The Bethel Area APRS Frequency is 144.390 MHz, simplex with no tone. The club’s digipeater with high-gain antenna became operational on the KYUK tower on November 24, 2009 around 1800 hours. We are not sure of the range of the system yet, but as we get more data, we will post that here.
Current Bethel APRS Tracking
The club is beginning to venture into APRS for Western Alaska. This is new to most of our operators, and for the community as well. Just a reminder, to utilize this system, you must be a licensed operator. If you are not a licensed operator, there are a number of resources on the right-hand side of this page, as well as people listed throughout this website who will help you get your license.
For those of you that are licensed amateur radio operators, are you are looking to put your HT or mobile on APRS for tracking and messages? Probably the most useful piece of information that you can have is that you should set your digipath on your HT to WIDE1-1, WIDE2-2. If you are going out as part of a hunting team and will be spread out around the tundra, far away from Bethel, you might even want to consider a WIDE3-3 digipath, but only if you find that you are not getting all the way back to Bethel.
This will give you three hops before your signal stops digipeating. Remember, the IGate going to the Internet is considered a hop, so you want to be sure to include that when thinking about how to set it up. For example, if you are in the village of Kasigluk fishing and you want your signal to be IGated to the Internet, your HT would transmit the original beacon. Someone elses HT would most likely pick that up during fishing season and digipeat that signal. That signal would then be sent to the club’s Kenwood digipeater and the Kenwood would send your data over the IGate to the Internet. Once the information is sent to the Internet, users can track your movements here or at http://aprs.fi. Since we have only one IGate in the area and we cover such a large expanse of land, combined with the fact that we don’t have a lot of Ham operators in the area, we feel it is acceptable at this time to go with a WIDE3-3 if necessary. If our Ham community grows over the years, this may have to be adjusted, but more Hams means more capabilities.
If you need information about APRS and some of the sofware available, please use the links below. The presentation that was given by Spencer Hamons - KL2RA during the August 6, 2009 club meeting can be found at this link. Under the basic setup information for the area is a list of resources for anyone looking for new tools or information about APRS.
When setting up your radio, you need to enter your callsign into the radio or the software that you are using. This is important for a couple of reasons. First, it allows others using APRS to know who they are exchanging information with. Secondly, it takes care of identifying your station for the identification requirements. Note, since APRS is an open standard, the packet holding your callsign is sufficient to meet the identification requirements.
The second piece of information that you need to consider when you are setting up your device or software is the SSID. This is like a suffix attached to your callsign. For example, my home station, digipeater and IGate on it is KL2RA-1, whereas my HT is KL2RA-7, and my mobile on my snowmachine will be KL2RA-9. See the guidelines for suffixes below:
|-0||Home Station, Home Station running IGate|
|-1||Digipeater, Home Station running a WIDEn-N Digi, Wx Digi|
|-2||Digipeater (#2 or) on 70cm|
|-4||HF to VHF Gateway|
|-5||IGate (Not home station)|
|-6||Operations via Satellite|
|-7||Kenwood D7 HH|
|-8||Boats, sailboats and ships (maybe 802.11 in the future)|
|-10||Operation via The Internet only|
|-11||APRStouch-tone users (and the occasional Balloons)|
|-12||Portable Units such as Laptops, Camp Sites etc.|
Finally, for that initial setup to start working without a lot of tweaking, be sure to enter in latitude and longitude coordinates for your station. If you are setting up a home station, this is can be set as a fixed number, since your station doesn’t move. Same for other informational objects such as repeaters and weather stations. However for mobiles and HT’s, a GPS with a NMEA feed can automatically update the position information. If you find that for some reason your station isn’t showing up online at http://aprs.fi, or in the map above, chances are good that it is because your station is not setup with a valid position, therefore it cannot be mapped.
- WinAPRS & MacAPRS
- Fairly capable software, half-way decent mapping support. $50 to register.
- Easiest-to-use APRS software, but no zoomable maps without purchase of Precision Mapping. This has excellent support of the bulletin board operations and messaging capabilities of APRS. Free registration is required, but well worth it. You will have to wait a couple of hours to get your registration code.
- Linux APRS software, that can be made to run under Mac OS X and Windows. Free.
- APRS for Microsoft MapPoint. Great maps, but very limited features. $104 with MapPoint, $30 without. Just a note, if you are a user from Alaska, the Microsoft maps tend to be “off” a bit.
- Newest Windows APRS software. Great GeoTIFF map support, several cool features. $50 to register.
APRS Map Servers
For those that don’t have APRS software installed or even a means of receiving packet radio transmissions, APRSworld and findU both offer Web-based mapping of APRS stations. For those of you that were at the August 6th BARK meeting, the live maps that were displayed were from APRS.fi. A link for a map centered on Bethel, Alaska can be found here. Note: This will open up a map in a new window.
Generic APRS Data Files
- Digipeater Overlay
- Always-current APRS overlay file showing all known Digipeaters. Can be used with WinAPRS, UI-View, and maybe Xastir. (Better to use Log file version for WinAPRS.)
- Current List of APRS Symbols
- There are many copies of the symbols.txt file floating around on the net, but this one is actually kept up to date.
- Always-Current List of Digipeaters
- Maintained by A Very Questionable Page Indeed, this APRS Position Overlay file includes all full-time digipeaters that have been reported to the site, even including the Power-Height-Gain information, although WinAPRS/MacAPRS do not display the range circles that this data implies. (Also valuable are the Rules of Digipeater Submissions).
Maps and Data Files for WinAPRS
- AFilter—Utility to filter feed from Internet APRS Feeds
- Out of the box, WinAPRS can connect to the APRS-IS Internet servers to receive APRS packets from all over the globe, but the thousands of packets you will receive each hour will quickly overload the program’s memory. By installing AFilter you can limit packets based on a radius around any one point, a list of your buddies, and many other attributes.
- Minimum Set of Maps
- Download 1globe.zip, extract 1globe.map, and place it in the
C:\Program Files\WinAPRS\Maps\folder. This is the simplest map that contains all the contries, and is needed to plot DX spots on. If you don’t plan on installing the TIGER maps, then please also download na.zip, extract na.map and place it in the same maps folder. This will give you the state borders for Canada, the U.S., and Mexico, including the major islands in the Carribbean.
- Latest FCC Callsign Database
- This is updated once a week on weekends (so downloading it every monday will keep you current), but before you download it, be forewarned that it is huge—66.1 MB at last check! Download this file, extract its contents from the archive, place them in the directory of your choice. Next, launch WinAPRS and select CallBook DataBase from the Settings menu, select FCC 2000 & Later from the top drop-down listbox, enter the full path to the
EN.idxfiles in the next two fields, respectively, and finally, press the Call Index button. Wait for the process to finish, and then press the OK button.
- National Weather Service County Warning Area Boundaries
- This NWS Shape File can be used by some APRS software to highlight which counties have weather warnings or alerts. These alerts are as special APRS packets, automatically generated from the NWS feed by software from KG5QD. This image of the Northern California County Warning Forecast Areas shows what the local regions look like. An example using Washington shows what this capability looks like. You should ocasionally download the latest files available from these pages, and place them in your
c:\Program Files\WinAPRS\NWSshape\directory. I have provided links to both the directory page (first line) and the most recent (second line) data file at the time of this writing, but please double-check the directory page ocasionally to make sure you are getting the latest file.
- County Warning Area Boundaries
- May 2, 2005 File. Everyone should have this one. It is the outlines for the County Warning Areas, there are only 121 of these
- AWIPS Counties
- May 2, 2005 File. These are the county outlines for 3232 (or so) counties including Alaska, Hawaii, Puerto Rico, and Guam.
- Public Forecast Zones
- November 2004 File. These are warning zones, which are similar in size to counties but have different boundaries.
- Coastal and Offshore Marine Zones
- May 24, 2005 File. These are of use mainly to those living near the coast.
- ZIP Code Database
- Download and place ZipCode.dat in your in your
c:\Program Files\WinAPRS\DATA\directory to enable ZIP Code lookups.
- Airport Database
- Download and place Airport.dat in your
c:\Program Files\WinAPRS\DATA\directory to enable lookups of U.S. Airports.
- DXCC List
- If it is not already installed, download and place DXlist.dat in your
c:\Program Files\WinAPRS\DATA\directory to enable lookups of DXCC Entities.
- Audio Alarms
- WinAPRS is not supplied with a complete set of WAV files for audio alarms, so you might want to download this set that Peter, K6WEB has compiled/created: WinAPRS-AudioAlarms1.0.zip, and then place them in your
- Digipeater Log
- Always-current APRS log file showing all known Digipeaters. Shows proper icon and remains visible even when map is panned or zoomed, unlike Overlays. Save to disk, and then use File>Open to display the log
- Text Labels and City Names for Tiger Maps
- From the Census Web site, download and place places2k.txt in your
c:\Program Files\WinAPRS\Tiger\directory to enable display of city name in the TIGER maps and to allow searching for cities in the maps. Once installed, please delete
C:\Program Files\Labels\National.txt, which provides a similar set of text labels for the older style WinAPRS maps, and which will create duplicate labels on TIGER maps if it is present.
ARDF-Capable APRS Software
- WinAPRS & MacAPRS
- While WinAPRS has built-in direction finding features, the documentation and operation thereof is confusing and insufficient. But this will be our first testbed platform for group foxhunts. The software’s problems include lack of a single non-modal (or otherwise) dialog that can be used to create and update DF reports, an inability to actually send out DF reports (due to the poor documentation), and a few others.
- From the specs, this looks promising, in that it supports a wide variety of maps, is free, and can supposedly create sophisticated DF reports which even include the angle of uncertainty (think a pie-wedge instead of a line) to make the composite DF reports more useful.
- The original is limited in that it only supports the rudimentary DosAPRS map format, but it offers the most complete support for the APRS DF features.
- This software has no built-in DF features, though a plug-in, DF-Plot, is available for older versions that will plot three DF reports and create an APRS object at their intersection. Supposedly, DF-Plot will even respond to a non-standard DF report format in APRS beacon comment fields: %bbb%aaa, where bbb is the bearing in degrees, and aaa is the accuracy, also in degrees.
- This has got to be the most convoluted piece of software I have ever tried. It might work great, but I was not able to follow the documentation well enough to figure out how to get it to import maps or do anything else useful.
TNCs and Sound Card Interfaces
- Packet Engines
- A packet engine is software that replicates the functionality of a real TNC. The one K6WEB has used is Homebrew Sound Card Interfaces. Stephen Smith’s sound card interface designs offer a good explanation about the level conversions that are necessary. Radio Ministries has a good page describing how to make a bare-bones sound card interface, though readers are warned that the lack of level conversion or isolation for the audio lines renders this the quick-and-dirty approach. Flex32 has another description of a simple q&d soundcard interface.
APRS and GPS-Related Standards
- APRS Specifications
- For much of its life, APRS was loosely documented in the many text files that are part of the APRSdos documentation files. Recently, it has been formalized as a specification in cooperation with TAPR: APRS Protocol Specification 1.01 (PDF file, adopted August 31, 2000), APRS Protocol Specification Addendum 1.1, APRS Protocol Specification Erratta, June 2004.
- Height Above Average Terrain (HAAT)
- An international standard used for determining signal coverage of radio signals. The antenna height above the average terrain elevations from 3.2 to 16 kilometers (2 to 10 miles) from the antenna for the eight directions spaced evenly for each 45° of azimuth starting with true north. Note: In general, a different antenna height above average terrain will be determined in each direction from the antenna. The average of these eight heights is the antenna height above average terrain. In some cases, such as seashore, fewer than eight directions may be used. For international coordination, it is officially measured in meters, even by the FCC in the USA.
- Main National Frequency: 144.39 MHz
- This is the frequency that stations and digipeaters listen and beacon on.
- Alternate National Frequency: 144.99 MHz (proposed)
- This is a proposed beacon-only frequency, to serve as an alternate input for digipeaters, which would then transmit heard posits on 144.39 MHz.
- 2.5mm Stereo Phone Plug/Jack Serial Port
- (Discouraged because it is a poor choice of connector for mobile use because the spring metal connectors in stereo phone jacks can cause intermitent connections when exposed to vibration such as you might find in a car, and because its three conductors are not enough for two-way data and power, which needs four pins.) This scheme is used for connecting serial GPS receivers to radios and other ham equipment, the 2.5mm stereo phone jack serial port standard was documented by Bob Bruninga, in his APRSdos documentation as the means of connecting GPS devices to Mic-E encoders. According to this documentation, on the 2.5mm jack (TNC end), Tip is used for TXD (data out), Ring is used for RXD (data in), and Sleve is used for GND (ground). This wiring pattern is used by the Pocket Tracker, the Kenwood TMD-700A, the Kenwood . Any references to the use of a 2-conductor mono phone plug/jack for GPS units is antiquated, as it supports only one-way data transmission, although the Baker2Vegas group found they had fewer problems with vibration using the mono connectors. Blue Hills Innovations offers pre- made GPS-to-TNC cables, at least for the Garmin-to-Kenwood connectors. If you are using some radios, specifically Alinco’s, this type of connector is their “standard” data connector for the front of the radio.
- TNC Packet Jack
- A 6-pin mini-DIN connector that handles audio in, audio out, PTT, and squelch signals.
- Wireless Industry Mounting Bracket Standards
- If you need to mount a GPS receiver, APRS display, radio, or other equipment in your car, there is an industry-standard mounting hole pattern. The AMPS hole pattern was created by the Association of Mobile Phone Systems, and consists of four holes in a rectangular pattern measuring .750 inches by 1.188 inches. An alternative hole pattern was created by NEC (National Electronic Commission)? Mounting brackets using these hole patterns are available from Haltof Product Design, Ram Mounting Systems, Pro.Fit International, PanaVise Products, and DXer Case.
- NMEA 0183 Interface Standard Version 2.0 (NMEA-0183 2.0
- The National Marine Electronics Association’s GPS interface standardThe NMEA FAQThe standard plain text format that most GPS receivers output via a serial port. There are different types of GPS sentences, including:
- For position and height. Looks like:
- For position only. Looks like:
(Geeks might be interested to know about the CANbus, from which NMEA-2000, a new marine data bus, was derived.)
This post was written by shamons on August 2, 2009