[Elecraft] K3 TX delay

[Vic, K2VCO]

I think you are confusing two things.

The hold time after RF output before receive can be as long as you want. 
The time between key down and RF output in the K3 can be from 8 ms to 
about 14 ms before keying is affected. It goes up to 20 ms, but at this 
point, the keyed elements are shortened. Most radios do not allow 
adjustment to this delay at all. Some (ICOM) radios actually drop the 
amp key output before RF output ends!

I agree with Don that for fast CW QSK the amplifier should be capable of 
switching in about 5 ms. This is not hard to achieve, but you can't do 
it with cheap open-frame relays. The original SB-220 doesn't represent 
the state of the art anymore.

For special situations like mast-mounted preamps, etc. you may need a 
sequencer. This won't provide QSK but will ensure that everything 
changes over properly. I don't think the K3 is in any way lacking as far 
as QSK sequencing is concerned.

On 2/15/12 6:23 AM, briana wrote:
> Alternatively buy any Kenwood, Yeasu et al which has this figured out.
> This has been a long standing problem with the K3.
>
> I'd like to hear from Elecraft that it "can't be fixed".
>
> 73 de Brian/K3KO
>
> On 2/15/2012 9:07 AM, Don Wilhelm wrote:
>> Igor,
>>
>> Yes, longer T-R delay times can chop off the leading edge of CW elements.
>> The proper answer is to add QSK capability to the amplifier.
>> If that is not possible or desirable, you may have to use a PTT footswitch.
>>
>> If the amplifier is not capable of QSK operation at the keying speeds
>> you use, there is not much that can be done in the K3 to compensate for
>> the amplifier inadequacy.
>>
>> 73,
>> Don W3FPR
>>
>>
>> On 2/15/2012 7:21 AM, Igor Sokolov wrote:
>>
>>> I wonder if there are plans to properly implement programmable TX delay in
>>> K3 in the near future.
>>> Current implementation works only with 8 ms delay. Attempts to increase this
>>> setting to max 20 ms ruin CW timing especially at high  CW speed.
>>> Unfortunately 8 ms is too short for many of power amps, let alone other
>>> external switching (stack control, external TX/RX switches etc) Separate
>>> sequencer is obvious answer but carry additional box is not in line with my
>>> purpose of light weight contest or  dx peditions. Is there any other
>>> solution?
>>>
>>> 73, Igor UA9CDC
>>>
>>>
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>
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-- 
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/