Clever K3 macro trick

Tonight I sat down to fiddle with the macros of my Elecraft K3. As I already use M1-M4 for CW memories, I only had the PF1 and PF2 buttons available.

It was the blog post "K-3 Rotating Macros" of W8TN that made me aware of a clever trick for using a macro to reprogram itself. This gives the possibility to have two rather than one function in the PF2 button. My need is for a button that can toggle between the typical pile-up functions Split+1 and Cleanup. In addition I have another macro that toggles speakers on and off.

Scratchy Tivoli Audio Model One

The Model One has been a huge success. But in many ways it is a daring retro design judging from all the features that are missing in this radio. I am thinking of features such as a customizable equalizer, a digital display, and memory presets. It just has a plain old analog tuning dial for FM and AM.

The radio could as far as I can tell just as well have been made in the 70's except for some of the IC's which are used. Actually it is easy to see the similarity with the even older KLH Model 18 from the 60's, and yes - Henry Kloss played a role in both radio designs. But that makes for easy repairs, such as a seemingly common fault in the FM tuning capacitor, which over time may develop contact problems.

The best of the Baofeng handhelds

How do the cheap Baofeng handhelds compare? I have had the Baofeng UV-5R since I bought it from the 409shop in April 2012, but recently I noticed that the UV-B5, UV-B6, and UV-82 have appeared on the market also. If I should need another handheld transceiver for VHF/UHF, is there any advantage in getting any of the other models?

I prepared the following table in order to highlight differences and similarities. Bold characters signify an improvement for what I conceive to be typical radio amateur use.

Elecraft K3 modifications

There aren't that many modifications that you can do to the Elecraft K3. This is very different from the K2 as in my list I now have 138 different modifications for it. But Elecraft does have a few K3 enhancements and mods on their home page and here are two additional modifications that I have done to my K3.

Plug-in roofing filters on
main RX board

The first one is to add a wideband LC-filter (roofing filter). The filter was inspired by ideas from W5DHM with three tuned sections at the IF frequency of 8.215 kHz. It is to the right in the image. It is not the best of filters, and probably compromises performance somewhat, most likely because of its low image rejection 30 kHz away. It has however served me well as a receiver filter for the latest version of K1JT's software WSJT-X. That software processes a 4 kHz band for both the JT65 and JT9 digital modes, and the LC-filter has demonstrated to me the utility of having a wide roofing filter for reception of those modes. The filter also works well for listening to broadcast AM which was what W5DHM designed it for in the first place.

Studies on Morse code recognition

Nice drawing of Morse key by Dutch
radio amateur Dick Kraayveld, PA3ALM
(http://www.morsecode.nl/pa3alm.html)

In the early 90's there were some interesting studies performed on Morse code recognition and the effects of pitch frequency, signal to noise ratio, and code speed. They were part of the PhD work of Peter Montnémery who is a medical doctor and also radio amateur SM7CMY. I reread these papers now since there was a discussion on the pitch frequency (CW pitch resolution) just recently on the Elecraft mailing list. This discussion comes up from time to time, as it did for instance in 2006 also (Sidetone questions -- copy speed vs sidetone pitch).

The two first papers are probably the most interesting ones for radio amateurs, so therefore I have posted their abstracts and a key figure from each of them also.

The simplest possible AM transmitter

Here's a design for a 1 MHz amplitude modulated (AM) transmitter. I've been looking a while for something like this, a simple short range AM transmitter for the medium wave band, as I needed something for demonstration of my collection of old radios.

The result is the AM transmitter shown here in an Altoids tin on top of a Radionette Kurér radio. This is a portable tube radio from the 1950's. Several hundred thousands were produced, and it was exported from Norway to 60 countries. It is still popular among collectors.

The transmitter is as simple as it gets. The heart of it is a 1 MHz crystal oscillator in a can. Its 5 Volt power is modulated via an audio transformer, one taken from the output of a transistor amplifier (primary 147 ohms - secondary 3 ohms). I drive the modulator from my cell phone into the low resistance side of the transformer and get good audio when the phone's volume is set to maximum.

Q codes from the streets of Paris

I had the privilege of living in Paris with my wife a few years ago. At that time, 2008/2009, the series for car license plates had just come to Q. That made it easy to find plates with many of the Q codes which are used as abbreviations in radio communications. What follows is the result of walking the streets of Paris, mostly between the 5. and the 13. arrondissement:

Here is a broadcast to all radio amateurs: 

What's in a name - radio societies all over the world

The IARU HF Championship took place this weekend. This is the contest where every country has national stations which exchange the abbreviation of the radio amateur society. Therefore it was an opportunity to reflect on what the names of the national societies mean. Many of the names in the IARU list portray the heritage of a hundred years. It is not so strange then that this may make some of them hard to understand and even a bit old-fashioned.

Starting with the ARRL - American Radio Relay League or NRRL (Norwegian ...) then this is about a network of stations relaying messages in a country with large distances. This is a bit 1920's to me. Looking at the ARRL web page it looks as if the the ARRL agrees and really would like to modernize the name to the National Association for Amateur Radio. The Portuguese may already have modernized it a bit by the use of network instead of relay: "Rede dos Emissores Portugueses"  (Network of Portuguese Transmitters), or perhaps it is just because this is the same word as "relay" in Portuguese?