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ZL3AI > APRDIG 02.03.03 10:01l 424 Lines 16668 Bytes #999 (0) @ WW
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From: ZL3AI@ZL3VML.#80.NZL.OC
To : APRDIG@WW
Subject: Re: Item-by-Item-RX N.F. [was: Holy Grail of APRS Network Performance
From: Mark Cheavens <mcheavens@usa.net>
Date: Thu, 27 Feb 2003 07:18:08 -0600
X-Message-Number: 16
The whole PHG system is broken since the formula used to calculate the
"range" from PHG assumes the world is flat.......It is NOT!
If I put in the correct PHG numbers on any of my digi sights the resulting
circles are absurd!
So instead we have to modify/change/alter the numbers so that the resulting
range is correct.
Mark Cheavens
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Subject: RE: APRS Computer - Voice Traffic Logging
From: "Brian Webster" <radiowebst@yahoo.com>
Date: Thu, 27 Feb 2003 08:25:50 -0500
X-Message-Number: 17
It's funny you ask about this, I was just looking at an old QST (January
2002) and it had done a review on a piece of software that uses the sound
card as a VOX recorder. It creates wave files and time stamps them, not
really compressed but with vox it would not record continuously. The article
says its free and can be downloaded at http://iz8bly.sysonline.it/index.htm
Brian, N2KGC
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Subject: Re: APRS Computer - Voice Traffic Logging
From: Bruce Coates <bruce.coates@sk.sympatico.ca>
Date: Thu, 27 Feb 2003 07:30:45 -0600
X-Message-Number: 18
Hi Robert.
I've experimented with a few programs to do this and finally settled on
Scanner Recorder. (http://www.davee.com/scanrec/index.html) It's a very
small program that records through the sound card and stores it in a file in
a variety of formats. The nice thing it has is a squelch that stops the
recording during periods of silence. It also creates a companion log file
that records the start and stop time of every transmission.
73 - Bruce - VE5BNC
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Subject: RE: APRS Computer - Voice Traffic Logging
From: "Richard Garcia" <k4gps@bellsouth.net>
Date: Thu, 27 Feb 2003 08:49:39 -0500
X-Message-Number: 19
Check out a shareware program called Scanner Recorder.
Rich
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Subject: Re: What Beaconet is Was: Holy Grail of APRS Network Performance
From: Alex <kr1st@amsat.org>
Date: Thu, 27 Feb 2003 09:05:59 -0500
X-Message-Number: 20
"Ev Tupis (W2EV)" wrote:
>By the way...you also assume that BEACONet is a "general purpose weak-signal DX
>propagation study system". In fact the Full Monty is available at
>http://www.BEACONet.org and would clear things up a bit for you.
Actually, Ev, what Beaconet is and what it is not, is not always clear,
not even from the web site. The web site actually suggests that it _is_
a general purpose propagation study system. Mind you, there's a huge
difference between how you read your web site and how others, maybe less
informed folks read it.
In fact, because of that suggestion by your web site I got interested
because of the potential for propagation studies, but it seems that
Beaconet is turning into some sort of VHF contesting tool. Sure there
are folks putting HF beacons on the air, and for some reason there seems
to be a collective QSY to different bands every once in a while. However
a clear direction where Beaconet is going is not always very obvious.
Oftentimes there's a focus on too many things at the same time (CU2QSO,
protocol changes, 2 meter transatlantic attempts, one moment everyone
seems to be into HF, then VHF, PSK31, AX.25, then contesting support,
something about a Live server etc.) which leaves a chaotic impression
with newcomers I think. I'm not saying that these are not worthwhile
efforts, I just think that a newcomer to Beaconet probably wonders what
in the world this group of people is trying to do.
On you webs site you advertise to think outside the box. Sometimes you
need to step outside your own box, look at your box, and see if the
labels on it are correct.
73,
--Alex KR1ST
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Subject: Re: TXD (Final answer?)
From: radio_q@juno.com
Date: Thu, 27 Feb 2003 07:12:37 -0700
X-Message-Number: 21
>On Wed, 2003-02-26 at 17:31, Bob Bruninga wrote:
>>What is the shortest TXD that works RELIABLY through an
>OPEN-SQUELCH TNC, such as the Kantronics KPC-3 or similar?
I've watched this thread, including the reports of very short TXD's because
the transmitter can do it because of this or that special technical feature
etc.
This discussion has been on the SIG several times in the past 5 years or so
and my comment has always been that it does no good to send a packet so
quick the receiver is not able to stabilize it's AGC and thus distorts the
leading edge of the packet with a resultant error This results in a
retransmission of your original packet which makes the few milliseconds
saved by reducing the TXD a very moot point.
What I have done is to do some tests by making a path which only includes
the digi I wish to 'test'. With a given value of TXD on my system, I send
10 carriage return only packets and see how many are repeated by the digi.
I then reduce the TXD and try it again. Given there may be some collisions
from transmitters I cannot hear at my location, the result has always been
that when I get my TXD set too low, there is a dramatic reduction in the
number of packets that are repeated by the digi. Upping that value a bit
serves as my minimum TXD as it is what is needed by the SYSTEM I am trying
to use.
Jim K5QQ
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Subject: Re: What Beaconet is
From: radio_q@juno.com
Date: Thu, 27 Feb 2003 07:15:59 -0700
X-Message-Number: 22
On Thu, 27 Feb 2003 09:05:59 -0500 Alex <kr1st@amsat.org> writes:
>On you webs site you advertise to think outside the box. Sometimes
>you need to step outside your own box, look at your box, and see if the
>labels on it are correct.
>
>73,
>--Alex KR1ST
AMEN!
Jim
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Subject: RE: TXD (Final answer?)
From: Bob Bruninga <bruninga@usna.edu>
Date: Thu, 27 Feb 2003 09:31:48 -0500 (EST)
X-Message-Number: 23
Yep, i Guess Im thinking of a D7 transmitting, so the only unknown is the
lockup time of the KPC-3 type open squelch TNC, since the digipeater
receiver is already on freq and squelch is open...
Bob
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Subject: Re: More APRS weather
From: "Spider" <spider@rivcom.net>
Date: Thu, 27 Feb 2003 07:39:51 -0700
X-Message-Number: 24
----- Original Message -----
From: "Charles H. Rahe, II" <crahe@infi.net>
To: "TAPR APRS Special Interest Group" <aprssig@lists.tapr.org>
Cc: "TAPR APRS Special Interest Group" <aprssig@lists.tapr.org>
Sent: Wednesday, February 26, 2003 8:02 PM
Subject: [aprssig] Re: More APRS weather
>Pleasure boats have a federal documentation number and/or a state
>registration number. They no longer are required to have an FCC call
>sign for non international vhf operation.
>
>Charlie, AI3L
>
>Miller Scott Contr 30SCS/FTI wrote:
>>Thanks to everyone who's responded with input on snow measurement. Sounds
>>like there's some interest after all.
>>
>>Now, what about maritime WX reports? Anyone doing that with APRS, or
>>wishing they could?
Scott, FIRENET does Ships, buoys and C-Man stations. We are using the
standard WX station format for APRS.
You can see them and their packets on Firenet. If your spec is going to go
beyond APRS, then you could add other items to all the various objects.
Flexibility would be the wise to incorporate into your spec, so that things
are not written in stone as with most specs. Sometimes specs are written by
small groups of men that may not (very likely) have a complete handle on the
complexity an object can have. Want a real spec? Make if flexible and user
definable,,,,make it a living spec and go beyond the mechanics of
programming....now wouldn't that be a concept!
A weather station, for an example just off the top of my head could have
over 100 data fields depending on the complexity of the station and it's
function. To set a standard in stone for a weather station is only good for
a specific application.
RAWS stations have different specs than that of a Metar station and both of
those are different than an RWIS or ALERT station station. Different specs
for different applications and nothing wrong with any of them.
For a Buoy,
The World Meteorological Organization (WMO) assigns a 5-character
alpha-numeric station identifier to all weather observation stations,
including moored buoys, drifting buoys, and C-Man. Generally, these IDs are
location specific, except for drifting buoys which retain their identifier
assigned by deployment location. Before 1977, however, the moored buoy IDs
were of the following form: EB-## (e.g., EB-4, EB-12), which bore no
relation to its location. In the data inventory summary, EB IDs are listed
under the appropriate station ID, if applicable.
The WMO station identification system is very simple. Identifiers are in the
form of "&&###" where "&&" represents a WMO oceanic or continental region
and ### denotes a specific location (e.g., 46042, 41003). With respect to
regions, 32 denotes stations in the Pacific off the coast of South America,
41 -- the Atlantic off of the southeast U.S. coast, 44 -- the Atlantic Ocean
north of North Carolina, 42 -- the Gulf of Mexico, 45 -- the Great Lakes,
46 -- the U.S. coastal Pacific Ocean, 51 -- the Hawaiian Islands, 52 --
Guam.
Station identifiers for C-MAN sites in the U.S. are determined through a
national system. It is alphanumeric with the format: AAAS#. "S#" is the
first alphabetic letter for the state where the C-MAN site is located
followed by the number of its location in alphabetized order of that state
in ascending sequence (L1 -- Louisiana, N6 -- New York, N7 -- North
Carolina). "AAA" is composed of alphabetic letters and is an abbreviation of
the location. As an example, Grand Isle, LA is represented by GDIL1, Lake
Worth, FL -- LKWF1, and Tatoosh Island, WA -- TTIW1.
C-MAN stations that are a part of the former WESTPAC-AMOS program are
identified using the WMO system, since WESTPAC data were transmitted
internationally. WESTPAC stations were identified by 91###, where ### is the
number assigned to the specific location.
STATION ID: Five-digit WMO Station ID used since 1976. ID's can be
reassigned to future deployments within the same 1 degree square.
DATE: UTC
TIME: To the nearest hour, UTC. This gets more detailed
Data are classified according to the following groups. Any data field that
contains "9 filled" represents missing data for that observation hour.
(Example: 999.0 99.0)
A. Standard meteorological data.
ATMP: Air temperature (Celsius).
WTMP: Sea surface temperature (Celsius).
DEWP: Dewpoint temperature taken at the same height as the air
temperature measurement.
PRES: Sea level pressure (hPa). For C-MAN sites and Great Lakes buoys,
the recorded pressure is reduced to sea level using the method described
in NWS Technical Procedures Bulletin 291 (11/14/80).
WSPD: Wind speed (m/s) averaged over an eight-minute period for buoys
and a two-minute period for land stations. Reported Hourly.
WDIR: Wind direction (the direction the wind is coming from in degrees
clockwise from true N) during the same period used for WSPD.
GST: Peak 5 or 8 second gust speed (m/s) measured during the eight-minute
or two-minute period. The 5 or 8 second period can be determined by
payload,
WVHT: Significant wave height (meters) is calculated as the average of
the highest one-third of all of the wave heights during the 20-minute
sampling period.
APD: Average wave period (seconds) of all waves during the 20-minute
period.
DPD: Dominant wave period (seconds) is the period with the maximum wave
energy.
MWD: Mean wave direction corresponding to energy of the dominant period
(DOMPD). The units are degrees from true North just like wind direction.
VIS: Station visibility (statute miles)
PTDY: Pressure Tendency is the direction (plus or minus) and the amount
of pressure change (hPa)for a three hour period ending at the time of
observation.
TIDE: The periodic rising and falling of the earth's oceans. Tide is
measured in feet.
DETAILED WAVE SUMMARY
HO: Significant Wave Height is the average height (meters) of the
highest one-third of the waves during a 20 minute sampling period.
SWH: Swell height is the vertical distance (meters) between any swell
crest and the succeeding swell wave trough.
SWP: Swell Period is the time (usually measured in seconds) that it takes
successive swell wave crests or troughs pass a fixed point.
SWD: Swell Direction is the compass direction from which the swell wave
are coming from.
WWH: Wind Wave Height is the vertical distance (meters) between any wind
wave crest and the succeeding wind wave trough (independent of swell waves).
WWP: Wind Wave Period is the time (in seconds) that it takes successive
wind wave crests or troughs to pass a fixed point.
WWD: Wind Wave Direction is the compass direction (degrees) from which
the wind waves are coming.
Steepness: Wave steepness is the ratio of wave height to wave length and
is a indicator of wave stability. When wave steepness exceeds a 1/7 ratio-
the wave becomes unstable and begins to break.
AVP: Average Wave Period is the average period (seconds) of the highest
one-third of the wave observed durng a 20 minute sampling period.
MWD: Mean wave direction corresponding to energy of the dominant period
(DOMPD). The units are degrees from true North just like wind direction. )
DEP01,DEP02,... The distance from the sea surface to the middle of the
depth cells, or bins, measured in meters.
DIR01,DIR02,... The direction the ocean current is flowing toward.
0-360 degrees, 360 is due north, 0 means no measurable current.
SPD01,SPD02,... The speed of the ocean current measured in cm/s.
C. Continuous Winds
DIR Ten-minute average wind direction measurements in
degrees clockwise from true North.
SPD Ten-minute average wind speed values in m/s.
GDR Direction, in degrees clockwise from true North, of
the GSP, reported at the last hourly 10-minute segment.
GSP Maximum 5-second peak gust during the measurement
hour, reported at the last hourly 10-minute segment.
GMN The minute of the hour that the GSP occurred, reported
at the last hourly 10-minute segment.
D. Spectral Wave Data
Spectral wave density Energy in (meter*meter)/Hz, for each frequency
bin (typically from 0.03 Hz to 0.40 Hz).
Spectral wave direction Mean wave direction, in degrees from true
North, for each frequency bin.
Directional Wave Spectrum = C11(f) * D(f,A), f=frequency (Hz), A=Azimuth
angle measured clockwise from true North to the direction wave is from.
D(f,A) = (1/PI)*(0.5+R1*COS(A-ALPHA1)+R2*COS(2*(A-ALPHA2))), in
which R1 and R2 are nondimensional and ALPHA1 and ALPHA2
are respectively mean and principal wave directions. In terms of
Longuet-Higgins Fourier Coefficients R1 = (SQRT(a1*a1+b1*b1))/a0,
R2 = (SQRT(a2*a2+b2*b2))/a0, ALPHA1 = 270.0-ARCTAN(b1,a1),
ALPHA2 = 270.0-(0.5*ARCTAN(b2,a2)+{0. or 180.}).
E. Water Level
TG01, TG02,...,TG10 Six-minute water levels representing the
height, in feet, of the water above or below Mean Lower Low Water (MLLW).
Please subtract 10 ft. from every value to obtain the true water level
value.
F. Marsh-McBirney Current Measurements
DIR Direction the current is flowing TOWARDS,
measured in degrees clockwise from North.
SPD Current speed in cm/s.
G. Oceanographic Data
Salinity (SAL) Conductivity is measured and converted to
salinity by a known functional relationship between the measured electrical
conductivity of seawater temperature and pressure.
H. DART Measurements
T (TYPE) Measurement Type:
1 = 15 minute measurement;
2 = 1 minute measurement; and
3 = 15 second measurement.
HEIGHT Height of water column in meters.
I hope this help with your spec.
Jim, WA6OFT
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