[Ham-Mac] QST: New Feature in fldigi-3.21.12 for TXLevel Control

[Dick Kriss]

((This is repost and hopefully the plain text format is easier to read))

One of the really useful features in the new fldigi-3.21.12 maintenance release is the 
addition of the transmit level attenuator or TXLevel slider.  This addition under the
Configure/Sound Card/Audio panel is a very welcome addition for all users. 

Shortly after receiving the Kenwood TS-590S, I was able to replace the Keyspan 
Serial-to-USB adapter for Rig Control and the SignaLink USB by using a direct USB
interface between the iMac and the TS-590S. The TS-590S as well as the new Icom 
IC-7410 use the same chipset family contained in the Signalink USB. The only 
downside to the direct USB interface was I really missed the TX knob on the face 
of the SignaLink USB that let me adjust out ALC on-the-fly. 

The Kenwood TS-590S Menu item #64 for Audio Input for Data is a step function 
control and I found Step #3 was too high and Step #2 was too low. The step function
makes it useless for adjusting out ALC. The only way I could adjust the audio level 
was to open the OS X System Preferences/Sound/Output panel and use the Output 
volume slider. This was not a good solution for on-the-fly adjustments and the 
output from fldigi was such that I had to keep the OS X slider down to less then 2% 
with very little wiggle room for fine tuning.

Dave, W1HKJ, solved the ALC adjustment issue with the addition of the transmit 
level attenuator to fldigi under the Sound Card configuration panel. 

With the new TXLevel slider set to about -9 db to -10 db of attenuation I am now 
able to set the OS X Sound/Output volume slider to about 25% and put the TS-590 
Menu Item #64 back to the factory default #4 setting. This gets me in the ball park 
and I then use the new keyboard shortcuts to fine tune and/or adjust on-the-fly.  For 
Mac users the keyboard shortcuts are Command(-) and Command(=). Linux and 
Windows users use the ALT key.

I have tested the TXLevel in two contests and in daily PSK-31 and RTTY QSOs. I
keep the TS-590's S-Meter option set to ALC and track power on an external meter. 
When ALC starts to show (usually after a band or mode change), I adjust it out by
tapping the Command(-) or (=) keys. Each tap equals 0.1 db steps.

The new fldigi-3.21.12 with the TXLevel can be downloaded at

http://www.w1hkj.com/download.html

and the new transmit level attenuator (TXLevel) is described toward the 
bottom of Sound Card Setup help file at

http://www.w1hkj.com/FldigiHelp-3.21/SoundCardSetup.html

Thanks to Dave W1HKJ for this FB addition to fldigi.  Try it, I feel sure you 
will agree it is a welcome addition.

73 Dick AA5VU