[amsat-bb] Re: Sat Tracking and SatPC32 w/ICOM rig - CT-17 hardware modneeded

Erich Eichmann erich.eichmann at t-online.de
Sun Apr 12 14:35:22 PDT 2009

Hello Bill,
the SatPC32.Exe and SatPC32ISS.Exe files that come with the 12.8 setup file
require the hardware handshaking  I have described in the Readme(Icom) text
(the "normal" SatPC32 only with the semi duplex radios IC-706MKIIG and
IC-7000 when used as single radio for satellite operation, SatPC32ISS with
the IC-910H for "inband" operation in non-satellite mode).

Meanwhile this hardware handshaking is no longer necessary. Some time ago I
have uploaded patch files on my website www.dk1tb.de (English page
"Downloads", sect. 5 "Patches"). With the IC-910H and IC-7000 the PTT status
is now checked via the software (CAT command hex. 1C. I didn't know that
command when I released 12.8. My manual doesn't mention it).
The IC-706MKGII doesn't provide such command, but Tony Monteiro, AA2TX,
found a solution also for that radio and told me the trick - many thanks to
him. So, also this radio does no longer  require the extra line between the
ACC jacket and the PC's serial port.

On my website I have described how to use the patch files.

73s, Erich, DK1TB

----- Original Message ----- 
From: "Bill Dzurilla" <billdz.geo at yahoo.com>
To: <amsat-bb at amsat.org>
Sent: Sunday, April 12, 2009 9:05 PM
Subject: [amsat-bb] Sat Tracking and SatPC32 w/ICOM rig - CT-17 hardware

> This may be old news to many but perhaps will save a few hours of
> frustration for newcomers.
> In my prior post about HRD Sat Tracking slowness with my Windows Vista
> computer, I reported there that ST was working very slowly with my Lenovo
> desktop running Windows Vista, but that it ran at normal speed with a
> laptop running Windows XP. However, the frequencies were not tracking
> properly -- the transmit frequency would "stick" as the receive frequency
> on my IC-7000.
> It seems there is a hardware cause for this issue. After I gave up trying
> to get HRD Sat Tracking to work with the laptop, I downloaded SatPC32,
> another program that automatically sets transmit and receive frequency to
> account for doppler. The same "sticking" problem occurred with that
> program.
> The ReadMe(Icom) in SatPC32 provides what appears to be an explanation for
> this issue:
> **************************
> With ICOM half duplex transceivers (IC-706MKIIG, IC-7000) hardware
> handshaking must be installed to suspend computer control while the radio
> is transmitting. Frequency changes are theoretically possible while the
> radio
> is transmitting, but frequency errors will occur, i.e., the frequencies
> of VFO A and VFO B will be exchanged.
> Unfortunately there is no way to check the PTT state of the radio via
> the CAT software. Therefore hardware handshaking is needed to prevent
> writing to the radio while it is transmitting. On the radio side pin 7
> of the ACC socket can be used for this purpose. The voltage at this pin
> is approximately + 8.0 V while the radio is in RX mode. In TX mode the
> voltage at pin 7 drops to 0.
> Pin 7 of the ACC socket must be connected with the CTS pin of the
> serial port on the PC side (pin 8 of the 9-pin, pin 5 of the 25-pin
> RS232 cable connector). I have connected these pins via a diode
> and a 5K resistor, see Acc_Com.jpg in this sub folder.
> When the radio pulls down the voltage at pin 7 to 0, it signals the PC
> not to send data. As soon as the radio is back in RX mode the frequencies
> are updated by the program.
> ATTENTION! There must be NO bridge between pins 7 and 8 of the 9-pin
> (5 and 4 of the 25-pin) cable connector at the PC side! Otherwise the
> voltage at Pin 8 (rsp.Pin 5) and therefore also at Pin 7 of the ACC
> socket will be pulled down and the radio will be switched into transmit
> mode. The sketches in the Icom sub folder provide this bridge. If it is
> built in, please, remove it.
> The 25-pin Connector at the ICOM CT-17 also provides a bridge between
> pins 4 and 5 and other pins. The CTS pin of the cable connector at the
> PC side must be connected only to Pin 7 of the ACC socket.
> *************************
> Thus, as I appreciate this, a standard ICOM CT-17 CAT cable will not work
> properly with SatPC32, and presumably not with HRD Sat Tracking either.
> Can anyone confirm this? Does anyone sell modified CT-17 cables that will
> do the job?
> 73, Bill NZ5N
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