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ZL3AI > APRDIG 25.07.03 08:52l 264 Lines 10270 Bytes #999 (0) @ WW
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From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
Subject: Re: Running aprs in the car with a laptop
From: "Dick Stanich" <dick@kb7zva.com>
Date: Tue, 22 Jul 2003 7:19:39
X-Message-Number: 8
RadioShack made an adjustable DC adapter. At least they did a couple of
years ago. Mine still works.
CAT. NO. 273-1825
Input: 11-16VDC 4A Max
Output: 6-21VDC
Works nice with my Compaq Presario. I'm sure there are other units that
work as well.
Dick, KB7ZVA
APRSWest.net
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Subject: Re: $25 GPS - price includes 1200 bps data Radio !!!!
From: Rich Garcia <k4gps@bellsouth.net>
Date: 22 Jul 2003 10:49:50 -0400
X-Message-Number: 9
WOZ is also an amateur radio operator I think, so the idea was not all
that far off of the "apple tree". (No Pun intended)
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Subject: Re: $25 GPS - price includes 1200 bps data Radio !!!!
From: Steve Dimse <k4hg@tapr.org>
Date: Tue, 22 Jul 2003 11:10:16 -0400
X-Message-Number: 10
Read carefully (and between the lines).
My best guess, what is in the $25 unit is not a GPS as we know it, but
rather just the receiver side. I'll bet it sends just the timing signals it
hears, and leaves it to the base station to "do the math" and produce a
location. This saves the cost of the expensive CPU capable of solving
simultaneous equations, and the battery drain that CPU would create.
This approach has been mentioned as a possiblity for cell phone to handle
GPS location for the mobile 911 requirement...I do not know if it has ever
been implemented or deployed before.
Steve K4HG
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Subject: Re: $25 GPS - price includes 1200 bps data Radio !!!!
From: "Mike Yetsko" <myetsko@insydesw.com>
Date: Tue, 22 Jul 2003 11:34:48 -0400
X-Message-Number: 11
>Read carefully (and between the lines).
>
>My best guess, what is in the $25 unit is not a GPS as we know it, but rather
>just the receiver side. I'll bet it sends just the timing signals it hears, and
>leaves it to the base station to "do the math" and produce a location. This
>saves the cost of the expensive CPU capable of solving simultaneous equations,
>and the battery drain that CPU would create.
>
>This approach has been mentioned as a possiblity for cell phone to handle GPS
>location for the mobile 911 requirement...I do not know if it has ever been
>implemented or deployed before.
>
>Steve K4HG
You know, that's actually not a bad idea. Thing is, if you have an
application that doesn't actually need the final packaged data, why spend
the resources to calculate it that way at that time.
In cell phones, unless they have a lat/long readout, why bother there too?
I wonder how much you really do save? Maybe 2K in code space for the
routines? I'm sure there are math packages that would give the tools to do
it even on 8-bit processors.
But how much does 2K or so of space really hit you in internal resources?
If this is 'The Woz', I would examine why closely. Remember, this guy came
from a background of a computer with bit banging for serial and floppy I/O
to save the price of a chip.
On the other hand, to be fair, there's a lot to be said of the issues that
have to be addressed when you are at a $25 price point...
If the system works, and it probably will, it may not be too 'expandable'
or 'hackable' without some SERIOUS effort to make it work for other
applications. And isn't that really what the people here are looking for?
Mike
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Subject: aprs2.net Tier 2 Update
From: "Phil Pacier, AD6NH" <ad6nh@arrl.net>
Date: Tue, 22 Jul 2003 11:42:1
X-Message-Number: 12
Hello all! Time for a quick update on the ARPS Tier 2 network. All five
servers are coordinated and stable at this time. Users can add all of the
Tier 2 servers to their lists for a nearly-uninterrupted APRS feed. The
idea is, if one server goes down for maintenance or any other reason, your
APRS client software will automatically rotate to the next server in the
list. All of the ports with the exception of the regional ports are exactly
the same on each server, including the 14580 user-defined filter port.
arizona.aprs2.net (APRSWEST)- Port 14579=West US, Port 14578=East US
socal.aprs2.net (APRSCA)- Port 14579=California
texas.aprs2.net (APRSTAMU)- Port 14579=Central US, Port 14578=Texas
knoxville.aprs2.net (APRSKNOX)- Port 14579=East US
uk.aprs2.net
For more information, check the soon-to-be-completed http://www.aprs2.net
webpage. Enjoy! 73
Phillip Pacier - AD6NH
socal.aprs2.net
http://www.aprsca.net
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Subject: Re: $25 GPS - price includes 1200 bps data Radio !!!!
From: "Scott Miller" <scott@opentrac.org>
Date: Tue, 22 Jul 2003 11:40:05 -0700
X-Message-Number: 13
Yes, the system is known as Assisted GPS, and it's used in the T720
cellphone on my belt right now. See
http://www.lucent.com/livelink/090094038000e51f_White_paper.pdf.
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Subject: peet ult 2100 to kpc3+ settings
From: "Dennis" <walkerdh@telusplanet.net>
Date: Tue, 22 Jul 2003 12:42:14 -0600
X-Message-Number: 14
Hi all.
Helping a freind setup his Peet Ult 2100 and Kpc3+ to output our local wx to
aprs. I could use some help with
the settings in the kpc3+. If someone could send me their
settings , off the sig I would appreciate it. TIA.
dennis (ve6dhw
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Subject: Re: [ Wes Johnston ] Re: APRS IP address
From: "Gregg G. Wonderly" <gregg@skymaster.cytetech.com>
Date: Tue, 22 Jul 2003 13:43:17 -0500
X-Message-Number: 15
>why is 802.11b any different than tcp/ip @ 9600 or 57,600? It's just the
>transport layer for pete's sake....
Wes, I think the primary issue is the nature of the RF beast. Path loss at
2.4ghz is huge. Mobile ops will be darn difficult without hundreds of
nodes. If we use the existing consumer goods, we have to stay at 1 watt
without power control as specified in Part 97. So, there needs to be lots
of discussion about how to manage the issues associated with these devices
from a technology and a regulation perspective...
We have a 2.4ghz ATV system in our area that has several segments of the
spectrum dedicated to 6mhz wide VSB. Anyone operating longhaul links on
2.4ghz SS in our area will have some signal integrity problems in the areas
closest to the transmitters (12 watts into 21dB antennas). If they are
interfering with the VSB signals and are not willing to work the issues, Part
97 says SS must not interfere with other modes.
So, there are many things that we all need to be aware of and try and find
solutions for!
-----
gregg@cytetech.com (Cyte Technologies Inc)
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Subject: Re: Running aprs in the car with a laptop
From: "Gregg G. Wonderly" <gregg@skymaster.cytetech.com>
Date: Tue, 22 Jul 2003 13:49:21 -0500
X-Message-Number: 16
>Does anyone run a laptop in the car ?
>
>I would like suggestions. DC-DC converter or inverter ?
>
>Which is best ?
I found that there is a 400watt inverter at Sam's Club for $xx At that
price, it beats the deal on most in car DC-DC adapters. And, it provides
other services too. Just remember to read the instructions that say 1Amp
current for every 10Watts of power. I tried to run mine off the supplied
adapter cable. pluged through a low cost splitter that must of had 100000
gauge wire in it. With just my laptop plugged into it, it blew up. The
voltage loss through the wire starved the device into a current sucking frenzy
that resulted in a fried device. I have replaced it with a new one and have
10 guage wire from the battery. Works fine now.
-----
gregg@cytetech.com (Cyte Technologies Inc)
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Subject: Re: Running aprs in the car with a laptop
From: Henk de Groot <henk.de.groot@hetnet.nl>
Date: Tue, 22 Jul 2003 20:47:36 +0200
X-Message-Number: 17
At 21:35 23-7-03 +1000, Andrew VK4TEC wrote:
>Does anyone run a laptop in the car ?
>
>I would like suggestions. DC-DC converter or inverter ?
I use an inverter from 12 volt to 230 volt (that's what we have here) and
just plugin the powersupply of the laptop. This also works also for any
future laptop that I might own some day and also other 230 volt equipment
that I want to take with me (in-car charging of a camcorder for example).
I did some measurements, the PSU of the laptop is labeled 125 VA, but I did
not believe this was actually used. With my laptop, a Compaq presario 1200
series, it consumes about 15 Watt in idle (screen on, HD spinning) and I
measured 50 Watt peak when the CPU is busy and the CD drive is starting to
spin. So 50 Watt should be enough and 100 Watt surely can do it.
The inverter I have is the smallest I could find with sufficient power. It
is capable of delivering 100 Watt continuesly and 200 Watt "short time" (so
it says in the box...). It claims > 90% efficiency and doesn't run very hot
when in use. It's 490 grams and its size is 135 x 75 x 40 mm.
In my setup both the Laptop and the TH-D7 (via a wall-wart switching PSU,
selectable up to 12V, 1500mA) are supplied by the inverter. Reason for also
powering the TH-D7 this way is because the inverter already occupies the
lighter socket and the TH-D7 is shielded perfectly from peaks pulses on the
car's 12 V DC line this way.
Since both the laptop and the TH-D7 PSU are switching powersupplies it
doesn't matter much that the inverter does not deliver a high qualty
sine-wave - switching PSU's rectify the mains power anyway before doing
anything with it.
To be complete the make, although I don't think they have exaclty this one
in the US:
I.V.T. Innovative Versorgungstechnik GmbH
Dienhof 14
D-92242 Hirschau
Germany
Phone (49)9622/7 12 21 + 7 12 22
Telefax (49)9622/7 12 20
They are sold by Conrad electronics, www.conrad.de and www.conrad.nl
I hope this helps. Kind regards,
Henk.
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