Elecraft

[K3] Issue with HI CUR on 12m

Classic

List

Threaded

31 messages Options

Bill Coleman-2

[K3] Issue with HI CUR on 12m

Back in early December, I installed two KSYN3As in my K3 SN 7071. Sometime after that, I noticed that on 12m, I’m seeing a HI CUR indication when I set the power level to more than about 80-85 watts. The K3 will back off on the power level, then slowly ramp back up until it hits HI CUR again.

I don’t remember seeing this before. After the KSYNC3A install, I ran the transmit gain calibration at both 5 and 50 watts, as specified in the instructions. Just in case something went awry, I ran it again.

I’m still seeing this problem. What causes HI CUR at 85 watts? The K3 ought to be able to produce over 110 watts on 12m.

I’m not seeing this issue on other bands.

No issues with calibration
Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
Web: http://boringhamradiopart.blogspot.com
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901

______________________________________________________________
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]

Don Wilhelm

Re: [K3] Issue with HI CUR on 12m

Bill,

Is this into a dummy load (bypass the ATU or tune the ATU into the dummy
load).
If it is into an antenna, there are a whole lot of guesses about how the
antenna behaves with higher power levels than your antenna analyzer
shows. So check it with a dummy load to eliminate the possibility that
the problem is in the antenna.

Put an external wattmeter in line with the dummy load to eliminate
questions about the calibration on the K3 wattmeter.

If you can measure the actual current drawn, that would also be helpful.

73,
Don W3FPR

On 1/11/2020 11:18 AM, Bill Coleman wrote:
> Back in early December, I installed two KSYN3As in my K3 SN 7071. Sometime after that, I noticed that on 12m, I’m seeing a HI CUR indication when I set the power level to more than about 80-85 watts. The K3 will back off on the power level, then slowly ramp back up until it hits HI CUR again.
>
> I don’t remember seeing this before. After the KSYNC3A install, I ran the transmit gain calibration at both 5 and 50 watts, as specified in the instructions. Just in case something went awry, I ran it again.
>
> I’m still seeing this problem. What causes HI CUR at 85 watts? The K3 ought to be able to produce over 110 watts on 12m.
>
> I’m not seeing this issue on other bands.
>
> No issues with calibration
______________________________________________________________
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]

Bob McGraw - K4TAX

Re: [K3] Issue with HI CUR on 12m

In reply to this post by Bill Coleman-2

Is the power supply at 14 volts or so? And what does the radio show the voltage to be in key down transmit into a dummy load. Low voltage will demand more current to produce 100 watts.

I run my supply at 14.25 V no load and the radio shows 13.8V during 100 watts transmit. Voltage drop should be 0.5 volts or less.

Bob, K4TAX

Sent from my iPhone

> On Jan 11, 2020, at 10:31 AM, Bill Coleman <[hidden email]> wrote:
>
> Back in early December, I installed two KSYN3As in my K3 SN 7071. Sometime after that, I noticed that on 12m, I’m seeing a HI CUR indication when I set the power level to more than about 80-85 watts. The K3 will back off on the power level, then slowly ramp back up until it hits HI CUR again.
>
> I don’t remember seeing this before. After the KSYNC3A install, I ran the transmit gain calibration at both 5 and 50 watts, as specified in the instructions. Just in case something went awry, I ran it again.
>
> I’m still seeing this problem. What causes HI CUR at 85 watts? The K3 ought to be able to produce over 110 watts on 12m.
>
> I’m not seeing this issue on other bands.
>
> No issues with calibration
> Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
> Web: http://boringhamradiopart.blogspot.com
> Quote: "Not within a thousand years will man ever fly!"
> -- Wilbur Wright, 1901
>
> ______________________________________________________________
> 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]

Nr4c

Re: [K3] Issue with HI CUR on 12m

Check antenna.

Also, check into dummy load and report back.

Sent from my iPhone
...nr4c. bill

> On Jan 11, 2020, at 11:45 AM, Bob McGraw K4TAX <[hidden email]> wrote:
>
> Is the power supply at 14 volts or so? And what does the radio show the voltage to be in key down transmit into a dummy load. Low voltage will demand more current to produce 100 watts.
>
> I run my supply at 14.25 V no load and the radio shows 13.8V during 100 watts transmit. Voltage drop should be 0.5 volts or less.
>
> Bob, K4TAX
>
>
> Sent from my iPhone
>
>> On Jan 11, 2020, at 10:31 AM, Bill Coleman <[hidden email]> wrote:
>>
>> Back in early December, I installed two KSYN3As in my K3 SN 7071. Sometime after that, I noticed that on 12m, I’m seeing a HI CUR indication when I set the power level to more than about 80-85 watts. The K3 will back off on the power level, then slowly ramp back up until it hits HI CUR again.
>>
>> I don’t remember seeing this before. After the KSYNC3A install, I ran the transmit gain calibration at both 5 and 50 watts, as specified in the instructions. Just in case something went awry, I ran it again.
>>
>> I’m still seeing this problem. What causes HI CUR at 85 watts? The K3 ought to be able to produce over 110 watts on 12m.
>>
>> I’m not seeing this issue on other bands.
>>
>> No issues with calibration
>> Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
>> Web: http://boringhamradiopart.blogspot.com
>> Quote: "Not within a thousand years will man ever fly!"
>> -- Wilbur Wright, 1901
>>
>> ______________________________________________________________
>> 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]

Bill Coleman-2

Re: [K3] Issue with HI CUR on 12m

In reply to this post by Bob McGraw - K4TAX

I checked this. Voltage was 13.8 volts no load, dropped about a volt under load.

I cranked it up to 14.4 volts no load, and it’s better, but still getting HI CUR indication above 90 watts.

> On Jan 11, 2020, at 11:43 AM, Bob McGraw K4TAX <[hidden email]> wrote:
>
> Is the power supply at 14 volts or so? And what does the radio show the voltage to be in key down transmit into a dummy load. Low voltage will demand more current to produce 100 watts.
>
> I run my supply at 14.25 V no load and the radio shows 13.8V during 100 watts transmit. Voltage drop should be 0.5 volts or less.
>
> Bob, K4TAX
>
>
> Sent from my iPhone
>
>> On Jan 11, 2020, at 10:31 AM, Bill Coleman <[hidden email]> wrote:
>>
>> Back in early December, I installed two KSYN3As in my K3 SN 7071. Sometime after that, I noticed that on 12m, I’m seeing a HI CUR indication when I set the power level to more than about 80-85 watts. The K3 will back off on the power level, then slowly ramp back up until it hits HI CUR again.
>>
>> I don’t remember seeing this before. After the KSYNC3A install, I ran the transmit gain calibration at both 5 and 50 watts, as specified in the instructions. Just in case something went awry, I ran it again.
>>
>> I’m still seeing this problem. What causes HI CUR at 85 watts? The K3 ought to be able to produce over 110 watts on 12m.
>>
>> I’m not seeing this issue on other bands.
>>
>> No issues with calibration
>> Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
>> Web: http://boringhamradiopart.blogspot.com
>> Quote: "Not within a thousand years will man ever fly!"
>> -- Wilbur Wright, 1901
>>
>> ______________________________________________________________
>> 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]
>
>

Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
Web: http://boringhamradiopart.blogspot.com
Quote: "Not within a thousand years will man ever fly!"
-- Wilbur Wright, 1901

______________________________________________________________
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]

Bill Coleman-2

Re: [K3] Issue with HI CUR on 12m

Curious. I’m doing a lot of antenna work right now. I had to remove my 12/17/30m trap inverted V to get my beam off the tower.

In the meantime, I’m making due with a 20/40/80m trap dipole.

If I use 12m on the 20/40/80m dipole using a tuner, I’m not having any HI CUR issues, even when running 100 watts.

I think what I’m seeing is an RF in the shack issue. The 20/40/80m antenna feed point is about 70 feet further away than the old 12/17/30m antenna.

> On Sep 5, 2020, at 10:41 PM, Bob McGraw K4TAX <[hidden email]> wrote:
>
> I suggest you perform a TX Gain calibration using the K3 Utility. A known accurate dummy load is all that is required.
>
> I’d say that a 1 volt drop is excessive. Check power cable connectors. Also add a dedicated ground conductor between the ground terminal on the radio and power supply ground terminal.
>
> The displayed voltage on the radio should be about 0.5 volt difference between RX and TX, CW mode key closed. These measurements should be made using a dummy load.
>
> 73
> Bob, K4TAX
>
>
> Sent from my iPhone
>
>> On Sep 5, 2020, at 7:15 PM, Bill Coleman <[hidden email]> wrote:
>>
>> I checked this. Voltage was 13.8 volts no load, dropped about a volt under load.
>>
>> I cranked it up to 14.4 volts no load, and it’s better, but still getting HI CUR indication above 90 watts.
>>
>>> On Jan 11, 2020, at 11:43 AM, Bob McGraw K4TAX <[hidden email]> wrote:
>>>
>>> Is the power supply at 14 volts or so? And what does the radio show the voltage to be in key down transmit into a dummy load. Low voltage will demand more current to produce 100 watts.
>>>
>>> I run my supply at 14.25 V no load and the radio shows 13.8V during 100 watts transmit. Voltage drop should be 0.5 volts or less.
>>>
>>> Bob, K4TAX
>>>
>>>
>>> Sent from my iPhone
>>>
>>>>> On Jan 11, 2020, at 10:31 AM, Bill Coleman <[hidden email]> wrote:
>>>>
>>>> Back in early December, I installed two KSYN3As in my K3 SN 7071. Sometime after that, I noticed that on 12m, I’m seeing a HI CUR indication when I set the power level to more than about 80-85 watts. The K3 will back off on the power level, then slowly ramp back up until it hits HI CUR again.
>>>>
>>>> I don’t remember seeing this before. After the KSYNC3A install, I ran the transmit gain calibration at both 5 and 50 watts, as specified in the instructions. Just in case something went awry, I ran it again.
>>>>
>>>> I’m still seeing this problem. What causes HI CUR at 85 watts? The K3 ought to be able to produce over 110 watts on 12m.
>>>>
>>>> I’m not seeing this issue on other bands.
>>>>
>>>> No issues with calibration
>>>> Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
>>>> Web: http://boringhamradiopart.blogspot.com
>>>> Quote: "Not within a thousand years will man ever fly!"
>>>> -- Wilbur Wright, 1901
>>>>
>>>> ______________________________________________________________
>>>> 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]
>>>
>>>
>>
>> Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
>> Web: http://boringhamradiopart.blogspot.com
>> Quote: "Not within a thousand years will man ever fly!"
>> -- Wilbur Wright, 1901
>>
>>
>
>

Bill Coleman-2

Re: [K3] Issue with HI CUR on 12m

In reply to this post by Don Wilhelm

Don,

I finally got around to running my K3 into a dummy load.

I had no problem running 100w or even 110w with a dummy load. Current draw from the power supply was 22 A and 23 A, respectively, on the K3 display. No HI CUR indications.

External wattmeter validates the output.

I was getting the HI CUR indication on a trap 30/17/12m inverted V. I had to take it down, and now I’m using a trap 80/40/20m dipole through the tuner. No HI CUR indication on that antenna, either.

Even though I have current baluns on both antennas, I’m thinking that my HI CUR problem may be related to RF feedback in the shack.

Do you concur?

I’m in the process of a number of shack improvements, including antenna replacements and grounding and bonding, so that might take care of it.

> On Jan 11, 2020, at 11:29 AM, Don Wilhelm <[hidden email]> wrote:
>
> Bill,
>
> Is this into a dummy load (bypass the ATU or tune the ATU into the dummy load).
> If it is into an antenna, there are a whole lot of guesses about how the antenna behaves with higher power levels than your antenna analyzer shows. So check it with a dummy load to eliminate the possibility that the problem is in the antenna.
>
> Put an external wattmeter in line with the dummy load to eliminate questions about the calibration on the K3 wattmeter.
>
> If you can measure the actual current drawn, that would also be helpful.
>
> 73,
> Don W3FPR
>
> On 1/11/2020 11:18 AM, Bill Coleman wrote:
>> Back in early December, I installed two KSYN3As in my K3 SN 7071. Sometime after that, I noticed that on 12m, I’m seeing a HI CUR indication when I set the power level to more than about 80-85 watts. The K3 will back off on the power level, then slowly ramp back up until it hits HI CUR again.
>> I don’t remember seeing this before. After the KSYNC3A install, I ran the transmit gain calibration at both 5 and 50 watts, as specified in the instructions. Just in case something went awry, I ran it again.
>> I’m still seeing this problem. What causes HI CUR at 85 watts? The K3 ought to be able to produce over 110 watts on 12m.
>> I’m not seeing this issue on other bands.
>> No issues with calibration

Robin Szemeti

Re: [K3] Issue with HI CUR on 12m

Antenna feed impedance under 50R? Take some measurements with a cheap VNA

On Mon, 12 Oct 2020 at 01:55, Bill Coleman <[hidden email]> wrote:

> Don,
>
> I finally got around to running my K3 into a dummy load.
>
> I had no problem running 100w or even 110w with a dummy load. Current draw
> from the power supply was 22 A and 23 A, respectively, on the K3 display.
> No HI CUR indications.
>
> External wattmeter validates the output.
>
> I was getting the HI CUR indication on a trap 30/17/12m inverted V. I had
> to take it down, and now I’m using a trap 80/40/20m dipole through the
> tuner. No HI CUR indication on that antenna, either.
>
> Even though I have current baluns on both antennas, I’m thinking that my
> HI CUR problem may be related to RF feedback in the shack.
>
> Do you concur?
>
> I’m in the process of a number of shack improvements, including antenna
> replacements and grounding and bonding, so that might take care of it.
>
> > On Jan 11, 2020, at 11:29 AM, Don Wilhelm <[hidden email]>
> wrote:
> >
> > Bill,
> >
> > Is this into a dummy load (bypass the ATU or tune the ATU into the dummy
> load).
> > If it is into an antenna, there are a whole lot of guesses about how the
> antenna behaves with higher power levels than your antenna analyzer shows.
> So check it with a dummy load to eliminate the possibility that the problem
> is in the antenna.
> >
> > Put an external wattmeter in line with the dummy load to eliminate
> questions about the calibration on the K3 wattmeter.
> >
> > If you can measure the actual current drawn, that would also be helpful.
> >
> > 73,
> > Don W3FPR
> >
> > On 1/11/2020 11:18 AM, Bill Coleman wrote:
> >> Back in early December, I installed two KSYN3As in my K3 SN 7071.
> Sometime after that, I noticed that on 12m, I’m seeing a HI CUR indication
> when I set the power level to more than about 80-85 watts. The K3 will back
> off on the power level, then slowly ramp back up until it hits HI CUR again.
> >> I don’t remember seeing this before. After the KSYNC3A install, I ran
> the transmit gain calibration at both 5 and 50 watts, as specified in the
> instructions. Just in case something went awry, I ran it again.
> >> I’m still seeing this problem. What causes HI CUR at 85 watts? The K3
> ought to be able to produce over 110 watts on 12m.
> >> I’m not seeing this issue on other bands.
> >> No issues with calibration
>
> Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
> Web: http://boringhamradiopart.blogspot.com
> Quote: "Not within a thousand years will man ever fly!"
> -- Wilbur Wright, 1901
>
> ______________________________________________________________
> 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]

Don Wilhelm

Re: [K3] Issue with HI CUR on 12m

In reply to this post by Bill Coleman-2

Bill,

I would suggest that you check the SWR on the antenna before concluding
it is an RF feedback problem.
Don't forget that the balun may be breaking down with power and show no
problem at lower power (like from an antenna analyzer).

Don W3FPR

On 10/11/2020 8:53 PM, Bill Coleman wrote:

> Don,
>
> I finally got around to running my K3 into a dummy load.
>
> I had no problem running 100w or even 110w with a dummy load. Current draw from the power supply was 22 A and 23 A, respectively, on the K3 display. No HI CUR indications.
>
> External wattmeter validates the output.
>
> I was getting the HI CUR indication on a trap 30/17/12m inverted V. I had to take it down, and now I’m using a trap 80/40/20m dipole through the tuner. No HI CUR indication on that antenna, either.
>
> Even though I have current baluns on both antennas, I’m thinking that my HI CUR problem may be related to RF feedback in the shack.
>
> Do you concur?
>
> I’m in the process of a number of shack improvements, including antenna replacements and grounding and bonding, so that might take care of it.
>
>> On Jan 11, 2020, at 11:29 AM, Don Wilhelm <[hidden email]> wrote:
>>
>> Bill,
>>
>> Is this into a dummy load (bypass the ATU or tune the ATU into the dummy load).
>> If it is into an antenna, there are a whole lot of guesses about how the antenna behaves with higher power levels than your antenna analyzer shows. So check it with a dummy load to eliminate the possibility that the problem is in the antenna.
>>
>> Put an external wattmeter in line with the dummy load to eliminate questions about the calibration on the K3 wattmeter.
>>
>> If you can measure the actual current drawn, that would also be helpful.
>>
>> 73,
>> Don W3FPR
>>
>> On 1/11/2020 11:18 AM, Bill Coleman wrote:
>>> Back in early December, I installed two KSYN3As in my K3 SN 7071. Sometime after that, I noticed that on 12m, I’m seeing a HI CUR indication when I set the power level to more than about 80-85 watts. The K3 will back off on the power level, then slowly ramp back up until it hits HI CUR again.
>>> I don’t remember seeing this before. After the KSYNC3A install, I ran the transmit gain calibration at both 5 and 50 watts, as specified in the instructions. Just in case something went awry, I ran it again.
>>> I’m still seeing this problem. What causes HI CUR at 85 watts? The K3 ought to be able to produce over 110 watts on 12m.
>>> I’m not seeing this issue on other bands.
>>> No issues with calibration
> Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
> Web: http://boringhamradiopart.blogspot.com
> Quote: "Not within a thousand years will man ever fly!"
> -- Wilbur Wright, 1901
>

Bill Coleman-2

Re: [K3] Issue with HI CUR on 12m

SWR on the problem antenna is below 1.2:1. It’s a trap dipole - designed for that band.

It is unlikely the balun is “breaking down”. It’s a current balun - #43 ferrite beads on RG-313 coax. It can easily handle a kW or more.

> On Oct 12, 2020, at 2:12 AM, Don Wilhelm <[hidden email]> wrote:
>
> Bill,
>
> I would suggest that you check the SWR on the antenna before concluding it is an RF feedback problem.
> Don't forget that the balun may be breaking down with power and show no problem at lower power (like from an antenna analyzer).
>
> Don W3FPR
>
> On 10/11/2020 8:53 PM, Bill Coleman wrote:
>> Don,
>>
>> I finally got around to running my K3 into a dummy load.
>>
>> I had no problem running 100w or even 110w with a dummy load. Current draw from the power supply was 22 A and 23 A, respectively, on the K3 display. No HI CUR indications.
>>
>> External wattmeter validates the output.
>>
>> I was getting the HI CUR indication on a trap 30/17/12m inverted V. I had to take it down, and now I’m using a trap 80/40/20m dipole through the tuner. No HI CUR indication on that antenna, either.
>>
>> Even though I have current baluns on both antennas, I’m thinking that my HI CUR problem may be related to RF feedback in the shack.
>>
>> Do you concur?
>>
>> I’m in the process of a number of shack improvements, including antenna replacements and grounding and bonding, so that might take care of it.
>>
>>> On Jan 11, 2020, at 11:29 AM, Don Wilhelm <[hidden email]> wrote:
>>>
>>> Bill,
>>>
>>> Is this into a dummy load (bypass the ATU or tune the ATU into the dummy load).
>>> If it is into an antenna, there are a whole lot of guesses about how the antenna behaves with higher power levels than your antenna analyzer shows. So check it with a dummy load to eliminate the possibility that the problem is in the antenna.
>>>
>>> Put an external wattmeter in line with the dummy load to eliminate questions about the calibration on the K3 wattmeter.
>>>
>>> If you can measure the actual current drawn, that would also be helpful.
>>>
>>> 73,
>>> Don W3FPR
>>>
>>> On 1/11/2020 11:18 AM, Bill Coleman wrote:
>>>> Back in early December, I installed two KSYN3As in my K3 SN 7071. Sometime after that, I noticed that on 12m, I’m seeing a HI CUR indication when I set the power level to more than about 80-85 watts. The K3 will back off on the power level, then slowly ramp back up until it hits HI CUR again.
>>>> I don’t remember seeing this before. After the KSYNC3A install, I ran the transmit gain calibration at both 5 and 50 watts, as specified in the instructions. Just in case something went awry, I ran it again.
>>>> I’m still seeing this problem. What causes HI CUR at 85 watts? The K3 ought to be able to produce over 110 watts on 12m.
>>>> I’m not seeing this issue on other bands.
>>>> No issues with calibration
>> Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
>> Web: http://boringhamradiopart.blogspot.com
>> Quote: "Not within a thousand years will man ever fly!"
>> -- Wilbur Wright, 1901
>>
>

Robin Szemeti

Re: [K3] Issue with HI CUR on 12m

But remember, there are two basic loading conditions that will give a SWR
of 1.2:1 ...

60R+J0 will give 1.2:1 and pull a current lower than a perfect match ...

42R+J0 will give 1.2:1 and pull a current greater than a perfect match ...

(and of course all the reactive permutations around the load circle) ...

On Tue, 13 Oct 2020 at 01:56, Bill Coleman <[hidden email]> wrote:

> SWR on the problem antenna is below 1.2:1. It’s a trap dipole - designed
> for that band.
>
> It is unlikely the balun is “breaking down”. It’s a current balun - #43
> ferrite beads on RG-313 coax. It can easily handle a kW or more.
>
> > On Oct 12, 2020, at 2:12 AM, Don Wilhelm <[hidden email]> wrote:
> >
> > Bill,
> >
> > I would suggest that you check the SWR on the antenna before concluding
> it is an RF feedback problem.
> > Don't forget that the balun may be breaking down with power and show no
> problem at lower power (like from an antenna analyzer).
> >
> > Don W3FPR
> >
> > On 10/11/2020 8:53 PM, Bill Coleman wrote:
> >> Don,
> >>
> >> I finally got around to running my K3 into a dummy load.
> >>
> >> I had no problem running 100w or even 110w with a dummy load. Current
> draw from the power supply was 22 A and 23 A, respectively, on the K3
> display. No HI CUR indications.
> >>
> >> External wattmeter validates the output.
> >>
> >> I was getting the HI CUR indication on a trap 30/17/12m inverted V. I
> had to take it down, and now I’m using a trap 80/40/20m dipole through the
> tuner. No HI CUR indication on that antenna, either.
> >>
> >> Even though I have current baluns on both antennas, I’m thinking that
> my HI CUR problem may be related to RF feedback in the shack.
> >>
> >> Do you concur?
> >>
> >> I’m in the process of a number of shack improvements, including antenna
> replacements and grounding and bonding, so that might take care of it.
> >>
> >>> On Jan 11, 2020, at 11:29 AM, Don Wilhelm <[hidden email]>
> wrote:
> >>>
> >>> Bill,
> >>>
> >>> Is this into a dummy load (bypass the ATU or tune the ATU into the
> dummy load).
> >>> If it is into an antenna, there are a whole lot of guesses about how
> the antenna behaves with higher power levels than your antenna analyzer
> shows. So check it with a dummy load to eliminate the possibility that the
> problem is in the antenna.
> >>>
> >>> Put an external wattmeter in line with the dummy load to eliminate
> questions about the calibration on the K3 wattmeter.
> >>>
> >>> If you can measure the actual current drawn, that would also be
> helpful.
> >>>
> >>> 73,
> >>> Don W3FPR
> >>>
> >>> On 1/11/2020 11:18 AM, Bill Coleman wrote:
> >>>> Back in early December, I installed two KSYN3As in my K3 SN 7071.
> Sometime after that, I noticed that on 12m, I’m seeing a HI CUR indication
> when I set the power level to more than about 80-85 watts. The K3 will back
> off on the power level, then slowly ramp back up until it hits HI CUR again.
> >>>> I don’t remember seeing this before. After the KSYNC3A install, I ran
> the transmit gain calibration at both 5 and 50 watts, as specified in the
> instructions. Just in case something went awry, I ran it again.
> >>>> I’m still seeing this problem. What causes HI CUR at 85 watts? The K3
> ought to be able to produce over 110 watts on 12m.
> >>>> I’m not seeing this issue on other bands.
> >>>> No issues with calibration
> >> Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
> >> Web: http://boringhamradiopart.blogspot.com
> >> Quote: "Not within a thousand years will man ever fly!"
> >> -- Wilbur Wright, 1901
> >>
> >
>
> Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
> Web: http://boringhamradiopart.blogspot.com
> Quote: "Not within a thousand years will man ever fly!"
> -- Wilbur Wright, 1901
>
> ______________________________________________________________
> 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]

Jim Brown-10

Re: [K3] Issue with HI CUR on 12m

In reply to this post by Bill Coleman-2

On 10/12/2020 5:55 PM, Bill Coleman wrote:
> It is unlikely the balun is “breaking down”. It’s a current balun - #43 ferrite beads on RG-313 coax. It can easily handle a kW or more.
That's a common mode choke, and #43 is a terrible material for the HF
bands. See my "cookbook" at k9yc.com/publish.htm as well as the Ham's
RFI tutorial, which explains things conceptually.

"handle a kW," perhaps, but only because it's also unlikely to be doing
anything useful. :)

73, Jim K9YC
______________________________________________________________
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]

Alan - G4GNX

Re: [K3] Issue with HI CUR on 12m

In reply to this post by Bill Coleman-2

This happened to me on a multi-band antenna, with SWR changing, but no
Hi Cur warning.

I would be transmitting for months, using only 100W with no issues. I
added in a KPA500/KAT500 combination and apart from a short test at
400W, I continued to use it at 200W (SSB) max.
After a month or so, the SWR would change - mid QSO. A quick retune and
I was able to continue. Over a few weeks the occurrence was more
frequent. Using a Rig Expert analyser, no fault or bad SWR was indicated
and I (wrongly) guessed that the 400W Guanella balun was breaking down
at power over 100W. In the meantime I ordered a new 1KW balun made for
that antenna, but before it arrived, during a QSO there was a
catastrophic "occurrence" with all kinds of warnings and the SWR was off
the scale.

A check with a multimeter indicated a dead short somewhere in the
feedline (RG58). I also took the balun apart and found no fault. As I'd
ordered a new balun, I decided to change it anyway. I don't have the
power to exceed the new balun's spec, so it should last forever - RF
wise. ;-)

Obviously I replaced the co-ax feeder - I now use Westflex 103 with much
larger ferrites (to fit the new cable size) as a common mode choke. All
now works as it should and shows no sign of breakdown, even at 400W (max
legal for the UK).

The old co-ax is a different matter. With both ends disconnected (open)
connecting one end to the analyser showed a short circuit about 15 feet
along its length. I cut out a section either side and the remaining two
pieces showed 'open' as they should. On visual inspection I find that
the braid of the co-ax has migrated through the center insulation and is
touching the inner conductor, indicating that a fair amount of heat has
been generated. The area in question was right where the common mode
ferrites had been fitted, although there were no tell-tale marks on the
ferrites or the outer casing of the co-ax. It's fairly obvious that a
high voltage node has caused an internal flashover which in turn has
changed the characteristic which has resulted in a high current node
which has generated the heat.

You may well be right that your balun is not faulty, but you should
check it anyway as well as checking out all the other aspects of the
installation. If you can, replace the feeder. You may be surprised at
what you find.

73,

Alan. G4GNX

------ Original Message ------
From: "Bill Coleman" <[hidden email]>
To: "Don Wilhelm" <[hidden email]>
Cc: "Elecraft" <[hidden email]>
Sent: 13/10/2020 01:55:16
Subject: Re: [Elecraft] [K3] Issue with HI CUR on 12m

>SWR on the problem antenna is below 1.2:1. It’s a trap dipole - designed for that band.
>
>It is unlikely the balun is “breaking down”. It’s a current balun - #43 ferrite beads on RG-313 coax. It can easily handle a kW or more.
>
>> On Oct 12, 2020, at 2:12 AM, Don Wilhelm <[hidden email]> wrote:
>>
>> Bill,
>>
>> I would suggest that you check the SWR on the antenna before concluding it is an RF feedback problem.
>> Don't forget that the balun may be breaking down with power and show no problem at lower power (like from an antenna analyzer).
>>
>> Don W3FPR
>>
>> On 10/11/2020 8:53 PM, Bill Coleman wrote:
>>> Don,
>>>
>>> I finally got around to running my K3 into a dummy load.
>>>
>>> I had no problem running 100w or even 110w with a dummy load. Current draw from the power supply was 22 A and 23 A, respectively, on the K3 display. No HI CUR indications.
>>>
>>> External wattmeter validates the output.
>>>
>>> I was getting the HI CUR indication on a trap 30/17/12m inverted V. I had to take it down, and now I’m using a trap 80/40/20m dipole through the tuner. No HI CUR indication on that antenna, either.
>>>
>>> Even though I have current baluns on both antennas, I’m thinking that my HI CUR problem may be related to RF feedback in the shack.
>>>
>>> Do you concur?
>>>
>>> I’m in the process of a number of shack improvements, including antenna replacements and grounding and bonding, so that might take care of it.
>>>
>>>> On Jan 11, 2020, at 11:29 AM, Don Wilhelm <[hidden email]> wrote:
>>>>
>>>> Bill,
>>>>
>>>> Is this into a dummy load (bypass the ATU or tune the ATU into the dummy load).
>>>> If it is into an antenna, there are a whole lot of guesses about how the antenna behaves with higher power levels than your antenna analyzer shows. So check it with a dummy load to eliminate the possibility that the problem is in the antenna.
>>>>
>>>> Put an external wattmeter in line with the dummy load to eliminate questions about the calibration on the K3 wattmeter.
>>>>
>>>> If you can measure the actual current drawn, that would also be helpful.
>>>>
>>>> 73,
>>>> Don W3FPR
>>>>
>>>> On 1/11/2020 11:18 AM, Bill Coleman wrote:
>>>>> Back in early December, I installed two KSYN3As in my K3 SN 7071. Sometime after that, I noticed that on 12m, I’m seeing a HI CUR indication when I set the power level to more than about 80-85 watts. The K3 will back off on the power level, then slowly ramp back up until it hits HI CUR again.
>>>>> I don’t remember seeing this before. After the KSYNC3A install, I ran the transmit gain calibration at both 5 and 50 watts, as specified in the instructions. Just in case something went awry, I ran it again.
>>>>> I’m still seeing this problem. What causes HI CUR at 85 watts? The K3 ought to be able to produce over 110 watts on 12m.
>>>>> I’m not seeing this issue on other bands.
>>>>> No issues with calibration
>>> Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
>>> Web: http://boringhamradiopart.blogspot.com
>>> Quote: "Not within a thousand years will man ever fly!"
>>> -- Wilbur Wright, 1901
>>>
>>
>
>Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
>Web: http://boringhamradiopart.blogspot.com
>Quote: "Not within a thousand years will man ever fly!"
> -- Wilbur Wright, 1901
>
>______________________________________________________________
>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]

John Oppenheimer

Re: [K3] Issue with HI CUR on 12m

In reply to this post by Jim Brown-10

Hi Jim,

For high power Balun Applications, most critical parameter is Ferrite
core loss which causes core heating. Core loss, parallel resistance
(Rp), can be computed from complex permeability data from Fair-Rite.

https://www.kn5l.net/Balun-CM/Balun31-43/
Models FT240 10T with 31 and 43 materials. G.Zo is selected to indicate
maximum possible core dissipation watts. Maximum core dissipation
accrues when ground to antenna external conductor electrical length =
1/2 wavelength multiples. 1/2 wavelength multiples reflects ground
impedance to the Balun.

As shown, at 1.8MHz, maximum core dissipation for 1kW key down could be
4W for 31 material and 3.6W for #43 material. Probably not enough
difference to worry about.

The two CMRR traces, red and yellow, are below about -20dB. Difference
in choking ability is insignificant in this range.

The model includes a parallel capacitor for self resonance. Though is
not critical, as reactance does not result in heating. Core loss, Rp,
causes core heat rise.

All in all, not much difference between 43 and 31 for these two Baluns.

John KN5L

On 10/12/20 9:05 PM, Jim Brown wrote:
> #43 is a terrible material for the HF
> bands.
______________________________________________________________
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]

Jim Brown-10

Re: [K3] Issue with HI CUR on 12m

On 10/13/2020 8:12 AM, John Oppenheimer wrote:
> Hi Jim,
>
> For high power Balun Applications, most critical parameter is Ferrite
> core loss which causes core heating. Core loss, parallel resistance
> (Rp), can be computed from complex permeability data from Fair-Rite.

Hi John,

While I respect your engineering chops, you clearly don't understand how
ferrite common mode chokes work. They DEPEND on the loss component
coupled from the ferrite core, which has a broad peak around resonance
of the winding. Fair-Rite's #31 material is MnZn, which exhibits two
resonances. One is formed by the inductance of the winding and the
capacitance between turns; the second is a dimensional resonance that
results from standing waves within the core. #43 material is NiZn; these
materials do NOT exhibit dimensional resonance, because loss is low at
the frequencies where it would occur.

At HF, the two resonances in multi-turn chokes on #31 cores combine to
provide a much broader resonance, comparable to what happened in
stagger-tuned IFs. This has two implications. First, the broader
resonance allows the choke to cover more bands.

Second, and more important, ferrite cores have wide manufacturing
tolerances that cause the resonances to shift in frequency. The broader
impedance curve formed by chokes on #31 material allows a designer to
specify chokes that will work within a specified frequency range with
that tolerance variation; it is NOT possible with the much narrower
impedance curve of chokes wound on #43 or #52 material.

My "choke cookbook" is the result of first characterizing nearly 200 #31
cores of a given size, selecting cores at the tolerance limits for each
size, winding and measuring more than a thousand chokes on these
"limits" cores. The cookbook is based on chokes working with all of
those "limits" cores.

After seeing recommendations from a ham in the UK for #52 material, I
bought 40 of these cores over a period of about four weeks, splitting
the order between four franchised vendors (that is, ten from each
vendor). I characterized those cores, selected cores at limits, and
wound chokes using that ham's recommendations. I could not reproduce his
results -- the tolerance variation moved their resonance away from their
intended operating range.

I learned about dimensional resonance from a classic engineering book on
ferrite applications by E. C. Snelling that a colleague found for me in
the engineering library of the U of Chicago, where he was on faculty.
Snelling's work is considered "the bible" by engineers working in mfg
and application of ferrites. It's reference 7 in the AES paper, and is
also referenced in the tutorial.

These concepts are discussed in detail in an AES paper from 2005 and in
a tutorial I wrote for hams in 2007, the latter updated several times
over the years.

http://k9yc.com/AESPaperFerritesASGWeb.pdf
http://k9yc.com/RFI-Ham.pdf

The "cookbook" is here. http://k9yc.com/2018Cookbook.pdf

73, Jim K9YC
______________________________________________________________
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]

John Oppenheimer

Re: [K3] Issue with HI CUR on 12m

Jim, can you be more specific with flaws within the SimSmith model?

I've updated https://www.kn5l.net/Balun-CM/Balun31-43/ with Balun CMRR
window image. So that others don't need to load SimSmith and model from
the ZIP file link.

John KN5L

On 10/13/20 12:45 PM, Jim Brown wrote:
> you clearly don't understand how
> ferrite common mode chokes work.
______________________________________________________________
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]

Jim Brown-10

Re: [K3] Issue with HI CUR on 12m

On 10/13/2020 11:41 AM, John Oppenheimer wrote:
> Jim, can you be more specific with flaws within the SimSmith model?

John, I suggest that you study my email and the references I cited. Also
study the early pages in the Fair-Rite catalog, one devoted to each
material, showing plots of mu' and mu'' vs frequency.

73, Jim K9YC
______________________________________________________________
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]

John Oppenheimer

Re: [K3] Issue with HI CUR on 12m

Hi Jim,

The SimSmith model includes Fair-Rite complex permeability files, which
is the basis of the Ferrite model.

John KN5L

On 10/13/20 2:23 PM, Jim Brown wrote:
> On 10/13/2020 11:41 AM, John Oppenheimer wrote:
>> Jim, can you be more specific with flaws within the SimSmith model?
>
> John, I suggest that you study my email and the references I cited. Also
> study the early pages in the Fair-Rite catalog, one devoted to each
> material, showing plots of mu' and mu'' vs frequency.
>
> 73, Jim K9YC
______________________________________________________________
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]

Bill Coleman-2

Re: [K3] Issue with HI CUR on 12m

In reply to this post by Jim Brown-10

While it may not be a “perfect” material, it was what I had on hand, and I measured over 800 ohms choking impedance on the band of interest.

It’s definitely doing something useful.

I have your cookbook, and will use it for future projects.

> On Oct 12, 2020, at 10:05 PM, Jim Brown <[hidden email]> wrote:
>
> On 10/12/2020 5:55 PM, Bill Coleman wrote:
>> It is unlikely the balun is “breaking down”. It’s a current balun - #43 ferrite beads on RG-313 coax. It can easily handle a kW or more.
> That's a common mode choke, and #43 is a terrible material for the HF bands. See my "cookbook" at k9yc.com/publish.htm as well as the Ham's RFI tutorial, which explains things conceptually.
>
> "handle a kW," perhaps, but only because it's also unlikely to be doing anything useful. :)
>
> 73, Jim K9YC
> ______________________________________________________________
> 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]

Bill Coleman-2

Re: [K3] Issue with HI CUR on 12m

In reply to this post by Alan - G4GNX

I was not seeing any SWR shifts on this antenna. A check with an ohmmeter shows no shorts.

This antenna is currently on the ground due to other work on the tower. I’m considering replacing the antenna entirely. It’s been up over 10 years, and the traps could use re-work.

> On Oct 13, 2020, at 10:47 AM, Alan - G4GNX <[hidden email]> wrote:
>
> This happened to me on a multi-band antenna, with SWR changing, but no Hi Cur warning.
>
> I would be transmitting for months, using only 100W with no issues. I added in a KPA500/KAT500 combination and apart from a short test at 400W, I continued to use it at 200W (SSB) max.
> After a month or so, the SWR would change - mid QSO. A quick retune and I was able to continue. Over a few weeks the occurrence was more frequent. Using a Rig Expert analyser, no fault or bad SWR was indicated and I (wrongly) guessed that the 400W Guanella balun was breaking down at power over 100W. In the meantime I ordered a new 1KW balun made for that antenna, but before it arrived, during a QSO there was a catastrophic "occurrence" with all kinds of warnings and the SWR was off the scale.
>
> A check with a multimeter indicated a dead short somewhere in the feedline (RG58). I also took the balun apart and found no fault. As I'd ordered a new balun, I decided to change it anyway. I don't have the power to exceed the new balun's spec, so it should last forever - RF wise. ;-)
>
> Obviously I replaced the co-ax feeder - I now use Westflex 103 with much larger ferrites (to fit the new cable size) as a common mode choke. All now works as it should and shows no sign of breakdown, even at 400W (max legal for the UK).
>
> The old co-ax is a different matter. With both ends disconnected (open) connecting one end to the analyser showed a short circuit about 15 feet along its length. I cut out a section either side and the remaining two pieces showed 'open' as they should. On visual inspection I find that the braid of the co-ax has migrated through the center insulation and is touching the inner conductor, indicating that a fair amount of heat has been generated. The area in question was right where the common mode ferrites had been fitted, although there were no tell-tale marks on the ferrites or the outer casing of the co-ax. It's fairly obvious that a high voltage node has caused an internal flashover which in turn has changed the characteristic which has resulted in a high current node which has generated the heat.
>
> You may well be right that your balun is not faulty, but you should check it anyway as well as checking out all the other aspects of the installation. If you can, replace the feeder. You may be surprised at what you find.
>
> 73,
>
> Alan. G4GNX
>
>
> ------ Original Message ------
> From: "Bill Coleman" <[hidden email]>
> To: "Don Wilhelm" <[hidden email]>
> Cc: "Elecraft" <[hidden email]>
> Sent: 13/10/2020 01:55:16
> Subject: Re: [Elecraft] [K3] Issue with HI CUR on 12m
>
>> SWR on the problem antenna is below 1.2:1. It’s a trap dipole - designed for that band.
>>
>> It is unlikely the balun is “breaking down”. It’s a current balun - #43 ferrite beads on RG-313 coax. It can easily handle a kW or more.
>>
>>> On Oct 12, 2020, at 2:12 AM, Don Wilhelm <[hidden email]> wrote:
>>>
>>> Bill,
>>>
>>> I would suggest that you check the SWR on the antenna before concluding it is an RF feedback problem.
>>> Don't forget that the balun may be breaking down with power and show no problem at lower power (like from an antenna analyzer).
>>>
>>> Don W3FPR
>>>
>>> On 10/11/2020 8:53 PM, Bill Coleman wrote:
>>>> Don,
>>>>
>>>> I finally got around to running my K3 into a dummy load.
>>>>
>>>> I had no problem running 100w or even 110w with a dummy load. Current draw from the power supply was 22 A and 23 A, respectively, on the K3 display. No HI CUR indications.
>>>>
>>>> External wattmeter validates the output.
>>>>
>>>> I was getting the HI CUR indication on a trap 30/17/12m inverted V. I had to take it down, and now I’m using a trap 80/40/20m dipole through the tuner. No HI CUR indication on that antenna, either.
>>>>
>>>> Even though I have current baluns on both antennas, I’m thinking that my HI CUR problem may be related to RF feedback in the shack.
>>>>
>>>> Do you concur?
>>>>
>>>> I’m in the process of a number of shack improvements, including antenna replacements and grounding and bonding, so that might take care of it.
>>>>
>>>>> On Jan 11, 2020, at 11:29 AM, Don Wilhelm <[hidden email]> wrote:
>>>>>
>>>>> Bill,
>>>>>
>>>>> Is this into a dummy load (bypass the ATU or tune the ATU into the dummy load).
>>>>> If it is into an antenna, there are a whole lot of guesses about how the antenna behaves with higher power levels than your antenna analyzer shows. So check it with a dummy load to eliminate the possibility that the problem is in the antenna.
>>>>>
>>>>> Put an external wattmeter in line with the dummy load to eliminate questions about the calibration on the K3 wattmeter.
>>>>>
>>>>> If you can measure the actual current drawn, that would also be helpful.
>>>>>
>>>>> 73,
>>>>> Don W3FPR
>>>>>
>>>>> On 1/11/2020 11:18 AM, Bill Coleman wrote:
>>>>>> Back in early December, I installed two KSYN3As in my K3 SN 7071. Sometime after that, I noticed that on 12m, I’m seeing a HI CUR indication when I set the power level to more than about 80-85 watts. The K3 will back off on the power level, then slowly ramp back up until it hits HI CUR again.
>>>>>> I don’t remember seeing this before. After the KSYNC3A install, I ran the transmit gain calibration at both 5 and 50 watts, as specified in the instructions. Just in case something went awry, I ran it again.
>>>>>> I’m still seeing this problem. What causes HI CUR at 85 watts? The K3 ought to be able to produce over 110 watts on 12m.
>>>>>> I’m not seeing this issue on other bands.
>>>>>> No issues with calibration
>>>> Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
>>>> Web: http://boringhamradiopart.blogspot.com
>>>> Quote: "Not within a thousand years will man ever fly!"
>>>> -- Wilbur Wright, 1901
>>>>
>>>
>>
>> Bill Coleman, AA4LR, PP-ASEL Mail: [hidden email]
>> Web: http://boringhamradiopart.blogspot.com
>> Quote: "Not within a thousand years will man ever fly!"
>> -- Wilbur Wright, 1901
>>
>> ______________________________________________________________
>> 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]