Originally Posted by SoonerSailor
The display on the 7400 might make it easier to identify a channel that is already busy, such that one doesn't step on a link already in progress - which happens a bit too frequently methinks. Whether it would be better than a careful listen, I don't know.
Both Dragons have a built-in busy detector. The status is available in software
(used by RMS-Express but not, I believe, Airmail). It is also reflected by the front panel TFC indicator on the DR-7400. I don't recall
seeing any indicator on the OLED of the DR-7800.
I know the busy detect circuit responds to Pactor
, RTTY, and Packet. It is supposed to work for PSK-31, JT-65, Olivia, radiofax, etc. and indeed for anything except a constant carrier.
For most cruisers only really interested in using Pactor
for e-mail with Sailmail or Winlink (or Shipcom or Bushemail or CruiseEmail) there is no substitute for listening carefully.
For those truly interested in a waterfall display (which is just an energy v. time display) a software
based on a computer will be much better. In addition to the waterfall display in RMS Express programs including multipsk, DigiPan, and Echolink have first rate displays.
Incidentally many people install Pactor modems buried somewhere in the boat. Flip the #1 dip switch on the back of the modem
to the 'ON' position and, if you use power from the radio
for the modem
, the modem will automatically turn on and off with the radio