[Elecraft] Key Clicks

[Bob McGraw K4TAX]

With my P3 I observe many CW signals that are wide.  And key clicks are 
easily recognized.  Likewise, transmit phase noise is also recognized as 
some signals are wide and some are very narrow.    Casual observations  
seem to center on one particular brand of radio that is most prone to 
have key clicks.   I've owned 2 of them and both were plagued with key 
clicks.   On one CW net which I participate, one of the ops can send a 
single dit or dah and I'll know exactly who it is.   His signal is that 
identifiable.

Yes, amps with slow relays are very prone to generate key clicks.   Even 
amps with vacuum relays with an accelerator circuit are often a bit 
slow.  One of the current, on the market, new amps selling today has a 
switching time which I measured of about 15 ms. There is no way this amp 
should be used in a QSK station operation or even a Semi-QSK unless the 
delay time is extended out to 17 ms to 18 ms.    That is one reason I 
sold it and purchased a KPA500.

Some amps contain a circuit which prevents hot switching. However, if 
the delay is not sufficient, the amp will not switch into transmit.  
This amp also uses two lines between the amp and radio.  One is the amp 
command, and the other is the radio command which occurs after the amp 
has switched.   I've owned one of those and the matching radio and it is 
a super combination for QSK operation.

I am also aware that several of the new ARRL Volunteer Monitor stations 
have and are reporting those stations with wide signals and stations 
with key clicks.

73

Bob, K4TAX


On 6/6/2020 8:00 PM, David Gilbert 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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