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ZL3AI > APRDIG 03.07.03 09:14l 118 Lines 4244 Bytes #999 (0) @ WW
BID : 1559-ZL3AI
Read: GUEST
Subj: TAPR Digest, Jun 30, 3/3
Path: DB0FHN<DB0RGB<OK0PPL<DB0RES<ON0AR<ZL2BAU<ZL3VML
Sent: 030702/1328Z @:ZL3VML.#80.NZL.OC #:3570 [Chch-NZ] FBB7.00i $:1559-ZL3AI
From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
Subject: Re: Data from KPC-3+/failure analysis of balloon payload
From: Bob Bruninga <bruninga@usna.edu>
Date: Mon, 30 Jun 2003 12:40:51 -0400 (EDT)
X-Message-Number: 16
On Mon, 30 Jun 2003, Rochte, Robert wrote:
>Payload had 2" thick styrofoam walls all around with minimal venting, so
>cold shouldn't have been a problem. Aluminized mylar was added to the
>outside to limit solar heating of the box. The volume of the box was
>relatively large (>1000 in^3) to avoid excessive heat build-up from the
>equipment.
Sounds like a perfect way to guarantee that it got as cold as possible.
COuld have gotten to (minus) 60 degrees if there was any air leakage at
all. Being in -60 degree air would take a lot of electroncs heat to keep
it warm. Probablyu orders of magnitude below the pwer levels you were
running.
>Yes, it was definitely listening on 144.39 and set to relay. I hadn't
>considered that the channel might saturate given the extended LOS -- this
>sounds like a distinct possibility!
Wowha! thats it. 144.39 never goes silent at altitude. A TNC must be
set to FULL DUPLEX or some other means to make sure it does not hold-off
transmitting when the channel is busy or it will never transmit.
Bob
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Subject: Re: Raw Mic-E conversions?
From: "Maiko" <maiko@langelaar.net>
Date: Mon, 30 Jun 2003 12:19:17
X-Message-Number: 17
Dick wrote :
>Yes, NOSaprs has a switch to ignore doing anything to Mic-E's. We
>tested it with an IGate across the desert from me. Seems to work OK
>now.
The latest release of NOSaprs will now have MIC-E conversions switched
to OFF as the default. It's unfortunate *we* had to learn this the hard
way, but I'm glad the issue seems to be resolved. My apologies for any
chaos that was created because of this.
>We have had this discussion before...
Can anyone enlighten me when the *official* decision was made to stop
having Igates convert raw MIC-E packets when passing them to the APRS
internet system ? I recall a discussion, but I got the impression that
a consensus was never reached on it.
Maiko Langelaar / VE4KLM
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Subject: HAAT calculator site?
From: "Brian Webster" <bwebster@wirelessmapping.com>
Date: Mon, 30 Jun 2003 14:46:46 -0400
X-Message-Number: 18
Does anyone have the link to the site where you can go to calculate your
HAAT, I must have deleted it from my bookmarks.
Thank you,
Brian N2KGC
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Subject: Bit stuffing
From: "Scott Miller" <scott@opentrac.org>
Date: Mon, 30 Jun 2003 14:46:20 -0700
X-Message-Number: 19
Got a quick question... I'm finally getting back to writing the modulator
code for my tracker, and I went back to the AX.25 docs to make sure I had
the bit stuffing right. I think the 2.0 document has an error, though:
"Any time five contiguous one bits are sent the sending station shall insert
a zero bit after the first one bit. During frame reception, any time five
contiguous one bits are received, a zero bit immediately following five one
bits shall be discarded."
The key thing here is the bit about 'insert a zero bit after the FIRST one
bit'. That doesn't make any sense to me. That would change a sequence of
11111 to 101111, right? Which wouldn't decode properly, because you
wouldn't have a zero following five one bits. The 2.2 version seems to have
it right; it states that the zero bit should be inserted after the FIFTH one
bit.
Is there a corrigendum for the 2.0 doc someplace that I'm missing? Or is
the copy on the TAPR site just a misprint?
Scott
N1VG
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Subject: Re: Bit stuffing
From: John Hansen <hansen@fredonia.edu>
Date: Mon, 30 Jun 2003 18:22:57 -0400
X-Message-Number: 20
I don't know where this error crept in. I've always used the ARRL's
publication of the AX.25 protocol (not sure what version that was) and I've
never noticed it. However, I can confirm that what you've cited is in
error... The stuffed bit comes after the 5 ones. Good spotting!
John W2FS
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