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

[iain macdonnell - N6ML]

On Fri, Dec 7, 2012 at 11:00 AM, hawley, charles j jr
<c-hawley at illinois.edu> wrote:
> So with the new firmware the KPA500 would tolerate a high VSWR for a few more milliseconds to give the tuner time to interrupt keying?

Yes. It may still kick in the attenuator temporarily, but it shouldn't
hard-fault.


> I was thinking of ways to not send a keying line with the K3 when using "tune". But this doesn't seem possible with the K3...I take it the PTT is used internally in the K3 or no RF comes out.
> I deal with turning the KPA to standby now anyway for the MFJ 998 tuner, so I'm used to remembering...but am looking forward to tha KAT500...and if the KPA doesn't mind a little non-hard fault, so much the better.

I used a MFJ-998 before I got the KAT500 too. I had the KPA500
configured to switch to standby mode on band-change, then I'd transmit
a bit to get the MFJ to tune, then put the KPA500 in Operate. I
operated the KAT500 that way at first too (during early field-test),
but since the firmware for both KAT500 and KPA500 have matured, I've
turned off the option to standby-on-band-change on the KPA500, and
have been happily QSYing around with no resulting hard faults.

73,

    ~iain / N6ML




> On Dec 7, 2012, at 12:31 PM, "iain macdonnell - N6ML" <ar at dseven.org> wrote:
>
>> It should be noted that the KAT500 does not "regenerate" the PTT
>> signal, rather it (only) interrupts it (by opening relay contacts).
>> Therefore it can't really delay the initial PTT signal going to the
>> amp... it can only interrupt it as fast as it can, when it detects
>> high VSWR.
>>
>> As Gary mentioned, there is newer KPA500 firmware that alleviates the
>> problem of hard faults when it detects high VSWR before the KAT500 has
>> time to interrupt the keying line, but it appears that that new KPA500
>> firmware has not been generally released yet.
>>
>> 73,
>>
>>    ~iain / N6ML
>>
>>
>>
>>
>> On Fri, Dec 7, 2012 at 4:10 AM, Igor Sokolov <ua9cdc at gmail.com> wrote:
>>> I think what happens is KAT500 needs few msec to determine the operating
>>> frequency and measure SWR. There is currently no delay between PTT going
>>> into KAT500 from the radio and PTT going out into the KPA500. These few msec
>>> is enough for KPA500 to switch itself to fault condition.
>>> Here programmable PTT delay in KAT500 would be very helpful. Especially so
>>> with other makes of the amplifiers.
>>> I have discussed it with Elecraft tech support and they say this feature is
>>> on their to do list. Lets hope that the next firmware revision of KAT500
>>> will have that feature implemented.
>>>
>>> 73, Igor UA9CDC
>>>
>>> ----- Original Message ----- From: "Chris Johnson" <elecraft at ozy.us>
>>> To: <Elecraft at mailman.qth.net>
>>> Sent: Friday, December 07, 2012 3:35 PM
>>> Subject: [Elecraft] [KAT500] Help with KeyLine Interrupt on KPA500 (Video)
>>>
>>>
>>>
>>>> Hi Guys,
>>>>
>>>> I made a video and posted it on youtube to better explain the issue I'm
>>>> having.   Please watch and then reply to it here if you would.
>>>>
>>>> Much appreciated
>>>>
>>>> http://www.youtube.com/watch?v=QtCPvKKM3_c
>>>>
>>>> Chris
>>>> K6OZY
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