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KAT500 Key Line Interrupt when in BYP mode?

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KAT500 Key Line Interrupt when in BYP mode?

When the KAT500 is powered on but in the Bypass mode will it still open the key line to the KPA500 at the preset level (3.0:1 in my case) if the load suddenly goes above 3:1?

The situation is a remote autotuner connected to a 33’ vertical that I use for bands that I do not have a resonant antenna. On those bands the KAT500 is in the BYP mode. A remote switch brings all of the antenna choices in on a single coax which connected to the KAT500.

73 - Mike - K9JRI

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Re: KAT500 Key Line Interrupt when in BYP mode?

Mike:

> On Sep 2, 2018, at 11:27 AM, Michael Blake via Elecraft <[hidden email]> wrote:
>
> When the KAT500 is powered on but in the Bypass mode will it still open the key line to the KPA500 at the preset level (3.0:1 in my case) if the load suddenly goes above 3:1?

To confirm, is your SWR 3.0:1 or 2.0:1??

According to the KAT500 manual (page 21) you can use the KAT500 Utility Program to set VSWR thresholds for keying an amplifier, “Also, you can set an SWR threshold at which the key line will not close to enable the external amplifier to protect it from excessive SWR.” These thresholds can be set for all bands or individual bands. This would presumably work with bypass mode as bypass is defined as bypassing the tuning elements in the tuner’s matching network while the tuner’s SWR meter continues to function and the antenna selector will still switch to the antenna chosen for a particular band.

I haven’t made adjustments using the Utility Program so I cannot speak from personal experience nor do I know what the default values are for VSWR threshold as I’m not currently where my ham station is to confirm. You will need to experiment carefully to ensure that you get the intended results.

Also keep in mind that the KPA500 protects itself. See page 19 of the KPA500 manual (“Fault Conditions”) which discusses SWR measurements by the KPA500 itself where “minor faults” in VSWR will result in a 3 dB reduction in output (“Attenuator Faults”) and continues to operate (if the SWR improves the attenuator is removed). In the case of severe SWR problems the amplifier goes into standby (“Hard Faults”). Hard faults require intervention by the operator to place the amplifier in ‘operate’ presuming that the cause of the excessive SWR has been resolved.

The more basic question is what SWR levels the KPA500 will operate. According to the KPA500 manual (page 17) the amplifier is designed for 1.5:1 or less (the amplifier SWR LEDs are green). Between 1.5 and 2.1 the LEDs are yellow, and above 2.1 the LEDs are red. I could not find a reference in the manual that defines at what SWR level an “attenuator fault” or a “hard fault” due to high SWR are generated, but this suggests that an attenuator fault presumably happens when SWR is above 2.1 which is why I’m wondering if there’s a typo in your first sentence regarding current SWR.

The KAT500 manual (page 21) also notes, “The Elecraft KPA500 amplifier also works efficiently into a load SWR of 1.5:1. Suggested values are 1.8:1 to launch an automatic tuning operation and 1.2:1 for bypass.”

Hope this helps,

Barry Baines, WD4ASW
(Currently in Boston, MA)

>
> The situation is a remote autotuner connected to a 33’ vertical that I use for bands that I do not have a resonant antenna. On those bands the KAT500 is in the BYP mode. A remote switch brings all of the antenna choices in on a single coax which connected to the KAT500.
>
> 73 - Mike - K9JRI
>
>
>
>
>
>
>
> ______________________________________________________________
> 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]

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Elecraft mailing list

Re: KAT500 Key Line Interrupt when in BYP mode?

Dick from Elecraft answered my question. The short answer to my question was “no”.

To answer your question, yes the key line interrupt is set for 3.0:1 as it should be.

Mike - K9JRI

> On Sep 2, 2018, at 13:01, Barry Baines <[hidden email]> wrote:
>
> Mike:
>
>> On Sep 2, 2018, at 11:27 AM, Michael Blake via Elecraft <[hidden email]> wrote:
>>
>> When the KAT500 is powered on but in the Bypass mode will it still open the key line to the KPA500 at the preset level (3.0:1 in my case) if the load suddenly goes above 3:1?
>
> To confirm, is your SWR 3.0:1 or 2.0:1??
>
> According to the KAT500 manual (page 21) you can use the KAT500 Utility Program to set VSWR thresholds for keying an amplifier, “Also, you can set an SWR threshold at which the key line will not close to enable the external amplifier to protect it from excessive SWR.” These thresholds can be set for all bands or individual bands. This would presumably work with bypass mode as bypass is defined as bypassing the tuning elements in the tuner’s matching network while the tuner’s SWR meter continues to function and the antenna selector will still switch to the antenna chosen for a particular band.
>
> I haven’t made adjustments using the Utility Program so I cannot speak from personal experience nor do I know what the default values are for VSWR threshold as I’m not currently where my ham station is to confirm. You will need to experiment carefully to ensure that you get the intended results.
>
> Also keep in mind that the KPA500 protects itself. See page 19 of the KPA500 manual (“Fault Conditions”) which discusses SWR measurements by the KPA500 itself where “minor faults” in VSWR will result in a 3 dB reduction in output (“Attenuator Faults”) and continues to operate (if the SWR improves the attenuator is removed). In the case of severe SWR problems the amplifier goes into standby (“Hard Faults”). Hard faults require intervention by the operator to place the amplifier in ‘operate’ presuming that the cause of the excessive SWR has been resolved.
>
> The more basic question is what SWR levels the KPA500 will operate. According to the KPA500 manual (page 17) the amplifier is designed for 1.5:1 or less (the amplifier SWR LEDs are green). Between 1.5 and 2.1 the LEDs are yellow, and above 2.1 the LEDs are red. I could not find a reference in the manual that defines at what SWR level an “attenuator fault” or a “hard fault” due to high SWR are generated, but this suggests that an attenuator fault presumably happens when SWR is above 2.1 which is why I’m wondering if there’s a typo in your first sentence regarding current SWR.
>
> The KAT500 manual (page 21) also notes, “The Elecraft KPA500 amplifier also works efficiently into a load SWR of 1.5:1. Suggested values are 1.8:1 to launch an automatic tuning operation and 1.2:1 for bypass.”
>
>
> Hope this helps,
>
> Barry Baines, WD4ASW
> (Currently in Boston, MA)
>
>>
>> The situation is a remote autotuner connected to a 33’ vertical that I use for bands that I do not have a resonant antenna. On those bands the KAT500 is in the BYP mode. A remote switch brings all of the antenna choices in on a single coax which connected to the KAT500.
>>
>> 73 - Mike - K9JRI
>>
>>
>>
>>
>>
>>
>>
>> ______________________________________________________________
>> 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

Re: KAT500 Key Line Interrupt when in BYP mode?

Mike:

> On Sep 2, 2018, at 1:27 PM, Michael Blake <[hidden email]> wrote:
>
> Dick from Elecraft answered my question. The short answer to my question was “no”.
>
> To answer your question, yes the key line interrupt is set for 3.0:1 as it should be.

Thanks for the update and glad to hear that your question was answered.

That said, my reply was only based upon reading the KAT500 and KPA500 manuals. So I’m wondering how my attempt to be helpful resulted in a “misinterpretation” of what are in the manuals. Does the VSWR threshold not work in Bypass mode, or is it something else that is in play?

I’m also wondering (perhaps Dick can answer this) at what point(s) the KPA500 “soft” and “hard” faults kick-in on VSWR. If you’re running at 3.0:1 VSWR with no issues, what are the set points for fault detection?

73,

Barry, WD4ASW

>
> Mike - K9JRI
>
>> On Sep 2, 2018, at 13:01, Barry Baines <[hidden email]> wrote:
>>
>> Mike:
>>
>>> On Sep 2, 2018, at 11:27 AM, Michael Blake via Elecraft <[hidden email]> wrote:
>>>
>>> When the KAT500 is powered on but in the Bypass mode will it still open the key line to the KPA500 at the preset level (3.0:1 in my case) if the load suddenly goes above 3:1?
>>
>> To confirm, is your SWR 3.0:1 or 2.0:1??
>>
>> According to the KAT500 manual (page 21) you can use the KAT500 Utility Program to set VSWR thresholds for keying an amplifier, “Also, you can set an SWR threshold at which the key line will not close to enable the external amplifier to protect it from excessive SWR.” These thresholds can be set for all bands or individual bands. This would presumably work with bypass mode as bypass is defined as bypassing the tuning elements in the tuner’s matching network while the tuner’s SWR meter continues to function and the antenna selector will still switch to the antenna chosen for a particular band.
>>
>> I haven’t made adjustments using the Utility Program so I cannot speak from personal experience nor do I know what the default values are for VSWR threshold as I’m not currently where my ham station is to confirm. You will need to experiment carefully to ensure that you get the intended results.
>>
>> Also keep in mind that the KPA500 protects itself. See page 19 of the KPA500 manual (“Fault Conditions”) which discusses SWR measurements by the KPA500 itself where “minor faults” in VSWR will result in a 3 dB reduction in output (“Attenuator Faults”) and continues to operate (if the SWR improves the attenuator is removed). In the case of severe SWR problems the amplifier goes into standby (“Hard Faults”). Hard faults require intervention by the operator to place the amplifier in ‘operate’ presuming that the cause of the excessive SWR has been resolved.
>>
>> The more basic question is what SWR levels the KPA500 will operate. According to the KPA500 manual (page 17) the amplifier is designed for 1.5:1 or less (the amplifier SWR LEDs are green). Between 1.5 and 2.1 the LEDs are yellow, and above 2.1 the LEDs are red. I could not find a reference in the manual that defines at what SWR level an “attenuator fault” or a “hard fault” due to high SWR are generated, but this suggests that an attenuator fault presumably happens when SWR is above 2.1 which is why I’m wondering if there’s a typo in your first sentence regarding current SWR.
>>
>> The KAT500 manual (page 21) also notes, “The Elecraft KPA500 amplifier also works efficiently into a load SWR of 1.5:1. Suggested values are 1.8:1 to launch an automatic tuning operation and 1.2:1 for bypass.”
>>
>>
>> Hope this helps,
>>
>> Barry Baines, WD4ASW
>> (Currently in Boston, MA)
>>
>>>
>>> The situation is a remote autotuner connected to a 33’ vertical that I use for bands that I do not have a resonant antenna. On those bands the KAT500 is in the BYP mode. A remote switch brings all of the antenna choices in on a single coax which connected to the KAT500.
>>>
>>> 73 - Mike - K9JRI
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>> ______________________________________________________________
>>> 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

Re: KAT500 Key Line Interrupt when in BYP mode?

Dave, yes my question was “do the VSWR Thresholds work when the KAT500 is in the Bypass mode” and the answer was No, they do not. There are workarounds of course but the question was specifically when the KAT500 had been placed in the Bypass mode with the front panel button. The manual did not mention this mode selection’s VSWR protections or lack there-of.

73 - Mike - K9JRI

> On Sep 2, 2018, at 2:56 PM, Barry Baines <[hidden email]> wrote:
>
> Mike:
>
>> On Sep 2, 2018, at 1:27 PM, Michael Blake <[hidden email]> wrote:
>>
>> Dick from Elecraft answered my question. The short answer to my question was “no”.
>>
>> To answer your question, yes the key line interrupt is set for 3.0:1 as it should be.
>
>
> Thanks for the update and glad to hear that your question was answered.
>
> That said, my reply was only based upon reading the KAT500 and KPA500 manuals. So I’m wondering how my attempt to be helpful resulted in a “misinterpretation” of what are in the manuals. Does the VSWR threshold not work in Bypass mode, or is it something else that is in play?
>
> I’m also wondering (perhaps Dick can answer this) at what point(s) the KPA500 “soft” and “hard” faults kick-in on VSWR. If you’re running at 3.0:1 VSWR with no issues, what are the set points for fault detection?
>
> 73,
>
> Barry, WD4ASW
>
>
>>
>> Mike - K9JRI
>>
>>> On Sep 2, 2018, at 13:01, Barry Baines <[hidden email]> wrote:
>>>
>>> Mike:
>>>
>>>> On Sep 2, 2018, at 11:27 AM, Michael Blake via Elecraft <[hidden email]> wrote:
>>>>
>>>> When the KAT500 is powered on but in the Bypass mode will it still open the key line to the KPA500 at the preset level (3.0:1 in my case) if the load suddenly goes above 3:1?
>>>
>>> To confirm, is your SWR 3.0:1 or 2.0:1??
>>>
>>> According to the KAT500 manual (page 21) you can use the KAT500 Utility Program to set VSWR thresholds for keying an amplifier, “Also, you can set an SWR threshold at which the key line will not close to enable the external amplifier to protect it from excessive SWR.” These thresholds can be set for all bands or individual bands. This would presumably work with bypass mode as bypass is defined as bypassing the tuning elements in the tuner’s matching network while the tuner’s SWR meter continues to function and the antenna selector will still switch to the antenna chosen for a particular band.
>>>
>>> I haven’t made adjustments using the Utility Program so I cannot speak from personal experience nor do I know what the default values are for VSWR threshold as I’m not currently where my ham station is to confirm. You will need to experiment carefully to ensure that you get the intended results.
>>>
>>> Also keep in mind that the KPA500 protects itself. See page 19 of the KPA500 manual (“Fault Conditions”) which discusses SWR measurements by the KPA500 itself where “minor faults” in VSWR will result in a 3 dB reduction in output (“Attenuator Faults”) and continues to operate (if the SWR improves the attenuator is removed). In the case of severe SWR problems the amplifier goes into standby (“Hard Faults”). Hard faults require intervention by the operator to place the amplifier in ‘operate’ presuming that the cause of the excessive SWR has been resolved.
>>>
>>> The more basic question is what SWR levels the KPA500 will operate. According to the KPA500 manual (page 17) the amplifier is designed for 1.5:1 or less (the amplifier SWR LEDs are green). Between 1.5 and 2.1 the LEDs are yellow, and above 2.1 the LEDs are red. I could not find a reference in the manual that defines at what SWR level an “attenuator fault” or a “hard fault” due to high SWR are generated, but this suggests that an attenuator fault presumably happens when SWR is above 2.1 which is why I’m wondering if there’s a typo in your first sentence regarding current SWR.
>>>
>>> The KAT500 manual (page 21) also notes, “The Elecraft KPA500 amplifier also works efficiently into a load SWR of 1.5:1. Suggested values are 1.8:1 to launch an automatic tuning operation and 1.2:1 for bypass.”
>>>
>>>
>>> Hope this helps,
>>>
>>> Barry Baines, WD4ASW
>>> (Currently in Boston, MA)
>>>
>>>>
>>>> The situation is a remote autotuner connected to a 33’ vertical that I use for bands that I do not have a resonant antenna. On those bands the KAT500 is in the BYP mode. A remote switch brings all of the antenna choices in on a single coax which connected to the KAT500.
>>>>
>>>> 73 - Mike - K9JRI
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> ______________________________________________________________
>>>> 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]
>>>
>

ANDY DURBIN

KAT500 Key Line Interrupt when in BYP mode?

In reply to this post by Elecraft mailing list

"The Elecraft KPA500 amplifier also works efficiently into a load SWR of 1.5:1"

Any such claim is at best misleading. There may be some 1.5:1 loads that that the KPA500 will be happy with but there are other 1.5:1 loads that it will object to, to the point of giving multiple PA DISS faults. 1.5:1 SWR does not define the load characteristics. A 1.5:1 load could be pure R or it could be a complex impedance. The efficiency, PA dissipation, and risk of fault trip are not defined by the SWR.

73,
Andy k3wyc

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Bob McGraw - K4TAX

Re: KAT500 Key Line Interrupt when in BYP mode?

The value of SWR doesn't really inform us about the load impedance, line
current or line voltage conditions existing.

In the case of a 1.5:1 SWR, the load Z is 75 ohms, with a power of 500
watts the line current is 2.58 amps with a voltage of 193.6 volts.

At the same time a 1.5:1 SWR, the load Z is 33.3 ohms, at 500 watts the
line current is 3.87 amps and with a voltage of 129 volts.

Both 75 ohms and 33.3 ohms represent a 1.5:1 SWR with reference to a 50
ohm source.

The points being related to the circuit designs, how much current or how
much voltage exceeds the component ratings? Hence we see
manufacturers specifying maximum SWR values. Added to the above is
the Xl and Xc values plus R for a complex impedance.

73

Bob, K4TAX

On 9/2/2018 2:21 PM, ANDY DURBIN wrote:

> "The Elecraft KPA500 amplifier also works efficiently into a load SWR of 1.5:1"
>
> Any such claim is at best misleading. There may be some 1.5:1 loads that that the KPA500 will be happy with but there are other 1.5:1 loads that it will object to, to the point of giving multiple PA DISS faults. 1.5:1 SWR does not define the load characteristics. A 1.5:1 load could be pure R or it could be a complex impedance. The efficiency, PA dissipation, and risk of fault trip are not defined by the SWR.
>
> 73,
> Andy k3wyc
>
>
>
>
>
>
> ______________________________________________________________
> 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]
>