Cause of no audio on one band?

billspeedie

Not sure what I did but I no longer hear any audio in the headphones from my 6500 when on 17 meters. The other bands are fine, and WSJT works fine on 17, though I there's no sound if I put the headphones on when making a contact on that band.

A moment ago I went to 15 meters and the sound is good. I use a pair of mini speakers plugged into the audio in my PC to keep Windows from rearranging my sound, and use the 'phones when operating CW.

The RX stream on Slice A says "streaming data at 424 kbps" when on 17 mtrs but the red slider isn't showing anything, while it does show on the other bands where I can hear stuff. That's probably the best clue, but I need to figure out what I accidentally shut off.

Thanks for any suggestions,

Bill -- KA6T

K0FLY

Is the slice volume slider set to zero on 17 meters? It appears this adjustment is variable by band.

Gayle K0FLY

Mike-VA3MW

Can you post a screen shot of SmartSDR when it fails please.

billspeedie

Mike, thanks for assisting. Here's my screenshot showing all 3 monitors:

I suspect that I did one or more things wrong when trying unsuccessfully to get fldigi set up for the rtty contest. -- Bill, KA6T

Mike-VA3MW

Hi Bill

Sadly, I can't open them enough to read the control panel. Can you resend the audio part of the control panel? They have been resized to be super small.

billspeedie

Mike, here's the SSDR screen. Hopefully this will be readable after it's resized. For what it's worth, I accidentally hit one of the function keys on my keyboard and realized I can hear in the headphones what's stored in CWX (without CWX being selected). Also, I have noticed recently that the noise floor disappeared from the bottom of the display, only on 17 meter CW. Strangely, this is only on CW, not on DigiU when using WSJTX.

Thanks again, Bill - KA6T.

ka9ees

RF Power is set to zero.

billspeedie

OK, finally discovered what I had done. When operating FT8 on 17 meters in Slice A, I had opened the AGC drop-down menu and changed the AGC to Off. Since I was operating a digi mode and don't use speakers, I didn't realize that this killed the headphone audio. There was no problem while I was using WSJT but when I put the 'phones on and switched to CW, I couldn't hear anything. Changing the AGC setting to anything but Off brought back the sound in my headphones for CW. None of the other bands were affected by my changing this on 17, but I didn't try it anywhere else, so I'm guessing it's slice-specific.

The SSDR User Guide for v.2.5.1 on page 47 says "The Automatic Gain Control (AGC) drop-down menu allows the user to select Fast, Medium, Slow and Off AGC settings". Maybe a line should be added to say that it also kills the headphone audio for CW. Or maybe it's been changed in SSDR v.3 as I'm still using v.2.

Bill, KA6T

Mike-VA3MW

Bill

Can you also update to 2.8 please.

https://www.flexradio.com/software/smartsdr-v2-8-1/

thanks

billspeedie

Thanks for the prompt, Mike. I just updated to v.2.8.1. Will have to check in on the Community more often, so I don't miss future updates.

The situation is still the same after the update. Invoking AGC Off kills the headphone audio. I tried it on 17 and 15 meters and assume it would be the same on the rest of the bands. Maybe I have some other setting that causes it, but It's not a problem for me now that I know how the radio reacts and can adjust accordingly.

I appreciate your time and the upgrade suggestion.

Bill, KA6T

Mike-VA3MW

Can you show your AGC-T settings please.

My guess is that it is set to Zero.

billspeedie

Mike, the AGC-T setting is at 50. I'm sure this is heresy, but I've never fiddled with optimizing AGC-T. Running low power with a dipole 20 feet up, I've found that if I have difficulty hearing a station they almost never hear me. On FT8, for instance, I generally don't call anyone who reads with a higher negative number than -16 or so. I have had contacts where there's QSB and both reports get logged at around -20 but that doesn't often happen. My noise level right now on 15 meters is about -130, so I'm lucky to be in a pretty quiet urban area, I guess.

Bill, KA6T

Mike-VA3MW

That AGC-T is the most powerful tool on the receiver. You will need to adjust it multiple times / day and as you change antennas and bands. It is your friend.

Properly adjusted, the background noise almost disappears. This is a good thing.

https://www.flexradio.com/videos/flex-6000-receiver-tuning-how-the-agc-t-works/