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ZL3AI  > APRDIG   18.07.04 01:47l 282 Lines 11847 Bytes #999 (0) @ WW
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Subj: TAPR Digest, Jul 14, 1/1
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From: ZL3AI@ZL3VML.#80.NZL.OC
To  : APRDIG@WW

TAPR APRS Special Interest Group Digest for Wednesday, July 14, 2004.

1. RE: Does anyone have Evermore GM305 . pdf  or pin-outs?
2. Re: APRS 144.39 dual channel upgrade
3. Re: APRS 144.39 dual channel upgrade
4. Re: an EXTREMELY BASIC question time...
5. Re: an EXTREMELY BASIC question time...
6. Re: APRS 144.39 dual channel upgrade

----------------------------------------------------------------------

Subject: RE: Does anyone have Evermore GM305 . pdf  or pin-outs?
From: "Cap Pennell" <cap@cruzio.com>
Date: Tue, 13 Jul 2004 22:13:18 -0700
X-Message-Number: 1

The information appears here
http://www-ri.hive.no/nmea/GM-X205_UG_revB.pdf
as is mentioned at
http://www.pocketaprs.com/gps.html
73, Cap KE6AFE

>-----Original Message-----
>From: bounce-aprssig-36475@lists.tapr.org
>[mailto:bounce-aprssig-36475@lists.tapr.org]On Behalf Of TJ Hvasta
>Sent: Tuesday, July 13, 2004 18:50 PM
>To: TAPR APRS Special Interest Group
>Subject: [aprssig] Does anyone have Evermore GM305 . pdf or pin-outs?
>
>
>Hello all,
>
>I purchased two Evermore mouse-type GPS receiver modules, GM-305 & -308,
>from DeLuo.com but they didnt come with any documentation.  Does anyone
>have any docs for these receivers?  I found one place that has a
>.pdf file,
>but it's a bad link and I couldn't decode the correct one.
>Even something on the pin-outs for power/data...
>
>Any help would be very much appreciated.
>
>Thanks!
>
>TJ, NS2E
>Mesa, AZ

----------------------------------------------------------------------

Subject: Re: APRS 144.39 dual channel upgrade
From: "Robert Bruninga" <bruninga@usna.edu>
Date: Wed, 14 Jul 2004 10:26:33 -0400
X-Message-Number: 2

>>>"Richard Amirault" <ramirault@erols.com> 7/13/04 7:07:24 PM >>>
>>There is nothing illegal or wrong about operating [a
>>repeater and not requiring all users to first listen on
>>the input before keying up..]  similarly there is nothing
>>wrong with operating a DIGI [on a very sparsely loaded
>>channel] that way either.

>Sorry, I don't agree. (boy, Bob, every once and a while 
>you sure come up with some strange ideas;-)  Richard

We disagree then.  And you are still overlooking common sense, pracitcal
design, common practice and the very low probabilities on the channel.

1)  My point was that it is COMMON PRACTICE in the amateur  radio service
to transmit on repeater input channels without  first listening to the
input channel when that channel is INTENDED for such shared use.

2) And *listening* on the input of a REPEATER or a DIGI will *absolutely*
not tell you if the channel is clear, it will only tell you if maybe your
neighbor is not using it, but not the other 90 to 95% of the area heard by
the repeater.

So, common sense, practical design, and common use tells the practical
engineer, that LISTENIG first on the input only gains you a 5 to 10% chance
of avoiding a collision, but in this design, the statistics of a collision
already are down in the 2 to 3% range anyway.  Then the GAIN of your
insistance of listening first is only 0.003 in this proposed design.

You can count the number of angels on the head of pin your way, but to me,
your trying to squeeze out three-tenths-of-one-percent of channel
improvement by requiring EVEYONE in the community to purchase a second
radio receiver and second TNC is completely impractical and without any
merit relative to the cost or to the intended mission.

de WB4APR, Bob

----------------------------------------------------------------------

Subject: Re: APRS 144.39 dual channel upgrade
From: Fritz Anderson <fritza@manoverboard.org>
Date: Wed, 14 Jul 2004 11:19:31 -0500
X-Message-Number: 3

On 13 Jul 2004, at 6:07 PM, Richard Amirault wrote:

>And in such cases those other signals (non or different PL) are *not* trying
>to get into your local repeater .. they are trying to get into *their*
>repeater (which is usually a lot closer to them than your machine)  If you
>transmit over such a signal on the channel you are *not* causing
>interference at all, since the other party has a stronger signal into his
>repeater than you .. and you have a stronger signal into your repeater than
>his.

It seems to me that there is a disagreement on the nature of the rule that
amateur transmissions should not cause interference. Apologies in advance
to non-US list members for my grinding away at US regulations...

One side sees the principle as being that amateurs should not jam each
other (the noninterference rule, 97-101(d) itself), and should be courteous
in adjusting their operations so that others can share the spectrum (the
good operating practice rule, 97-101(a)). The argument on this side is that
the proposed split operation is not jamming at all -- it is not
transmission with the _intention_ of denying spectrum to another -- and is
better operating practice in that it makes 144.39 more available to
stations that need it.

The other sees the jamming rule as aimed not at bad actors (people who mean
to jam) but at every instance of QRM as an evil in itself, which everyone
must combat even at the sacrifice of other benefits. In criminal law, the
standard (it is said) would not be "intentional" interference, but
"reckless" or even "negligent" interference. Under the proposal, the users
of the split frequency would not be taking the last possible measure of
care to avoid QRM, and so not doing what they should to combat the evil.

My own take is that the interference rule itself prohibits only "willful or
malicious" QRM. The target is bad guys, not clear channels. It is the
good-operating-practice rule that prohibits most of the illegal
interference that in fact happens. This matches up with our instincts: When
some lid jumps randomly on a frequency and starts calling CQ without
listening, we call him a jerk, not a jammer. And, the great majority of
interference on the amateur bands is unavoidable even with painstaking
care, because no transmitting station can possibly know what every
receiving station will hear.

Surely an agreed operating practice that makes bandwidth more available to
all users is a better practice than the alternative. If we agree on that, I
think that takes the good-operating-practice rule out of the picture, and
leaves only the much-narrower intentional-QRM rule. The rule says, "No
amateur operator shall willfully or maliciously interfere with or cause
interference to any radio communication or signal." We agree there's no
question of malice. And, I think, the 95+% chance of not colliding with
another signal, in a nonconnected digital mode in which collisions are part
of the design, takes willfulness out of the picture. The intention of the
split-frequency user is to permit _more_ users of the spectrum, not to
hinder anyone else. Affirmatively good operating practice, in accordance
with a coordinated band plan, cancels out willfulness and malice.

-- F

----------------------------------------------------------------------

Subject: Re: an EXTREMELY BASIC question time...
From: "Curt, WE7U" <archer@eskimo.com>
Date: Wed, 14 Jul 2004 09:54:23 -0700 (PDT)
X-Message-Number: 4

On Tue, 13 Jul 2004, JBCrafts wrote:

>I am going on a road trip in a week, I would like to build up a tracker. The
>last time I had a tracker, I used a dual port TNC from Paccomm (ARE THEY
>STILL IN BUSINESS? THEY NEVER ANSWER EMAILS!!!), this time I am just going
>to resurrect an old TNC.
>
>EXACTLY what do I need to do to get this thing on the air? IE paths, BText
>etc...
>
>Do I parse a sentence from the GPS? which one?
>
>The TNC is an OLD OLD Tempo with a built in receive printer. How do I get
>the TNC to send on the GPS data?

I haven't heard of a Tempo TNC.  Tempo radios I do recall.

I strongly suspect that the APRS support you'll need in your TNC just isn't
there.  You need commands that allow you to choose the GPS string to parse,
and to decide how often to beacon out that info.  If they're not in your
manual, you don't have them.

Old TNC's make wonderful home stations, where you can hook them to a
computer to do your beaconing and use the TNC commands to do RELAY digipeat
for mobiles in your area.

I might suggest that you invest in a Kantronics KPC-3+ if you want a recent
TNC that can do it all, or for a whole lot less you can go for a
transmit-only APRS TNC such as the OpenTracker, the TinyTrack-3, or the
TigerTrak.  See this page for links to each of them:

http://www.findewe.com/nwaprs/SearchAndRescue

Another option is to use a PDA or a laptop along with that old TNC.
That is a much more complicated system for mobile use.

There are also radios with built-in APRS capability.  The most capable ones
are the Kenwood TH-D7A(G) (handheld) and the Kenwood TM-D700A.  Alinco has
a mobile rig with an optional TNC board also.

For what it's worth, I ran a TinyTrak-1 and TinyTrak-2 for a while, am now
running an OpenTracker while mobile.  Sometimes I run a PC attached to an
old AEA PK-88 TNC.  The PC has two serial ports so I can hook the GPS into
that and have Xastir send out my mobile positions.  That TNC is not capable
of doing it (too old).

--
Curt, WE7U			         http://www.eskimo.com/~archer
"Lotto:    A tax on people who are bad at math." -- unknown
"Windows:  Microsoft's tax on computer illiterates." -- WE7U
"The world DOES revolve around me:  I picked the coordinate system!"

----------------------------------------------------------------------

Subject: Re: an EXTREMELY BASIC question time...
From: "Mark Fellhauer" <sparkfel@qwest.net>
Date: Wed, 14 Jul 2004 10:52:14 -0700
X-Message-Number: 5

At 09:54 AM 7/14/2004, Curt, WE7U wrote:

>I haven't heard of a Tempo TNC.  Tempo radios I do recall.

Oh man!  Tempo TNC...  the mention of which brings back some good memories.
The Tempo MPP-1 (Mobile Packet Printer) was distributed by Henry Radio.
Tasco chip in a funky case.  The unique feature of this TNC was a built-in
thermal printer that used standard 2" wide receipt paper.  It also had a
swivel mounting bracket.

There was also a commercial variant that had an encyption function (which I
think was also present on the ham radio version).

I acquired several of these TNC's at a swap meet (around 1996?), both
commercial and Ham variants.  The commercial ones were actually pulled out
of service from an LA area Burger King, where they had an order booth for
the drive-thru separated from the main building.   One still had a receipt
for a Whopper combo in it.

For a year or so, the Sioux Falls Digi I-gate was run on a Tempo TNC.  That
was around 1998.  At some point in the late 1990's a Henry Radio employee
told me they still had a "closet" full of unsold MPP-1's.   I wonder what
happened to them?

Now I feel old.  Have I really been involved in APRS for over a decade?
Yup!

----------------------------------------------------------------------

Subject: Re: APRS 144.39 dual channel upgrade
From: "Robert Bruninga" <bruninga@usna.edu>
Date: Wed, 14 Jul 2004 17:35:41 -0400
X-Message-Number: 6

The Annapolis, MD 144.99 alt channel input is now on the air at about 150'
height above average terrain.  The call is 99ANAP with BText having the HAM
call of W3ADO.

There is one more lesson learned.  After building the 555 oscillator for
bundling packets, we realized (duh) that that then prohibits one from using
the remote sysop feature. So we have disabled it.  The net gain of the 555
on such a low duty cycle channel anyway was very small.

The real gain is the spreading out packets onto two input channels so that
everyone sees less collisions...

The objective is NOT greater channel capacity (the channel is already
saturated) but better reliabilty through fewer collisions for existing
local users.

See details under ALOHA paragraph on:

http://www.ew.usna.edu/~bruninga/aprs/fix14439.html

de WB4APR, Bob

---

END OF DIGEST



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