GM, Tobias,
Locally, when we start a digi net, NC sends a Tune.
1. This allows RX stations to adjust their radio+hardware sound card+CODEC+fldigi so that they have a clean sig in the SIG panel. I prefer to do this Tune at ~512 Hz, because the SIG panel has no time controls, and a 500 Hz tone is the best we can do for horizontal viewing. Many prefer 1000 or 1500 Hz, but it is much more difficult to see incoming signal distortion at those frequencies.
I have asked in the past to have a much shorter time (wave more spread out) in the SIG display, but has not happened yet. There may be a reason for this, but I havna heard. Even if we don't have a time adjustment, we could really benefit from swapping to a time that is much shorter than the current SIG trace, and then swap back to the current one if that is of use to some.
2. NC can then ask a competent station to report its Tune signal quality. The signal can be perfectly clean in the fldigi display, but by the time it hits the air waves it can be distorted. There are many different individual brand-model signal processes. For example, the Kenwood V71 massages data signals to put them in a p-p window that the amp can handle. The Kenwood F6 HT can easily clip a too-high p-p audio signal. fldigi is pretty robust when it comes to signal processing (see FFTs), but it still pays to have the cleanest signal possible. So a competent station operator, with a properly adjusted audio stream, can look at the NC signal and report its quality. All this is the matter of a few minutes, so not a big burden.
3. Should a station need to send to NC, it can likewise use Tune to verify good signal quality, potentially saving the time to retransmit.
73 Rich NE1EE
The Dusty Key
On the banks of the Piscataqua
Rich NE1EE