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Re: Marex news, ISS radio status

Miles overstates the D700 problems.  The memory channels didn't  
become corrupted; they are fine.  Physically, the radio is fine.   
What happened was that the programmed operating modes (PMs, in D700  
terminology) were overwritten by unplanned (and unknown) changes,  
probably during the SSTV try-outs.  Without reliable PMs, changing  
modes requires a lengthy and error-prone procedure to switch between  
packet operations and school contacts.  Therefore, the radio was  
manually put in the school contact configuration and left there.   
That is its primary mission.

Fixing the PMs does not require an OS load (whatever that means).   
The custom EPROM firmware, which modified some of the D700's  
functions for space use, doesn't need to be changed.  The PMs are  
just operator configurations that can be reloaded from a computer via  
a serial port on the front of the radio, without disassembling  
anything.  All that is needed is the computer, crew training, and  
scheduled crew time to do it (all of which are hard to arrange on ISS).

-- Dave, W8AAS

On Apr 5, 2007, at 3:26 PM, MM wrote:

> ISS Amateur Radio Status: April 5, 2007
> By Miles Mann WF1F,
> Voice and Packet:
> The Kenwood D700 celebrated its 3-year of service last
> December.  However after three years of 24/7 usage has
> taken its toll.  Last August the memory channels
> became too corrupted to be reliable.  The procedures
> given to the crew to configure a channel combination
> did not always match the instructions and there were a
> few times when I heard the ISS crew calling for a
> school and ISS was on the wrong uplink frequency.  The
> D700 was removed from Public access last August and is
> only being used for pre-arranged school schedules,
> etc.
> The good news is that we may get an opportunity to
> reload the OS on the D700 during the upcoming crew
> change. The D700 on ISS is running a special OS and
> channels setup, created just for the ISS.  If time
> allows, the D700 will get a fresh OS reload to set it
> back to the launch configuration.  The OS reload, also
> includes a very complex channel configuration and
> other unique settings.  The OS reload requires the
> removal of the covers and the installation of a
> special ribbon cable.  See the attached link (bottom
> left Picture).  As a back up plan, if the reload
> fails, a few basic channels may be hand keyed into the
> radio.

Sent via sarex@amsat.org. Opinions expressed are those of the author.
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