I assume you may have seen this... for that radio
"
Also documented is the PC-Radio interface I have constructed for which
I make little or no claim of originality!
Radio Set up
Quite simply put, the manual that came with the radio in some areas is
at best misleading, and in others actually wrong. Lets start with the
basics. When the radio is in data mode there are two actual modes
available. One is "DATA LSB" where both the DATA and LSB indicators
are showing, and the other "DATA USB" where both the DATA and USB
indicators are showing.
What the manual doesn't tell you is that "DATA LSB" is FSK RTTY only,
and "DATA USB" is AFSK RTTY and also suitable for use on all sound
card based digital modes. On the back of the radio is an "AFSK-FSK"
switch. All this switch does is route pin one of the data port either
to the audio circuitry when in "AFSK" or to the tone generator when in
"FSK".
So, for most of us this switch needs to be in "AFSK" mode and the
radio in "DATA USB". The actual sideband that the radio is in is
controlled by menu item U-46. For typical RTTY operation, this needs
to be set to "2125-L", this sets the carrier injection up for an
offset of 2.125 kHz in a pseudo-LSB mode, so that the transceiver
actually is operating in LSB mode even though the display still
indicates "DATA USB". Conversely setting menu item U-46 to "2125-U"
will put the radio in USB mode.
It would appear that many digimode operators have experienced problems
trying to run the FT-920 in true Data mode. Reports I have seen
include "I used the Yaesu Data port on the original design but had to
disconnect the data in line and move it to the Yaesu phone patch in
jack. I discovered that the data port is only functional in the data
mode (not in standard modes like USB and LSB) and the data mode adds
information to the data in line, which causes problems."
It is worth noting at this point that the audio in via the data port
is only active when the radio is in Data mode. However, the use of the
data port has a number of advantages over using the mic socket or
"phone patch" connections, here are some of the best:
1.
The mic socket is not active in data mode, so you don't need to
plug the mic back in every time you wish to operate phone and rip it
out again when you go back onto digimodes. The mic gain control can be
left set for phone use.
2.
There is also no risk at all of transmitting in data modes with
the speech processor switched on -- go on we've all done it -- it's
not active.
3.
In DATA mode the Narrow "CW" filter is active when the narrow
button is pressed. This is not available in true SSB modes. In QRM
type conditions on PSK or RTTY this is very valuable. You tune the
signal in, hit the narrow button and then wind the shift control until
the signal is loud and clear. What QRM?
Radio PC Interface
I wanted to build an interface for the Radio to PC that would work on
all sound card based digimodes, but it seemed a useful feature to add
a keyboard CW facility via the Comm port DTR line with PTT for all
modes utilising the RTS line. A search of the web located the
following useful site:
http://www.qsl.net/wm2u/inter_ft.html
>From here there is a link to KC7DS's web site where a suitable
interface can be found:
http://www.qsl.net/kc7dh/sndcrd.htm
