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ZL3AI > APRDIG 26.11.03 20:09l 273 Lines 9441 Bytes #999 (0) @ WW
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From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
TAPR APRS Special Interest Group Digest for Sunday, November 23, 2003.
1. DigiTravler Remote Antenna
2. Re: DigiTravler Remote Antenna
3. Re: DigiTravler current
4. Re: APRSdos floppy?
5. Re: What low current draw radio for solar powered site?
6. RE: Scott Ratchford
7. OMNI DFing on APRS.
8. Re: DigiTravler current
9. Re: What low current draw radio for solar powered site? k7fw
10. Proper Digipeater Settings
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Subject: DigiTravler Remote Antenna
From: Larry McDavid <lmcdavid@lmceng.com>
Date: Sat, 22 Nov 2003 21:58:43 -0800
X-Message-Number: 1
Has anyone successfully used a remote amplified antenna with the Radio
Shack DigiTravler?
--
Best wishes,
Larry McDavid W6FUB
Anaheim, CA (20 miles southeast of Los Angeles, near Disneyland)
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Subject: Re: DigiTravler Remote Antenna
From: "J. Lance Cotton" <joe@lightningflash.net>
Date: Sun, 23 Nov 2003 00:12:42 -0600
X-Message-Number: 2
Larry McDavid wrote:
>Has anyone successfully used a remote amplified antenna with the Radio
>Shack DigiTravler?
I haven't heard of anyone doing that yet, but the "brain" of the GPS is the
chip from Sony:
http://products.sel.sony.com/semi/PDF/GXB2000.pdf
All you must do is open up the metal cover that houses this chip and solder
in your own antenna connector or cable. There is no connector for an
external antenna in the digitraveler unless you put one there yourself.
Other fun things that can be done after taking the cover off of this chip:
1. Wire up a 1.8v to 3.0v lithium "watch battery" to pin 8 (the battery
backup pin) of the sony chip and then if you convert the GPS to external
power through the serial cable, you can keep the GPS almanac information
when power is disconnected, increasing (theoretically) the time to first fix.
2. Take some DGPS data stream from your DGPS receiver or other source and
feed it into pin 5 of the sony chip. Now you have high-precision positions
coming out.
-Lance
--
J. Lance Cotton, KJ5O
joe@lightningflash.net
Three Step Plan: 1. Take over the world. 2. Get a lot of cookies. 3. Eat the
cookies.
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Subject: Re: DigiTravler current
From: "Donald Jacob" <djacob1@socal.rr.com>
Date: Sat, 22 Nov 2003 22:20:43 -0800
X-Message-Number: 3
Mike,
Thanks that's exactly the info I was looking for..
Don WB5EKU
----- Original Message -----
From: "Mike Yetsko" <myetsko@insydesw.com>
>Well, with 3 AAA batteries supposedly spec at 16 hours...
>
>The data sheet says less than 75ma in full operation. 5ua in standby.
>
>Should work fine with a 78L05 inside the case...
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Subject: Re: APRSdos floppy?
From: "KE4RCO" <ke4rco@qsl.net>
Date: Sun, 23 Nov 2003 08:21:52 -0500
X-Message-Number: 4
Re: APRSdos floppy?
I have used and still use on occasion APRSDOS on a floppy, cutting out
almost all the docs, and most of the maps,I did leave in the OPS -DIGI
stuff.
It is used on a 33 mhz laptop with no hdd and only 2mg ram. the thing just
keeps going, is solid and dependable. and I am only using about half of the
space on the floppy. And it does save to it occasionally since I am
registered, I have not tried it without registration on a floppy to see if
it still goes through the save process. I think the version I have on floppy
is like 730 something. old version, but still solid.
Cost for cheap 33mhz laptop at swapfest
$10
Cost for APRSDOS scaled down to floppy
$0
Knowing it is up and running and if I take a lightning hit I am not out a
lot of money
$Priceless
For everything else there's Ham Radio
KE4RCO
Kevin
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Subject: Re: What low current draw radio for solar powered site?
From: Bob Bruninga <bruninga@usna.edu>
Date: Sun, 23 Nov 2003 11:41:05 -0500 (EST)
X-Message-Number: 5
On Sat, 22 Nov 2003, Spider wrote:
>>There are many 5W HT's available for about $100 I think. TX power is not
>>an issue at all. Its the receiver power that is the bulk of solare power
>>you will need.
>>
>>Bob
>
>Bob, I've seen you write of this before and I scratch my head every
>time! Even living in a desert rural community, the digi's in the area
>are transmitting more than 50% of the time and I think to myself that
>what you say just does not make sense.
OOPS, yes, I was talking about a mobile. Yes, I was wrong. But also it
is impossible to transmti 50% of the time. because that would require
100% perfectly synchronized packets.
My guess is that for a digi (In a porperly designed system and with users
only trying to operate within the ALOHA rules of engagement (20%) channel
capacity, then 20% would be the typical DIGI TX time. But even in a
worstcase collision limited system (like most networks and uwers that have
not yet endoresed the new paradigm), I wiould thinkn that the transmitter
can not be much above 30%.
>Soooo, can I assume that you are speaking of just a mobile unit or
>portable unit that may only transmit once every few minutes or so?
>Another thing to consider is the GPS draw! These units like the Deluo
>and others pull about 100ma all the time. This, along with a
>transceiver, can add up.
Thats one of the advantages of the NOID design. You can track a
cigarette box sized device all over the country that will run for a year
on four AA cells. It has no GPS, and it only wakes up to transmit a
0.3 sec packet once every 10 minutes via the path of RELAY,WIDE2-2.
You cannot get a precise position, but you can tell what digi it is near
from anywhere in the world. Again, no good for precise positioning, but
could track your parents RV enough to know what national park they are
in...
This is the "vicinity Tracking" concept...
>On another point, I thinks it's interesting this hand help gps units can
>go a day or so on a couple three AA cells but the Deluo type units pull
>so much current!
Yep, the GPS is the biggie!
>Jim, WA6OFT
de WB4APR@amsat.org, Bob
PCsat WEB page http://www.ew.usna.edu/~bruninga/pcsat.html
ISS-APRS FAQ: http://www.ew.usna.edu/~bruninga/iss-faq.html
CUBESAT Designs http://www.ew.usna.edu/~bruninga/cubesat.html
APRS LIVE pages http://www.ew.usna.edu/~bruninga/aprs.html
APRS SATELLITES http://www.ew.usna.edu/~bruninga/astars.html
MIM/Mic-E/Mic-Lite http://ssdl.stanford.edu/mims/
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[commercial content deleted]
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Subject: OMNI DFing on APRS.
From: Bob Bruninga <bruninga@usna.edu>
Date: Sun, 23 Nov 2003 12:22:04 -0500 (EST)
X-Message-Number: 7
Besides Vehicle tracking, the SECOND most important value of APRS to ham
radio I thought would be DFing.
And so I designed into APRSdos the ability to LOCATE FOXes and JAMMERs to
their neighborhoods by simplying plotting the inverse of their signal
strength. This can easily locate down to a mile or so where he IS.
AND no one needs ANY tools whatsoever but a signal strength report. And
NOT hearing the jammer direct is even more valuable because it identifies
large areas where the jammer IS NOT!
I am disappointed that APRS users do not use this technique as a matter of
routine to quickly isolate the origin of signals. Is this because
1) People dont know its there?
2) Users dont know how to use it?
3) Client software other than APRSdos didn't support it?
Lets all get proficient at this. It is a great service that APRS can
offer the amateur community and somthing that is TRIVIAL to use, yet gives
great reward...
To see an APRSdos plot of DFing by signal strength contours see
http://www.ew.usna.edu/~bruninga/dfing.html
de WB4APR@amsat.org, Bob
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Subject: Re: DigiTravler current
From: Dale Mosby <dale@archcape.com>
Date: Sun, 23 Nov 2003 11:31:38 -0800
X-Message-Number: 8
I have an old analog 300 mA meter wired up to Anderson connectors so just
ran out to the car and put this in line with my TinyTrak 3 and
DigiTraveler. This shows:
TinyTrack 3 and DigiTraveler = 40 mA
DigiTraveler only = 35 mA
The DigiTraveler has the modification with internal 78L05 regulator for
power, and LED clipped so that is not lit. The TinyTrak has red and green
LEDs on (power and GPS lock).
If the question was to figure out if you can use a 78L05 instead of 7805 to
power DigiTraveler the answer is yes.
Note that this meter is old and a 300 mA scale. The TT3 document states
that current draw is: 6.6 mA plus 3.3 mA per LED lit. I had two LEDs lit so
current should be about 12 mA instead of around 5 that I measured.
I can wire a digital meter to this if a better measurement is needed but I
think we can safely say that a 78L05 will be fine to power both the TT3 and
DigiTraveler, and when used with a car battery the DigiTraveler has a
negligible draw and the TT3 has no draw.
Dale Mosby, K7FW
dale@archcape.com
At 01:55 PM 11/22/2003 -0800, Donald Jacob wrote:
>Possibly missed this earlier and can't find info, how much current does the
>DigiTravler draw in its operational mode?
>
>Thanks,
>
>Don WB5EKU
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