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ZL3AI > APRDIG 30.10.06 20:55l 314 Lines 10024 Bytes #999 (0) @ WW
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Subj: [APRSSIG] Vol 28 #26, 1/2
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From: ZL3AI@ZL2BAU.#87.NZL.OC
To : APRDIG@WW
Today's Topics:
1. RE: Too many digi's ? (Robert Bruninga)
2. AI5TX-7 Digi down for now (Mark Earle)
3. RE: Too many digi's ? (Robert Bruninga)
4. Radar images... (Steve Dimse)
5. RE: Radar images... (scott_at_opentrac.org)
6. Re: Radar images... (Mike Heskett)
7. Sign Post (Eric Weber)
8. RE: PHG calculation formula? (Dave Baxter)
9. RE: PHG calculation formula? (Alan P. Biddle)
10. Re: PHG calculation formula? (Steve Huston)
----------------------------------------------------------------------
Message: 1
Date: Wed, 25 Oct 2006 16:21:03 -0400
From: "Robert Bruninga" <bruninga_at_usna.edu>
Subject: RE: [aprssig] Too many digi's ?
>The TN digi in question is a "T" overlay. It's so old, the
>TNC needs to be replaced to get up ot standard.
But an old "T" digi can be set to at least some compatibility as-is. IT
can be set with the four aliases of WIDE1-1, WIDE2-2, WIDE2-1, and WIDE3-3
and it will at least support the first hop of everyone in the footprint.
And being high up, that is a lot of coverage I think. But if no one
remembers the remote-sysop password and has to go up the mountain anyway,
then I agree, replacement is the best strategy.
But if there is remote sysop capability, then it can be fixed today to be
quasi compatible with the new-N paradigm as is. Then it gets a "P" overlay
to show its new capability. The full discussion on upgrading an old "T"
PacComm digi is found in:
http://cadigweb.ew.usna.edu/~bruninga/aprs/PacComm-settings.txt
De Wb4APR, Bob
See the web page
------------------------------
Message: 2
Date: Wed, 25 Oct 2006 15:40:30 -0500
From: Mark Earle <wa2mct_at_mearle.com>
Subject: [aprssig] AI5TX-7 Digi down for now
Attn: APRSSIG and especially Central Texas readers:
The AI5TX-7 digipeater near LaGrange, TX somewhat east of Austin is down
for now.
Tower work and painting are underway. Several antennas have been removed
to facilitate this work.
It will return to service when the work is completed, which is 30 to 60
days out.
This digipeater normally covers one of the drive routes from Austin to
Houston.
--
) ) de WA2MCT Mark
( ( Echolink 99190 Grid Square EL17HQ
) ) You will be assimilated... oooh, coffee!!
_|****| http://www.findu.com/cgi-bin/find.cgi?wa2mct-7 Home
( | | http://www.findu.com/cgi-bin/find.cgi?call=wa2mct-9 Mobile
`|____| wa2mct_at_mearle.com wa2mct_at_juno.com wa2mct_at_arrl.net
------------------------------
Message: 3
Date: Wed, 25 Oct 2006 18:29:27 -0400
From: "Robert Bruninga" <bruninga_at_usna.edu>
Subject: RE: [aprssig] Too many digi's ?
>them when using a capatible path (WIDE1-1,TN on the London
>side, and TN,WIDE2-1 on the TN side)...
><snip>
A few notes about using SSn-N routing:
1) Unless N is bigger than the preferred WIDEn-N, then just use WIDEn-N.
2) To go beyond the local WIDEn-N and still stay within state, that is what
the SSn-N system was designed for.
3) Since SSn-N does not trace, the best way to use it is to use the path of
SS1-1,SSn-N. This will cause the FIRST digi and the LAST digi to be
included in the path on arrival.
Good luck
De Wb4APR
------------------------------
Message: 4
Date: Wed, 25 Oct 2006 19:23:04 -0400
From: Steve Dimse <steve_at_dimse.com>
Subject: [aprssig] Radar images...
At least I know people are using the system. I checked my email for the
first time in three hours and got a dozen messages telling me the NEXRAD
images were no longer working on findU. It appears NOAA stopped serving
pages on srh.noaa.gov, switching the name to srh.weather.gov. Rather than
editing 154 geo files (three places on each of two servers, 900 files
total), I put in a kludge to do the switch in the radar-find cgi. This will
work for the way most of the radar images are served, but things that use
the geo file directly will be broken until I get around to sed'ing the geo
files.
Steve K4HG
------------------------------
Message: 5
Date: Wed, 25 Oct 2006 16:48:38 -0700
From: <scott_at_opentrac.org>
Subject: RE: [aprssig] Radar images...
If it's just the host name that's changed and not the URI, you should be
able to set the server's host file to point srh.noaa.gov to the address for
srh.weather.gov, assuming it's the server that's fetching images.
Scott
N1VG
------------------------------
Message: 6
Date: Wed, 25 Oct 2006 19:18:44 -0500
From: Mike Heskett <mheskett_at_mindspring.com>
Subject: Re: [aprssig] Radar images...
At 06:23 PM 10/25/2006, you wrote:
>At least I know people are using the system. I checked my email for
>the first time in three hours and got a dozen messages telling me the
>NEXRAD images were no longer working on findU. It appears NOAA
>stopped serving pages on srh.noaa.gov, switching the name to
>srh.weather.gov. Rather than editing 154 geo files (three places on
>each of two servers, 900 files total), I put in a kludge to do the
>switch in the radar-find cgi. This will work for the way most of the
>radar images are served, but things that use the geo file directly
>will be broken until I get around to sed'ing the geo files.
>
>Steve K4HG
There was also the following problem this afternoon:
....INTERNET CONNECTION TO THE NATIONAL WEATHER SERVICE IS DOWN...
ALL EXTERNAL INTERNET CONNECTIVITY TO NATIONAL WEATHER SERVICE OFFICES
WITHIN THE SOUTHERN REGION HAS BEEN LOST DUE TO A CUT FIBER OPTICS LINE.
TELEPHONE COMPANY TECHNICIANS ARE WORKING ON THE PROBLEM...
==/===/===/===/===/===/===/===/===/===/===/===/===/===/===/===/===/
Mike Heskett
WB5QLD WWW
Hurst, TX
O-
------------------------------
Message: 7
Date: Wed, 25 Oct 2006 21:52:00 -0700 (PDT)
From: Eric Weber <webmanou812_at_yahoo.com>
Subject: [aprssig] Sign Post
Greetings gang...
I have been running a sign post on the local intersections around my
area....
Are they really needed?
It is basically just posting "my" highway speeds as there is not much APRS
vehicle traffic past these spots....
If it is not needed, I'll drop the program....but if there is a use for it,
or the data being used for something, then I'll enable it again...
Thoughts?
Ideas?
no flames needed.....
73
Eric
kc0ahk
------------------------------
Message: 8
Date: Thu, 26 Oct 2006 10:17:04 +0100
From: "Dave Baxter" <dave_at_emv.co.uk>
Subject: RE: [aprssig] PHG calculation formula?
OK, so what exactly do you do with...
power = pow(base_power, 2.00)
Comma 2.00? Is there a function designator missing somewhere, as that
looks like you're calling a function "pow" with two indipendant values,
"base_power" and the value of 2.
And for that matter...
haat = (10 * pow(2.00, base_haat))
10 times the result of calling pow(x, y) again?
Dave G0WBX.
Bob's .mil and .edu sites are unavailable again, or it's the continuing
DNS colic they seem to suffer from..
>From: Gregory A. Carter [mailto:aprssig_at_gcarter.infodns.com]
>Sent: Wednesday, October 25, 2006 12:34 AM
>To: aprssig_at_lists.tapr.org
>Subject: [aprssig] PHG calculation formula?
>
>Here's the snippet that calcs it from OpenAPRS's daemon...
>
>power = pow(base_power, 2.00);
>haat = (10 * pow(2.00, base_haat));
>gain = pow(10.00, (base_gain / 10));
>range = sqrt((2 * haat * sqrt((power / 10) * (gain / 2))));
>
>73
>
>Greg
>N7NXS
>
>On 10/24/06, Alan P. Biddle < APBIDDLE_at_mailaps.org
><mailto:APBIDDLE_at_mailaps.org> > wrote:
>
>I was looking for the formula which is used for the PHG values for the
>beacon. No problem finding a site which would calculate it, but I flunked
>Google 101 on the formula itself.
>
>TNX
>
>Alan
>WA4SCA
------------------------------
Message: 9
Date: Thu, 26 Oct 2006 14:08:31 -0000
From: "Alan P. Biddle" <APBIDDLE_at_MAILAPS.ORG>
Subject: RE: [aprssig] PHG calculation formula?
Dave,
Had to problems accessing the site.
Here is a clip of the relevant section.
Alan
WA4SCA
===================================
POWER-HEIGHT-GAIN: This optional field replaces the CSE/SPD fields with a
report of transmitter power, antenna height-above-average-terain and
antenna gain. APRS uses this to plot radio range circles around all
stations. The following details the format to be used in the BText of
a TNC dedicated as an APRS digipeater:
!DDMM.mmN/DDDMM.mmW#PHG5360/WIDE...(identifying comments)...
| | | | |||| |_____ makes station show up green
| | | | ||||________ Omni (Direction of max gain)
| | | | |||_________ Ant gain in dB
| | | | ||__________ Height = log2(HAAT/10)
LAT LONG | | |___________ Power = SQR(P)
| |_____________ Power-Height-Gain identifier *
|_______________ # is symbol for digipeater
As you can see by the integers in the PHG string, there are only 10
possible values for each of these fields as follows:
DIGITS 0 1 2 3 4 5 6 7 8 9 Equation
-------------------------------------------------------------------
POWER 0, 1, 4, 9, 16, 25, 36, 49, 64, 81 watts SQR(P)
HEIGHT 10,20,40, 80,160,320,640,1280,2560,5120 feet LOG2(H/10)
GAIN 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 dB
DIR omni,45,90,135,180,225,270, 315, 360, . deg (D/45)
The DIRECTIVITY field offsets the PHG circle by one third in the
indicated direction. This means a front to back range of 2 to 1.
Most often this is used to indicate a favored direction or a null
even though an OMNI antenna is at the site. Note that 0 means
OMNI and 8 means 360 or a NORTH offset.
HIGHTS are ABOVE-AVERAGE TERRAIN! Not above ground or sea
level. ALso, since DOS version 8.0 the Height character may be any
ascii character 0-9 and above. This is so that higher heights for
aircraft or satelites may be incorportated.
On receipt, the PHG values are converted to a usable radio range using
the following algorithms:
POWER = P^2
H = 10 as a default
H = ASCII(Hchar)-51 converts it to a decimal value
HAAT = 10*2^H
GAIN = 10^(G/10) converts from DB to decimal
RANGE = SQR(2*H*SQR((P/10)*(GAIN/2)))
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