[amsat-bb] ISS-Digipeating (APRS) with the IC-9100 - Tip

Stefan Wagener wageners at gmail.com
Sun Aug 31 20:50:14 UTC 2014

Two years ago, I wrote a short paper outlining the use of the IC-9100 with
an external interface (see file section of the IC-9100 Yahoo group –
_iss_ic9100.pdf) to dipgipeat via the International Space Station (ISS).

In the meantime, I was always wondering why digipeater operation with some
of the software modem programs was not possible with the USB connection
alone. Reading the excellent description by Hans DC1RJJ (see file section
of the IC-9100 Yahoo group – _IC-9100_PTT-CW_via_USB_modification.pdf), it
became clear to me that Icom did not enable the RTS and DTR signals of the
two virtual COM ports (required by some programs) and PTT can only be
triggered via a CI-V command or external hardware. I wasn’t ready to
perform the hardware modification as described by Hans to enable these
functions within the IC-9100. However, he pointed to a software program
that will use the CI-V commands together with programs that normally don’t
have that function. This program is called “Icom Keying” and was written by
Bill ND0B (see file section of the IC-9100 Yahoo group).

In order to get the IC-9100 to digipeat via the USB com ports and to use a
number of programs at the same time, I had to create some virtual serial
ports to allow the use of:

1.      1. SatPC32-ISS for Doppler control;

2.      2. Sound modem software by UZ7HO to RX and forward packets for UISS
as well as TX the packets from my location;

3.      3. Run the ICOM Keying program (CI-V command);

4.      4. UISS by ON6MU for ISS APRS.

Creating the virtual serial ports was done with a software by Eterlogic (
eterlogic.com) called VSPE (Virtual Serial Ports Emulator). I use the 64bit
version for my Windows 8.1 OS, however the 32bit works fine.

First, I created pair of virtual ports that are linked. Use port numbers
that are available on your computer. I used Com9 and Com10. This pair is
used by the Icom Keying program (Com9) and the SoundModem software by UZ7HO
(Com10, which tries to trigger PTT via RTS signal which is intercepted by
the Icom Keying program and translated in CI-V commands).

Now, the Icom keying program needs a real Com port (USB Com3 for the
IC-9100 in my system) to trigger the radio to go the TX (CI-V Command).
However, SatPC32-ISS also wants the same Com port for doppler control.
Consequently, I created a splitter with the VSPE for these two programs to
share the IC-9100 Com port 3. I linked a new virtual port (Com8) to my real
port Com3 and pointed both programs (SatPC32 & Icom Keying) to Com8 the
virtual Com port for sharing.

Starting everything up requires a little bit of a sequence:

1.     1. VSPE needs to be running

2.     2. Start the Icom Keying program

3.     3. Start SoundModem

4.     4. Start UISS

5.     5. Start SatPC32-ISS

This way, I am now able to do APRS digipeating without any additional
hardware just using the one and only USB cable between the IC-9100 and the

Let me know if you have questions,

73, Stefan, VE4NSA

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