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KPA500 problem

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marvwheeler

KPA500 problem

After switching from cw to sideband I have no output from either the K3S or
the KPA500. Simply putting the KPA500 into standby allows output from the
K3S. I think I have a switching problem. Where should I look?

Thanks

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Don Wilhelm

Re: KPA500 problem

That is a mystery.
The KPA500 is simply an amplifier, so it should amplify the K3S PEP
power for SSB the same as it does for CW.
Take a look at the drive power from the K3S. If you are overdriving the
KPA500 in SSB, it may be switching in an attenuator.
That could result from having too much compression on your SSB setting
in the K3S.
Have you set the PER BAND power in the K3S to limit the power to the
KPA500 when in operate mode? See the KPA500 manual pages 9 and 10.

73,
Don W3FPR

On 10/9/2017 11:55 PM, [hidden email] wrote:

> After switching from cw to sideband I have no output from either the K3S or
> the KPA500. Simply putting the KPA500 into standby allows output from the
> K3S. I think I have a switching problem. Where should I look?
>
>
>
> Thanks
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> 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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Jack Brindle-2

Re: KPA500 problem

Marvin;

Assuming that you have the AUX I/O cable connected from the KPA500 to the K3, and you have RADIO set to K3 in the KPA500 menu, then I suspect you have dialed the power down to 0 on the K3 when the KPA is enabled.

The KPA tells the K3 its state when it switches to STBY or OPER. The K3 uses this info to set the power level when you have the K3 set for PER BAND power as Don mentions. I don’t know if the per-band setting for power includes mode,
but since this is one of the few things the K3 does when the KPA changes its operating mode, it makes sense that the problem is a very low power setting in the K3.

If this isn’t the situation, be sure to check the AUX I/O cable to make sure that none of the pins are bent. Also make sure that pin 11 of the connector is missing. If it is not, then I would suggest that you might want to remove it and/or turn off the DIGOUT1 signal.

Other than that, Don is right. This is a mystery.

- Jack, W6FB

> On Oct 9, 2017, at 9:29 PM, Don Wilhelm <[hidden email]> wrote:
>
> That is a mystery.
> The KPA500 is simply an amplifier, so it should amplify the K3S PEP power for SSB the same as it does for CW.
> Take a look at the drive power from the K3S. If you are overdriving the KPA500 in SSB, it may be switching in an attenuator.
> That could result from having too much compression on your SSB setting in the K3S.
> Have you set the PER BAND power in the K3S to limit the power to the KPA500 when in operate mode? See the KPA500 manual pages 9 and 10.
>
> 73,
> Don W3FPR
>
> On 10/9/2017 11:55 PM, [hidden email] wrote:
>> After switching from cw to sideband I have no output from either the K3S or
>> the KPA500. Simply putting the KPA500 into standby allows output from the
>> K3S. I think I have a switching problem. Where should I look?
>> Thanks
>> ______________________________________________________________
>> 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]