Monitoring Packets

On 8/24/2010 9:45 AM, Robert Bruninga wrote:

With today's sound cards in every PC, surely there is a free O-Scope display.  If so, then there is no excuse for any ham to not use this tool for cleaning up some of the trash we see on 144.39. 

There is a very simple and FREE app for this on my website.

Go to wa8lmf.net/miscinfo

Scroll down the list of downloadable stuff and look for WaveTools.exe .

Right-click and download this self-extracting archive of 4 audio applets for your sound card.

Four separate small programs turn your sound card into a dual-trace audio scope -or- a sine/triangle/square-wave audio generator -or- a volume-unit meter -or- an audio spectrum analyzer switchable between a linear and log scale.

Note that the dual-trace scope function requires that you have a stereo input sound system -- most computer MIC inputs are MONO. If the machine has a LINE level input, it will be stereo. Or use the inexpensive USB-connected "iMic" external audio system described here:

http://wa8lmf.net/ham/imic

which provides a stereo low-level MIC input.

I've used WaveTools in the field with my mobile laptop connected to the mini-DIN "data" jack output of my D700's discriminator output many many times to troubleshoot packet audio issues.

Some further observations on the WaveTool utilities.

1) These are actually 16-bit Windows 3.1 programs, but they work well on 32-bit Windows 2000 and Windows XP systems. They will NOT work on Windows Vista or Windows 7, since the 16-bit compatibility layer (a.k.a. the "thunker") that has existed in 32-bit Windows since Win 95 was quietly dropped in Vista and beyond.

Note that this breaks many older supposedly 32-bit programs. Many early Win95/Win98 "32-bit" programs contained chunks of 16-bit code (especially device drivers) recycled from their 16-bit Windows 3.1 predecessors. Such programs depend on the thunker to seemlessly run the mix of 16- and 32-bit code.

2) Windows XP allows multiple applications to access the sound card simultaneously. The WaveTool scope or spectrum analyzer can run AT THE SAME TIME as the AGW Packet Engine, APRS Messenger, mmSSTV, MixW or other other sound card app for a REAL TIME display of the incoming signals being fed into these apps.

3) The WaveTool scope in dual-trace mode can do the tricks "real" scopes do of displaying A-only, B-only A and B, A-B, A+B and A vs B vector displays.

Lighthouse Weekend

> Almost 300 lighthouses will be on the air for the 2010 International Lighthouse/Lightship weekend, 8/21- 8/22.

If they have an APRS radio and change their SYMBOL to the lighthouse symbol, then we can see them on http://aprs.fi

Or, if enough of them select the Lighthouse symbol, then you can see them on:

http://www.findu.com/cgi-bin/symbol.cgi?icon=\L&limit=200

And, they can all communicate with each other and anyone else on the planet's APRS radio by sending an APRS message to CQSRVR with the first two words of the message being "CQ LOTA ..."

See how www.aprs.org/cqsrvr.html

An easy way to make contact.
Bob, Wb4APR

SSID Recommendation Update

Bob Bruninga has updated his recommended SSID suggestions. The big change is that before it was keyed mainly to choose the symbol and now it is purpose driven. For example, it's not that -9 is a car, now it's the main mobile.

The complete publication is at : http://aprs.org/aprs11/SSIDs.txt

Here's the main content.

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APRS SSID Standard Applications                           9 June 2010

---------------------------------------------------------------------

Updated 9 June 2010 for more flexibility

Revised 2 June 2004 to add -10, -11, 12 and -15

SSID's have seen two different uses in APRS.  Initially as an ICON indicator back in the early 1990's.  But that is obsolete for over a decade.  Now SSID's are used as an informal way of indicating one of several different typical APRS applications.

Since many small displays for the handheld and mobile operator show nearby APRS station callsigns that flash up on the screen, it is nice to have some idea of what type of station or activity might be involved simply from the callsign SSID without having to push buttons, search lists, or look at maps to find out more about them. 

 SSID RECOMMENDATIONS:  It is very convenient to other mobile operators or others looking at callsigns flashing by, to be able to recognize some common applications at a glance.  Here are the recommendations for the 16 possible SSID's (the limit of 16 comes from the 4 bits available in the AX.25 protocol.  Note, The SSID of zero is dropped by most display applications.  So a callsign with no SSID has an SSID of 0.

-0 Your primary station usually fixed and message capable
-1 generic additional station, digi, mobile, wx, etc
-2 generic additional station, digi, mobile, wx, etc
-3 generic additional station, digi, mobile, wx, etc
-4 generic additional station, digi, mobile, wx, etc
-5 Other network sources (Dstar, Iphones, Blackberry's etc)
-6 Special activity, Satellite ops, camping or 6 meters, etc
-7 walkie talkies, HT's or other human portable
-8 boats, sailboats, RV's or second main mobile
-9 Primary Mobile (usually message capable)
-10 internet, Igates, echolink, winlink, AVRS, APRN, etc
-11 balloons, aircraft, spacecraft, etc
-12 APRStt, DTMF, RFID, devices, one-way trackers*, etc
-13 Weather stations
-14 Truckers or generally full time drivers
-15 generic additional station, digi, mobile, wx, etc

* One-way trackers can use any symbol the owner desires, -9, etc but if the owner wants to indicate that a particular mobile is not message capable and he cannot receive message traffic, then he might want to use the -12 indication.

SV2AGW Packet Engine Freeware Update

After about 5 years, a new version of the FREE version of the AGW Packet Engine has been released.

Version 2010-805 just went up on SV2AGW's web site a few days ago. According to the site, changes have been made to address new sound cards and to work better with USB -- serial dongles for PTT keying.

I can't say I saw any difference in performance in 4 installations on my various computers, but the setup dialog does make it a bit simpler to select between multiple sound cards if you have more than one on your computer.

Get it here:


http://www.sv2agw.com/downloads/default.htm

Scroll down below the "Pro" version at the top of the page.

[ Note that the freeware version of AGWpe only supports the high (2100/2300 Hz) "PK-232" tones on HF 300-baud packet, while the pay-for "Pro" version also supports the standard (1600/1800 Hz) KAM/TNC2/MFJ-127x tones on HF. ]

*** IMPORTANT*** The AGW sound card TNC works well, --BUT-- is very sensitive to sound card sampling rate errors. Many cheap motherboard-based sound systems have MAJOR errors in their sampling rates which will keep AGW from working. (You will see the incoming audio on the built-in scope or waterfall display, but nothing ever decodes.)

Verify your soundcard's sampling rate with the CheckSR.exe test utility bundled with the MixW multi-mode soundcard program at:

http://mixw.net/index.php?j=downloads

Download and install the latest version of MixW as a trial. The CheckSR utility is a completely separate single-file-exe program placed in the MixW folder during the setup. It will function by itself, even if you don't purchase and activate MixW after the trial period.

If the 11025 Hz sampling rate is off by more than 50-100 Hz, you may want to consider an alternative sound system. An inexpensive USB-connected external sound system that works well is the Griffin Electronics "iMic" reviewed here on my web site:

http://wa8lmf.net/ham/imic.htm


Stephen H. Smith wa8lmf (at) aol.com

APRS Links

We have a full list of links on the NWAPRS homepage. Here's some links to new and interesting projects.

• HF APRS with PSK63 - finally something better than 300 baud packet for APRS on HF.
• APRS Messenger - the program for HF APRS with PSK63
• APRSLINK - APRS interface to WINLINK2000 Email
• SV2AGW Software Downloads - including update of freeware version of AGWPE

APRS Link to Winlink2000

I'm trying to understand why my I-gate is getting packets from WLNK-1. It appears that WLNK-1 (no call sign?)
is in Halifax, NS! Why would these packets route there my system?

That is the APRS link to the WinLink 2000 system. Hams can preregister their callsigns with the WinLink system and use the APRS system to check and/or pull emails off the system. It's actually a great system that gets very little use.

http://www.winlink.org/aprslink

Brian N2KGC

TEMP Digipeating for SAR and other Activities

Bottom line - your D700 or D710 mobile should have TEMP configured as one of the digipeater aliases.

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Yes position reporting is perfect for SAR, but what most Hams are not training for is text messaging too. APRS text messaging provides the ability to do AD-HOC comms ANYWHERE and beyond simplex range.

You can extend the range of any APRS HT (for text comms and positions) as far as you want with mobile D700/D710 radios. (I was suprised to see that the FTM-350 does not appear to digipeat?). AD-HOC Rnage extension of packet is far easier than setting up an AD-HOC voice repeater for wilderness coverage.

Yes, a mobile D700/D710 can also serve as a voice cross band repeater, but only one hop. With DIGIPEATING, the range can be extended indefinately by additional mobiles. AND ALL D700/D710 mobile should already be fully configured for always-on digipeating via TEMPn-N, so as long as there are D700's at the event, text messaging should work as far as they travel.

If every D700/710 you know of is not configured this way, why not!??? Who will help make it happen if not you. (I think the D710 digipeater defaults to TEMPn-N enabled.

All SAR teams have to do is use the path TEMP3-3 or so to go three hops back to HQ via ANY availalbe D700/710. Try it next time you are simplex-near a D710...

SAR teams and other Ham response groups should include text messaging (and TEMPn-N mobile digis) as a routine COMMS RANGE EXTENDER in wilderness terrain and practice its use!. See www.aprs.org/TEMPn-N.html

Bob, WB4APR

IGates on Default APRS-IS User-Defined Port

The javAPRSSrvr sysops (aprs.net core servers and aprs2.net servers) use port 14580 as a user-defined filter port (no default filter). If no filter is applied by the client, it functions properly for IGates (maintains a last-heard list for the client and performs proper message and related posit passing in addition to any messages and related posits for the logged in client). A filter is not needed for proper IGate operation and will make your IGate software use much less resources than a full feed simply because there will be very few packets your IGate will have to process.

Adding filters is best suited for GUI clients because you want to see more than just what you might see on RF. Standalone and non-GUI IGates are best used on a user-defined port as you describe (port 14580) with no filter specified. This will provide proper IGate operation while minimizing impact on your system and your bandwidth to the Internet.

Hope this helps.

73,

Pete AE5PL
pete at ae5pl dot net

UI-View32 Meteor Mode

Hunting meteors with APRS is an interesting twist. Here's some info from the manual of UI-View32

UI-View32 Meteor Mode is a special mode in which the program can be used to transmit beacon frames very frequently. It is designed to be used for meteor scatter propagation tests.

Two different modes of operation are possible - "Interval" mode and "Burst" mode.

• Interval Mode - A single beacon frame is transmitted at a specified time interval.
  
  
• Burst Mode - Beacon frames are transmitted continuously for a period of seconds. You can specify how long the burst should be, and when you want it to start in terms of the number of seconds into each minute
  .
• Port - The port on which you wish to use Meteor Mode.
  
  
• Unproto address - The address to which you want to send the beacon frames, including any digis. The destination address and digis should be separated with commas, do not used 'V' or 'VIA'. Examples - CQ would address the beacon frames to CQ, CQ,RELAY would address the beacons to CQ via RELAY.
  
  
• Beacon - The text of the beacon you want to send. For meteor scatter use, the beacon should be as short as possible. The shortest beacon that can usefully be interpreted by APRS software is probably your IARU locator surrounded by square brackets, e.g. "[IO92XX]", and that is the beacon you are recommended to use.
  
  

NOTE - The following four automatic beacon input buttons cannot be used until you have input your latitude and longitude in Station Setup.

• Grid - Automatically input a grid square beacon.
  
  
• Grid-in-status - Automatically input an APRS "grid in status" format position beacon.
  
  
• Posit - Automatically input a normal APRS position beacon.
  
  
• Comp'd - Automatically input a compressed APRS position beacon.
  
  
• Interval (only used in Interval mode) - The interval, in seconds, at which you wish to transmit a single beacon.
  
  
• Start (only used in Burst mode) - The number of seconds into each minute at which you want the burst of beacon frames to start. You can specify more than one time, e.g. "0,30" would mean "start a burst at 0 seconds into each minute and another burst at 30 seconds into each minute". If you were conducting a trial with someone, then they might specify "15,45", so that your transmissions interleaved.
  
  
• Duration (only used in Burst mode) - The length in seconds of each burst of frames. UI-View converts the specified duration into a number of frames to send. The calculation is accurate, but it makes two assumptions - (a) that you are using 1200 baud, and (b) that your TNC will transmit continuously when fed with a stream of frames. If your TNC releases the PTT every few frames (the TH-D7 appears to behave in this way.), then you will need to make allowances for it, because a specified duration of, say, 10 seconds, will result in an actual burst length of perhaps 15 seconds.