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K3 - why SWR change with an amplifier

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Jorge Diez - CX6VM-2

K3 - why SWR change with an amplifier

Hi,

I noticed that SWR change in my K3 if I use the amp or if it´s in standby.

For example in my 20 mts yagi, the SWR with the antenna direct to the K3 is
1.5:1.

If I put the antenna through he amplifier, in STBY the SWR is 1.5:1 but with
the aomlifier is in Operation the SWR is 2.0:1

Thanks,

Jorge

CX6VM/CW5W

K3 #4077

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Don Wilhelm-4

Re: K3 - why SWR change with an amplifier

Jorge,

With the amplifier in standby, the K3 wattmeter sees the antenna SWR -
the same as when the antenna is connected to the K3.
When the amp is switched to operate, the K3 will see the input SWR of
the amplifier - and that has no relationship with the antenna.

73,
Don W3FPR

On 3/29/2012 7:10 PM, Jorge Diez - CX6VM wrote:

> Hi,
>
>
>
> I noticed that SWR change in my K3 if I use the amp or if it´s in standby.
>
>
>
> For example in my 20 mts yagi, the SWR with the antenna direct to the K3 is
> 1.5:1.
>
>
>
> If I put the antenna through he amplifier, in STBY the SWR is 1.5:1 but with
> the aomlifier is in Operation the SWR is 2.0:1
>
>
>
> Thanks,
>
> Jorge
>
> CX6VM/CW5W
>
> K3 #4077
>
>

ab2tc

Re: K3 - why SWR change with an amplifier

Hi,

But is it normal for the KPA500 input SWR to be 2:1?

Knut - AB2TC

Don Wilhelm-4 wrote

Jorge,

With the amplifier in standby, the K3 wattmeter sees the antenna SWR -
the same as when the antenna is connected to the K3.
When the amp is switched to operate, the K3 will see the input SWR of
the amplifier - and that has no relationship with the antenna.

73,
Don W3FPR

<snip>

Don Wilhelm-4

Re: K3 - why SWR change with an amplifier

He did not say it was a KPA500! Maybe it was some other amplifier that
we cannot comment on.
If it were the KPA500, I would have asked "what bands".

73,
Don W3FPR.

On 3/29/2012 7:26 PM, ab2tc wrote:

> Hi,
>
> But is it normal for the KPA500 input SWR to be 2:1?
>
> Knut - AB2TC
>
>
> Don Wilhelm-4 wrote
>> Jorge,
>>
>> With the amplifier in standby, the K3 wattmeter sees the antenna SWR -
>> the same as when the antenna is connected to the K3.
>> When the amp is switched to operate, the K3 will see the input SWR of
>> the amplifier - and that has no relationship with the antenna.
>>
>> 73,
>> Don W3FPR
>>
>> <snip>
>>
>
> --
> View this message in context: http://elecraft.365791.n2.nabble.com/K3-why-SWR-change-with-an-amplifier-tp7419653p7419681.html
> Sent from the Elecraft mailing list archive at Nabble.com.
> ______________________________________________________________
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Jorge Diez - CX6VM-2

Re: K3 - why SWR change with an amplifier

Don

The amplifier is a Drake L7

I will test with a ALS1300 to see what happens

So what do you think? My L7 is doing something bad?

I really dont like to see more than 3 bars in my K3 SWR meter. I tune with the internal tuner and is better, but I dont know if I had something bad that I need to solve

Thanks
Jorge

Enviado desde mi BlackBerry® device de Antel

-----Original Message-----
From: Don Wilhelm <[hidden email]>
Sender: [hidden email]
Date: Thu, 29 Mar 2012 19:39:03
To: ab2tc<[hidden email]>
Reply-To: [hidden email]
Cc: <[hidden email]>
Subject: Re: [Elecraft] K3 - why SWR change with an amplifier

He did not say it was a KPA500! Maybe it was some other amplifier that
we cannot comment on.
If it were the KPA500, I would have asked "what bands".

73,
Don W3FPR.

On 3/29/2012 7:26 PM, ab2tc wrote:

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w0mu

Re: K3 - why SWR change with an amplifier

Does the L7 have a tuned input? If so you might need to adjust the
tuned input on each band for the best match to the rig.

Mike W0MU

W0MU-1 CC Cluster w0mu.net

On 3/29/2012 6:22 PM, Jorge Diez CX6VM wrote:

> Don
>
> The amplifier is a Drake L7
>
> I will test with a ALS1300 to see what happens
>
> So what do you think? My L7 is doing something bad?
>
> I really dont like to see more than 3 bars in my K3 SWR meter. I tune with the internal tuner and is better, but I dont know if I had something bad that I need to solve
>
> Thanks
> Jorge
>
>
> Enviado desde mi BlackBerry® device de Antel
>
> -----Original Message-----
> From: Don Wilhelm<[hidden email]>
> Sender: [hidden email]
> Date: Thu, 29 Mar 2012 19:39:03
> To: ab2tc<[hidden email]>
> Reply-To: [hidden email]
> Cc:<[hidden email]>
> Subject: Re: [Elecraft] K3 - why SWR change with an amplifier
>
> He did not say it was a KPA500! Maybe it was some other amplifier that
> we cannot comment on.
> If it were the KPA500, I would have asked "what bands".
>
> 73,
> Don W3FPR.
>
> On 3/29/2012 7:26 PM, ab2tc wrote:
>> Hi,
>>
>> But is it normal for the KPA500 input SWR to be 2:1?
>>
>> Knut - AB2TC
>>
>>
>> Don Wilhelm-4 wrote
>>> Jorge,
>>>
>>> With the amplifier in standby, the K3 wattmeter sees the antenna SWR -
>>> the same as when the antenna is connected to the K3.
>>> When the amp is switched to operate, the K3 will see the input SWR of
>>> the amplifier - and that has no relationship with the antenna.
>>>
>>> 73,
>>> Don W3FPR
>>>
>>> <snip>
>>>
>> --
>> View this message in context: http://elecraft.365791.n2.nabble.com/K3-why-SWR-change-with-an-amplifier-tp7419653p7419681.html
>> Sent from the Elecraft mailing list archive at Nabble.com.
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
> ______________________________________________________________
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Don Wilhelm-4

Re: K3 - why SWR change with an amplifier

In reply to this post by Jorge Diez - CX6VM-2

Jorge,

If the K3 does not fault and reduce power, it may be OK - SWR = 2:1 is
the "trip point" for the KPA3 power reduction.
Do check all bands, it could be better (or worse) on some bands as
opposed to others.

73,
Don W3FPR

On 3/29/2012 8:22 PM, Jorge Diez CX6VM wrote:

w0mu

Re: K3 - why SWR change with an amplifier

He says it is happening with an Alpha 89 too. Something is not right.

What happens when you hook the antenna directly into the K3?

Mike W0MU

W0MU-1 CC Cluster w0mu.net

On 3/29/2012 6:34 PM, Don Wilhelm wrote:

> Jorge,
>
> If the K3 does not fault and reduce power, it may be OK - SWR = 2:1 is
> the "trip point" for the KPA3 power reduction.
> Do check all bands, it could be better (or worse) on some bands as
> opposed to others.
>
> 73,
> Don W3FPR
>
> On 3/29/2012 8:22 PM, Jorge Diez CX6VM wrote:
>> Don
>>
>> The amplifier is a Drake L7
>>
>> I will test with a ALS1300 to see what happens
>>
>> So what do you think? My L7 is doing something bad?
>>
>> I really dont like to see more than 3 bars in my K3 SWR meter. I tune with the internal tuner and is better, but I dont know if I had something bad that I need to solve
>>
>> Thanks
>> Jorge
>>
>>
>> Enviado desde mi BlackBerry® device de Antel
>>
>> -----Original Message-----
>> From: Don Wilhelm<[hidden email]>
>> Sender: [hidden email]
>> Date: Thu, 29 Mar 2012 19:39:03
>> To: ab2tc<[hidden email]>
>> Reply-To: [hidden email]
>> Cc:<[hidden email]>
>> Subject: Re: [Elecraft] K3 - why SWR change with an amplifier
>>
>> He did not say it was a KPA500! Maybe it was some other amplifier that
>> we cannot comment on.
>> If it were the KPA500, I would have asked "what bands".
>>
>> 73,
>> Don W3FPR.
>>
>> On 3/29/2012 7:26 PM, ab2tc wrote:
>>> Hi,
>>>
>>> But is it normal for the KPA500 input SWR to be 2:1?
>>>
>>> Knut - AB2TC
>>>
>>>
>>> Don Wilhelm-4 wrote
>>>> Jorge,
>>>>
>>>> With the amplifier in standby, the K3 wattmeter sees the antenna SWR -
>>>> the same as when the antenna is connected to the K3.
>>>> When the amp is switched to operate, the K3 will see the input SWR of
>>>> the amplifier - and that has no relationship with the antenna.
>>>>
>>>> 73,
>>>> Don W3FPR
>>>>
>>>> <snip>
>>>>
>>> --
>>> View this message in context: http://elecraft.365791.n2.nabble.com/K3-why-SWR-change-with-an-amplifier-tp7419653p7419681.html
>>> Sent from the Elecraft mailing list archive at Nabble.com.
>>> ______________________________________________________________
>>> 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
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> ______________________________________________________________
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>> Post: mailto:[hidden email]
>>
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>>
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Rick WA6NHC

Re: K3 - why SWR change with an amplifier

In reply to this post by Jorge Diez - CX6VM-2

Did you leave the K3 tuner online when bringing the amp online?

The K3 tuner should be OFF when using an amp. Another DOH! moment?
:o)

Rick wa6nhc

-----Original Message-----
From: Jorge Diez CX6VM

Don

The amplifier is a Drake L7

I will test with a ALS1300 to see what happens

So what do you think? My L7 is doing something bad?

I really dont like to see more than 3 bars in my K3 SWR meter. I tune with
the internal tuner and is better, but I dont know if I had something bad
that I need to solve

Thanks
Jorge

-----Original Message-----
From: Don Wilhelm

He did not say it was a KPA500! Maybe it was some other amplifier that
we cannot comment on.
If it were the KPA500, I would have asked "what bands".

On 3/29/2012 7:26 PM, ab2tc wrote:

> Hi,
>
> But is it normal for the KPA500 input SWR to be 2:1?
>
> Knut - AB2TC
>
> Don Wilhelm-4 wrote
>> Jorge,
>>
>> With the amplifier in standby, the K3 wattmeter sees the antenna SWR -
>> the same as when the antenna is connected to the K3.
>> When the amp is switched to operate, the K3 will see the input SWR of
>> the amplifier - and that has no relationship with the antenna.
>>
>> 73,
>> Don W3FPR

Jorge Diez - CX6VM-2

Re: K3 - why SWR change with an amplifier

In reply to this post by w0mu

I just tested with the 89 and also have different readings.

With the antenna directly into the K3, SWR is 1.5:1

When both amps are in stby, SWR is 1.5:1

Will do some measurements on different bands and will let you know

73,
Jorge

-----Mensaje original-----
De: [hidden email]
[mailto:[hidden email]] En nombre de W0MU Mike Fatchett
Enviado el: Jueves, 29 de Marzo de 2012 09:39 p.m.
Para: [hidden email]
Asunto: Re: [Elecraft] K3 - why SWR change with an amplifier

He says it is happening with an Alpha 89 too. Something is not right.

What happens when you hook the antenna directly into the K3?

Mike W0MU

W0MU-1 CC Cluster w0mu.net

On 3/29/2012 6:34 PM, Don Wilhelm wrote:

> Jorge,
>
> If the K3 does not fault and reduce power, it may be OK - SWR = 2:1 is
> the "trip point" for the KPA3 power reduction.
> Do check all bands, it could be better (or worse) on some bands as
> opposed to others.
>
> 73,
> Don W3FPR
>
> On 3/29/2012 8:22 PM, Jorge Diez CX6VM wrote:
>> Don
>>
>> The amplifier is a Drake L7
>>
>> I will test with a ALS1300 to see what happens
>>
>> So what do you think? My L7 is doing something bad?
>>
>> I really dont like to see more than 3 bars in my K3 SWR meter. I tune
>> with the internal tuner and is better, but I dont know if I had
>> something bad that I need to solve
>>
>> Thanks
>> Jorge
>>
>>
>> Enviado desde mi BlackBerry® device de Antel
>>
>> -----Original Message-----
>> From: Don Wilhelm<[hidden email]>
>> Sender: [hidden email]
>> Date: Thu, 29 Mar 2012 19:39:03
>> To: ab2tc<[hidden email]>
>> Reply-To: [hidden email]
>> Cc:<[hidden email]>
>> Subject: Re: [Elecraft] K3 - why SWR change with an amplifier
>>
>> He did not say it was a KPA500! Maybe it was some other amplifier
>> that we cannot comment on.
>> If it were the KPA500, I would have asked "what bands".
>>
>> 73,
>> Don W3FPR.
>>
>> On 3/29/2012 7:26 PM, ab2tc wrote:
>>> Hi,
>>>
>>> But is it normal for the KPA500 input SWR to be 2:1?
>>>
>>> Knut - AB2TC
>>>
>>>
>>> Don Wilhelm-4 wrote
>>>> Jorge,
>>>>
>>>> With the amplifier in standby, the K3 wattmeter sees the antenna
>>>> SWR - the same as when the antenna is connected to the K3.
>>>> When the amp is switched to operate, the K3 will see the input SWR
>>>> of the amplifier - and that has no relationship with the antenna.
>>>>
>>>> 73,
>>>> Don W3FPR
>>>>
>>>> <snip>
>>>>
>>> --
>>> View this message in context:
>>> http://elecraft.365791.n2.nabble.com/K3-why-SWR-change-with-an-ampli
>>> fier-tp7419653p7419681.html Sent from the Elecraft mailing list
>>> archive at Nabble.com.
>>> ______________________________________________________________
>>> Elecraft mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>>> Help: http://mailman.qth.net/mmfaq.htm
>>> Post: mailto:[hidden email]
>>>
>>> This list hosted by: http://www.qsl.net Please help support this
>>> email list: http://www.qsl.net/donate.html
>>>
>> ______________________________________________________________
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>> 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
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>>
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>> email list: http://www.qsl.net/donate.html
>>
> ______________________________________________________________
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>
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WE5ST

Re: K3 - why SWR change with an amplifier

In reply to this post by Don Wilhelm-4

My K3 was seeing similar SWR with an AL811H. It was intermittent and was independent of switch position, standby/operate. The antenna is a SteppIR so SWR was always less than 2:1. With the amp removed the problem is gone.
I don't yet know the cause since the amp is in the shop. It seems likely that it's something on the I/O board and my money is on the two small relays. But I'm an appliance operator so who knows?

On Mar 29, 2012, at 7:34 PM, Don Wilhelm <[hidden email]> wrote:

Jack - WE5ST

N5GE-2

Re: K3 - why SWR change with an amplifier

In reply to this post by w0mu

I believe the Drake L7 is basically the same as the L4B. If so, the amp has
tuned input. The rear panel should have holes for tuning the input to match the
rig. Be sure you use an insulated screw driver when adjusting the inputs.

Amateur Radio Operator N5GE
ARRL Lifetime Member
QCWA Lifetime Member

On Thu, 29 Mar 2012 18:29:30 -0600, W0MU Mike Fatchett <[hidden email]> wrote:

>Does the L7 have a tuned input? If so you might need to adjust the
>tuned input on each band for the best match to the rig.
>
>Mike W0MU
>
>W0MU-1 CC Cluster w0mu.net
>
>
>On 3/29/2012 6:22 PM, Jorge Diez CX6VM wrote:
>> Don
>>
>> The amplifier is a Drake L7
>>
>> I will test with a ALS1300 to see what happens
>>
>> So what do you think? My L7 is doing something bad?
>>
>> I really dont like to see more than 3 bars in my K3 SWR meter. I tune with the internal tuner and is better, but I dont know if I had something bad that I need to solve
>>
>> Thanks
>> Jorge
>>
>>
>> Enviado desde mi BlackBerry® device de Antel
>>
>> -----Original Message-----
>> From: Don Wilhelm<[hidden email]>
>> Sender: [hidden email]
>> Date: Thu, 29 Mar 2012 19:39:03
>> To: ab2tc<[hidden email]>
>> Reply-To: [hidden email]
>> Cc:<[hidden email]>
>> Subject: Re: [Elecraft] K3 - why SWR change with an amplifier
>>
>> He did not say it was a KPA500! Maybe it was some other amplifier that
>> we cannot comment on.
>> If it were the KPA500, I would have asked "what bands".
>>
>> 73,
>> Don W3FPR.
>>
>> On 3/29/2012 7:26 PM, ab2tc wrote:
>>> Hi,
>>>
>>> But is it normal for the KPA500 input SWR to be 2:1?
>>>
>>> Knut - AB2TC
>>>
>>>
>>> Don Wilhelm-4 wrote
>>>> Jorge,
>>>>
>>>> With the amplifier in standby, the K3 wattmeter sees the antenna SWR -
>>>> the same as when the antenna is connected to the K3.
>>>> When the amp is switched to operate, the K3 will see the input SWR of
>>>> the amplifier - and that has no relationship with the antenna.
>>>>
>>>> 73,
>>>> Don W3FPR
>>>>
>>>> <snip>
>>>>
>>> --
>>> View this message in context: http://elecraft.365791.n2.nabble.com/K3-why-SWR-change-with-an-amplifier-tp7419653p7419681.html
>>> Sent from the Elecraft mailing list archive at Nabble.com.
>>> ______________________________________________________________
>>> 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
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> ______________________________________________________________
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>>
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