AmateurRadio.com

Kit Hall GM4EMX has sent details about a new unattended APRS iGate that will be located at his QTH in Aberdeen. The callsign will be MB7UAB.

Kit told me something I didn’t know about the allocation of callsigns for APRS stations in the UK.

• All APRS station callsigns start with MB7U (for Unconnected, I would guess.)
• A single letter following the U denotes a digipeater (e.g. our local digi MB7UQ)
• Two letters following the U denote an iGate.

I hope Kit’s new iGate will soon spark some activity in the Aberdeen area which up until now has been pretty much an APRS desert.

An apt title for this post, but also for the software in question. Yet Another APRS Client (YAAC from now on) is a new program written by Andrew, KA2DDO that has recently entered beta test status. I stumbled across it a few days ago and am now running it on my G4ILO-2 VHF iGate.

YAAC map display with US Geological Survey topographic data.)

YAAC is written in Java so it runs equally well on Windows, Mac and Linux platforms as long as you have a recent Java runtime installed.

YAAC is open source software and uses open source mapping (Open Street Map – OSM). APRSISCE does too, but whereas it uses bitmap tiles, YAAC uses vector-based map data. This makes the maps look a bit different (more as if they were drawn by a spider.) You can easily add topographical data from the US Geological Survey (the screenshot above shows this.) YAAC also supports the use of scanned-in maps but I haven’t tried this.

YAAC is very easy to use. There is a wizard to help you set up the program, though there is also an expert mode that allows you to get to all the settings directly. There are far fewer things that can be changed than APRSIS32 has which is one reason it is easier to use, but YAAC’s user interface is more standard. A File menu is on the left of the menu bar, Help on the right, and all the configuration settings are on a multi-tabbed dialog box not nested in three levels of menus. YAAC would be an ideal program for someone new to APRS, which is not to belittle the program in any way as it does all the things that most users would be perfectly happy with.

YAAC supports a wide range of TNCs including TNC2 compatibles and the Kenwood mobiles. In APRS mode the Kenwood D700/D710 can only be used receive-only. In Packet mode the Kenwood can be used as a KISS TNC. Believe it or not I hadn’t realized it had this capability until Andrew pointed it out to me. Just two commands (KISS ON, RESTART) are needed to put the Kenwood into KISS mode. The other thing that confounded me for quite a while is that the Kenwood TNC expects hardware flow control. Once that setting had been made everything started to run perfectly.

YAAC’s “Radio View”

One disadvantage of using the Kenwood D700/D710 in Packet mode is that the rig’s display doesn’t show any APRS information.However, Andrew has implemented a rather neat “radio view” which emulates the Kenwood display. The only extra thing that would make the emulation complete would be to limit it to only those packets received over the radio. With an APRS feed covering a wide area the display changes too quickly to be readable.

YAAC doesn’t provide as much information about APRS objects as APRSISCE does.The window on the right is what you get when you click on one of the G4ILO icons. When two or more stations are co-located the calls overwrite one another making them unreadable. APRSISCE manages to position the calls so they don’t overlap at all.

Because YAAC uses vector graphics it does a better job of displaying APRS icons and even orients the icons of moving objects in the direction of motion. Zoom in to street level and you’ll discover that icons are provided for points of interest. I was quite impressed when I saw what was displayed for our small town of Cockermouth. I think these objects come from OSM data.

Street-level display of Cockermouth including places of interest

You might get the impression that I really like this new APRS client. It appears to be well designed, well written and is well supported by Andrew, its developer. It’s a very impressive piece of software. I originally intended just to try it out for a couple of days but I think I’ll stick with it for the time being.

Good news for APRS enthusiasts with Android devices. Lynn Deffenbaugh, KJ4ERJ, is embarking on a port of his popular and successful APRSISCE to the Android platform, called APRSISDR.

I use the words “embarking on” advisedly. Although there is a Yahoo group and a collection of testers (including yours truly) the software is in an embryo stage at the moment. You can see the beginnings of an APRS client starting to form but Lynn is really just testing the Android platform at the moment to see how various key things can be accomplished. I would hazard a guess that it will take several months before something usable appears, though those who were in at the start of APRSISCE development will recall that it advanced in leaps and bounds. It’s going to be a fun ride, but for most I think it will be best to wait patiently for more news to emerge. Watch this space!

I know when summer is here when I have to keep on tweaking the tuning of my MFJ magnetic loop antenna throughout the day. Having an antenna farm in the attic (or loft as it is more commonly called over here) protects the antennas from the depredations of the elements but it does subject them to extremes of temperature during the summer months. As the loft warms up during the morning the metal of the magnetic loop expands. Because the magnetic loop is a very sharply tuned antenna this has an effect on the SWR. I don’t know what the temperature in the loft reaches on a sunny day but I wouldn’t want to go up there.

I’m not talking about a small change. I may tune the antenna to achieve a 1.2:1 SWR first thing in the morning and by lunchtime it can have increased to 2:1 or more. This wouldn’t be so noticeable if I was moving around the bands retuning as I go. But I use the magnetic loop for my 30m APRS station which stays on 10.1473MHz all day and every day. (It does a jolly good job there, by the way.) If I don’t pop into the shack now and again and give the antenna a quick tune I could be subjecting the transceiver to a higher SWR than is good for it.

The magnetic loop is the only antenna I have that will cover 30m, so I don’t have any alternative for my APRS system. This need for retuning affects all the bands I can use the loop on, not just 30m.

I suppose my multiband dipole also expands and contracts with temperature, but because the tuning is broader the effect on the SWR is less noticeable. Outdoor antennas have their tuning affected by rain or ice, of course, so I’m not alone in having to put up with weather effects on my antennas.

I have just spent what seems like several hours trying to find out why my weather station data sent by Cumulus to the APRS network vanishes without trace. I have tried using the wxnow.txt method of generating APRS weather objects in APRSISCE and that does work, but unfortunately it messes with the MYCALL setting in my Kenwood TM-D710 converse mode TNC. So I thought that I would avoid the problem by getting Cumulus to send the data to APRS-IS directly.

The data packets were being sent but they never showed up on aprs.fi. I produced debug logs for both Cumulus and APRSISCE. These showed the packets being sent. So where did they disappear to?

To cut a long story short, Cumulus was sending the data packet with a path of TCPXX*. This is listed as “deprecated” in the APRS spec but it is actually blocked by the APRS-IS network software. The CWOP (Citizens Weather Observer Program) which I believe runs on an older version of the software, is not so picky so no-one had encountered the problem before. Can you believe that I must be the first person to try sending weather data to the APRS network using the Cumulus software?

Yesterday Olga and I set up a new weather station in the garden. It is a Nevada WH3080 SOLAR. It took a while for me to figure out how to put it together but I got there in the end with a bit of help from Olga (who took the radical step of reading the instructions!)

The sky is always blue in Cumbria!

We had a bit of trouble mounting the weather station in the garden. The manufacturer supplies two large hose clips (you can see them in the picture) which are not the ideal hardware for attaching a pole to another pole. But they did the job, if not very elegantly.

There were no problems receiving the weather station on the control panel sitting on the shack PC 10m away. This Nevada weather station transmits on 868MHz so no interference from or to 70cm amateur transmissions. No problems with the software either, not with EasyWeather nor with Cumulus which is what I will be using.

The software setup went so easily that I couldn’t see how it was working. When I plugged the display console into a USB port the PC went “ding dong” to acknowledge a new USB device had been connected but I couldn’t find the new device anywhere. I expected it would appear as a serial port in Device Manager but no new ports were added. I didn’t have to specify a COM port in either program either. How the console talks to the weather software is a mystery. I’m not planning to write my own software to process the weather data but I’m still curious as to how the software gets the data.

Using the example web pages provided with Cumulus I set up a Cockermouth Weather page very easily. Cumulus creates a wxnow.txt file which APRSIS32 uses to generate an APRS weather object. However I have just noticed that Cumulus can send updates to the APRS network directly. That would be a simpler way of doing it, but that way the weather object would not get transmitted to the local APRS network. I’ve since discovered an issue when using APRSIS32 to generate a weather object via a converse mode TNC, but hopefully Lynn KJ4ERJ the author of APRSIS32 will come up with a fix for it.

A few days ago my Fox Delta WX1 Micro Weather Station stopped working. As it turned out, I just had to switch off the power and switch it on and it started working again . But while I was waiting for the rain to stop so I could go out and look at the device I began thinking about getting a better weather station – one that measures wind speed and direction and rainfall as well as temperature, humidity and pressure.

When you start to look at weather stations the choice is overwhelming. My first priority was that it should work with APRSISCE and generate the file wxnow.txt that it uses to update weather objects. That requirement led to the stipulation that it should be compatible with the free weather software Cumulus, which creates the required file. There is a list of weather stations that work with this software, which narrowed the choice down a little. After reading many reviews the best choice seemed to be the Davis Vantage Vue. Unfortunately this cost about four times more than I was willing to pay, so it was back to the drawing board.

The weather stations made by the Chinese firm Fine Offset and sold under the Watson brand name seemed to meet my criteria at a more reasonable price. However, browsing through the reviews on Eham.net and elsewhere there were quite a high proportion of dissatisfied users. Complaints about anemometers that stopped rotating, poor wireless reception and so on. With weather stations as with everything else, it seems, you get what you pay for.

Despite the reviews I am tempted to get one of the Watson W6861 solar weather stations. But before I did I thought I would take the opportunity to ask my readers for their experiences. Many of you must have home weather stations. So which ones are good, which are bad and which should be avoided at all costs? I await your comments with interest.