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ZL3AI > APRDIG 01.11.06 05:39l 229 Lines 9094 Bytes #999 (0) @ WW
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Subj: [APRSSIG] Vol 28 #30, 3/4
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To : APRDIG@WW
Message: 17
Date: Sun, 29 Oct 2006 20:27:19 -0800
From: "Stephen H. Smith" <wa8lmf2_at_aol.com>
Subject: Re: [aprssig] Official pronunciation of APRS?
scott_at_opentrac.org wrote:
>>From an efficiency standpoint, I'd say the 'apers' pronunciation is the
>clear winner. Two syllables vs. four - except maybe in places like Texas.
>They can make 'yes' into a two-syllable word down there. =] Better
>compatibility, too. It's a lot easier to pronounce WinAPRS and APRSWorld
>that way.
I've always verbalized it with a short "A" as "appirs" with the first
syllable as in "apple".
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Message: 18
Date: Mon, 30 Oct 2006 16:03:12 +1030
From: "Ben Lindner" <vk5jfk_at_activ8.net.au>
Subject: Re: [aprssig] Official pronunciation of APRS?
why dont we just call it tracking ot trackin' it would save all the
confusion on how to pronounce a 4 letter abbreviation.
No offence to the creator of APRS
Ben Lindner
VK5JFK
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Message: 19
Date: Sun, 29 Oct 2006 23:18:13 -0800
From: "Stephen H. Smith" <wa8lmf2_at_aol.com>
Subject: [aprssig] *** APRS TNC Test CD Now Available ***
*** APRS TNC Test CD Now Available ***
I have produced a CD containing signals for testing and comparing the
performance of different packet TNCs, and radios that might be used with
these TNCs. The recordings of live off-the-air APRS activity are also
useful for demonstrations in locations where live signals aren't available,
such as a basement conference room.
This disk is a "CD-Plus" combination disk that contains CD-ROM data files
viewable on a computer, and standard CD audio files playable on any normal
home or car audio CD player, boombox or DiskMan.
The audio files could also be played on an old CD-ROM drive standalone,
without a computer, by connecting the TNC under test to the drive's front
panel earphone jack, or to the 4-pin analog audio jack on the drive's rear
panel. (A CD-ROM drive normally doesn't need computer support to play audio
CDs. A drive with a front panel volume control and track-select button is
preferred.)
Playing back standard CD audio rather than CD-ROM .wav or .aiff audio
data files avoids the timing errors and incorrect playback sample rates
that often accompany low-cost software-based PC sound systems (i.e.
motherboard AC97-based systems).
Details on the disk, links for downloading the 530MB image file for
creating this CD, and a link for purchasing a ready-made CD, are located on
my website at:
http://wa8lmf.net/TNCtest
Scott, N1VG, of OpenTrac fame ( http://opentrac.org ) is handling the sale
of recorded disks on his Argentdata e-commerce site, and has also
graciously volunteered to host the large downloadable CD image files on his
server.
About The Tracks
---- Track 1 is an off-the-air recording of 40 minutes of activity on
144.39 MHz in Los Angeles, California, during the afternoon rush hour at
about 5:00 PM when the channel is totally saturated to several hundred
percent of the Aloha threshold. It contains a variety of over- and
under- deviated signals, packet collisions, rapid-fire packets with
practically no pause between them, raw NMEA string trackers, TinyTraks,
clueless idiots using CW ID on packet, etc. All periods of dead air over
about 1 second have been edited out so that 40 minutes of real-life
activity have been compressed to 25 minutes on the CD.
This track is intended to be played back directly into TNCs to compare
the performance of various TNCs "under fire" in the real world. The
rapid pace of the packets should be a good test of the ability of
buffers in TNCs and associated applications to hand a rapid flow of data
without overrunning.
---- Track 2 is identical to Track 3 except that a precise
6db-per-octave/20db-per-decade de-emphasis between 300 and 3000 Hz has
been applied to simulate the typical de-emphasis found at the volume
control or speaker output of the typical land-mobile receiver. This can
used to evaluate the relative performance of TNCs in handling raw
non-deemphasized discriminator audio vs de-emphasized speaker audio. The
effectiveness of jumper-selected equalization networks available inside
some TNCs can also be tested. This track was created by applying the
graphic equalizer filter in Adobe Audition set to simulate the standard
EIA land-mobile radio de-emphasis curve.
---- Track 3 is a recording of a Kenwood D700 transceiver sending a
Mic-E position report, taken from the wideband low-distortion
discriminator output of an IFR1500 service monitor. This recording of a
single packet was then copied and pasted repeatedly in the Adobe
Audition audio editor. The result is 20 bursts each minute, for 5
minutes, for a total of 100 absolutely identical packets.
This track is intended to modulate an RF signal generator. Connect the
CD player to the external modulation input of a generator, and set the
playback level so that the data bursts deviate the generator about 3.5
KHz. Connect a radio's receive audio output to the TNC under test.
Connect the RF generator to the radio's antenna input. While the
recording is playing, gradually decrease the generator RF output level
until the TNC starts failing to decode. Since the recording contains
exactly 100 bursts, counting the number of successful decodes can
directly indicate the percent success rate at various RF carrier levels.
Possible uses of this track:
1) Compare different TNCs connected to the same radio.
2) Connect the same TNC to different radios to compare the
weak-signal data performance of various receivers.
3) Evaluate the relative receive performance of audio taken from the
radio's speaker versus audio taken from dedicated "data" or "packet"
jacks or outputs. (De-emphasis and audio bandwidth may be different at
these two sources.)
--- Track 4 is an off-air recording of 25 minutes of a single mobile
D700 beaconing every 12 seconds (maximum beacon rate) on a quiet channel
(no other stations) while driving around the San Gabriel Valley area of
Los Angeles. The signals were monitored in Pasadena, California. Most of
the drive test course was 8-10 miles from the fixed station, far enough
away from the monitoring fixed station to create some mobile flutter,
multipath and loss of quieting. In several stretches, several successive
packets are audible on the recording but failed to decode with the AGW
packet engine.
Again, this recording was taken from the non-de-emphasized direct
discriminator output of a Yaesu FT-1500b via the 6-pin mini-din data
connector.
This track is intended to be played back directly into TNCs under test.
An APRS application running on a computer attached to the TNC should
create a realistic moving object.
The three following tracks are for TNC alignment rather than testing.
They are intended to evaluate TNC demodulator tolerance to tone "skew"
(unequal levels of the 1200 and 2200 Hz tones).
---- Track 5 is a direct recording of one minute of a KPC3+ TNC in the
CAL mode sending the alternating 1/0 test pattern (i.e. alternating
between 1200 and 2200 Hz tones) with both tones at the same amplitude.
---- Track 6 is the same recording with a precise 6 dB/octave 20
dB/decade DE-emphasis applied as in Track 3 above.
---- Track 7 is the same recording with a mirror-image precise 6
dB/octave 20 dB/decade PRE-emphasis applied.
--
Stephen H. Smith wa8lmf (at) aol.com
EchoLink Node: 14400 [Think bottom of the 2M band]
Home Page: http://wa8lmf.com --OR-- http://wa8lmf.net
NEW! TNC Test CD
http://wa8lmf.net/TNCtest
JavAPRS Filter Port 14580 Guide
http://wa8lmf.net/aprs/JAVaprsFilters.htm
UI-View Misc Notes and FAQ
http://wa8lmf.net/aprs/UIview_Notes.htm
"APRS 101" Explanation of APRS Path Selection & Digipeating
http://wa8lmf.net/DigiPaths
Updated "Rev G" APRS http://wa8lmf.net/aprs
Symbols Set for UI-View,
UIpoint and APRSplus:
------------------------------
Message: 20
Date: Mon, 30 Oct 2006 02:14:06 -0600
From: "John Habbinga" <kc5zrq_at_gmail.com>
Subject: [aprssig] APRSTV Episode 6 is now available
I finally got episode 6 of APRSTV posted. It shows the installation of a
system that has a DStarInterface station on VHF, an EchoLink station on UHF
and an APRS receive only I-Gate on the same frequency as the EchoLink
station.
You can view the video at http://www.aprstv.com.
--
John Habbinga, KC5ZRQ
Lubbock, Texas
http://find-you.com/cgi-bin/find.cgi?call=KC5ZRQ*
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Message: 21
Date: Mon, 30 Oct 2006 05:35:33 -0500
From: Steve Dimse <steve_at_dimse.com>
Subject: Re: [aprssig] Official pronunciation of APRS?
I've never heard Bob pronounce it apers, I've also always said A P R S.
Steve K4HG
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Message: 22
Date: Mon, 30 Oct 2006 06:18:48 -0500 (Eastern Standard Time)
From: "James Smith" <k9apr_at_tawg.org>
Subject: Re: [aprssig] Official pronunciation of APRS?
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