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KX3 - SWR Display of "--"

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stan levandowski

KX3 - SWR Display of "--"

I just got a KXPA100 yesterday. It seems to work as specified except
that above 10 watts of power, the KX3 display randomly {like in "not all
the time"} shows two dashes instead of the SWR.

I do not have the internal tuner option. I am using my SGC237
autocoupler into a center fed Zepp. My W2 wattmeter shows the proper
power output and the SWR is usually 1:1 or very close.

This does not occur at power levels at or below 10 watts which means
it's most likely not the KX3's problem but rather the amplifier's
behavior.

Happens on different bands and frequencies. If this is documented
somewhere then I've missed it.

73, Stan WB2LQF
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vk2rq

Re: KX3 - SWR Display of "--"

Above 10W of power, the KX3 will disable the internal KXAT3 ATU and rely on the amplifier to supply the SWR readings over the ACC1 cable. However, the SWR bridge for the amplifier is part of the KXAT100 ATU option for the amplifier, so if this option is not equipped, the amplifier will not be able to supply any SWR readings. I'm guessing this is the reason you are seeing the '--' dashes for SWR when operating above 10W. If the behaviour is intermittent, it may indicate a problem with your ACC1 cable connection.

73, Matt VK2RQ

> On 22 Nov 2014, at 3:06 am, stan levandowski <[hidden email]> wrote:
>
> I just got a KXPA100 yesterday. It seems to work as specified except that above 10 watts of power, the KX3 display randomly {like in "not all the time"} shows two dashes instead of the SWR.
>
> I do not have the internal tuner option. I am using my SGC237 autocoupler into a center fed Zepp. My W2 wattmeter shows the proper power output and the SWR is usually 1:1 or very close.
>
> This does not occur at power levels at or below 10 watts which means it's most likely not the KX3's problem but rather the amplifier's behavior.
>
> Happens on different bands and frequencies. If this is documented somewhere then I've missed it.
>
> 73, Stan WB2LQF
> ______________________________________________________________
> 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]

Dick Dievendorff-4

Re: KX3 - SWR Display of "--"

Sorry Matt, this isn't quite right.

The KXPA100's SWR bridge is on its LPF board, and is part of all KXPA100's,
with or without the KXAT100 Antenna Tuner Option.

The KX3 currently doesn't display the KXPA100's SWR, it instead displays the
KX3 SWR measurement.

When the KXPA100 is PA Bypassed (under about 10 watts), the KX3 SWR bridge
sees the antenna impedance, so the SWR display is appropriate. However when
the KXPA100 is not bypassed, the KX3 SWR display is of the input of the
KXPA100.

Wayne has on his KX3 firmware "todo" list a task to display KXPA100 SWR on
the KX3 display when appropriate.

The KX3 displays dashes when its power is too low for an accurate SWR
measurement.

The KXPA100's view of the antenna system SWR can be displayed with the
KXPA100 Utility Operate Page, LEDs on an KXAT100-equipped KXPA100, or an
external SWR meter like our W2.

73, Dick, K6KR

-----Original Message-----
From: Elecraft [mailto:[hidden email]] On Behalf Of Matt
VK2RQ
Sent: Friday, November 21, 2014 11:36 AM
To: stan levandowski
Cc: Elecraft
Subject: Re: [Elecraft] KX3 - SWR Display of "--"

Above 10W of power, the KX3 will disable the internal KXAT3 ATU and rely on
the amplifier to supply the SWR readings over the ACC1 cable. However, the
SWR bridge for the amplifier is part of the KXAT100 ATU option for the
amplifier, so if this option is not equipped, the amplifier will not be able
to supply any SWR readings. I'm guessing this is the reason you are seeing
the '--' dashes for SWR when operating above 10W. If the behaviour is
intermittent, it may indicate a problem with your ACC1 cable connection.

73, Matt VK2RQ

> On 22 Nov 2014, at 3:06 am, stan levandowski <[hidden email]> wrote:
>
> I just got a KXPA100 yesterday. It seems to work as specified except that
above 10 watts of power, the KX3 display randomly {like in "not all the
time"} shows two dashes instead of the SWR.
>
> I do not have the internal tuner option. I am using my SGC237 autocoupler
into a center fed Zepp. My W2 wattmeter shows the proper power output and
the SWR is usually 1:1 or very close.
>
> This does not occur at power levels at or below 10 watts which means it's
most likely not the KX3's problem but rather the amplifier's behavior.
>
> Happens on different bands and frequencies. If this is documented
somewhere then I've missed it.

>
> 73, Stan WB2LQF
> ______________________________________________________________
> 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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delivered to [hidden email]

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Help: http://mailman.qth.net/mmfaq.htm
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vk2rq

Re: KX3 - SWR Display of "--"

Thanks Dick, that's good to know. It makes sense to include an SWR bridge in the basic amplifier, because then you can provide protection against antenna faults and other high SWR conditions.

73, Matt VK2RQ.

> On 22 Nov 2014, at 7:01 am, Dick Dievendorff <[hidden email]> wrote:
>
> Sorry Matt, this isn't quite right.
>
> The KXPA100's SWR bridge is on its LPF board, and is part of all KXPA100's,
> with or without the KXAT100 Antenna Tuner Option.
>
> The KX3 currently doesn't display the KXPA100's SWR, it instead displays the
> KX3 SWR measurement.
>
> When the KXPA100 is PA Bypassed (under about 10 watts), the KX3 SWR bridge
> sees the antenna impedance, so the SWR display is appropriate. However when
> the KXPA100 is not bypassed, the KX3 SWR display is of the input of the
> KXPA100.
>
> Wayne has on his KX3 firmware "todo" list a task to display KXPA100 SWR on
> the KX3 display when appropriate.
>
> The KX3 displays dashes when its power is too low for an accurate SWR
> measurement.
>
> The KXPA100's view of the antenna system SWR can be displayed with the
> KXPA100 Utility Operate Page, LEDs on an KXAT100-equipped KXPA100, or an
> external SWR meter like our W2.
>
> 73, Dick, K6KR
>
>
> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of Matt
> VK2RQ
> Sent: Friday, November 21, 2014 11:36 AM
> To: stan levandowski
> Cc: Elecraft
> Subject: Re: [Elecraft] KX3 - SWR Display of "--"
>
> Above 10W of power, the KX3 will disable the internal KXAT3 ATU and rely on
> the amplifier to supply the SWR readings over the ACC1 cable. However, the
> SWR bridge for the amplifier is part of the KXAT100 ATU option for the
> amplifier, so if this option is not equipped, the amplifier will not be able
> to supply any SWR readings. I'm guessing this is the reason you are seeing
> the '--' dashes for SWR when operating above 10W. If the behaviour is
> intermittent, it may indicate a problem with your ACC1 cable connection.
>
> 73, Matt VK2RQ
>
>> On 22 Nov 2014, at 3:06 am, stan levandowski <[hidden email]> wrote:
>>
>> I just got a KXPA100 yesterday. It seems to work as specified except that
> above 10 watts of power, the KX3 display randomly {like in "not all the
> time"} shows two dashes instead of the SWR.
>>
>> I do not have the internal tuner option. I am using my SGC237 autocoupler
> into a center fed Zepp. My W2 wattmeter shows the proper power output and
> the SWR is usually 1:1 or very close.
>>
>> This does not occur at power levels at or below 10 watts which means it's
> most likely not the KX3's problem but rather the amplifier's behavior.
>>
>> Happens on different bands and frequencies. If this is documented
> somewhere then I've missed it.
>>
>> 73, Stan WB2LQF
>> ______________________________________________________________
>> 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]
>

Don Wilhelm-4

Re: KX3 - SWR Display of "--"

In reply to this post by stan levandowski

Stan,

That indication is "normal" when the power level is too low for a valid
SWR computation.
The KX3 SWR indication is used below 10 watts, but the KXPA100
indication is used above that level.
It should go away if you increase (or decrease) the power a bit. It
sounds as though you are operating right on that critical threshold.

73,
Don W3FPR

On 11/21/2014 11:06 AM, stan levandowski wrote:

> I just got a KXPA100 yesterday. It seems to work as specified except
> that above 10 watts of power, the KX3 display randomly {like in "not
> all the time"} shows two dashes instead of the SWR.
>
> I do not have the internal tuner option. I am using my SGC237
> autocoupler into a center fed Zepp. My W2 wattmeter shows the proper
> power output and the SWR is usually 1:1 or very close.
>
> This does not occur at power levels at or below 10 watts which means
> it's most likely not the KX3's problem but rather the amplifier's
> behavior.

stan levandowski

Re: KX3 - SWR Display of "--"

In reply to this post by Dick Dievendorff-4

Dick and Matt, thanks for the responses. Now I'm better informed which
is always a good thing!
Have a pleasant Thanksgiving, folks.

I must say that the level of integration between the KX3 and the KXPA100
is simply stunning!

As a dedicated QRP op for over half a century it was very difficult for
me to make this purchase just on general principles. I finally bought
it to help the OTHER guy out during long ragchews, not for myself. I'm
a very charitable guy.....

73, Stan WB2LQF

On Fri, Nov 21, 2014 at 03:01 PM, Dick Dievendorff wrote:

> Sorry Matt, this isn't quite right.
>
> The KXPA100's SWR bridge is on its LPF board, and is part of all
> KXPA100's,
> with or without the KXAT100 Antenna Tuner Option.
>
> The KX3 currently doesn't display the KXPA100's SWR, it instead
> displays the
> KX3 SWR measurement.
> When the KXPA100 is PA Bypassed (under about 10 watts), the KX3 SWR
> bridge
> sees the antenna impedance, so the SWR display is appropriate.
> However when
> the KXPA100 is not bypassed, the KX3 SWR display is of the input of
> the
> KXPA100.
>
> Wayne has on his KX3 firmware "todo" list a task to display KXPA100
> SWR on
> the KX3 display when appropriate.
>
> The KX3 displays dashes when its power is too low for an accurate SWR
> measurement.
>
> The KXPA100's view of the antenna system SWR can be displayed with the
> KXPA100 Utility Operate Page, LEDs on an KXAT100-equipped KXPA100, or
> an
> external SWR meter like our W2.
>
> 73, Dick, K6KR
>
>
> -----Original Message-----
> From: Elecraft [mailto:[hidden email]] On Behalf Of
> Matt
> VK2RQ
> Sent: Friday, November 21, 2014 11:36 AM
> To: stan levandowski
> Cc: Elecraft
> Subject: Re: [Elecraft] KX3 - SWR Display of "--"
>
> Above 10W of power, the KX3 will disable the internal KXAT3 ATU and
> rely on
> the amplifier to supply the SWR readings over the ACC1 cable. However,
> the
> SWR bridge for the amplifier is part of the KXAT100 ATU option for the
> amplifier, so if this option is not equipped, the amplifier will not
> be able
> to supply any SWR readings. I'm guessing this is the reason you are
> seeing
> the '--' dashes for SWR when operating above 10W. If the behaviour is
> intermittent, it may indicate a problem with your ACC1 cable
> connection.
>
> 73, Matt VK2RQ
>
>> On 22 Nov 2014, at 3:06 am, stan levandowski wrote:
>>
>> I just got a KXPA100 yesterday. It seems to work as specified except
>> that
> above 10 watts of power, the KX3 display randomly {like in "not all
> the
> time"} shows two dashes instead of the SWR.
>>
>> I do not have the internal tuner option. I am using my SGC237
>> autocoupler
> into a center fed Zepp. My W2 wattmeter shows the proper power output
> and
> the SWR is usually 1:1 or very close.
>>
>> This does not occur at power levels at or below 10 watts which means
>> it's
> most likely not the KX3's problem but rather the amplifier's behavior.
>>
>> Happens on different bands and frequencies. If this is documented
> somewhere then I've missed it.
>>
>> 73, Stan WB2LQF
>> ______________________________________________________________
>> 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]
>
>

stan levandowski

Re: KX3 - SWR Display of "--"

In reply to this post by Don Wilhelm-4

That's exactly what I experienced. Tweaking the power level "fixed"
it. I was messing at about 12-13 watts when it first occured.
Increased to 15 and it went away.

Don't laugh.....for a 50+ year veteran of QRP operating, it's not that
easy to turn the knob up to 75 or 100 watts. I have to wean myself in a
serie

On Fri, Nov 21, 2014 at 03:11 PM, Don Wilhelm wrote:

> Stan,
>
> That indication is "normal" when the power level is too low for a
> valid SWR computation.
> The KX3 SWR indication is used below 10 watts, but the KXPA100
> indication is used above that level.
> It should go away if you increase (or decrease) the power a bit. It
> sounds as though you are operating right on that critical threshold.
>
> 73,
> Don W3FPR
>
> On 11/21/2014 11:06 AM, stan levandowski wrote:
>> I just got a KXPA100 yesterday. It seems to work as specified
>> except that above 10 watts of power, the KX3 display randomly {like
>> in "not all the time"} shows two dashes instead of the SWR.
>>
>> I do not have the internal tuner option. I am using my SGC237
>> autocoupler into a center fed Zepp. My W2 wattmeter shows the proper
>> power output and the SWR is usually 1:1 or very close.
>>
>> This does not occur at power levels at or below 10 watts which means
>> it's most likely not the KX3's problem but rather the amplifier's
>> behavior.
>
>