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RE: re: NO-45 carrier every 20 seconds



Unless I'm mistaken, anyone with a PK-232 can accomplish this, by selecting ASCII mode, ABAUD of 1200 baud (the on-air baud rate for ASCII), and the VHF / wide-spaced modem.  If I recall right, the command would be "VHF ON" to achieve this.  The data rate from the PC to the TNC should be higher than the on-air rate.  Depending on the length of the file to be sent, correctly functioning flow control might be necessary.  Hope that helps!

73, Bob, KD7NM

>-----Original Message-----
>From: Michael Swartwout [mailto:mas@wustl.edu]
>Sent: Wednesday, October 22, 2003 12:38 PM
>To: amsat-bb@AMSAT.Org
>Subject: Re: [amsat-bb] 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	
>----
>Sent via amsat-bb@amsat.org. Opinions expressed are those of 
>the author.
>Not an AMSAT member? Join now to support the amateur satellite program!
>To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
>

----
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