KPA500 clicking

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KPA500 clicking

Wes (N7WS)
I'm a relatively new owner of a KPA500.  I'm also, thanks to the new K3
firmware, using QSK for the first time in my ham career.

These two facts have led to me hearing a slight clicking noise emanating from
the amp that follows the keying. This is unrelated to drive or output power,
since it happens in the TX Test mode too.  I understand that PIN diodes are used
for RF switching but it still sounds like a reed relay to me.

Any explanation?  (Hint) Having a schematic would probably make this self
explanatory.

Wes  N7WS
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Re: KPA500 clicking

W1KSZ
I looked a copy of the Manual and found only a block diagram. I cannot
imagine
them not supplying a schematic. Maybe it's an oversight ??

73 es HNY, Dick, W1KSZ


On 12/29/2014 2:58 PM, Wes (N7WS) wrote:

> I'm a relatively new owner of a KPA500.  I'm also, thanks to the new
> K3 firmware, using QSK for the first time in my ham career.
>
> These two facts have led to me hearing a slight clicking noise
> emanating from the amp that follows the keying. This is unrelated to
> drive or output power, since it happens in the TX Test mode too.  I
> understand that PIN diodes are used for RF switching but it still
> sounds like a reed relay to me.
>
> Any explanation?  (Hint) Having a schematic would probably make this
> self explanatory.
>
> Wes  N7WS
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
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>
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>

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Re: KPA500 clicking

AJ8MH-Radio.Joe.Hutchens
In reply to this post by Wes (N7WS)
I have clicking, but it doesn't following the keying.  (Maybe you meant
AFTER keying.)  It happens after a long transmission...for the most
part.  It has to do with flexing of the heatsink or other parts of the
chassis when the unit heats and cools.  I believe it's been covered here
before.

Joe ( AJ8MH )
http://webpages.charter.net/aj8mh-radio/

On 12/29/2014 4:58 PM, Wes (N7WS) wrote:

> I'm a relatively new owner of a KPA500.  I'm also, thanks to the new
> K3 firmware, using QSK for the first time in my ham career.
>
> These two facts have led to me hearing a slight clicking noise
> emanating from the amp that follows the keying. This is unrelated to
> drive or output power, since it happens in the TX Test mode too.  I
> understand that PIN diodes are used for RF switching but it still
> sounds like a reed relay to me.
>
> Any explanation?  (Hint) Having a schematic would probably make this
> self explanatory.
>
> Wes  N7WS
> ______________________________________________________________
> 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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Re: KPA500 clicking

Don Wilhelm-4
In reply to this post by Wes (N7WS)
Wes,

The KPA500 T/R switching is all electronic, so no reed relays are involved.

Are you certain the clicking noise is coming from the KPA500?  There may
be some audio from the speaker/headphones from the K3 when returning to
receive.  QSK OLD vs. QSK NEW might change the behavior unless it is
truly coming from the KPA500 (which would likely indicate some
mechanical effect - likely due to heating).

The fact that you hear it in TX TEST mode indicates that it is not a
heating problem, but check closely to determine if it is actually in the
K3 audio on a return to RX from TX condition.

73,
Don W3FPR


On 12/29/2014 4:58 PM, Wes (N7WS) wrote:

> I'm a relatively new owner of a KPA500.  I'm also, thanks to the new
> K3 firmware, using QSK for the first time in my ham career.
>
> These two facts have led to me hearing a slight clicking noise
> emanating from the amp that follows the keying. This is unrelated to
> drive or output power, since it happens in the TX Test mode too.  I
> understand that PIN diodes are used for RF switching but it still
> sounds like a reed relay to me.
>
> Any explanation?  (Hint) Having a schematic would probably make this
> self explanatory.
>
> Wes  N7WS
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
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>
> 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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Re: KPA500 clicking

Wes (N7WS)
In reply to this post by AJ8MH-Radio.Joe.Hutchens
No, I mean exactly what I said, it follows the keying, just as if a relay is
being actuated. And as I said, it has nothing to do with heat.


On 12/29/2014 3:34 PM, Joe Hutchens AJ8MH-Radio wrote:
> I have clicking, but it doesn't following the keying.  (Maybe you meant AFTER
> keying.)  It happens after a long transmission...for the most part.  It has to
> do with flexing of the heatsink or other parts of the chassis when the unit
> heats and cools.  I believe it's been covered here before.
>
> Joe ( AJ8MH )

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Re: KPA500 clicking

Wes (N7WS)
In reply to this post by Don Wilhelm-4
More on this mystery.  The sound is also audible in the K3.  It is definitely
mechanical and only happens (in both units) when the Aux cable is connected and
the KPA is in Operate, in other words when it goes into or out of transmit.  The
Speaker is Off in the K3, the sound is NOT audible in the headphones. It happens
in either QSK or Semi.  I can also hear a single click when going into or out of
Tune.

RF may be switched with PIN diodes, but there are some relays in there someplace.

This isn't, I suppose, a real problem; more of a curiosity and apparently, a
test of reading comprehension.

Now, exactly where are those schematics located?

Wes  N7WS


On 12/29/2014 5:38 PM, Don Wilhelm wrote:

> Wes,
>
> The KPA500 T/R switching is all electronic, so no reed relays are involved.
>
> Are you certain the clicking noise is coming from the KPA500? There may be
> some audio from the speaker/headphones from the K3 when returning to receive.  
> QSK OLD vs. QSK NEW might change the behavior unless it is truly coming from
> the KPA500 (which would likely indicate some mechanical effect - likely due to
> heating).
>
> The fact that you hear it in TX TEST mode indicates that it is not a heating
> problem, but check closely to determine if it is actually in the K3 audio on a
> return to RX from TX condition.
>
> 73,
> Don W3FPR
>
>
> On 12/29/2014 4:58 PM, Wes (N7WS) wrote:
>> I'm a relatively new owner of a KPA500. I'm also, thanks to the new K3
>> firmware, using QSK for the first time in my ham career.
>>
>> These two facts have led to me hearing a slight clicking noise emanating from
>> the amp that follows the keying. This is unrelated to drive or output power,
>> since it happens in the TX Test mode too.  I understand that PIN diodes are
>> used for RF switching but it still sounds like a reed relay to me.
>>
>> Any explanation?  (Hint) Having a schematic would probably make this self
>> explanatory.
>>
>> Wes  N7WS
>> ______________________________________________________________
>

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Re: KPA500 clicking

mcduffie
In reply to this post by Wes (N7WS)

> RF may be switched with PIN diodes, but there are some relays in there someplace.

No TR relay.  Amp is quiet as a mouse when keying/unkeying, even in QSK.  There
IS a STBY/OPER relay, I assume, as I can hear it when I go in and out of OPER.
Also, band switching, of course.

There are ticks due to heating in the heat sink, but not in time with keying.
Random, and varying rate.  Documented on this group previously.

Have you asked Elecraft (not this list) for a diagram?

Gary
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Re: KPA500 clicking

Robert Friess
What you are hearing is due to magnetostrictive force causing the windings
of the inductors in the TR switch to bang against their cores as the TR
switch bias is applied.  There are no relays.

73
Bob, N6CM, KPA500 design engineer.

On Mon, Dec 29, 2014 at 10:23 PM, <[hidden email]> wrote:

>
> > RF may be switched with PIN diodes, but there are some relays in there
> someplace.
>
> No TR relay.  Amp is quiet as a mouse when keying/unkeying, even in QSK.
> There
> IS a STBY/OPER relay, I assume, as I can hear it when I go in and out of
> OPER.
> Also, band switching, of course.
>
> There are ticks due to heating in the heat sink, but not in time with
> keying.
> Random, and varying rate.  Documented on this group previously.
>
> Have you asked Elecraft (not this list) for a diagram?
>
> Gary
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
>
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> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>
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Re: KPA500 clicking

Wes (N7WS)
Bob,

Thanks for your answer.

Hopefully, it lays to rest the idea that I didn't know what I was talking about
when I described it as the sound of a reed relay following the key.
  (Hmm, mechanical motion initiated by electromotive force....sort of describes
a relay doesn't it?)

That said, I'm not sure the phenomenon is totally due to magnetostriction.
"Coil Noise" may be a better explanation. (http://en.wikipedia.org/wiki/Coil_noise)

In the case at hand, I'm a bit concerned about having this happen.  Perhaps it's
from spending too many years around a failure analysis lab or doing vibration
testing on assemblies, where with a strobe light we could watch things move to
the point of failure.

What is Elecraft's fix?

Wes


  On 12/30/2014 12:29 AM, Robert Friess wrote:

> What you are hearing is due to magnetostrictive force causing the windings
> of the inductors in the TR switch to bang against their cores as the TR
> switch bias is applied.  There are no relays.
>
> 73
> Bob, N6CM, KPA500 design engineer.
>
> On Mon, Dec 29, 2014 at 10:23 PM,<[hidden email]>  wrote:
>
>>> RF may be switched with PIN diodes, but there are some relays in there
>> someplace.
>>
>> No TR relay.  Amp is quiet as a mouse when keying/unkeying, even in QSK.
>> There
>> IS a STBY/OPER relay, I assume, as I can hear it when I go in and out of
>> OPER.
>> Also, band switching, of course.
>>
>> There are ticks due to heating in the heat sink, but not in time with
>> keying.
>> Random, and varying rate.  Documented on this group previously.
>>
>> Have you asked Elecraft (not this list) for a diagram?
>>
>> Gary
>>

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Re: KPA500 clicking

Jack Brindle-2
Make sure the big toroid power transformer is tightened down properly. The tendency is to avoid tightening it too much, fearing some damage will occur. The transformer needs a bit more than that. I'm sure you will get a better feel for it shortly.

- JackB, W6FB

Sent from my iPad

> On Dec 31, 2014, at 7:45 PM, Wes (N7WS) <[hidden email]> wrote:
>
> Bob,
>
> Thanks for your answer.
>
> Hopefully, it lays to rest the idea that I didn't know what I was talking about when I described it as the sound of a reed relay following the key.
> (Hmm, mechanical motion initiated by electromotive force....sort of describes a relay doesn't it?)
>
> That said, I'm not sure the phenomenon is totally due to magnetostriction. "Coil Noise" may be a better explanation. (http://en.wikipedia.org/wiki/Coil_noise)
>
> In the case at hand, I'm a bit concerned about having this happen.  Perhaps it's from spending too many years around a failure analysis lab or doing vibration testing on assemblies, where with a strobe light we could watch things move to the point of failure.
>
> What is Elecraft's fix?
>
> Wes
>
>
>> On 12/30/2014 12:29 AM, Robert Friess wrote:
>> What you are hearing is due to magnetostrictive force causing the windings
>> of the inductors in the TR switch to bang against their cores as the TR
>> switch bias is applied.  There are no relays.
>>
>> 73
>> Bob, N6CM, KPA500 design engineer.
>>
>> On Mon, Dec 29, 2014 at 10:23 PM,<[hidden email]>  wrote:
>>
>>>> RF may be switched with PIN diodes, but there are some relays in there
>>> someplace.
>>>
>>> No TR relay.  Amp is quiet as a mouse when keying/unkeying, even in QSK.
>>> There
>>> IS a STBY/OPER relay, I assume, as I can hear it when I go in and out of
>>> OPER.
>>> Also, band switching, of course.
>>>
>>> There are ticks due to heating in the heat sink, but not in time with
>>> keying.
>>> Random, and varying rate.  Documented on this group previously.
>>>
>>> Have you asked Elecraft (not this list) for a diagram?
>>>
>>> Gary
>>>
>
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Re: KPA500 clicking

Wes (N7WS)
I considered, and rejected that possibility early on.  That said, when I get a
chance I'll see if something cold-flowed.


On 12/31/2014 10:41 PM, Jack Brindle wrote:
> Make sure the big toroid power transformer is tightened down properly. The tendency is to avoid tightening it too much, fearing some damage will occur. The transformer needs a bit more than that. I'm sure you will get a better feel for it shortly.
>
> - JackB, W6FB
>
>

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