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ZL3AI > APRDIG 20.01.04 15:14l 238 Lines 9358 Bytes #999 (0) @ WW
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Subj: TAPR Digest, Jan 18, 2/5
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From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
Subject: Re: Attended vs Unattended
From: "Richard Amirault" <ramirault@erols.com>
Date: Sun, 18 Jan 2004 13:25:25 -0500
X-Message-Number: 8
----- Original Message -----
From: "Bob Bruninga" <bruninga@usna.edu>
Subject: [aprssig] Attended vs Unattended
(snip)
>"Presence" or "active" at a station is defined as APRS Keyboard or Mouse
>activity within the last 10 minutes.
(snip)
I understand that you've got to 'draw the line' somewhere, but this will
give a false indication of stations that have live operators but are doing
something else. That is .. a fully operation APRS station is within both
eye and ear shot but who are talking on another radio or reading the paper
.... or watever. Also, not every APRS station has a mouse.
If the indicator is changed to something the operator must do .. toggle a
key (I'm here/I'm not here) then you have the problem of operator error.
Forgetting to "check out" when walking away, or forgetting to "check in".
Is it going to be a problem if there is a fully manned station, but the
'indicator' says NOT ?? Will folks not send messages that might have
otherwise?
I understand what you are trying to do Bob, but I don't think it can be
implemented properly and will only cause other complications.
Richard Amirault N1JDU Boston,
MA, USA
www.erols.com/ramirault "Go Fly A Kite"
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Subject: Re: Attended vs Unattended
From: Steve Dimse <k4hg@tapr.org>
Date: Sun, 18 Jan 2004 13:34:54 -0500
X-Message-Number: 9
On 1/18/04 at 12:52 PM Bob Bruninga <bruninga@usna.edu> sent:
>Using the N/S byte for this flag should be backwards compatible. But we
>need to checkout all existing software before going forward with this.
>I'd check out my D700, but my wife took off with the car... :-(
I suspect there will be a lot of incompatibilities. My release of javAPRS
is not compatible, Pete would have to say if he has changed this code since
I gave it to him, but either way, a LOT of javAPRS sites would need to be
updated to use this. There needs to be time to roll out changes to all
users of javAPRS, and I suspect other clients would need to be updated as
well.
Certainly findU is not presently compatible, though it would not be hard
for me to change, since there are only two servers running it.
It is important to test all cases, as parsers may be written in different
ways, as I've discussed in regard to the error page. javAPRS used this code
to determine hemisphere:
if (theString.charAt(i+7) == 'S') theReport.position.lat *= -1;
with this code, any character other than S places a person in the northern
hemisphere. I could just have easily written:
if (theString.charAt(i+7) != 'N') theReport.position.lat *= -1;
in which case any character other than N places someone in the southern
hemisphere.
findU uses the power of regular expressions to first make sure the entire
lat/lon code matches the template of a valid lat/lon (including the lat
hemisphere character must be either N or S, then applying the conversion.
findU will fail on any lower case character, but javAPRS would seem to pass
if the test case was only lower case n (and e). Therefore, before assuming
that a program works correctly with the new protocol, be sure to verify the
program places reports in the correct position of all 4 map sectors with
both upper and lower cases. Also, there is no guarantee that the code for,
say a weather station parse in the same manner a ! packet, and so on, so
you must check each type of packet separately.
Also, effort needs to be made to get all those people using lower case
errors now to fix their errors. A quick look at findU's error page shows 5
stations using lower case characters there now, all seem to be manually
entered digis.
A lot of work, but if the APRS WG ratifies this change in the spec, I would
make the change in findU. I don't even know if I have a system that could
compile my version of javAPRS, but if I can do it, I will, but again, not
until the change is ratified.
Steve K4HG
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Subject: RE: PCsat Endangered
From: "Scott Miller" <scott@3xf.com>
Date: Sun, 18 Jan 2004 10:39:53 -0800
X-Message-Number: 10
If *I* ever build a satellite, I'm going to include some sort of automated
'thumping' mechanism, like the one I envisioned for my old flaky TV.
There's nothing like good old percussive maintenance for things like this.
=]
Scott
N1VG
-----Original Message-----
Subject: [aprssig] PCsat Endangered
PCsat has a stuck relay that has the XMTRS crossconnected and is thus
consuming TWICE the normal transmit power on EVERY packet. The command
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Subject: RE: PCsat Endangered
From: Earl Needham <needhame1@yucca.net>
Date: Sun, 18 Jan 2004 12:22:01 -0700
X-Message-Number: 11
At 11:39 AM 1/18/2004, Scott Miller wrote:
>If *I* ever build a satellite, I'm going to include some sort of automated
>'thumping' mechanism, like the one I envisioned for my old flaky TV.
>There's nothing like good old percussive maintenance for things like this.
>=]
You could just include my stepmother, along with a rolling pin...<G>
Earl
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Subject: Re: Digital HF QRP?
From: Jeff King <jeff@aerodata.net>
Date: Sun, 18 Jan 2004 14:23:05 -0500
X-Message-Number: 12
On Fri, 16 Jan 2004 15:27:53 -0800, Scott Miller wrote:
>Expensive is bad. I'm not so much interested just for my own use...
>it's something I think would be useful for a lot of people if it was
>cheap and simple. As you can probably tell from my OpenTracker
>design, I favor keeping complexity in software, where it can be
>duplicated cheaply. Keep the hardware simple and cheap, and figure
>out how to get the most out of it.
The Warbler doesn't even need a Rig interface, so that is about as simple and
cheap as you can get.
>PSK31 would be better than PACTOR because, as I understand it, you
>could get better channel utilization out of it.
PSK31 is narrower bandwidth, but as far as data throughput, Pactor obviously
has it beat hands down. And while PSK31 is not a ARQ protocol, there is no
law saying you couldn't make it one. Moe Wheatly has released some API's for
it and one fellow even wrapped it in a ActiveX driver.
That much being said, I'd look hard and long at MFSK16. I've very impressed
with it, it is very forgiving with TX settings as contrasted with MT63 and
Q15X25. Not very fast, but a little faster then PSK31.
>I imagine having a box with something like the Warbler
>integrated with a DSP engine, and having a small LCD display and
>keyboard.
Well...... small LCD displays are kind of a pain, in particular if you want
to do any kind of messaging. So, your going to find most folks are hooking it
up to a laptop. Then all of a sudden, you have all these free software that
can do all the modems we have been talking about. Now, remind me again why
you wanted to do a hardware based DSP project? ;-)
>You'd put up an antenna, and it'd send out a ping on one
>of a given set of input channels. Multiple base stations,
>interconnected by Internet or higher speed RF links would work
>together to acknowledge your station, assign a channel/timeslot, and
>dole out any queued messages. More like an alphanumeric paging
>service than a BBS, really.
Sounds alot like WinLink. Maybe you should take one of the public domain
soundcard modes, such as MFSK16, MT63 or Q15X25 and adapt it to it? Q15X25
has free drivers for both windows and Linux.
>Anyway, I guess it's something to put on my list to check out when I
>get some more DSP experience...
Or you can do it right now, at least with PSK31, and no DSP experience, with
this:
http://www.qsl.net/ae4jy/pskcoredll.htm
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Subject: RE: PCsat Endangered
From: "Scott Miller" <scott@3xf.com>
Date: Sun, 18 Jan 2004 11:44:38 -0800
X-Message-Number: 13
I'll throw in a mother-in-law for redundancy. =]
And to keep this thread marginally on-topic, I'm thinking of putting a
battery voltage monitoring circuit in my tracker. What I've come up with so
far is just a two resistor voltage divider, with a tap going to a spare A/D
input. The A/D is internally referenced to the MCU's supply voltage, which
comes from a regulator, either a 78L05 or AN77L05. Is this the accepted way
to do such a thing, or is there a better approach, keeping in mind that I
don't have the ability to change the A/D reference voltage?
Scott
N1VG
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Subject: Re: Attended vs Unattended
From: "Spider" <spider@rivcom.net>
Date: Sun, 18 Jan 2004 12:58:02 -0700
X-Message-Number: 14
From: "Bob Bruninga" <bruninga@usna.edu>
>To help APRS in its "real-time" significance,
>I am proposing an added BIT in the POSIT report
>to indicate whether an ACTIVE operator is present or not.
Not sure an active operator is present or not has anything to do with real
time.
Just of the top...not pondering this....I am not liking this.
Jim, WA6OFT
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