APRS via Soundcard - No TNC. Multipsk Reviewed: By: Andy K3UK Updated December 10, 2006.
I am happy to report that APRS via Multipsk works very well, this is a good option for those that do not have a hardware TNC. Some aspects of APRS in Multipsk are still in beta test, with the latest beta release being 4.1.2. The software is by Patrick F6CTE. I have operated packet with various TNC's over the years and also have used UI-View 32 fairly extensively. I gave up using UI-View with my PK232 because I did not want to use serial ports, all my digital mode activity is via a PC-to-radio USB interface (Microkeyer). I did use AGWPE with UI-View successfully but always found that to be a bit of a pain to set-up. Patrick's inclusion of APRS/Packet in Multipsk makes it quite easy to get active on HF, or VHF APRS. It is simply a case of inserting a couple of parameters (longitude/latitude, etc) and clicking on "APRS" as a mode. No having to install other software or drivers. Don't forget to switch to 300 baud if you want to use it on HF. Really, two minutes set up time is all that is needed . I Patrick's software uses UI-View maps (or other APRS maps) . This is extremely useful, just copy your existing maps over to the multipsk/maps folder, enable the maps inside Multipsk and you can view the maps within Multipsk and watch as stations populate the map. The weather information is graphically displayed as it is received. It is a little different than UI-View , In UI-View the weather data is displayed by clicking on a callsign on your map and the info "pops-up" on the map. In Multipsk, clicking on the map will display all the data received from the station , not directly on the map but in the weather station graphic next to the map. Patrick added this feature after I released my first review, a very nice addition and excellent response to user feedback!. The graphic display will indicate your distance from the stations and includes a window that displays the raw text as it is decoded. APRS in Multipsk also allows you to display on the map , "all stations" that you have received since booting up the program , or display stations monitored during a particular hour. Again, a very useful feature. I do not see any way to easily list just the stations your are receiving direct, versus those relayed by digipeating stations. I also do not see the ability to "filter" the stations by a specified radius from your station , but since I use APRS exclusively on HF, I'm interested in seeing all stations regardless of distance. I have a little trouble with some of the available windows for APRS in Multipsk. The " Packet APRS Frames decoding/coding " window contains some beautiful graphics and maps, but the window remains "on top" . Thus, I am unable to do anything on my computer unless I remember to minimize it. Within the " Packet APRS Frames decoding/coding " window, there is a button labeled "transmission". Clicking on this brings up another window full of useful packet parameter setting. I find myself confused when I have this open. The "options" "resp/beacon" "mail" buttons on the Multipsk main screen do not respond if these windows are left open. I have to toggle back and forth trying to find what mistakes I have made, what I have left open. The " Packet APRS Frames decoding/coding " window also has an "exit" button that I have clicked on several times thinking that it will take me make to the main Multipsk window, it does but closes the beacon operations. I think I am supposed to minimize , rather than "exit". Maybe it is just me, but I find it confusing. APRS in Multipsk allows you to configure most packet/APRS parameters such as "wide", "echo", "trace", "relay" plus set Frack, TXdelay, Paclen, and the usual things you would expect if you were using a TNC. Patrick has added many options that will allow you to work APRS and keep your station consistent with your region's expectations. As previously mentioned, I use APRS on HF and the settings are not as critical. Still, I have some learning to do about what is optimal. APRS in Multipsk allows you to "repeat" frames received from others stations and there is an option that will beacon your "repeat" capabilities every minute. I'm a little nervous about doing this on 10151 in North America, I'm not sure if this extra traffic will cause any problems or not. However, I did test the "echo/repeat" feature , and it works well. I like the audio "beep" that you can set to sound whenever you receive a valid APRS packet frame. The "repeat" feature, and Multipsk's amazing inclusion of Reed Solomon signal identification (encode and decode) , has some intriguing other possibilities. I have experimented beyond the traditional APRS utility and have spent a few hours using APRS/Packet on non-traditional frequencies. Recently I used APRS Multipsk in 80M , I announced my frequency via several email groups. I thought it would be useful to use the APRS features, including the maps, to alert digital mode experimenters that I was on frequency and available for QSOs. I did get one response , but found that the noise on 80M makes for difficult 300 baud packet decoding. The RS ID ,that uses MFSK16, was almost always received but the subsequent 300 baud packet was not. Multipsk supports APRS "mail" but I have not used that feature ...yet. I have more to learn (and re-learn) but thought I would mention that this works very well and is a good alternative to other APRS applications, No TNC required. I should mention that I use Commander from the DX-Lab suite, this interfaces seamlessly with Multipsk and enables PTT and other aspects of rig control. If you activate your APRS station, please check your regional recommendations for various settings. Andy K3UK.
