A history lesson from call signs

World empires and colonies in 1914, also at
the time of the 1. Int. Radiotelegraphic Convention.
Source Wikipedia Commons, user Andrew0921

There's a lot of history to read out from amateur radio call signs. Being interested in history as well as amateur radio I found that for some countries you can actually figure out which time period it got independence just by looking at the prefixes of the call sign. But on the other hand the history of the international conferences and the call sign allocations is as complex as politics can be so this short blog post can only scratch the surface of this complicated topic.

I have always been envious of those radio amateurs who have a call sign starting with a letter that reflects their country's name. This seems to be the privilege of big and powerful nations, or countries that were just lucky in having names that didn't overlap too much with those of other nations. Among the 1913 call signs one can find:

CQ DX Marathon and 2011 Activity

I just submitted data for all my radio contacts for 2011 to CQ DX Marathon. My log program is UcxLog by DL7UCX and I started by exporting the ADIF-log and then analyzing it with the recommended analysis program by AD1C.

In the process of doing the conversation I also happened to find the Contact Map tool from NS6T which generated this map from my 2000+ contacts in 2011. What it shows below it not so surprising - from my location in the south of Norway it is easiest to work Europe, Russia and the East Coast of the US, but it is nice anyway.

2011 contacts from LA3ZA, open in separate window for larger map.

My CQ DX Marathon result was 167 countries (165 real DXCC countries), 35 zones giving a total of 202 points which is a result I was very happy with. It was actually my highest country count in a single year since I got my license in 2001. Much of it must be attributed to the renewed activity of the sun last year which gave a lot of new opportunities on the 10 m band. All countries except one are CW (morse) contacts with a 100 W Elecraft K3. Antennas are a 75 m long horizontal loop for the lower bands up to and including 21 MHz, and a 5 m half wave wire vertical for 24 and 28 MHz. The length of the wire loop exceeds that for the Formula Class, so I had to submit my score in the Unlimited Class.

Now I am only looking for a software tool which can analyze my ADIF-file for US states and Russian oblasts, but so far I haven't been able to find any.

All I want for Christmas is a nerdy watch

As a self appointed nerd I have a special fascination for watches with binary displays or with morse code readouts. It seems as if such watches now have become designer objects. One reason may be that since everyone has a mobile phone with a clock these days, design can be promoted at the cost of functionality. Anyway, here are some nice watches to choose from for your wish list!

Personally I find the watches from The One to be among the nicest. Here is the Slim Square. The display is a bit hard to read, binary as it is. The trick is that the left-hand side shows the hours and the right-hand side minutes. Then just add up to get the hours and the minutes.

Multiple 28 MHz propagation paths and excellent conditions

Final 'F' in UA3MIF. Notice echoes of final dot
marked by arrows. Press image to enlarge.

There were excellent conditions during this weekend's Ukrainian contest. I was active on 10 m and noticed several reverberant signals coming from Russia and Kazakhstan around 11-12 UTC on 6. Nov.

Here is an example from UA3MIF (28 MHz, 11.30 UTC 6. Nov 2011, press link to hear audio) as received on my vertical end-fed dipole (omnidirectional) for 10 m and the K3.  See the picture for the final 'F' in his call sign and what seems to be multiple echoes. The final dot starts at 3.247 sec and multiples seem to occur at 3.322 and 3.373 seconds, i.e. after 75 and 126 ms.

Although 126 ms is almost 138 ms, the round-the-world travel time, I could need some help to interpret these delays based on the locations of the transmitter relative to me near Oslo, Norway. It was easier for a similar reverberant signal from JA3YBK some years ago.

Communication with vector potential waves

Field lines (black) and potential (red) for a dipole, static field. 

In QEX July/August 2011 Robert K. Zimmerman (NP4B, VE3RKZ) had an intriguing article entitled "Transmission and Reception of Longitudinally-Polarized Momentum Waves."  What he claims is that he has communicated over a distance of 1500 m at 1296 MHz using vector potential or momentum waves.

Unlike transversal electromagnetic (TEM) waves these are longitudinal waves just like sound waves. This may seem like real magic, but if true it would allow covert communications which is undetectable with ordinary radio receivers and antennas.

Elecraft K2 do's and don'ts

In July 2011 Don Wilhelm, W3FPR, suggested that someone ought to write a comprehensive K2 Owner's Manual. This posting does not qualify as one, but at least it lists some things to watch out for regarding the Elecraft K2.

Minimal stress on the headphone jack

By all means avoid this situation!  

• Failing headphone jack: One of the most frequent complaints is the need to replace the headphone jack. Mine has lasted for ten years by being careful not to put undue stress on it. The best thing to do is to use an angled plug for the headphone (left-hand image). Many headphones have that or one can use an extension cord with an angled plug. In either case, this is the best way to minimize the mechanical stress. The worst one can do is surely to put a long mini-jack to jack adapter plug directly into the headphone jack (right-hand image). Replacing the headphone jack is not hard if you follow these instructions from W3FPR.

Small voltmeter for a QRP rig

AT Sprint rig in an Altoids box, itself contained in a video case.
Digital voltmeter in lower left corner shows 12.0 Volts.
(Click for larger image)

Every battery-operated rig needs a voltmeter. I had a small analog voltmeter for my AT Sprint QRP (= low power), 4 Watt rig, but after it failed I wanted to upgrade it to a digital one. I found a miniature meter on Ebay which is perfect for a QRP rig and which I recommend.

Aurora, 50 MHz and the Elecraft P3

Tonight had nice aurora conditions on 6 meters due to a geomagnetic storm. The Elecraft K3/P3 combo did an excellent job in showing how wide the bandwidth of these CW signals has become after having been reflected off the aurora.

The first image shows the green cursor on SM7FJE's signal, the bandwidth is almost 1 kHz.