate. Always thought that it was RF getting into the KAT500 sensing
as I can usually back off to 300 Watts, force a KAT500 re-tune and continue.

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Jeffrey Otterson

Re: K3/KPA500/KAT500 SWR problem

In reply to this post by Ray Coles

I, too, have seen this spurious KAT500 retune problem.

I'm running a similar setup:
K3->KPA500->LP-100A->KAT500->coax->balun->ladder line->hf doublet

I'lll be happily working 75M and all of a sudden the KAT500 starts
re-tuning, and with the LP-100 alarm going off and the relays chattering in
the KAT500, it sounds a bit like all hell breaking loose.

I reverted the KAT500 to firmware version 1.32 and the problem *seems* to
happen less often... That could be my imagination, though. Also I think
that this has happened in MANUAL mode, as well as automatic.

Perhaps it would be useful to have an option to only re-tune during the
first few seconds of transmit?

Jeff
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Joe K2UF

Re: K3/KPA500/KAT500 SWR problem

In reply to this post by KD0Q

I have had a similar thing happen to me also. I have been in a contest on a
run freq. and suddenly the KPA500/KAT500 will fault. This is on CW. If I
do a 'tune' the amp/tuner will retune and I can continue. Of course in the
few seconds it takes I will usually lose the freq.

73, Joe K2UF

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of KD0Q-Glenn
Sent: Monday, December 30, 2013 9:24 AM
To: [hidden email]
Subject: Re: [Elecraft] K3/KPA500/KAT500 SWR problem

I experience this as well, only on 80 meters with the KPA500 in
operate. Always thought that it was RF getting into the KAT500 sensing
as I can usually back off to 300 Watts, force a KAT500 re-tune and continue.

Glenn - KD0Q

On 12/30/2013 07:59, Bill W2BLC wrote:

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W1KSZ

Re: K3/KPA500/KAT500 SWR problem

In reply to this post by Ray Coles

OK, so now we have heard from a few folks that have this problem.

As a soon to be purchaser of a similar set-up, I am quite concerned.
What is the solution to this problem ?

I read one post about putting the Tuner in Manual mode, but I also
read that another user has had the problem in Manual mode.

How does one fix this ?

73 es HNY, Dick, W1KSZ

On 12/30/2013 11:10 AM, Joe K2UF wrote:

> I have had a similar thing happen to me also. I have been in a contest on a
> run freq. and suddenly the KPA500/KAT500 will fault. This is on CW. If I
> do a 'tune' the amp/tuner will retune and I can continue. Of course in the
> few seconds it takes I will usually lose the freq.
>
> 73, Joe K2UF
>
> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of KD0Q-Glenn
> Sent: Monday, December 30, 2013 9:24 AM
> To: [hidden email]
> Subject: Re: [Elecraft] K3/KPA500/KAT500 SWR problem
>
> I experience this as well, only on 80 meters with the KPA500 in
> operate. Always thought that it was RF getting into the KAT500 sensing
> as I can usually back off to 300 Watts, force a KAT500 re-tune and continue.
>
> Glenn - KD0Q
>
> On 12/30/2013 07:59, Bill W2BLC wrote:
>> This is exactly why I want to see this complete discussion in full
>> view. It is a problem here also - occurring often and without any
>> obvious cause. Putting the tuner in AUTO or in MANUAL does not stop it
>> from happening. The tuner does not seem to understand the term MANUAL.
>>
>> My experience is from 75 meters - with no change in antennas - and
>> will occur on oft used frequencies in the middle of a transmission.
>> The tuner just suddenly decides it is time to make noises. I do not
>> use other bands and the antenna is a dipole that present no problems
>> to other rigs and tuners (read as nothing wrong with the antenna or
>> feedlines, which have all been completely checked).
>>
>> AT the very least, I now know I am not alone with this problem.
>>
>> Thanks,
>>
>> Bill W2BLC K-Line
>>
>> ______________________________________________________________
>> 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
>>
>>
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
>
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> Please help support this email list: http://www.qsl.net/donate.html
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

Igor Sokolov-2

Re: K3/KPA500/KAT500 SWR problem

In reply to this post by Jeffrey Otterson

It may be not relevant to this particular case but another reason for weird
KAT500 behavior can be strong interfering signal of a neighbor or nearby
broadcasting station. I did run into situations where such signals induced
up to 5 volts into low band antenna. Then KAT500 counts that signal as
reflected and thinks that SWR is very high. One may try to connect broadband
spectrum analyzer to the antenna and see what is going on. If it is
broadcasting signal well below ham bands then high pass filter between the
tuner and antenna can help.

73, Igor UA9CDC

----- Original Message -----
From: "Jeffrey Otterson" <[hidden email]>
To: <[hidden email]>
Sent: Monday, December 30, 2013 8:58 PM
Subject: Re: [Elecraft] K3/KPA500/KAT500 SWR problem

> I, too, have seen this spurious KAT500 retune problem.
>
> I'm running a similar setup:
> K3->KPA500->LP-100A->KAT500->coax->balun->ladder line->hf doublet
>
> I'lll be happily working 75M and all of a sudden the KAT500 starts
> re-tuning, and with the LP-100 alarm going off and the relays chattering
> in
> the KAT500, it sounds a bit like all hell breaking loose.
>
> I reverted the KAT500 to firmware version 1.32 and the problem *seems* to
> happen less often... That could be my imagination, though. Also I think
> that this has happened in MANUAL mode, as well as automatic.
>
> Perhaps it would be useful to have an option to only re-tune during the
> first few seconds of transmit?
>
> Jeff
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Bill-3

Re: FW: K3/KPA500/KAT500 SWR problem

In reply to this post by Dr. William J. Schmidt, II

In regards to proper grounding etc.: I think it is safe to say that K3
owners have a very good grasp of what is needed to construct and operate
a proper station - safety and RF wise.

I do, yet still went back over every last connector/connection/lug, etc.
Everything is locked down properly here. No baluns, good coax, and
everything is mechanical and soldered along the entire antenna routes.
Yet, the problem continues. Perhaps the most disconcerting part is that
my other auto tuners/rigs do not exhibit this difficulty. Perhaps the
KAT500 is seeing something the others do not.

The difficult part is never knowing when the tuner will take off and the
fact that MANUAL selection does not appear to make any difference. I
have been using MANUAL for a couple of months. I do not see that it has
made any difference in occurrences. The instances of "run-away" are
random and it is usually days between events.

Bill W2BLC K-Line
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Jim Bennett

Re: K3/KPA500/KAT500 SWR problem

In reply to this post by W1KSZ

Dick -

I've had my K-line (K3/P3/KPA500/KAT500) running here for a while on almost all the bands, mostly CW. I have yet to have it act up this way, or any other way, for that matter. I use an 88 foot long doublet at 45 feet for 40-6 meters, and two separate Inverted L antennas for 80 and 160. Single 6 foot long copper clad steel ground rod right outside the shack window.

Jim / W6JHB

On Monday, Dec 30, 2013, at Monday, 10:15 AM, Richard Solomon wrote:

> OK, so now we have heard from a few folks that have this problem.
>
> As a soon to be purchaser of a similar set-up, I am quite concerned.
> What is the solution to this problem ?
>
> I read one post about putting the Tuner in Manual mode, but I also
> read that another user has had the problem in Manual mode.
>
> How does one fix this ?
>
> 73 es HNY, Dick, W1KSZ
>
>
> On 12/30/2013 11:10 AM, Joe K2UF wrote:
>> I have had a similar thing happen to me also. I have been in a contest on a
>> run freq. and suddenly the KPA500/KAT500 will fault. This is on CW. If I
>> do a 'tune' the amp/tuner will retune and I can continue. Of course in the
>> few seconds it takes I will usually lose the freq.
>>
>> 73, Joe K2UF
>>
>> -----Original Message-----
>> From: [hidden email]
>> [mailto:[hidden email]] On Behalf Of KD0Q-Glenn
>> Sent: Monday, December 30, 2013 9:24 AM
>> To: [hidden email]
>> Subject: Re: [Elecraft] K3/KPA500/KAT500 SWR problem
>>
>> I experience this as well, only on 80 meters with the KPA500 in
>> operate. Always thought that it was RF getting into the KAT500 sensing
>> as I can usually back off to 300 Watts, force a KAT500 re-tune and continue.
>>
>> Glenn - KD0Q
>>
>> On 12/30/2013 07:59, Bill W2BLC wrote:
>>> This is exactly why I want to see this complete discussion in full
>>> view. It is a problem here also - occurring often and without any
>>> obvious cause. Putting the tuner in AUTO or in MANUAL does not stop it
>>> from happening. The tuner does not seem to understand the term MANUAL.
>>>
>>> My experience is from 75 meters - with no change in antennas - and
>>> will occur on oft used frequencies in the middle of a transmission.
>>> The tuner just suddenly decides it is time to make noises. I do not
>>> use other bands and the antenna is a dipole that present no problems
>>> to other rigs and tuners (read as nothing wrong with the antenna or
>>> feedlines, which have all been completely checked).
>>>
>>> AT the very least, I now know I am not alone with this problem.
>>>
>>> Thanks,
>>>
>>> Bill W2BLC K-Line
>>>
>>> ______________________________________________________________
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>>>
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>>>
>>>
>>
>> ______________________________________________________________
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>
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Jim Miller

Re: FW: K3/KPA500/KAT500 SWR problem

In reply to this post by Bill-3

Do you have coomon mode chokes on you feed lines?

Jim ab3cv

On Dec 30, 2013, at 1:29 PM, Bill W2BLC <[hidden email]> wrote:

In regards to proper grounding etc.: I think it is safe to say that K3 owners have a very good grasp of what is needed to construct and operate a proper station - safety and RF wise.

I do, yet still went back over every last connector/connection/lug, etc. Everything is locked down properly here. No baluns, good coax, and everything is mechanical and soldered along the entire antenna routes. Yet, the problem continues. Perhaps the most disconcerting part is that my other auto tuners/rigs do not exhibit this difficulty. Perhaps the KAT500 is seeing something the others do not.

The difficult part is never knowing when the tuner will take off and the fact that MANUAL selection does not appear to make any difference. I have been using MANUAL for a couple of months. I do not see that it has made any difference in occurrences. The instances of "run-away" are random and it is usually days between events.

Bill W2BLC K-Line
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Jim Bennett

Re: K3/KPA500/KAT500 SWR problem

They are on all of MY various HF antennas: doublet, Inverted L's, and a ground mounted vertical.

On Monday, Dec 30, 2013, at Monday, 11:54 AM, Jim Miller wrote:

> Do you have coomon mode chokes on you feed lines?
>
> Jim ab3cv
>
> On Dec 30, 2013, at 1:29 PM, Bill W2BLC <[hidden email]> wrote:
>
> In regards to proper grounding etc.: I think it is safe to say that K3 owners have a very good grasp of what is needed to construct and operate a proper station - safety and RF wise.
>
> I do, yet still went back over every last connector/connection/lug, etc. Everything is locked down properly here. No baluns, good coax, and everything is mechanical and soldered along the entire antenna routes. Yet, the problem continues. Perhaps the most disconcerting part is that my other auto tuners/rigs do not exhibit this difficulty. Perhaps the KAT500 is seeing something the others do not.
>
> The difficult part is never knowing when the tuner will take off and the fact that MANUAL selection does not appear to make any difference. I have been using MANUAL for a couple of months. I do not see that it has made any difference in occurrences. The instances of "run-away" are random and it is usually days between events.
>
> Bill W2BLC K-Line
> ______________________________________________________________
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> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>
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KD0Q

Re: FW: K3/KPA500/KAT500 SWR problem

In reply to this post by Jim Miller

Everything in the shack is grounded to an aluminum bus bar across the
back of the operating table which is tied with #6 solid copper to the
same point as the tower and AC Main grounds.

Just for reference, the antenna is a 260ft OCF Inverted Vee at 75 ft
using a Balun Designs #4115ocf 4:1/Choke combination balun. Coax shield
is grounded at the top and bottom of the tower.

Glenn - KD0Q

On 12/30/2013 13:54, Jim Miller wrote:

Don Wilhelm-4

Re: FW: K3/KPA500/KAT500 SWR problem

Hmmm, An aluminum bar tied to a copper wire! Be aware that there will
be oxidation at the junction point due to dissimilar metals unless
special bonding is used to slow (but not stop) the oxidation.

Just something to bear in mind.

73,
Don W3FPR
On 12/30/2013 3:23 PM, KD0Q-Glenn wrote:
> Everything in the shack is grounded to an aluminum bus bar across the
> back of the operating table which is tied with #6 solid copper to the
> same point as the tower and AC Main grounds.
>
> Just for reference, the antenna is a 260ft OCF Inverted Vee at 75 ft
> using a Balun Designs #4115ocf 4:1/Choke combination balun. Coax
> shield is grounded at the top and bottom of the tower.
>

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Bill OMara

Re: K3/KPA500/KAT500 SWR problem

In reply to this post by Igor Sokolov-2

I saw the problem when operating a Multi-op contesting and the 80M OP was
running 1.5kw and the RF is induced into the 160M Phased inverted L array
and the combination of induced energy and the SWR reflected power on the
array kick the KAT500 back into a retune mode. So, either local energy on
Broadcast energy will both make this happen.

I now have built coaxial Stubs and look forward to seeing if this solves my
Local energy problem.

73 Bill W4RM

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Igor Sokolov
Sent: Monday, December 30, 2013 1:28 PM
To: Jeffrey Otterson; [hidden email]
Subject: Re: [Elecraft] K3/KPA500/KAT500 SWR problem

It may be not relevant to this particular case but another reason for weird
KAT500 behavior can be strong interfering signal of a neighbor or nearby
broadcasting station. I did run into situations where such signals induced
up to 5 volts into low band antenna. Then KAT500 counts that signal as
reflected and thinks that SWR is very high. One may try to connect broadband
spectrum analyzer to the antenna and see what is going on. If it is
broadcasting signal well below ham bands then high pass filter between the
tuner and antenna can help.

73, Igor UA9CDC

----- Original Message -----
From: "Jeffrey Otterson" <[hidden email]>
To: <[hidden email]>
Sent: Monday, December 30, 2013 8:58 PM
Subject: Re: [Elecraft] K3/KPA500/KAT500 SWR problem

tomb18

Re: K3/KPA500/KAT500 SWR Problem

In reply to this post by Ray Coles

Hi
Its good to hear about all of these issues. I have the same issue as the last post. I went through a new set of cables, new kat500 board, and tons of trouble shooting with Elecraft. Happens the same on two completely different antennas each with completely different feedlines.
The solution is not there yet. There is perhaps an issue with hardware updates on the kpa500. I have an early unit that is about 2years old.
I haven't yet decided if I will send it in or live with it.
In my case it happens on many bands and every time I switch to a new frequency even though the kat had already tuned there.
Tom

-------- Original message --------
From: Roy Morris <[hidden email]>
Date: 30/12/2013 14:18 (GMT-05:00)
To: [hidden email]
Subject: [Elecraft] K3/KPA500/KAT500 SWR Problem

I have also experienced the FAULT LED coming on with indication of high SWR
during a SSB transmission on 75 meters. It corrects itself if I continue
talking, but it is annoying. I have firmware 1.42 loaded in the KAT500.
Roy Morris W4WFB

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