TX CW “splatter” - context -contests

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TX CW “splatter” - context -contests

Elecraft mailing list
I am using the term CW splatter to cover clicks, phase noise, IMD
 and  other hallmarks of a wide signal.

>>
>> To me, the graphs presented by K9YC are compelling.  It is clear that a
>> number of modern radios are significantly “dirtier” than others, while  a
>> TS590,  that currently costs under $1500 at DXE, looks quite clean. The
>> charts display TX spectrum images from mid range transceivers to
>> premium rigs (15 rigs total) such as the K3, Flex and others.  Take a
>> look at K9YC.com/TXnoise.pdf.
>>
>> A dirty TX rig has much less impact on casual operating, or even most
>> Dxing, as the band isn’t usually crowded.  It is another story in a contest
>> as many offenders run HP with huge antennas. They are LOUD. I have had
>> to move many times when a loud, splattering CW signal parks a few
>> KHZ away.
>>
>> The cost of a clean TX is insignificant compared to such station’s antenna,
>> feedline and tower investment- plus all the other peripherals such a BPFs.
>>
>> Anyone who operates contests has heard such signals many times.  
>> It begs credulity that owners who are serious competitors aren’t aware
>> of the issue. But it appears that little is done as most hams (including the
>> log checkers) are reluctant to press.   Rather than ignore the issue, radio
>> manufacturers need to lose sales due to poor TX performance by hams
>> voting with their dollars.  I am glad the ARRL now takes a more proactive
>> role in evaluating TX performance.
>>
>> I understand the argument that we need to encourage activity, especially
>> from modest stations. I could not agree more, but in contests it is the loud
>> stations with dirty signals -often using big antennas- that affect other
>> competitors adversely, not just those nearby.
>>
>> It is time to place as much emphasis on a clean TX as on impressive
>> receiver specs. Some manufacturers, including Elecraft, already have.
>>
>> The CW splatter problem is noticeable  in EU and NA, sometimes emanating
>> from huge MM stations. I imagine that it occurs worldwide, but the Asians are
>> not generally that loud so their splatter is buried in the noise.
>>
>> 73,
>> Phil KT3Y- KP2M
>>
>>
>>

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Re: TX CW “splatter” - context -contests

Jim Brown-10
On 6/11/2021 9:22 AM, PHILIP ALLARDICE via Elecraft wrote:
> I am using the term CW splatter to cover clicks, phase noise, IMD
>   and  other hallmarks of a wide signal.

Clicks and what we have long called splatter ARE exactly the same
mechanism -- intermod distortion of an amplitude modulated signal. In
the case of CW, its 100% amplitude modulation of a carrier by a
rectangular keying waveform. Phase noise is an entirely different
mechanism.

73, Jim K9YC
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