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ZL3AI > APRDIG 27.09.03 09:18l 273 Lines 9383 Bytes #999 (0) @ WW
BID : 1999-ZL3AI
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Subj: TAPR Digest, Sep 24, 2/3
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Sent: 030926/1339Z @:ZL3VML.#80.NZL.OC #:9083 [Chch-NZ] FBB7.00i $:1999-ZL3AI
From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
Subject: PCB prototyping
From: "Scott Miller" <scott@opentrac.org>
Date: Wed, 24 Sep 2003 14:55:07 -0700
X-Message-Number: 13
My tracker design is coming along - it's currently pretty similar to the
TinyTrak, though the next revision will be a bit more like the MIM with
telemetry inputs. So far I've been doing PCB production in-house
(in-garage, actually) using the usual photochemical method... works great
for prototyping, but for larger volume production it's not much fun. So I
have a couple of queestions...
First, I've got a friend who just got a brand new CNC milling machine and
can mechanically etch boards. He doesn't know what to charge for the
service, though. My current design is a 2"x3" single-sided board - it'll
probably be made 3 or 6 boards to a panel - and he currently doesn't have
hole drilling capability, so I'd have to do that by hand still. But he can
give me next-day results for small quantities with less effort than chemical
etching. What's a good fee to offer him?
Second, assuming I want to produce a hundred or more of these things, can
anyone recommend a good PCB manufacturer that's good with relatively small
orders? ExpressPCB is one of the few that list prices... 100 board from
them would cost me about $4.14 each. An outfit that will at least look at
an order and catch things that are seriously wrong would be nice - I'd hate
to pay $400 and find out I got the silkscreen on the wrong side. =]
Thanks...
Scott
N1VG
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Subject: Re: PCB prototyping
From: Doug Bade <doug@clecom.com>
Date: Wed, 24 Sep 2003 18:01:56 -0400
X-Message-Number: 14
I use ExpressPCB which is a different company and they have small
3 board test runs for a small amount, nothing fancy, but prove your boards...
Their cad program will give a board cost based on your design and
quantity.. Their C.A.D. is free... I have had a pretty good relationship
with them.
There service is as they say, and very consistent.
Doug KB8GVQ
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Subject: Re: WAS: TRACKING THIEF IS: 911 and GPS Phones
From: Dave VanHorn <dvanhorn@cedar.net>
Date: Wed, 24 Sep 2003 17:01:04 -0500
X-Message-Number: 15
At 04:17 PM 9/24/2003 -0400, Richard Garcia wrote:
>Sorry but it is not a "bunch of poop". GPS or as some call it GPRS
GPRS is General Packet Radio Service, and doesn't necessarily involve GPS.
Also, cell companies can triangulate, and know which cell a phone is coming
in through.
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Subject: Re: APRS PERL SPLIT Help needed
From: "Andrew Rich" <vk4tec@hotmail.com>
Date: Thu, 25 Sep 2003 08:03:21 +1000
X-Message-Number: 16
Thanks for your help Jon
My final question is this:-
How would one get
CALLSIGN>DEST,DIGI,DIGI,DIGI:PAYLOAD
to
CALLSIGN
DEST
DIGI,DIGI,DIGI,DIGI
PAYLOAD
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Subject: Re: APRS PERL SPLIT Help needed
From: "Andrew Rich" <vk4tec@hotmail.com>
Date: Thu, 25 Sep 2003 08:27:09 +1000
X-Message-Number: 17
Got it !
Cool
K4HG>APM344,TCPIP*,qAC,K4HG:_09221007c140s003g007t082r000p000P000h67b10139mU2K
calls: K4HG
dest : APM344
digis: TCPIP*,qAC,K4HG
payld: _09221007c140s003g007t082r000p000P000h67b10139mU2K
($callsign, $rest) = split(/>/,$_,2);
($dest, $rest) = split(/,/,$rest,2);
($digis, $payload) = split(/:/,$rest,2);
@digis = split(/,/,$digis);
print "calls: $callsign\n";
print "dest : $dest\n";
print "digis: $digis\n";
print "payld: $payload\n";
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Subject: Re: WAS: TRACKING THIEF IS: 911 and GPS Phones
From: Richard Garcia <k4gps@bellsouth.net>
Date: 24 Sep 2003 18:30:52 -0400
X-Message-Number: 18
Cell phone companies can triangulate but only if they have that feature
enabled. This is cutting edge at the moment and some are using it, some
are not and opting for the GPS phones. It is part of the 3 Phase 911
Rollout and will not be used in day to day operations at this time if
ever. Depending on where in the country you are and the carrier it may
or may not be available in the area.GPRS is used in the cell phone
industry for some model phones and others use GPRS in reference to the
GPS data that is sent for 911. I am sure that the word is used
incorrectly in many instances but it is becoming so common that is what
some know it as. Years ago ATT Wireless called their phones PCS, well
that was incorrect, they are not PCS they were in this area and most
others 800 Mhz, but they still called themselves PCS as Personal
Communications Service while in all reality PCS stood for the phone
services in the 1.8-9 Ghz band. It's all a play of words...not to
mention PTT.
As far as call traces yes you can tell what cell and what sector (alpha,
beta or gamma) the call is coming in from but that does not tell you
very much. You can also tell if it is in soft handoff between 2 cells
and 2 sectors which says more but means nothing unless a RF Eng. is
involved that knows the area or a cell technician that knows the area
well. These cases of tracking a live call can and have been done but
requires a court order, it is handled just like a wiretap. It would
never be used in the case of a stolen phone or bag.
OK now we are getting off topic but bottom line is just because your
phone has a GPS in it does not mean you can be tracked at will "a la'
APRS". There is a lot more than just having a GPS phone, laws,
regulations, liability and 911 Infrastructure in additon to the carrier
is the whole picture that must be looked at.
Think about it, "someone stole my car and my phone is in it, well your
car is at XYZ location sir". Later in the news you will be reading about
a husband who shot is wife and her boyfriend after he found out from
some operator where is wife was playing hanky panky.(For the female
readers please reverse the roles...no bias here!)
Rich
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Subject: SMACK protocol and simple modems
From: "Scott Miller" <scott@opentrac.org>
Date: Wed, 24 Sep 2003 15:42:01 -0700
X-Message-Number: 19
A variant of my tracker will have an XR2211-based FSK decoder, which adds RX
capability for about $1 in parts. It occurs to me that the only obstacle to
letting the tracker double as a TNC is the fact that it doesn't have enough
RAM to buffer an entire frame. But with the right asynchronous host
protocol, it ought to be able to serve as a modem at least. The SMACK
protocol seems to be just KISS with a CRC added in - it doesn't appear to be
the same CRC as the HDLC FCS used on the air, but that doesn't really
matter. The controller can check the incoming FCS on the fly, and if it
doesn't match, deliberately trash the CRC sent to the host so the frame gets
dropped.
Of course, with an open squelch receiver it'll mean a lot of dropped frames,
but it really shouldn't matter.
Think of the advantages... for slightly more than the cost of a TX-only
tracker, you've got something better than a Baycom modem in that it doesn't
require a 'real' serial or parallel port. You've just got to be careful
with flow control to make sure you don't overrun what meager transmit buffer
the device is capable of.
Thoughts?
Scott
N1VG
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Subject: Re: APRS PERL SPLIT Help needed
From: "Georgette Sampson" <georgette.sampson@cox.net>
Date: Wed, 24 Sep 2003 17:41:24 -0500
X-Message-Number: 20
($callsign, $rest) = split(/>/,$string,2);
2 fields on the left of the equal sign. Perl would use 3 by default, so
saying 2 speeds up the program if you do this a lot.
Manual:
"When assigning to a list, if LIMIT is omitted, Perl supplies a LIMIT one
larger than the number of variables in the list, to avoid unnecessary
work."
----- Original Message -----
>What does the comma two do ?
>
>plit(/>/,$string,2);
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Subject: Re: APRS PERL SPLIT Help needed
From: Richard Mulvey <lists@mulveyfamily.com>
Date: Wed, 24 Sep 2003 18:45:15 -0400
X-Message-Number: 21
This is much easier:
my $line="AA2YS>APR56,DIGI1,DIGI2,DIGI3:Paydirt";
$line =~ /(\S+)>([^,]+),(\S+):(\S+)/;
my ($call, $dest, $payload, @digis ) = ( $1, $2, $4, split( ',', $3 ));
print $call . ":\n" . $dest . ":\n" , join( ",", @digis ) . ":\n" .
$payload;
- Rich
--
Richard Mulvey <lists@mulveyfamily.com>
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Subject: Re: APRS PERL SPLIT Help needed
From: James Washer <washer@trlp.com>
Date: Wed, 24 Sep 2003 15:51:30 -0700
X-Message-Number: 22
How about
$string =~ m/^(\w+)>(\w+),([\w,]+):(\w+)/;
print "call=$1 dest=$2 digis=$3 payload=$4\n";
- jim
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Subject: Re: APRS PERL SPLIT Help needed
From: Jon Anhold <jon@snoopy.net>
Date: Wed, 24 Sep 2003 18:56:41 -0400
X-Message-Number: 23
As I said, I'm sure there's a more clever way of
doing it.. :)
-j
James Washer wrote:
>How about
>
>$string =~ m/^(\w+)>(\w+),([\w,]+):(\w+)/;
>print "call=$1 dest=$2 digis=$3 payload=$4\n";
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