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PX3 signal artifact - still seeking a solution

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PX3 signal artifact - still seeking a solution

> 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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David Herring

Re: PX3 signal artifact - still seeking a solution

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 <[hidden email]> 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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Ignacy

Re: PX3 signal artifact - still seeking a solution

In reply to this post by Elecraft mailing list

Do artifacts disappear when you have USB cable connected to the laptop but
disconnected from PX3?
Perhaps the USB cable acts like an antenna.

For RFI transmitted via USB cable, try USB isolator. E.g.,
https://www.amazon.com/SMAKN-Isolator-Digital-Isolation-Industrial/dp/B00XXPO4UG

Ignacy NO9E

--
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Jim Brown-10

Re: PX3 signal artifact - still seeking a solution

On 7/21/2020 11:10 AM, Ignacy wrote:
> Perhaps the USB cable acts like an antenna.

That often happens. But it can also excite a Pin One in whatever it is
connected to on either end.
>
> For RFI transmitted via USB cable, try USB isolator. E.g.,
> https://www.amazon.com/SMAKN-Isolator-Digital-Isolation-Industrial/dp/B00XXPO4UG

If you have more money than you need, perhaps. But all it takes is to
wind multiple turns of the "USB antenna" through a #31 ferrite clamp-on.
They cost a few bucks if you buy from industrial vendors like Arrow and
hit their minimum order of $50 for anything in stock. Fill up that
quantity with more ferrite cores -- most of us need them to kill noise
from the dozens of sources in our own homes!

See http://k9yc.com/KillingReceiveNoise.pdf

73, Jim K9YC

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David Herring

Re: PX3 signal artifact - still seeking a solution

Jim,

Having percolated on this for a while longer, another thought comes to mind. You mentioned that you tried a ferrite snap-on on the USB cable. In order to really be effective, the USB cable would best be tightly wrapped around the sides of the snap-on in something of a serpentine or sequential fashion, not just randomly coiled up like a garden hose. I don’t know the specifics of how you did it, but I mention this in case you did the garden hose method originally…in that instance it would be a worthy exercise to rework your choke, wrapping it properly and seeing if that then makes a difference.

Also, it’s not unheard of to need multiple snap-ons with multiple turns each to get enough impedance to choke out the unwanted signal. Especially if you can’t get 6 to 8 passes through the center of a single snap-on.

Oh, and once you get the snap-on wound, it’s highly recommended to cinch down a zip tie around the circumference to ensure that both ends of the ferrite material inside are making good contact with each other. If there’s the slightest gap, the thing won’t work worth squat.

Hope that helps, and that at least one of these suggestions you’ve been getting on the reflector solves your artifact issue. ;-)

73,
David - N5DCH

> On Jul 21, 2020, at 2:26 PM, Jim Brown <[hidden email]> wrote:
>
> On 7/21/2020 11:10 AM, Ignacy wrote:
>> Perhaps the USB cable acts like an antenna.
>
> That often happens. But it can also excite a Pin One in whatever it is connected to on either end.
>> For RFI transmitted via USB cable, try USB isolator. E.g.,
>> https://www.amazon.com/SMAKN-Isolator-Digital-Isolation-Industrial/dp/B00XXPO4UG
>
> If you have more money than you need, perhaps. But all it takes is to wind multiple turns of the "USB antenna" through a #31 ferrite clamp-on. They cost a few bucks if you buy from industrial vendors like Arrow and hit their minimum order of $50 for anything in stock. Fill up that quantity with more ferrite cores -- most of us need them to kill noise from the dozens of sources in our own homes!
>
> See http://k9yc.com/KillingReceiveNoise.pdf
>
> 73, Jim K9YC
>
>
>
> ______________________________________________________________
> Elecraft mailing list
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Grant Youngman-2

Re: PX3 signal artifact - still seeking a solution

If the cable is shielded, and the garbage is on the PC's USB signal lines, an external ferrite won’t do any good. I don’t know if the cable is shielded or not, but if it is, then the garbage may not be on the shield … and perhaps the USB isolator might be worth a try. Maybe. I don’t know anything about that device …

Grant NQ5T

> On Jul 21, 2020, at 5:36 PM, David Herring <[hidden email]> wrote:
>
> Jim,
>
> Having percolated on this for a while longer, another thought comes to mind. You mentioned that you tried a ferrite snap-on on the USB cable. In order to really be effective, the USB cable would best be tightly wrapped around the sides of the snap-on in something of a serpentine or sequential fashion, not just randomly coiled up like a garden hose. I don’t know the specifics of how you did it, but I mention this in case you did the garden hose method originally…in that instance it would be a worthy exercise to rework your choke, wrapping it properly and seeing if that then makes a difference.
>
> Also, it’s not unheard of to need multiple snap-ons with multiple turns each to get enough impedance to choke out the unwanted signal. Especially if you can’t get 6 to 8 passes through the center of a single snap-on.
>
> Oh, and once you get the snap-on wound, it’s highly recommended to cinch down a zip tie around the circumference to ensure that both ends of the ferrite material inside are making good contact with each other. If there’s the slightest gap, the thing won’t work worth squat.
>
> Hope that helps, and that at least one of these suggestions you’ve been getting on the reflector solves your artifact issue. ;-)
>
> 73,
> David - N5DCH
>
>
>
>> On Jul 21, 2020, at 2:26 PM, Jim Brown <[hidden email]> wrote:
>>
>> On 7/21/2020 11:10 AM, Ignacy wrote:
>>> Perhaps the USB cable acts like an antenna.
>>
>> That often happens. But it can also excite a Pin One in whatever it is connected to on either end.
>>> For RFI transmitted via USB cable, try USB isolator. E.g.,
>>> https://www.amazon.com/SMAKN-Isolator-Digital-Isolation-Industrial/dp/B00XXPO4UG
>>
>> If you have more money than you need, perhaps. But all it takes is to wind multiple turns of the "USB antenna" through a #31 ferrite clamp-on. They cost a few bucks if you buy from industrial vendors like Arrow and hit their minimum order of $50 for anything in stock. Fill up that quantity with more ferrite cores -- most of us need them to kill noise from the dozens of sources in our own homes!
>>
>> See http://k9yc.com/KillingReceiveNoise.pdf
>>
>> 73, Jim K9YC
>>
>>
>>
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:[hidden email]
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>> Message delivered to [hidden email]
>
> ______________________________________________________________
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Jim Brown-10

Re: PX3 signal artifact - still seeking a solution

On 7/21/2020 3:03 PM, Grant Youngman wrote:
> If the cable is shielded, and the garbage is on the PC's USB signal lines, an external ferrite won’t do any good. I don’t know if the cable is shielded or not, but if it is, then the garbage may not be on the shield … and perhaps the USB isolator might be worth a try. Maybe. I don’t know anything about that device …

Hi Grant,

See my earlier post in this thread and the reference cited -- the
problem is that the noise is NOT differential mode (inside the cable),
it's common mode, and often on the shield, due to its improper
termination inside the box.

73, Jim K9YC
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hhoyt

Re: PX3 signal artifact - still seeking a solution

In reply to this post by Elecraft mailing list

Hi Grant,

The shield only shields electrostatic fields and does not shield the
magnetic field from the inner conductors. If the garbage is on the USB
signal lines and common mode (likely), the ferrite will still be
effective. If the RFI is transverse (or differential) mode, then the
external fields from those signal conductors will largely cancel and
ferrite will have little or no effect.

BTW, Pro Audio Engineering is a first-line Fair-Rite dealer and we have
good stock on many mix 31 parts at good prices in small quantities.

Cheers & 73,
Howie / WA4PSC
www.proaudioeng.com

>>If the cable is shielded, and the garbage is on the PC's USB signal lines,
>>an external ferrite won?t do any good. I don?t know if the cable is
>>shielded or not, but if it is, then the garbage may not be on the shield
>>? and perhaps the USB isolator might be worth a try. Maybe.
>>I don?t know anything about that device ?
>>
>>Grant NQ5T

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Elecraft mailing list

Re: PX3 signal artifact - still seeking a solution

In reply to this post by Elecraft mailing list

Jim,

This sounds a lot like a problem I was experiencing with my KX3 while operating FT8. I was getting pulsating noise on the signal sent to the KX3 from my MacBook Pro laptop. I tried all the suggestions including bonding the computer and putting ferrites on all signal and power leads with no improvement. I finally noticed that Elecraft KXUSB cable connected from PX3 to the laptop for rig control has an LED which blinks at a rate (almost exactly once per second) with corresponds to the noise heard.

On the MacBook Pro I was using a port adapter which allows connecting a HDMI cable, a USB cable and an apple Lightning power cable to one of the 4 USB-C (Lightning) ports on the laptop. By simply moving the power cable from the adapter to a separate port the noise completely disappeared. Since you mention that your foul signal disappears when you disconnect the USB cable from your laptop I suspect you may be suffering the same problem. In my case, apparently when the LED pulses some of the power supply noise is coupled into the USB port and contaminates the signals. I was worried about transmit signals and did not see if any artifacts were showing on the PX during receive.

Phil -AA2EA
Louisville KY

>
>> On Jul 21, 2020, at 9:07 AM, James Smallwood via Elecraft <[hidden email]> 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
>> ______________________________________________________________