[CQ-Contest] Fwd: TX CW “splatter” - context -contests

Michael Ritz w7vo at comcast.net
Fri Jun 11 15:14:31 EDT 2021

I certainly noticed a LOT of issues with loud and wide key-clicks in the recent WPX CW contest. Some were as much as 2-3 kHz away from the carrier. 
Now, at the risk of getting flamed and knowing there are some that think the ARRL should keep their noses out of things, the Board's Programs and Services Committee (PSC) has recognized the transmitter/amplifier "cleanliness" problem, and is in the process of putting together a committee, that will include well-known subject matter experts, to develop an initiative to help with the situation. The initiative will be a combination of working with radio and amplifier manufacturers, and the contesting community, to set new transmit cleanliness standards, and have the ARRL Lab test and certify new gear to ensure compliance to these standards. Along with this is an education campaign to teach new contesters how to set their equipment up to ensure a clean signal. 

In a way the ARRL Lab is already working on this. Reference the recent June issue of QST, and the "Lab Notes" side bar in the Yaesu FT-DX10 review on page 45. Even though I haven't spoken with Ed Hare, W1RFI, in the lab yet, I was VERY glad to see that notation there. It shows that the fast CW rise time issue is recognized by the lab as an issue! The result was that the crew in the Lab worked with Yaesu change the CW rise-time default setting to something slower to minimize clicks. A step in the right direction!

Now we need to take things to the next step and formalize it, along with other transmitter parameters.

I expect this to get this committee formally kicked off after the July ARRL Board meeting. 

(Fire suit on) - Comments?  


> On 06/11/2021 9:42 AM PHILIP ALLARDICE via CQ-Contest <cq-contest at contesting.com> wrote:
> This post is my response to a thread on the Elecraft page, but it applies 
> to contesters. I am not a technical expert. Is it possible that “hot switching 
> of an amp” causes clicks? Or are there other drivers of CW spatter aside 
> from the well documented causes?  I am aware that some modern rigs 
> have adjustable waveforms to reduce clicks.
> It took restraint to not identify repeat offenders, some of whom are 
> often near the top of the MM or SO listings.
> Thanks and 73.
> Begin forwarded message:
> > From: PHILIP ALLARDICE <KT3Y at aol.com>
> > Date: June 11, 2021 at 12:22:50 EDT
> > To: elecraft at mailman.qth.net
> > Subject: TX CW “splatter” - context -contests
> > 
> > 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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