Software:
Having tried nearly every available software, we found
ease of setup and operation in available freeware, that will surpass
that found in shareware. My hat is off to the programmers who make the
marvelous free software available.
I highly recommend new users to try Digipan first.
This is a great PSK31 freeware, and I will be using screen captures
from this
software to show new users how to setup. After you have a handle on how
to operate, then
you might want to test drive a fancier software.. I use mostly
Hamscope here,
and PSK31 Deluxe. Hamscope will do a great job on RTTY if you
download the
MMTTY Engine
from the MMHamsoft web page, and put the file in the Hamscope
directory. They mesh well. The regular
MMTTY software is good, but making and using macros leaves much to
be desired. This is why I use the Engine only, in conjunction
with Hamscope, which has lots
of macro buttons available, and are very easy to setup and use.
Connections
and Setup:
Some rigs are connected via only 1 data port, where some use as many as
3 connections to the radio. We will break the interface down into
it's 3 sections.
RECEIVE AUDIO SECTION
The above section is for receive audio. On some installations, it is as
simple as shown. Please note, the left channel audio is the only audio
channels that are used, and is normally the tip of a 3.5mm stereo plug.
Always apply signal to the "Line In" jack if it is available, as using
the "Mic" input of the sound
card can cause distortion, due to preamplification at that jack.
TRANSMIT AUDIO SECTION
In figure 2, the transmit audio section is shown, including the
adjustment trimmer, which is normally pre set to a standard level while
being tested on the test bench. Also shown is the blocking capacitor.
Also, use "Line Out" as opposed to the Speaker output if at all
possible.
PTT SECTION
Figure 3 shows how the PTT is accomplished. The 1.2k resistor is a line
resistor to drop the serial port voltage to a level that will allow the
optoisolator to trigger the PTT of the rig, and is a value that the
manufacturer of the chip recommends. Note:
The optoisolator in the PTT circuit has been changed to a reed
relay in our current interfaces. More info is found later in this
E-Book.
Most software programs that will allow transmission,
utilize the
RTS or DTR pin of a serial port in conjunction with an optoisolator, or
relay, to switch the PTT. With some software, the Vox circuit of your
radio can do the
switching, instead of a relay, etc., but Vox will usually not work with rigs where
you are connecting to a data port.
Depending on the radio being interfaced, this can
use only a few
cables, or several. If your radio has a Data or Accessory port, that is
the best spot by far to connect to, as one can normally leave the
interface connected always, without interaction from mode to mode.
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