[Elecraft] [KAT500] Help with KeyLine Interrupt on KPA500(Video)

[Brian Alsop]

This whole issue has been solved by VHF/UHF stations a long time ago. 
They use a sequencer to key and unkey various components with 
appropriate delays to prevent damage.

They can be built or bought fairly cheaply.

Yes it would be desirable to have the "sequencing" be automatic.  One 
"size" is unlikely to fit all though.

73 de Brian/K3KO
On 12/9/2012 15:02, Igor Sokolov wrote:
> IMHO adapting amplifier to work with KAT500 is not the right way of
> doing it because KAT500 is supposed to work with many different amps of
> 600 watt class.
> Yes, PTT is generated by the radio and then passed to KAT500. KAT500
> should generate it's own PTT signal for PA based on it's own KAT500
> status and incoming PTT signal from the radio. If incoming PTT is
> present and antenna is matched then KAT500 generates PTT for the amp.
> This will create additional delay equal to switching time of KAT500
> relays (minimum) plus some time required to analyze frequency and bring
> KAT500 to matching state. That is the price to pay for use of the
> automatic tuner.
> This will exclude PA faults and relays hot switching in KAT500.
> But then this feature can be user selectable. If you do not need it just
> do not use it.
> The question remains, is it possible to do it all in the firmware or
> hardware mods will be required.
>
> 73, Igor UA9CDC
>
> ----- Original Message ----- From: "ke9uw" <c-hawley at illinois.edu>
> To: <elecraft at mailman.qth.net>
> Sent: Saturday, December 08, 2012 6:18 PM
> Subject: Re: [Elecraft] [KAT500] Help with KeyLine Interrupt on
> KPA500(Video)
>
>
>> The PTT is generated by the transceiver. The KAT500 passes it thru to
>> the amp
>> unless the KAT is tuning a high SWR. The problem is that the amp goes
>> into
>> fault before the KAT can OPEN the key line. Firmware in the KAT with some
>> delay is not the answer...it's already too slow for the amp. If there
>> is any
>> programmable delay in the KAT, then a firmware change might be to
>> speed that
>> up if possible. But I doubt that it is possible since it's a relay
>> opening
>> in the KAT which requires some milliseconds.
>> I'm guessing the only Elecraft solution is to delay the amp's response to
>> the high SWR so it doesn't "Fault" giving the KAT time to open the key
>> line.
>> So the change in firmware we are waiting on is for the KPA amp.
>> Help me if I'm missing something here.
>>
>>
>>
>> -----
>> Chuck, KE9UW
>> --
>> View this message in context:
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>>
>> Sent from the Elecraft mailing list archive at Nabble.com.
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