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Does adding a small ground screw to the QMX case make sense?

Every antenna should be perfectly resonate at the frequency being used.

SWR is then 1:1 For a vertical antenna, a counterpoise or ground is necessary.

FT8 requires a computer or laptop. I use a tuner just after the radio. I'm having

trouble with RF getting getting into the laptop. Computers are not really grounded.

This problem is very erratic, sometimes just slightly moving the tuner knob causes the

PC to shut down the wsjt-x program.

Get plenty of ferrites on the interconnecting cables and power cable and a good choke on the antenna feedline

Also although the QMX is low power try to get the antenna some metres from the shack?

I had run into a similar situation. And this solved it:
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Amazon.com: Digirig Shielded Short USB-A to USB-C Cable with Ferrites : Electronics

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I so use this:

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RF into the computer is gone.?

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For a vertical, a ground connection is only for lightning or static charge protection. It won't do much for rf. So without a proper counterpoise, there's going to be rf issues.?

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I use 2 raised tuned radials on my 1/4 wave vertical in the field, and the common mode choke is a nessesity for this set up.?

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73
de Roy - KI0ER
Littleton, Colorado USA

And if you have a 1:1 SWR match to your vertical, what are you using the tuner for??

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With the setup I described, I use 20 feet of coax, so that's my approx distance from me to the antenna.?

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73
de Roy - KI0ER
Littleton, Colorado USA

Maybe on the ground to the radio? Do you use an external tuner? If so then you can ground there.

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Fortunately USB-C cables are made for high-speed connectivity so they have better braid-shielding over the center conductors; Many of the older USB-A cables had miserable shielding and I had to do through a process to find good ones for my SDR Play Duo to minimize RFI. You can also get a couple of clip-on ferrites and wrap as many turns of the USB cable through the ferrite... The more turns through the ferrite the greater the attenuation will be.

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Not grounding at the tuner could result in some 'weird' effects where the SWR looks good leaving the radio to the tuner, but the radio and laptop are also acting like part of the antenna system.

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Tisha, AA4HA

Here's the proper link to the USB cable that I use between my QMX and PC.

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As I recall from other discussions on this topic within this group, the shield of the USB cable is not, by spec, supposed to connect to the ground side of both connected devices, which is surprising to the uninitiated. But many cable manufacturers do make that connection.

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73
de Roy - KI0ER
Littleton, Colorado USA

Screw and wing nut are nice, if there is space. If not, a "pigtail" with a FEMALE banana jack, then plug your ground in this way. Ferrite chokes, of course. Frankly, I seemed to have solve the majority of my grounding and RF issues solved with a metal pin (maybe 18") long in the ground about a foot from my 1:4 un-un that feeds a long wire strung up in the back yard (I am on ground floor) to a plant hanger maybe 35' away. Flat feed through the window sash to un-un, then to one end of the wire that runs up to the eves and then to the hook. HOA issues, so need to be discrete, of course. With an ATU-10 tuner, I seem to be able to get it to tune from 40 through 10. I do need to see what loss I get in the ATU-10, versus a Chinese Z match, or a 4SQRP "T" tuner. Every milliwatt helps...