HFI gates QRT

I have taken down my HFAPRS gates. The reason is they all use my MFJ magnetic loop antenna. At this time of the year it needs constant retuning due to temperature variations in the loft. So it is not practical to use it when I can not be in the shack to tweak the turning .

Tracking wildlife

I watching a wildlife programme on TV the other day which had a feature about urban foxes. The naturalists  had fitted radio collars to some of the foxes and were able to track them over a wide area.One fox went off on a trek that lasted a couple of weeks and covered a distance of several kilometres.

In another programme radios have been attached to larger birds such as geese and ospreys to track their migration paths.
I wonder what frequency is used? One of the maturalists in the urban fox project seemed to be trying to DF a fox using what looked auspiciouslylike a 3 element 2m Yagi. I've seen similar antennas used o locate larger animals in Africa.

I would love to know what technology they use. My Kenwood TH-D7E APRS radio - despite being too big to use as a tracker for anythimg much smaller than an elephant -  can run for only a few hours with the GPS enbled and the power set to a sufficient level to enable tracking over a reasonable distance.using a less than optimal transmitting ntenna.

A tiny Bluetooth TNC

One of the things I've been up to the last few weeks is testing a new Bluetooth TNC made by Rob WX9O who is selling them as Mobilinkd. I had to put testing on hold while my Motorola smartphone went away to be repaired (by BuzzBox whom I can recommend highly.) In the meantime word got round and Rob sold out of these gadgets before I could write about it.

The price was around $49.95 which I thought at the time was amazingly cheap and probably explains why they are all sold out at the time of writing. The module is a small PCB slightly smaller than a Baofeng UV-3R and if you remove the belt clip it can easily be fixed to the back of it. My picture shows it strapped to the back of one of the Baofeng's predecessors, where it makes a nice inexpensive and compact APRS tracker. The board and it's battery (which can be charged using a USB cable as shown in the photo) are shrink-wrapped in a tough translucent plastic casing.

Ready-made cables are available. Rob sent me a Kenwood-format two-pin connector which fits the later model Baofengs and the two worked together perfectly. The audio levels were just right on both transmit and receive.

Yes, receive. This is no mere tracker. It's a full KISS TNC and decoded all the packets received by the Baofeng. The software used was the latest APRSDroid running on my Motorola Milestone (a.k.a. Droid) smartphone.  Droid and TNC paired easily and made an effective APRS mobile station.

I did try to pair up the TNC with APRSISCE on an HTC Touch Pro running Windows Mobile 6.1. The two devices paired but could not connect as the Bluetooth software did not recognize the TNC as a valid device type. I think that is a limitation of the Windows Mobile Bluetooth software rather than the TNC module.

If you are interested in APRS and would prefer to do it over the radio rather than a cellular data connection (real hams use RF, right?) then this is a nice toy to play with.

New APRS IGate for Aberdeen

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.

Yet Another APRS Client

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.

Another Android APRS client

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!

Antenna expansion

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.

The case of the disappearing weather objects.

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?

A new weather station

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.

What weather station?

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.

Winlink using Robust Packet

Helge DF8LS has just published a web page showing how to send and receive email on HF using Winlink and the SCS Tracker TNC. I just sent an email to myself (isn't this one of the signs of madness?) and it was received, so the instructions are obviously good!

A Winlink session on HF

Mention of Winlink seems to cause strong emotions in some quarters. Personally I think using ham radio to send and receive email is rather cool, even if it is too slow to use for today's level of email use. It's a pity more hams don't activate their Winlink account, which is callsign @ winlink.org .

If you use APRS then you can also send and receive email by that means using a feature called APRSlink. The trouble is, I use it so infrequently that I forget the commands. It would be wise only to use it if the APRS channel is quiet like it is here.

A narrow escape!

I think I narrowly avoided a battery fire or explosion in the shack this morning. For the last 18 months or so I have been using my old HTC Touch 2 smartphone as my 2m APRS iGate (I hated it as a phone.) All that time it has been sitting in the desktop cradle talking to my Kenwood TM-D710 TNC via a Bluetooth connection and providing a 24/7 gateway that is silent (unlike my PC) and uses less power.

This morning Colin M0XSD sent me an APRS message and I took the phone out of the cradle so I could use its keyboard to reply. I noticed that it felt quite hot. After about 5 minutes conversation the battery died. Having been on permanent charge that should not have happened.

My dead Touch 2 battery - can you see the bulge?

I took the still warm Li-Ion battery out of the phone and noticed there was a distinct bulge on both sides of the casing. So I suppose that it was on the way to exploding or catching fire. Unfortunately the phone won't work with the battery removed and powered only from the desktop cradle. So my G4ILO-2 iGate is off the air. I will think again about the wisdom using a permanently-charged smartphone as an iGate in the future!

Derventio

I have been itching to try venturing further afield and thought we might go down to the river Derwent at Papcastle. I carried the Kenwood TH-D72 on my belt to track the walk using APRS and see how far we got. When we reached the path down to the river we saw a paper sign saying "Derventio." Olga thought - wisely with hindsight - that it would not be a good idea to walk down to the river as we would then have to climb back up again. We walked a bit further along the road and looked down towards the river where we could see substantial excavations were taking place. This looks like being a major archeological site. One day when I'm just a bit fitter we will go down and take a closer look.

We continued our walk with a loop through the village of Papcastle, then returned home the way we had come. On the way I heard and worked Richard G1JTD portable on the summit of Great Calva, and Liz M6EPW on my local SOTA summit of Watch Hill. That will undoubtedly be the first summit I will attempt but at the moment it is still too far - about 3 miles from our front door.

I was pretty tired and very sweaty by the time we got back to Cockermouth but I resisted Olga's suggestion that we finish the excursion by taxi. Although what we had done was an easy walk by normal standards this was my most ambitious outing since finishing my treatment.

When we got home I could see that our track had been perfectly recorded by APRS. I was happy with that - and with the two contacts I made. I had only been using one of those stubby antennas about 5 cm long which are a couple of dB down on a rubber duck.

I saved the track as a GPX file and then produced a report using one of the online GPX report generators. According to the report we had walked exactly 4 kilometres. 1.5km of this had been climbing for a total ascent of 87m. To me it felt as if I had just climbed Scafell Pike!

Robust Packet Radio

A couple of days ago Chris, HB9DDF sent me an email asking how to configure APRSIS32 to work with the SCS Tracker / DSP TNC. Digging through my configuration files to get the information he needed I thought: why not put the 30m APRS gateway back online? It had been off since I went into hospital last year and the K2 and magnetic loop were hardly ever used.

SCS Tracker DSP TNC and Elecraft K2 at G4ILO

I don't know if propagation is lousy or whether things have changed since I was last on HF APRS but there seemed to be a lot less activity on the 30m APRS frequency today. An hour went by without my receiving anything. I did, however, hear quite often the "whooshing" sound of Robust Packet Radio (RPR) stations a few hundred Hz down. So I decided to configure the TNC to work in RPR mode.

Robust Packet is a mode obtainable in 300baud and 600baud versions that has been designed to take advantage of the capabilities of digital signal processing (DSP) in order to obtain reliable communication over a normal less than perfect HF path. To anyone who has experience only of traditional 300baud FSK packet RPR has too be seen to be believed. Packet after packet was decoded and displayed by APRSIS32 while conventional packet transmissions on the adjacent channel just flickered the DCD lamp and were discarded due to errors.

Robust Packet is a proprietary mode developed by SCS and is only supported by SCS TNCs. As far as I know no description exists that would enable someone to develop a PC implementation that uses a sound card. In that respect it is pretty much like Icom and D-Star. I would much rather use an open standard.

G4ILO-10 joins the Robust Packet Network

But RPR works where the old-fangled 300baud FSK invented to work on the analogue modems of 30 years ago doesn't. I think it is in keeping with the spirit of ham radio to use state of the art technology where it provides clear benefits to communication.

So G4ILO is now part of the Robust Packet Network.

Baofeng in space!

If you like APRS and cheap Chinese radios you might be interested in this Spanish balloon project which will launch tomorrow (Sunday) from Madrid. The helium balloon will carry aloft two Baofeng UV-3R transceivers connected as a transponder with a 435.450MHz downlink and a 145.840MHz uplink, an APRS module on 144.800MHz beaconing the SSID EA1RCS-11, three cameras, a radio ionosonde and a parachute. The team anticipates that the balloon could go as high as 30km, making operation or reception possible over a large area of Spain and neighbouring countries.

For more information see the project website http://cienciactiva.com/.

Tracking the torch by APRS

You can follow the progress of the Olympic torch using APRS. The name of the torch is TORCH2012. The screenshot below shows it being tracked by APRSIS32.

If you don't have an APRS client you can follow the torch at aprs.fi by going to http://aprs.fi/?call=TORCH2012.

Look, No IP

A couple of years ago we changed our broadband Internet service provider. The new provider did not support a static IP address. I have a QNAP network attached storage device which is primarily used for backup. However, it's actually a Linux box that runs the LAMP (Linux, Apache, MySQL and PHP) software which I occasionally use as a web server for experimentation. I sometimes need it to be accessible from the internet. So I opened a free account with DynDNS in order to access the server using a host name.

Some time last year after I came out of hospital I started to receive emails from DynDNS informing me that my account was being disabled due to abuse and inviting me to open a paid account. As far as I could tell, the only "abuse" was that my script to inform DynDNS of my current IP address was running more than the number of times DynDNS permitted. I had no idea why it should start misbehaving like that and cynically thought it was just a ploy to convert free users to paid subscriptions. I was in no frame of mind to deal with the problem, nor to dig into my wallet, so I simply closed the account and had done with it. This would have had the effect of breaking some APRS-related functions on my site but I had other things of greater concern to think about.

A few days ago I decided to look into why the CDGVHF ANSRVR group was not sending any messages. ANSRVR is an APRS tool used to send APRS messages to groups of interested people. CDGVHF stands for Cumbria Dumfries and Galloway VHF group and it is intended to disseminate alerts about VHF and UHF openings in the Cumbria, Dumfries and Galloway area (grid square IO84.) It's essentially a filter that acts on emails sent out by DX Sherlock and converts them to APRS messages addressed to ANSRVR. I could, of course, just have the emails sent to my smartphone. But it's more fun to make use of ham radio!

I looked for an alternative free service to DynDNS and decided to try No-IP Free. As far as I can tell, No-IP won't accuse you of abuse for updating your IP address too frequently, in fact its client software appears to do this every few minutes which seems like plenty. It does have a requirement that you confirm your account is being used once a month, which could be a bit annoying, but I'll see what happens at the next update.

In the meantime, CDGVHF is now sending out propagation alerts again. To receive alerts of VHF and UHF openings in the IO84 area just send an APRS message to ANSRVR with the text CQ CDGVHF. You'll need to repeat this from time to time as the server unsubscribes you from the group after 8 hours of no activity, unless you are using KJ4ERJ's APRSISCE software which can maintain your subscription for you.

Propellor on Packet

My Gadget Gangster Parallax Propellor board has just modulated its first APRS packets. This is not down to any clever programming by me. I simply used the Spin APRS Object published by Richard, G3CWI based on code by Alex Erlank.

Richard had to make some changes to get Alex's code to work and I had to change a few things as well. Mostly they involved replacing Richard's callsign and position with my own! The AFSK output was connected to the mic input of my old TH-205E using a 0.1uF DC blocking capacitor. There is enough idle time at the start of the packet for VOX to be used if the transceiver supports it. Mine doesn't, so for test purposes I manually keyed the radio's PTT.

I found that my packets were not decoded by the Kenwood TM-D710 TNC when I used the option to include a path such as WIDE1-1,WIDE2-1. I'm not up to debugging the code. However, Richard had mentioned that calls less than 6 characters long needed to be padded with spaces so thanks to an inspired guess I found that that this applies to paths like WIDE1 as well.

There is a GPS object included with the code. I haven't tried the Propellor with my GPS module yet, mainly because the GPS doesn't pick up any satellites from inside the shack so I'd need to rig up a battery supply and take all the kit out to the garden to test it, where it's damp and cold. (Yes I know, I'm a wimp.)

The AX25 object contains a section intriguingly called "demodulator" which has been removed. So it seems that there may be some Spin code that would enable the Propeller to be used as a TNC to decode and display APRS packets. That isn't something I had particularly planned to do, but it would be interesting to see if it works better than the WB8WGA PIC based TNC that I built a year ago which is a bit fussy about the level of the input audio.

One of the options with the Propeller is a touch screen colour TFT display panel. With one of those a suitably clever person could make a very nice standalone APRS terminal. I think there's an Ethernet module as well, so it could even be an IGate...

FreeTrak progress

I have made some progress with the FreeTrak PIC based APRS tracker. I found a slightly newer version of the PICFlash programming software. At first this gave exactly the same warning message as the original version. But after a bit of random clicking I tried again and this time the software reported that it was writing to the chip. It verified OK as well. I don't know exactly what I did, but at least that hurdle was now passed.

FreeTrak configuration

I set the DIP switches on the EasyPIC board to link the PIC pins used for serial I/O to the serial output. That didn't seem to work the first time, either, but at the second attempt at powering up I saw the configuration prompt appear in the terminal window. I was able to complete the FreeTrak configuration with the PIC in the development board.

Next, I changed a DIP switch to put the chip in Run mode. Using a utility called NMEAGen I began sending simulated GPS messages to it using the same serial connection I used for configuration. The LED began flashing at 1 second intervals and using a crystal earpiece on the output pin I could hear the familiar sound of 1200baud packet bursts. I don't know why it appears to be transmitting at 1 second intervals, but perhaps it is something to do with the simulated GPS data.

FreeTrak schematic

So FreeTrak appears to be working. All I need to do now is build it on to a circuit board and attach it to my GPS module and a radio. Here's where I could use a little help from readers. The AFSK audio output of the FreeTrak uses an obsolete op-amp which is unobtainable. I presume I could just replace this with a simple transistor amplifier stage using a 2N3904 or similar, but do I really need anything at all, given that the audio will drive a sensitive microphone input? Could I get away with just a DC blocking capacitor and a trimpot to set the level?

The other thing I'm unsure about is how to interface the FreeTrak to my GPS module. I think the circuit shown is intended to work with GPS devices that use 5V TTL or even RS-232 signal levels. The data sheet for my bare GPS module states quite clearly that the absolute maximum voltage on any of the pins is 3.3V. The serial lines on the PIC measure close to 5V. How to connect them?

Mistaken identity

A couple of weeks ago I came across FreeTrak, a PIC based APRS tracker developed by N0QBH. I have wanted to build a small 'grab-and-go' tracker for a while now. The FoxTrak works fine but is too big and bulky by the time it is paired with an HT. The TH-D72 is too much hassle as I need strong reading glasses to see the LCD screen and inevitably go out with some essential menu option disabled. Consequently these days I rarely bother taking APRS with me when Olga and I go for a walk around town.

I sent off for a couple of PIC 16F628A microcontrollers, thinking that I could program them in my EasyPIC5 development board. But when I tried, I immediately hit a snag.

My PICFlash programmer detects a PIC 12F508 instead of a PIC 16F628A.

I don't think I've been sold a fake MCU. If I remove the 16F628A so there is no micro plugged in at all I still receive the same warning. So I don't know what to do. I've bricked too many PIC chips by programming them with the wrong settings to try crossing my fingers and clicking Yes. So it looks like my FreeTrak project is not going to get off the ground.