[Elecraft] PX3 signal artifact - still seeking a solution

[David Herring]

Jim,

There is grounding, bonding and choking.  You’ve tried grounding and choking, it may be time to try bonding. 

Try bonding the PC to the rig with the shortest run practical of either large copper wire or braid. See if that has an effect on the artifact. 

Also, did the choking reduce the strength of the artifact at all? 

I have learned a lot from and thus recommend the papers on grounding, bonding and choking from Jim Brown, K9YC. http://k9yc.com/publish.htm <http://k9yc.com/publish.htm>

73,
David - N5DCH



> On Jul 21, 2020, at 9:07 AM, James Smallwood via Elecraft <elecraft at mailman.qth.net> wrote:
> 
>> My station consists of a KX3 / PX3 connected via 100 ft of DX Engineering RG-8/U Low-Loss coax through an Alpha Delta antenna switch to a Balun Solutions 4:1 Unun tied to a 31 ft vertical antenna. The antenna and unun are grounded via a copper rod driven 3 feet into sandy soil in South Florida. The entire station is grounded to the ground system of my house by a single copper ground wire which is about 7 ft long. Each piece of station gear (including the antenna switch) is separately grounded to a 2 foot copper pipe tied to that ground. I run the station off a 12v 3Ah Bionenno LiPO battery.
>> 
>> My question concerns a visual signal artifact of about 5-7dB strength that appears on my PX3, just off the frequency to which I am tuned. The artifact has 2 peaks when viewed at higher resolution. The artifact (which has no audio component) appears to be closely associated with a new Elecraft-provided USB cable connecting my HP Pavillion PC to my PX3. Once the USB cable is disconnected from the PC, the artifact disappears from the PX3 display. As soon as the cable is reconnected, the artifact reappears.The artifact appears regardless of other signals being present.
>> 
>> I recently purchased and installed a range of Palomar Engineers ferrite snap-ons (>>Mix 31<<) which failed to mitigate this artifact. I coiled as much of the USB cable as possible then clipped on the ferrite beads. This had no effect. I placed additional ferrite beads on other wires and cables associated with my station, but observed no impact on the artifact.
>> 
>> I am wondering whether I may need a different mix ferrite. Based on what I have shared here, do other solutions present themselves?
> 
>> Thanks for sharing any insights or suggestions.
>> 
>> Jim - N7RCS
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