[Elecraft] K3 TX delay

[Joe Subich, W4TV]

On 2/15/2012 12:06 PM, Igor Sokolov wrote:

> I always use PTT foot switch. Even then longer then 8ms setting of TX
> delay affects CW. I do not understand why.

Apparently the K3 applies the TX Delay value to the CW input (key in)
regardless of Key Out status (e.g., is the radio already in transmit)
or VOX/QSK/PTT mode.  However, I have not heard the effect when using
PTT input - only when using QSK - and I can restore normal operation by 
adding "Keying compensation" (a fixed extension of each element) equal
to the TX Delay value in WinKey.

> Thank you everybody for you comments. It looks like external
> sequencer is the only solution. Pity.

I think most would agree that Elecraft should either delay the CW
element or add a fixed compensation equal to the TX Delay (which would
achieve the same result).  "Bit clipping" is a problem, particularly at
higher speeds.

73,

    ... Joe, W4TV


On 2/15/2012 12:06 PM, Igor Sokolov wrote:
> You are correct Rich.
> I always use PTT foot switch. Even then longer then 8ms setting of TX delay
> affects CW. I do not understand why. It is not brake in. It is just switched
> to TX and stays put. Why CW should be affected by this setting?
> My K3 is below 2000 serial number. I have just checked with my friend's
> above 6000 serial unit. It is still the same.  BTW  the internal delay
> between PTT into the radio and KEY OUT signal from the radio is about 6-6.5
> ms.  I assume there is only one relay in between. So if we have two relays
> in series externally or even one relay a bit more powerful (and therefore
> slower then the internal one) we have to use external sequencer. Even most
> popular power vacuum relays here have make time of 12-15 ms which precludes
> their use without external sequencer.
> Thank you everybody for you comments. It looks like external sequencer is
> the only solution. Pity.
>
> 73, Igor UA9CDC
>
>
> ----- Original Message -----
> From: "Richard Ferch"<ve3iay at storm.ca>
> To:<elecraft at mailman.qth.net>
> Sent: Wednesday, February 15, 2012 10:04 PM
> Subject: Re: [Elecraft] K3 TX delay
>
>
>> I think there's a bit more to it than that, Joe. My recollection, based
>> on my experience in SS CW a couple of years back, is that if CONFIG:TX
>> DLY is set to 20 ms, the K3's CW (with an external keyer) is "choppy"
>> even when using semi-breakin or PTT. I can't be 100% sure whether I was
>> using VOX or PTT, but I know for certain I was not using QSK, and I got
>> reports of "distinctive-sounding" CW, not just a truncated first
>> element. Setting CONFIG:TX DLY to 8 ms appears to have fixed it.
>>
>> 73,
>> Rich VE3KI
>>
>>
>> W4TV wrote:
>>
>>> One solution is to use a keyer like the K1EL WinKey that permits
>>> adding a fixed length to the elements to compensate for the K3's
>>> "bit clipping".  However, the proper solution would be for the K3
>>> to extend each element by the length of TX Delay when in QSK and
>>> extend the initial element by TX Delay when in semi-break in.
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