开云体育

I finished assembling a high-band QMX on a 2023 Rev 2 board. First power up, no smoke! Everything seems pretty good except for when I tap the left encoder to enter digital mode, a horrible screeching noise emanates from the Audio port. With headphones on, this is a painful surprise!?

Has anybody else noticed this? Is it a known issue?

Firmware is 1_00_017 16-Feb-2024

Hello,

Isn't the "IQ mode" setting in the "Digi interface" menu enabled, by any chance?
If not, you may also try a factory reset.

Regards,
YO3GFH
op. Adrian

Thank you Adrian.?

The IQ mode is not enabled. Also, I tried a factory reset but the issue remains.

73, Matt

Matt,
I had a similar problem with my QMX when I had metal knobs on the encoders. An ESD event from my finger would cause the screeching. Try grounding yourself before touching the QMX ( I am assuming you don't have any knobs on the QMX yet and are just turning the encoder shafts)
Gary
W9TD

Thanks Gary. Unfortunately this issue appears with and without the knobs. I guess if I’m going to figure this out I’m going to need to become friends with the schematic and try to reason out what in changing to “Digi” mode could cause this “noise” to appear at the audio port.

It sounds almost like it would when you picked up the phone while your 14.4K modem was active on the line.

The noise on an ESD event here was exactly that sound at full volume. Have not had the problem after I switched back to the plastic knobs.
Gary
W9TD

My original post title may be misleading. The symptom I’m seeing is the noise is present continuously when Digi mode is enabled, not just during the switching transitions.

Still investigating.

Cheers.

Thanks Hans. I’m embarrassed to say that I think you identified the issue correctly. After several uses in the field, the Digi mode background noise level seems entirely reasonable.?

I made several screwups in assembling the radio, and while I think I recovered successfully, there is always that little doubt in the back of your head “did I mess something else up and not catch it?”

at any rate, it’s “case closed” as far as I am concerned.

73, Matt

Hi Hans

I'm finding that the difference in level bewteen signals on cw and digital is enormous. Adjusting the volume for good listening on CW means it is deafening on digital. I havn't been able to find any settings to correct this. With a good level on digital signals, CW is inaudible.? Rev 3,? _017 firmware.

Tony