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Re: working AO-7 and FO-29 with a FT-817



Wally Strom wrote: 

Is there a preferred way to  work AO-7 and FO-29 with a half-duplex rig ?  One of the reason I bought my FT-817 was to work AO-7 and FO-29.

Wayne replies:

There is no need to fuss with lots of channel memories to emulate reverse VFO tracking.  Instead, you can use computer software to give you "virtual" reverse VFO tracking and automatically correct for Doppler shift.  SatPC32 and InstantTrack/InstantTune can do this with an FT-817.  The only hardware needed is the CT-62 serial interface cable and a spare serial port on your PC.  The software automatically updates your TX VFO as you tune the RX VFO across the transponder (reverse VFO tracking).  The software automatically adjusts your uplink and downlink to correct for changing Doppler shift.  Both of these programs have "transparent" tuning.  This means that the computer-controlled Doppler tuning stops automatically when it detects that you are manually tuning across the transponder.  Then the Doppler tuning automatically resumes after you stop tuning manually.  So you tune your radio normally.  The auto Doppler tuning doesn't "fight" you, but the TX VFO does track when you tune manually.  TX VFO tracking is instant with SatPC32, but has a 1-2 second delay with InstantTune.  The delay with InstantTune isn't really a problem because you shouldn't transmit while manually tuning, and you should always listen before you transmit.

InstantTrack is a DOS program.  The map display doesn't run in a "Window" on most PCs.  To see the world map you typically have to run it in full-screen mode.  You can run it in a window with only the text display (no map).  InstantTune only fucntions when the InstantTrack window is the "active" window.  This is a problem if you want to use a logging program or sound card software at the same time.   It is somewhat inconvenient to tweak the tuning values, and it doesn't have any on-screen frequency display.  You can purchase InstantTrack from the AMSAT online store:  http://www.amsat.org/amsat/catalog/software.html#it    You can download InstantTune for free from the AMSAT web site  http://www.amsat.org/amsat/ftpsoft.html#pc

SatPC32 is a 32-bit Windows program that works on all new PCs (that run Windows).  It multi-tasks with any other programs you want to use while auto-tuning your radio.  It has on-screen displays of up/down frequency and up/down Doppler.    You can download a free demo version of SatPC32 from the author's web site:  http://www.dk1tb.de/indexeng.htm    The demo version is fully functional, except that you must enter your lat/lon every time you start the program.  If you like it, I encourage you to "register" the program with AMSAT.  The author (DK1TB) donated this program to AMSAT so your registration fee is a donation to AMSAT.

Wayne Estes W9AE
Mundelein, IL, USA



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