In the K3, TxDelay is simply the time from PTT out going active until RF starts
being generated. PTT will negate after the generated signal goes to zero. The
default is 8 mSec, which is adequate for most competitive amplifiers. In QRQ
mode, the time is shortened to 3 or 4 mSec. If the K3 or K3S is running
barefoot, there is no advantage to setting TxDelay above the default. Its only
effect will be delaying signal generation by some time, but since the
transceiver is going directly to the antenna, there will be no effect on the
generated waveform; it will remain clean. The biggest effect of increasing
TxDelay with an amplifier will be to shorten QSK times - that is the time
between key-downs when we can hear signals in the RF path.
The problem occurs when the amplifier is not able to switch quickly enough to
follow the transceiver’s output waveform. It will then cut off the signal at
some point, causing major issues that will most likely sound a lot like key
clicks. The Elecraft amplifiers (KPA500 and KPA1500) use solid-state switching
and are able to switch in far less than 8 mSec; in fact they handle the K3 QRQ
mode quite well with adequate margin.
Perhaps it is not just transceivers that need scrutiny, but amplifier switching
times as well.
73!
Jack, W6FB
> On Jun 6, 2020, at 4:51 PM, N4ZR <n4zr@comcast.net> wrote:
>
> Pardon a dumb question, but isn't the TXDelay normally from TR relay
> actuation to first RF? I know that's the case with my K3. In that case,
> unless you're running QSK, I don't see how that would cause clicks throughout
> the transmission, just at the beginning of the first character.
>
> 73, Pete N4ZR
> Check out the Reverse Beacon Network
> at <http://reversebeacon.net>, now
> spotting RTTY activity worldwide.
> For spots, please use your favorite
> "retail" DX cluster.
>
> On 6/6/2020 3:29 PM, donovanf@starpower.net wrote:
>> Hi Tad,
>>
>>
>> I don't know the specific answer to your question, it depends on the
>> details of the IC-7610 design.
>>
>>
>> The October 2018 QST product review discusses the IC-7610 4 msec
>> keying rise time and the possibility that the 6 msec menue s election
>> may be a better choice.
>>
>>
>> In any case, 6 milliseconds should make you a better citizen than 4 msec.
>>
>>
>> 73
>> Frank
>> W3LPL
>>
>>
>>
>> ----- Original Message -----
>>
>> From: "Tad Danley" <tdanley@centurylink.net>
>> To: donovanf@starpower.net
>> Cc: cq-contest@contesting.com, "cwops" <cwops@groups.io>
>> Sent: Saturday, June 6, 2020 7:08:31 PM
>> Subject: Re: [CQ-Contest] WPX CW Signal Quality Concerns
>>
>> Frank, my IC-7610 has 6 and 8 millisecond options as well. Is there any
>> disadvantage to using 8 ms?
>>
>> Best regards,
>>
>> Tad Danley
>> K3TD
>>
>> ----- Original Message -----
>> From: donovanf@starpower.net
>> To: cq-contest@contesting.com, cwops <cwops@groups.io>
>> Sent: Sat, 06 Jun 2020 14:37:56 -0400 (EDT)
>> Subject: Re: [CQ-Contest] WPX CW Signal Quality Concerns
>>
>> That's an excellent step forward Bud. There's no excuse for intentional
>> key clicks but that's exactly the place where the Japanese manufacturers
>> have intentionally put us in 2020.
>>
>>
>> The current generation of Japanese transceivers are making key click
>> problems much worse than before. Our only hope is that contest
>> sponsors improve their rules and enforce them against contesters
>> taking advantage of the fast CW rise time menu options in their radios.
>>
>>
>> Manufacturers are completely irresponsible with their 4 millisecond
>> default CW rise times and egregiously irresponsible with menus
>> options that allow users to select 1 and 2 millisecond rise times.
>>
>>
>>
>>
>> Kenwood and Yaesu provide completely unacceptable 1 and 2
>> millisecond rise time menu options and Icom is almost as bad with
>> their 2 millisecond menu option.
>>
>>
>> Why are ARRL and the U.S. distributors not communicating with our
>> Japanese equipment manufacturers about the problems they're causing
>> and enabling?
>>
>>
>>
>> 73
>> Frank
>> W3LPL
>>
>> ----- Original Message -----
>>
>> From: "cqwpx director" <cqwpx.director@gmail.com>
>> To: cq-contest@contesting.com
>> Sent: Saturday, June 6, 2020 4:58:15 PM
>> Subject: [CQ-Contest] WPX CW Signal Quality Concerns
>>
>> I have received two (2) actionable complaints of signal quality issues
>> during WPX CW, which are both under review.
>>
>>
>>
>> We will investigate additional signal quality concerns. Please provide the
>> call to be reviewed, along with the date, time and band of the observed
>> signal quality issue.
>>
>>
>>
>> 73,
>>
>>
>>
>> Bud Trench, AA3B
>>
>> Director, CQ WPX Contest
>>
>> web: <https://cqwpx.com> https://cqwpx.com
>>
>> email: <mailto:director@cqwpx.com> director@cqwpx.com
>>
>>
>>
>>
>>
>> _______________________________________________
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>>
>>
>>
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