Noise on SSB TX - Flex 3000

Charlie_KB8CR

When in TX on SSB (Voice not Digi), I get a large rise in the TX waterfall without any voice input. When I have been able to make a contact, the other side says there is a big distortion in the modulation. Here is a screenshot of the mic keyed, but NO audio from the mic. Any ideas? It was working just fine, this just started.

Charlie KB8CR

Bill -VA3WTB

does it still do it with the mic un plugged?

Bill -VA3WTB

also check the mixer and see if any sliders are to high.
check the EQ gain, too high?
Try turning down all things, EQ gain, mic gain and mixer sliders, just to see what is driving noise into the audio.

Charlie_KB8CR

I'll try that...Standby

Charlie_KB8CR

Yes, it does it even with the mic unplugged. :-(

Bill -VA3WTB

Ok along with turning everything down to 0 you can think of,,,try un plugging everything that you don't have to have,,,speakers, head phones mic. try one at a time to find the problem,,,,

Charlie_KB8CR

Mixer level was high, but even at mid level, it's still there.

Bill -VA3WTB

I don't know when  this started, check all your settings, anything different? Vox? try shutting down and restart the radio and software?

Bill -VA3WTB

Have you unplugged everything not needed? speakers head sets

Charlie_KB8CR

Just reset to factory defaults, and it's still there.

Bill -VA3WTB

I gave you a lot to try. I don't know if you have done them, shut down the radio,,re start the radio and software
Other than these things I'm not sure what other things to look at...sorry

Charlie_KB8CR

Everything is unplugged except for antenna and Firewire. Keying with MOX on PowerSDR. It's still there. It only disappears if I turn the mixer to zero on mic input.

Charlie

Charlie_KB8CR

I've been on the air and making contacts right and left in the contest, but no idea what the audio sounds like. 

Charlie_KB8CR

Weird, but now on TX it rises only momentarily, then goes back down to the noise level. So I guess it sort of fixed itself? Who knows....it's working well at any rate.

Dudley WA5QPZ

Think that you may have had "Mic Boost "  checked in the Transmit tab of Setup ???   This would greatly increase your mic gain..   Also that may have as been a poor ground in the mic circuit somewhere,  the RJ45 connector on the front is easily broken .   

73,
Dudley
WA5QPZ

Patrick

Check, your VOX setting or just turn off if on....

Dudley WA5QPZ

Oh the raise and then fall is most likely the DE (Downward Expander) / Noise Gate  being enabled and clamping down on background noise..   Enabled in the same Transmit tab of Settings ..   Doing exactly what it should .   

Dudley 
WA5QPZ

Charlie_KB8CR

No, I didn't have Mic Boost on. VOX also was not on. I turned on the DE and left it on. Guess it is helping. 

Charlie KB8CR

Bill -VA3WTB

At this time it sounds like you will need to send it in for service. But here is the thing, what is the radio worth? how much to ship along with service bill. Could you locate another one? 3000 or would you move up to a pre owned 6500 or something? So consider cost to worth.

Tim - W4TME

@Charlie.  Sorry for the delay in responding.  I have a few comments regarding your issue.

1.) I do not think there is a problem with the radio.  It is working as I would expect it to based on the information you have provided.

2.) When you key the mic, with or without with the mic connected, it enables the codec and there is going to be low-level audio gain coming out of it, in addition to any other gain stages in the TX signal path, like the EQ and that low-level signal will show up in the panadapter.  The signal level is -50 dBm and that is very low.

3.) You have the RF preamp enabled and that will exacerbate any low-level RF signals inside the radio when transmitting and that will be shown on the panadapter.

4.) I suspect that you have an option enabled to show transmitted audio in the pandapter/waterfall when transmitting (this is not shown on CW) and because the ambient mic gain level is greater than the receiver's signal level, the waterfall is compensating for that change in signal gain.  Once it is enabled for a few seconds, the waterfall black level normalizes to the new ambient signal level,

5.) using the DE will help because it is gating the gain coming from the CODEC and other gain stages in the TX signal path (see #2)

Charlie_KB8CR

Tim....I think you found the problem !! I had no idea I had the Preamp on.....seldom touch that. It's working FB now. Thanks !!

Charlie KB8CR