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Re: re: NO-45 carrier every 20 seconds



John Mock wrote:
 > Yes, i can confirm this.  I have heard NO-45 transmitting a pair of
 > bursts of apparently unmodulated carrier (consistent with length of
 > an AX25 UI packet) every N seconds each time i've listened in the
 > several weeks.
 >
 > -- KD6PAG

That is Sapphire (NO-45)'s beacon; yes, it's just the carrier wave
bursting on/off (the two pulses, as timed, are '00' according to our bit
definitions).  That indicates that Sapphire is still working -- and has
been the only thing we've heard for the past 16 months.  Sapphire has
not responded to any connect attempts.  But with some help, we may be
able to change that.

We believe ('hope' is closer to the truth) that the problem is a
software bit flip in the TNC.  (We have the same Kantronics model as
PCSAT, without the luxury of two TNCs and without much power cycling to
clear the memory.)  If so, then a hard reset of the TNC should clear the
problem (the TNC code is stored in radiation-hardened chips).  If it's a
hardware problem, then we're stuck with those bursts.

We can force an external reset, but as is all-too-common with a student
project, the parts necessary to send the reset signal were long since
co-opted for other projects and the documentation is somewhat spotty.  Sigh.

I do know this much:  the reset works by sending an ASCII text file
(converted to 1200 baud AFSK tones, not AX.25 packet).  I tested the
reset many times in the mid-90s using PCPlus to upload the file and a
TCM3105 chip under Win 3.1.  However, if you try to use this stuff on a
newer (32-bit) Windows system, it crashes the terminal program.

I'm writing all of this to make an offer:  if anyone out there has any
easy way to generate the AFSK tones (like an old Bell-212) and access to
an older Windows system (anything with 16-bit DOS), we might be able to
recover Sapphire.  Sapphire doesn't do all that much (most importantly,
he doesn't have any repeater capabilities), but there are a few toys (a
digital camera).  Bob Bruninga may want to share some time (especially
trying to tweak Sapphire into an APRS digipeater), but for the most
part, the original spacecraft users don't have much use for it.

So if someone's got the time, interest and the right tools, let me know.
  Maybe we can put the vehicle to good use.

-Mike Swartwout
Sapphire operations lead (if you can call Sapphire 'operational')

-- 
----------------------------------------------------------------
Michael A. Swartwout			mas@me.wustl.edu
Assistant Professor 			work: 314/935-6077
Mechanical & Aerospace Engineering	fax:  314/935-4014
Washington University in St. Louis	
----
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