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ZL3AI > APRDIG 19.05.04 09:20l 253 Lines 7886 Bytes #999 (0) @ WW
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Subj: TAPR Digest, May 06, 1/1
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From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
TAPR APRS Special Interest Group Digest for Thursday, May 06, 2004.
1. Re: Garmin 38 Voltage?
2. Magellan SporTrak supply. Was Re: Garmin 38 Voltage?
3. DFing with the VX-2r tiny HT
4. 9600 baud on sound card
5. Re: 9600 baud on sound card
6. Location with up to date info on PHG(R)
7. RE: agwpe
8. RE: agwpe
9. WB4APR WX station!!! (funny)
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Subject: Re: Garmin 38 Voltage?
From: "Jason Rausch" <ke4nyv@hamhud.net>
Date: Thu, 6 May 2004 7:26:27
X-Message-Number: 1
The Garmin 38 needs 6-8VDC and NO MORE. For my 38 I ordered a 7808 and
strapped some 0.1uF caps to the input and output for filtering and it seems
to work fine. a 7805 is not enough for the 38, but will run a eTrex or
Geko unit just fine. 8.5VDC and up will kill a 38 and any of the other
same generation Garmins like the 45 and 45XL.
Jason KE4NYV
www.ke4nyv.com
RPC Electronics
www.ke4nyv.com/rpc
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Subject: Magellan SporTrak supply. Was Re: Garmin 38 Voltage?
From: "Jordi Costa" <bvjordi@bitsnvolts.com>
Date: Thu, 6 May 2004 15:20:34 +0200
X-Message-Number: 2
Any experience powering Magellan SporTrak ?. Seems it requires 3-3,3V.
EA3CIU
Jordi Costa
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Subject: DFing with the VX-2r tiny HT
From: "Robert Bruninga" <bruninga@usna.edu>
Date: Thu, 06 May 2004 10:44:18 -0400
X-Message-Number: 3
Toinght I'm going to do an APRS omni-DFing demo and needed to test my HT I
will use as the fox. So last night, I pulled over and stuck the HT on a
limb of a tree off the road.
With a rubber band around my VX-2r micro-mini HT, it was still going strong
after 2.5 hours when I had to turn it off, go to bed, and give it an
overnight charge.
Range on low-power was about 1 mile good and 2 miles absolute max over
average eastern treed terrain. And as amazing as this tiny HT is, it even
has a built-in CW ID!!!
Just thought I'd share the result...
After a short lecture on the APRS omni-DFing technique (but you dont need
APRS at all), then after the meeting the club members will try to find my
HT on their way home...
(though I could not get the CW-ID to work when the PTT was nailed down. The
CW id only works in the Automatic Range Transponder mode (ARTS)... but
then the brief TX bursts are too short to easily DF...
de WB4APR, Bob
----------------------------------------------------------------------
Subject: 9600 baud on sound card
From: Wes Johnston <wes@johnston.net>
Date: Thu, 06 May 2004 11:42:01 -0400
X-Message-Number: 4
I wrote to Buck Rogers (because he makes the sound card interfaces) to ask
about using them with 9k6....
Does 9600 baud work with the RASCAL? I am worried about the low frequency
response of the transformers for 9600.... have you used optoisolators for
the audio in and out on 9600?
Wes
here's the answer I got....
*****************************
The HIGH frequency response is where 9600 b/s is.
I think someone has left you out in left field.
********************************
Now I thought that low frequency response was the problem with 9600 radios
(in addition to slow TXD times). Does the g3ruh scrambler solve the low
frequency response problem?
What's the word on the street?
Wes
PS this is more on topic that arm chair lawyers!!! <grin>
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Subject: Re: 9600 baud on sound card
From: Jeff King <jeff@aerodata.net>
Date: Thu, 6 May 2004 13:23:05 -0400
X-Message-Number: 5
Hi Wes:
Yes, I wrote to Luke Skywalker ;-), and he told me that the purpose of the
G3RUH scrambler was to remove the low frequency components (long strings of
1's and 0's) of the data. This is so the 9600bps signal can travel over a AC
path (which is what caps and transformers are).
A DC coupled path would be best, but doesn't often exist. Take a look at this
GMSK modem (9600bps which many ham tnc's used):
http://www.cmlmicro.com/products/Datasheets/Docs/cmx909bd.pdf
on page 40 it has a discussion of AC coupling. Low frequency response DOES
make a difference, although it is possible that some magic occurs in the
sound card.
My biggest concern with sound card 9600bps TX is your hooked directly to the
varactor of the radio, and as such, the adjustments are critical for both
level and filtering. Certainly possible, but you no longer have the audio
passband and clipper keeping you somewhat within the channel. But no reason
it wouldn't work, but I'd think you'd want flat response from about 10hz to
10K hz for 9600bps on that transformer. 5 hz would be even better.
BTW, I got quite a few responses Off-SIG on the Anderson powerpoles.
--
Jeff King, jeff@aerodata.net on 5/6/2004
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Subject: Location with up to date info on PHG(R)
From: Sean Jewett <sean@rimboy.com>
Date: Thu, 6 May 2004 13:19:43 -0500 (CDT)
X-Message-Number: 6
I either found a error in aprsworld or the info I'm referring to is out of
date.
I'm working on the VUARC iGate. We set our PHG to 5400 based on the data
I input into
http://www.nashvilleaprs.net/apps/phgcalc.php
(I wrote that app). I used the data from Bob's page here:
http://web.usna.navy.mil/~bruninga/APRS-docs/PROTOCOL.TXT
and by that diagram 5400 is correct for our igate.
However, when I pull up the info on aprsworld I get this:
http://db.aprsworld.net/datamart/switch.php?call=AA4VU-1&table=position&maps=yes
In particular, this:
" Power: 25 watts Height: 25 feet Gain: 1 dB "
The power is correct but the height is way off and there should be no gain
according to my PHG setting (based on Bob's chart).
I know my D700 is showing the correct directional and power though I have
not looked close at the gain.
My question then is, which one is right? If aprsworld.net is right where
is the information it is based on?
On my todo list is to add the rate (R) to that calc at Nashvilleaprs.net.
If anyone has a good link to info on how the rate is calculated I'll be
more than happy to add it to my phgcalc. I've looked at
http://web.usna.navy.mil/~bruninga/aprs/probes.txt
but it's lacking in the ease of use that the PHG chart in protocols.txt
has ;)
Sean...
--
The punk rock will get you if the government don't get you first.
--Old 97's
_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
KG4NRC http://www.rimboy.com
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Subject: RE: agwpe
From: Wes Johnston <wes@johnston.net>
Date: Thu, 06 May 2004 18:19:54 -0400
X-Message-Number: 7
Gerhard!!! You the man!! RTS/CTS loopback works perfectly.
When running 3 wire serial TNC with AGWPE, short pins 7 and 8 on the de-9
connector together.
Wes
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Subject: RE: agwpe
From: "Gerhard F5VAG" <f5vag@nerim.net>
Date: Fri, 7 May 2004 01:54:35 +0200
X-Message-Number: 8
>-----Original Message-----
>
>Gerhard!!! You the man!! RTS/CTS loopback works perfectly.
No, I'm not. This was old knowledge from George's group I only
reiterated.
--
73 de Gerhard, F5VAG / DL7MW
APRSFR: http://france.aprs2.net
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Subject: WB4APR WX station!!! (funny)
From: wes@johnston.net
Date: Thu, 06 May 2004 21:49:46 -0400 (EDT)
X-Message-Number: 9
I couldn't help but poke a little fun at Bob Bruninga...
Here is a drawing of Bob's first weather station compatible with APRS....
http://www1.imscorporation.com/kd4rdb/wb4apr_wx_station.gif
The original is here:
http://web.ukonline.co.uk/archer/robinson2_frame.html
Wes
ham callsign: kd4rdb
find me: http://wesvan.zapto.org
---
END OF DIGEST
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