Waterfall problem with FLDIGI

[KK4TTR]

I've been using FLDIGI with an ICOM 7200 direct USB connection and Linux OS in a portable Go box.

The last time I set everything up at home after a field trip with the gear, there has been a dark band in the waterall a hundred KHz wide on all frequencies. Before I start trial and error from scratch tracking down the source of this issue, any thoughts what might be causing it? I'm guessing something in a connection has filtered the center of the frequency. Anybody seen this before?

TIA

 

[ka3jjz]

In the off chance no one answers, this is the Yahoo support group for fldigi...

https://groups.yahoo.com/neo/groups/win-fldigi/info

Mike

 

[KK4TTR]

Yep, posted there, too. Thanks!

It's kind of an odd thing. I'm clueless as to what might be causing it, and just trying to figure out where to start.

 

[902]

Do you mean 100 Hz? And, what segment of the audio passband? Is it always in the same place with relation to the frequency you've got dialed in? Does the audio sound uncharacteristically funky to you, like that piece is notched out?

I don't have a 7200, but I do use FLDIGI with a SignaLink USB with a custom cable plugged into the rear port of my Icom M-710. It works reliably.

I mostly use MT-63 and occasionally see switching power supply noise sweeping through, but never have noticed a fall to zero except at the passband edges. My radio can't notch anything and I don't have a DSP on it. The only thing I can do with that radio is shift the RX clarifier.

I'd like to recommend you check the receiver for either a DSP tone notch or IF notch that might have been inadvertently switched on during your field operation.

 

[KK4TTR]

Thanks for the reply! A FLDIGI user on the yahoo group replied with a suggestion to check the Manual Notch Filter (MNF). Apparently, they have the same rig. Anyway, that was the problem and it's nice to see the entire waterfall once again.

73,

 

[902]

Thanks for the reply! A FLDIGI user on the yahoo group replied with a suggestion to check the Manual Notch Filter (MNF). Apparently, they have the same rig. Anyway, that was the problem and it's nice to see the entire waterfall once again.

73,

Wow, that's got to be a sharp notch! Glad you got it going again.

73!