[Elecraft] Key Clicks

[Jack Brindle]

I read that also. It was not a KPA500 or KPA1500. The Elecraft amplifiers are designed with solid-state switching and are capable of switching very rapidly, in much less time than 8 mSec. In fact the amps will switch quickly enough to allow true QSK in the K3/K3S. Fred’s analysis is correct in this regards.

There is a trade off with slower switching amplifiers - requiring higher values for TxDelay means eliminating QSK times and this the ability to copy signals between key down times.

This is documented quite nicely in the K3 manual. See the entry for TxDelay on page 66 of the K3S Owner’s manual, Rev A1.

It is notable in the ongoing discussion that the K3 and K3S are called out as examples of transceivers that do things right. In fact those of us with both Elecraft transceivers and Elecraft amplifiers provide examples of some of the cleanest signals on the air.

73!
Jack, W6FB


> On Jun 6, 2020, at 6:00 PM, David Gilbert <ab7echo at gmail.com> wrote:
> 
> QSK has everything to do with it.  If you hot switch the amp you create
> sharp waveforms every element even if the K3 keying is soft.  The
> discussion on the contesting forum included comments that the default
> setting for TXDELAY on the K3 (apparently 008) isn't long enough and that
> it should be set to 009.  Not sure which amps were being considered.
> 
> 73,
> Dave   AB7E
> 
> On Sat, Jun 6, 2020 at 5:40 PM John Simmons <jasimmons at pinewooddata.com>
> wrote:
> 
>> I have operated a number of the 'big' CW contests. I have heard some
>> really, really wide sigs with horrible key clicks. Yes they were
>> strong.... but 10 KHz wide? Rob Sherwood and others have written about
>> this. Some of the really high-end rigs (non-Elecraft) allow user
>> adjustment of CW rise time to such short values that key clicks are
>> guaranteed. Yech!
>> 
>> -de John NI0K
>> 
>> Fred Jensen wrote on 6/6/2020 7:05 PM:
>>> True. TXDelay is a sequencing parameter to assure that downstream
>>> switching has completed before RF appears. The keying waveform
>>> [particularly the edges and "corners"] affect the sidebands and thus
>>> bandwidth of the CW signal.  I don't believe QSK has anything to do
>>> with it, at least for a K3.
>>> 
>>> 73,
>>> Fred ["Skip"] K6DGW
>>> Sparks NV DM09dn
>>> Washoe County
>>> 
>>> On 6/6/2020 4:55 PM, N4ZR wrote:
>>>> There's a big discussion going on in contesting circles online about
>>>> the problem of key clicks.  There's been a lot of discussion about
>>>> settings called things like TXDelay, but so far as I can tell (and
>>>> the manual confirms), the K3's TX delay is intended to protect
>>>> amplifier relays at the start of a transmission.  So long as you
>>>> don't run QSK, I would think that setting would have no influence on
>>>> key clicks after the rise of the first CW element.  True?
>>> 
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