4k of transmitted bandwidth on SSB.....actually......50-4000 khz to be exact. TTBF = Total Transmitted Bandwidth Frequency. It takes the place of 50-3050. You can toggle back and forth between those two choices....TTBF or 50-3050, but you can't have both in the TX BW menu at the same time (unfortunately). Same way with all of the Yaesu radios that do TTBF. You have to toggle the radio on and off holding the DNR and MODE buttons to go back and forth between TTBF and 50-3050 choices.
Please pardon my ignorance, but what is ttbf 4k mode and where is it documented?
why would you use this feature TTBF ?
First, a caveat/disclaimer : I am NOT a member of the ESSB "crowd". Do I enjoy listening to the FANTASTIC audio that many in that crowd have? Of course. As an Electrical Engineer with over 45 years of experience I can always appreciate technology "on display". I do on occasion....when I hear some of the ESSB crowd on the air....say like on 7.208 Mhz late in the evening...if I join in, sometimesI set my FTDX 101D to TTBF just because I can (the FTDX 10 is relegated to the camper, I only use it when camping). And of course, I'd never do that on a CROWDED band.............
So, why would you use this feature? Just like so many other facets of this great hobby, ESSB is a part of the hobby some enjoy. They enjoy setting up their audio to have superb quality....and those of who open up our receive and have quality radios and THE EARS/HEARING to hear it ....and quality speakers (I'm running an active Edifier monitor speaker feeding a passive Edifier speaker with EQ and a Yaesu SP2000 with a DX Engineering kit that includes the replacement speaker and the foam fill/insert). ....can clearly hear the difference. It sounds FANTASTIC. Why do it? Because they can.