Saturday, March 31, 2012

New WSPR map

In case you didn't know about it already, check out this new map of recent WSPR spots.

It's much faster than the 'official' one, which could bring Firefox to its knees on a slow computer. And it remembers all your preferences including zoom level. A must-bookmark, if you're a WSPR fan.

Wednesday, March 28, 2012


This year I have decided to focus on the high frequency bands - 10m and 6m - this spring and summer. The predictions for the peak of this solar cycle are not very good, as you can read in several blogs, but it's all we're going to get for the next 10 years so I may as well make the best of it.

To this end I have started WSPRing on 10m when I switch on in the morning, with the intention of moving up to 6m if there appears to be a chance of propagation. On the previous few days I have been rewarded with a two-way path to VK on 10m at quite decent signal strengths. Not bad for 5 watts to an attic dipole. But today I received not a single spot, not a single trace.

Although not the reason for the lack of spots today, I think there is a gremlin in the machine. Twice I have come up to the shack to see what is happening and found the K3 in transmit mode but with no RF output. The K3 monitor mode shows no audio is being sent to the radio, so it isn't a radio problem. The WSPR software settings haven't changed, and are correct. Restarting the program makes no difference. The only solution is that hoary old first resort of the computer technician: Switch it off and then switch it on again. Works every time. But I wish I knew why it is doing it.

Monday, March 26, 2012

No contest

At the weekend I noticed that the CQ WW WPX phone contest was on. I'm not a fan of phone contests - hollering your call into a mic over and over again is not my idea of fun - but I thought it might be interesting to see what I could hear or work on 10m when so many stations were on.

In the end I only made a handful of contacts. It was just too manic for my current state of mind. I couldn't remember the serial numbers I was given before typing them into the log, so I would have to wait for the station I worked to make another contact and see what the next serial number was. I much prefer CW contests using a code reader to print up the exchange so that I can just double-click the information to enter it error-free in the log.

I've just started my final cycle of chemotherapy and it has knocked me back a bit. So I think I'll stick to pastimes like WSPR and JT65 that have a more relaxed pace until I'm feeling better.

Saturday, March 17, 2012

Taking a tablet

A month or so ago I solicited the advice of my readers on the selection of a device for reading e-publications. I learned that the Kindle - my original choice - would not meet all of my needs, but I received some strong endorsements for the Apple iPad.

As someone who pays full price for SIM-free mobile phones just so as not to be tied to one provider, the idea of a device that only let you use what Apple approves and insists on being tethered to iTunes did not, unfortunately, appeal to me. My online activities are very Google-centric, I'm a fan of open source and I already have an Android smartphone so inevitably my thoughts turned to Android tablets. Someone mentioned that Maplin had some cheap tablet computers in their sale - the Archos Arnova 10 G2. Maplin is rarely the cheapest source of anything even in a sale so I visited a price comparison site and found that Carphone Warehouse had the Arnova for £10 cheaper and with free shipping. I checked some reviews and the majority were very positive, even though many qualified their comments with "for the price." The tablet was in my hands 24 hours and £139 later.

Archos Arnova 10 G2
As a tablet virgin my impressions probably aren't worth much but even I can tell that the Archos is not Apple build quality. The plastic case is more reminiscent of something that came out of a Christmas cracker. £11 on eBay got me a leatherette case/stand for the tablet so I don't see the case anyway. But as many reviewers said, it's a lot of tablet for the money. I haven't got around to trying any e-book readers yet but I've used it for email and web surfing and I love it already. Battery life is great, the tablet is silent as there is no fan inside and no Intel Pentium giving you a hot lap so it's a much better laptop device than a laptop.

One problem was that there was no Gmail app as I use on my smartphone. The Arnova doesn't come with the standard Android Market so the choice of apps is rather limited. I found some instructions for installing Android Market on the Arnova but as usual whenever I attempt something technical with computers I got error messages that aren't mentioned in the description. After trying a few things at random and on the point of giving up I noticed that Gmail had been installed and I had the full Market, except that it has been renamed Google Play. That probably confused me into thinking it was something to do with games, which I have no interest in.

The one thing I haven't managed to do yet is find an app for my blogging activities. On the PC I use Blogger Dashboard in a browser (Firefox, of course) but on Android Dashboard is no good for keeping up with the blogs I follow because the list of posts is in an iframe and the Android browser doesn't support scrolling in an iframe. Nor does the Dolphin browser, which I was led to believe would be the solution. I'll probably have to use gReader, as I do on the smartphone, but I'd hoped the tablet would let me use something a bit more sophisticated.

We watched a TV show on the Arnova using the BBC iPlayer and I was impressed by the quality. Until then I could never understand why anyone would want to watch TV on a computer but in fact the angular size of the Arnova screen in my lap is larger than that of the TV when I'm sitting in my armchair, so it's actually better. As you may gather, I'm pleased with my new gadget!

Wednesday, March 14, 2012

New toys

There is nothing like some new toys to cheer you up when things get a bit boring! The G4ILO shack received two new arrivals this morning. Actually there was a third, non-radio addition that came yesterday as well, but that will have to wait for another posting.

The arrivals are two new handies - one a Baofeng UV-3R+ VHF/UHF dual band transceiver (note the plus,) the other a Wouxun KG699E low band VHF transceiver for 4 metres. My original UV-3R has found a new home, whilst the Taiwanese "professional" radio I got for 4 metres is just a rubbish radio.

I haven't had time to get to know the new radios. The Wouxun in particular is not intuitive and will require some intensive study of the manual. The Baofeng is functionally identical to the UV-3R Mark II but the build quality is much superior - on a par with the Wouxun and favourably comparable to the ham radio brands like Yaesu.

A major plus of the UV-3R+ is that you now get a professional grade drop-in charger. Besides a more rugged-feeling case it also has a metal belt clip - a big improvement over the flimsy plastic one that came with the earlier model. I believe that both radios use Kenwood specification accessories. This will be useful, if true, as I have two Kenwood radios as well. One of the first things I will have to do is find a wiring diagram for the programming cable because the one I made for the UV-3R Mk I has a 3.5mm 4-pole plug and is no longer useful.

Sunday, March 11, 2012

First HF Opera QSO

Yes. Opera now has a QSO mode. I had to update KComm to allow the Opera contact to be logged, so I thought I'd add ROS for good measure. You never know. :)

eQSL still won't accept the mode "Opera" as it hasn't yet been added to the ADIF specification. It remains to be seen whether the mode catches on. It's an obvious rival to JT65A but the JT mode has a lot more users. Opera is not time-synchronous and allows a bit more free-text flexibility.

By the way, have any of you Blogger users noticed that you can't insert GIF images into blog posts any more? When I try, I just get an empty box. I have to save all my images as JPG which is not a very efficient format for screenshots.

Thursday, March 08, 2012

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...

World Kidney Day

With all the news about giant solar flares that could black out communications I was surprised to hear activity on 10 metres. I made a few contacts on SSB with my attic dipole, including A65EE in Dubai and TC2012WKD from Turkey: a special event station for World Kidney Day to raise awareness of the importance of kidneys to our health.

I like to operate on the highest frequencies I can. On the shortest wavelengths small antennas are at the least disadvantage.

Friday, March 02, 2012

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?