Thursday, October 13, 2011

New ISS object flying

Greetings APRS users,

There's a new ISS object flying in APRS-IS, but this object is different than others that have flown. It is flying with a MultiLine ( description of the approximate reception footprint. It moves every two minutes, so if you're using an APRS client that displays MultiLine information (APRSISCE/32 and xastir at a minimum), you'll be able to see the footprint coming and know to anticipate a pass (or realize that you just missed one).

The ISS object has a comment that says "Msg4Pass". That means to send an APRS message to "ISS" (without the quotes) from any message-capable APRS platform. This can be APRS radios (if you're in range of a message-gating IGate), any of the PC-based APRS messaging clients (like UI-View), or any of the new mobile APRS-IS clients, provided that they do messaging.

When "ISS" (not the real space station, but the APRS satellite server) will calculate the current or next pass of the ISS for an observer at your station's last beaconed position (it will say "Please Beacon Position" if it doesn't know where you are). The response will be one of the following:

Az: aaa El: lll LOS:xx:yyz - If you are in a pass
AOS: xx:yyz+aa:bbc - If you are not in a pass
AOS: NONE - If there are no passes for your location in the next two days.

aaa and lll are the azimuth and elevation for an observer at your location at the time the message was processed. LOS is Loss of Signal and xx:yyz is the time remaining in the pass and will vary to show sufficient time periods (hh:mmh, mm:ssm, sss).

AOS is Acquisition of Signal with xx:yyz being the delta time until the pass begins and +aa:bbc is the expected duration of the upcoming pass. The longer the pass, the higher you can expect the max elevation to be and the more chance of working it as it flies by.

But Wait! There's MORE! If the text you send to ISS is a known station identifier (say KJ4ERJ-12), the returned pass information will not be for your location, but for that station's last known location. To be clear, "@ call-SSID" is appended to the end of the response so you know which observer it is for. Of course, if the satellite server doesn't know where your specified station is locate, you will receive "Please Beacon Position" as a response.

And that's not all! This doesn't only work for the ISS, but for any of the other satellites found in the TLE set from You can send an APRS message to "AO-51" to find out when that satellite will pass within range. If you have any trouble figuring out which satellite name a message can be sent to, send an APRS message to KJ4ERJ-12 (or an e-mail to here) and I'll see if I can map the TLE entry to the responder station ID. And of course, you can also send any other known station ID to any of the satellites to get the current or next pass information for that station's location.

Give the service a try, and let me know how it works out. There's nothing to remember except the satellite name (including the dash in most cases) and the fact that you send a message to the satellite. Nothing like ANSRVR or CQSRVR or SATSRV, just send the message to the satellite by name and it will return the pass information.

Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32

PS. Don't look for ISS at as it flies too fast and is currently rejected by the speed limit filter. If you want to track the ISS object, add o/ISS* to your APRS-IS filter string. If you don't want to see it when it goes by, add -o/ISS* to your filter.

Here's a pair of chat transcripts with ISS and AO-51 (times are Eastern US):

21:35:39 New Chat Between KJ4ERJ-AP and ISS on 2011-10-13
21:35:41> foo (*2-21:35:41)
21:35:41< Az:325 El:12 LOS:4:19m
21:42:57> bar (*2-21:42:57)
21:42:57< AOS:4:44h+3:21m
21:48:41> WB4APR-15 (*2-21:48:41)
21:48:41< AOS:1:19h+8:23m @ WB4APR-15

21:43:09 New Chat Between KJ4ERJ-AP and AO-51 on 2011-10-13
21:43:11> FOO (*2-21:43:11)
21:43:11< AOS:5:45h+3:10m
21:43:26> ISS (*2-21:43:26)
21:43:26< AOS:5:45h+3:09m
21:43:37> N0GPS-3 (*2-21:43:37)
21:43:38< AOS:8:59h+12:24m @ N0GPS-3
21:48:58> WB4APR-15 (*2-21:48:58)
21:48:58< AOS:7:12h+13:23m @ WB4APR-15

Wednesday, August 31, 2011

14th Annual NWAPRS Summer Gathering

Invitation: Summer Gathering - Washington's Digital Ham Radio Event Sept 9-11, 2011

Please join us for the 14th Annual NWAPRS Summer Gathering.

This is a very social and very educational event right here in the Pacific Northwest in North Bend, WA. It is always the weekend after Labor Day.

The Summer Gathering is lots of fun and a great opportunity to learn and practice just about anything you can do with a computer and your ham radio.

We are expanding the event from the specific focus of APRS (the Automatic Packet/Position Reporting System) to a more general "Ham Radio's Digital Side". We continue to include much of APRS and developments in APRS and messaging as well as many other digital modes and software such as RMSExpress, NBEMS/FLDIGI, JT65 or WSPR or EasyPal, APRSMessenger, APRSISCE32. Sorry if that is all alphabet soup. We will make it all make sense at the event. Lots to learn and lots to try out.

Why would you want to do such a thing? Because there are modes out there that can allow you to operate less than a watt and be heard all around the world. Because you can do moonbounce with a modest station. Because you can work 28 dB below the noise and communicate all around the world. Or for the next emergency you can be ready with a modest station or compromised antennas and still communicate.

The sponsor for this event for the last 14 years has been the Northwest APRS Group

Review of the 13th Gathering in 2010

Tuesday, May 31, 2011

Balloon launch alerts

This could be handy...


---------- Forwarded message ----------
Date: Tue, May 31, 2011 at 8:32 AM
Subject: [aprsisce] Balloon launch alerts

I know there are a few on the list that like watching balloon flights
so I thought I would point out Jerry Gables auto alerts system.

I have messaged Lynn to see if this can be linked to the ANSRVR BALLON group.

The auto detect website is

And the group for email alerts

Seems to work very well

Steve Daniels

Tuesday, May 24, 2011

Now 5 APRS Channels!

I like Bob's idea of using different channels. That and the options
below are interesting to consider with our alt-frequencies.
Unfortunately we can't use the D700 (D710?) with split baud rates..
That would be interesting to transmit on the 9k6 channel and receive
on stock 144.39.

Bill - WA7NWP

---------- Forwarded message ----------
From: Bob Bruninga
Date: Mon, May 23, 2011 at 8:43 AM
Subject: [aprssig] Now 5 APRS Channels!
To: TAPR APRS Mailing List <>

Here is an updated recommendation for APRS channels in your APRS radio.  The
purpose of all these channels is to allow you to configure the A side of
your radio without ever turning down the radio volume on that side.  This
makes sure you are always listening for voice alert calls, but can mute the
packets temporarily or change to any of these other functions without having
to touch any menus or function buttons.

-- ------ ------- -------- --------- ----------------------------------
1) 144.39 simplex APRS raw No tone   for troubleshooting
2) 144.39 simplex APRSnorm CTCSS 100 with Voice Alert
3) 144.39 simplex APRSmute DCS xxx   for quiet or selcall at APRS events
4) 144.39 + 600   APRSevnt CTCSS 100 for special event with lots of HT's
5) 144.99 - 600   APRSdigi no tone   to be a WIDE1-1 offset digi

Notice, the change in channel 3.  The reason is, that unless you program the
actual CHANNEL NAMES shown above, then looking at the radio, you cannot tell
the difference between channel 2 and channel 3 operation.  Both show as
144.39 with CT.  But if you make the "mute" channel use an unknown DCS code,
then that channel will appear as 144.39 DC which is distinguishable from
144.39 CT.


aprssig mailing list

Tuesday, March 22, 2011

New version of APRS Messenger v2.99...

I've uploaded a beta version of APRS Messenger v2.99 to the website
and forum files section.

This version has some major changes so I've sent this out as a Special
Notice email.

It can now use comm ports up to 255 to connect to an external TNC or
GPS. Our new USB version of the APRS TNC Digi Tracker works well with

It can also connect to the AX25-SCS DSP TNC program in receive only
mode. This allows it to be used for receiving 300 bd AX.25 APRS
signals while monitoring APRS over digimodes on 30m. It also works on
1200 bd too so it could be used for example ISS APRS monitoring on one
receiver while working on terrestrial APRS with another.

When the AX25-SCS program is opened, the "Activate APRS-SCS support"
button clicked and the 300 or 1200 bd data rate selected via the
"Mode" tab you can now click on the command bar in APRS Messenger
v2.99 just above the
"TNC traffic or GPS NMEA sentences" text box and the connection will
open and the AX25-SCS program will start decoding APRS data on
receiver audio fed into the default sound card of the PC.

If the TCP/IP connection is lost, close and re-start AX25-SCS again.
Clicking the command bar will not re-start
the connection to AX25-SCS as it is still thinks the connection is open.

This feature used software copied from the now unsupported APRS-SCS
program written by John Blowsky, KB2SCS that originally worked with
the AX25-SCS program.

The AX25-SCS can be downloaded here:

At the request of Colin, GM0SUY I've also added a received message
output on TCP/IP local port 8064 so that APRS messages can be output
to other programs for analysis. This is to be used for 4x4 and car
rallying events in Scotland.

The only reason I'm calling it a beta version is that the program
doesn't completely close down when it's closed. It remains in RAM and
has to be closed down completely with the Windows Task manager.

Maybe the fix will be version 3.00!


Chris, G4HYG

Thursday, March 17, 2011

SmartBeaconing in Aircraft

Good path advice...

---------- Forwarded message ----------
From: <>
Subject: Re: [tracker2] Re: SmartBeaconing in Aircraft

Low data rates are a good thing, but a very important part of being a
courteous airborne user is the outgoing path.

WIDE1-1 should never be used as you have better HAAT than just about
every other station out there. You'll find through observation that
using no path at all will still get you heard over a very large area.
Since the OT2 has the ability to profile change based on altitude, I
would configure the unit to use no path at altitude, and WIDE2-1 down
near the ground.

Your decision altitude will need to be based on the terrain you fly
over, but with our balloon payloads flying over flat terrain can be
heard by stations hundreds of miles away by the time they are 500 ft
AGL. We have been flying balloons with no path on the last few flights
and having no problems hearing, tracking and recovering. The i-gates
pass the data with no problems, and we have little trouble finding the
landing location. There's usually no APRS infrastructure in the
recovery zone to light up with a path even if we did use one.


Oba, JA7UDE, the author of U2APRS is OK

---------- Forwarded message ----------
From: Chris <>

I've just received the following email from Oba, JA7UDE, the author of
the U2APRS program for the Android phone.


Thanks for writing. My family and I have "by chance" survived and are
now safe at home. My QTH is only 7km to the area that Tsunami hit.
Considering the tremendous damages, I have lost my words.


Oba's website is still working:

Wednesday, March 16, 2011


GM to the nwaprs group:

If you have an IRLP node, please consider running this script on the
node computer. This will add your node icon to the APRS-IS, and change
from an I (Idle) overlay to C (connected) overlay.

After you have done this, you can adjust your home station setting to
GATE this status to RF. If you're using UI-View, go to the FILE menu
and pull down EDIT IGATE.INI and add your node in this format
"IRLP-####" to the GATE TO RF. You will receive status changes over RF
when your IRLP node is active, and again idle.
To avoid duplicity, if you are transmitting your node info from a
WIDEn-N digi or as an object from within APRS, please remember to
remove that entry as it's no longer needed.

David K7GPS

Saturday, March 12, 2011

Can we use satellite digipeater for power outage region?

One alternative for you may be to use HF APRS over digimodes.

I've written a program to do this and it can also be used by a mobile
station with a GPS receiver to send position beacons many miles away
using PSK and GMSK modes. The usual frequency used for this is 10.1497
MHz. There are igates in the US, Australia and Europe already using this
APRS mode.

It's written using MMVARI as the sound card engine and it should be able
to send Japanese characters entered as APRS messages.

The webpage is:

Set up details are available on:

If you try it and you need any changes please let me know and I will
respond immediately.


Chris, G4HYG

Cross Country Wireless Ltd

Friday, March 11, 2011

New USB version of the APRS TNC Digi Tracker now released

We have now built up enough stock to finally release the new USB
version of our APRS TNC Digi Tracker.

It now has a USB port so that it can work with modern laptops,
notebooks and PCs.

It can be powered by either the 12V input on the 9 way D type radio
port or by the 5V feed through the USB port. This makes it very easy
to use with a notebook and handheld. The Digi Tracker is powered
through the USB cable and the Tx, Rx audio and PTT lines are connected
to the handheld radio.

It comes with a built in Sirf III GPS receiver with a SMA connector
for an external GPS antenna.

I've been using the prototype in my car over the last six months as a
tracker. It's fun to have the option to plug a USB cable between the
Digi Tracker and notebook for lunchtime portable APRS operation.

I've updated the web page with more details and an Operating Manual of
the USB version:

I've also made a new web page for the APRS Messenger Lite freeware
program that can program the new version using any PC Comm port up to
Comm 255 and also run as a receive only igate as well. The new web
page is:


Chris, G4HYG

Tuesday, February 15, 2011

Trackuino - New Simple APRS Tracker

An APRS tracker for the Arduino/Atmega328p platform.

Project Blog:

Sunday, January 23, 2011

APRS Messenger v2.98

I've just uploaded APRS Messenger v2.98 to the webpage:

This version now has a remote control feature to allow the APRS over HF digimodes and VHF TNC transmit functions to be enabled or disabled by an APRS message.

In the initial set-up screen you can enter the callsign and SSID of the remote control station. You can also enter the remote control messages to stop and start the igate transmit function. The defaults are "Igate transmit ON" and "Igate transmit OFF" but these can be changed to any 18 character message.

Remote control messages can be set over VHF (if a TNC is used), APRS over HF digimodes or the APRS-IS. A confirmation message "Confirm igate transmit ON" or "Confirm igate transmit OFF" is sent out to the remote control station over the APRS-IS if connected. When transmit is disabled the program still functions as a receive only Igate.

On HF digimodes the sound card transmit is enabled or disabled. Using a VHF TNC the comm port RTS output is enabled or disabled to control the TNC.

This is useful in countries where closedown arrangements have to be made for unattended use or where APRS igate operators would like a remote control facility when away from home.


Chris, G4HYG

Chris Moulding
Cross Country Wireless Ltd

New version of APRSISCE/32 released

A new version of APRSISCE/32 has been released in the APRSISCE Yahoo group ( Here's the major new features in this release. Please join the Yahoo group to download the full Release Notes if you're interested in more details. There's also a (woefully inadequate) Wiki available at

Major New Features:

AltNets (aprs101.pdf chapter 4) are supported.

"Auto-Reply" is now supported for responding from an unattended station

Support beaconing compressed locations as well as ambiguous positions

EchoLink nodes can now be queried, filtered, and displayed as objects

Dead Reckonging shows stations moving based on their last position, heading, and speed

WinMo Only: Track and Display Cellular coverage changes

Support fledgling AVRS server contacts directly from station popup menu (See

Support NWS Alert ( reception and MultiLine Object ( drawing. Click the "Counties" or "Zones" links to find your 3 character NWS office ID.

Weather information is parsed and displayed (summary in labels, details in popup)

Now support Weather Object / Station beaconing with WxNow.txt-format data file input

Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32

Saturday, January 22, 2011

Installing UI-View and Precision Mapping on Win7 and Vista

I have extensively updated the "UIview Notes" and "Using Precision Mapping 8" pages on my website, to reflect a new and improved installer for the Precision Mapping Server 7 plug-in for Uiview.

The new installer packaging for PMap Server 7.07 now works directly in Windows 7 (either 32 or 64 bit versions) without the clumsy and involved install procedure previously required. The same Precision Mapping Server Ver 7.07 is installed, but the installer program itself now works on these two newer versions of Windows.

Stephen H. Smith wa8lmf (at)
Home Page:

*** HF APRS over PSK63 ***

"APRS 101" Explanation of APRS Path Selection & Digipeating