28 December, 2013

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.

17 December, 2013

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.

05 December, 2013

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.

29 October, 2013

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.

21 October, 2013

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.

13 October, 2013

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.

12 August, 2013

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: 

15 July, 2013

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?

09 July, 2013

The radio amateurs are coming! Oslo Mini Maker Faire

"Have you dreamt about sending radio signals via the ionosphere? Or what about studying moon bounced echoes? Visit the radio amateurs and you can learn about analog and digital radio communications, antennas and electronics. There are 5-6000 radio amateurs in Norway, and they probably represent the oldest maker hobby.


This was the enthusiastic introduction that we were given on the web pages of Oslo Mini Maker Faire. It was arranged at Norwegian Museum of Science and Technology on April 6-7, 2013 in collaboration with the University of Oslo. There were close to 4000 visitors during the weekend and about 100 exhibitors. Our joint stand between the radio amateurs of the Asker/Bærum and Oslo clubs also had a constant stream of visitors.

17 June, 2013

Young operators in All Asian contest


The All Asian DX Contest is one of the more fun ones to participate in. One thing is the DX aspect of it, but I like it also because of the exchange of the age of the operators. In other contests one exchanges boring stuff like serial number 1, 2, 3, ... ; the CQ or IARU zone (14 and 18 for me); or the power output. But exchanging the age of the operators gives a little glimpse of the person behind the radio on the other side.

It also makes it possible to make a graph of the distribution of age. I had 62 contacts this weekend, of which 55 were unique. They were mainly in Asiatic Russia and Japan. The average age of the operators was 51.6 years - 7 years younger than me - and the graph shows the distribution. The bar for e.g. 54 is the percentage, 20 in this case, of operators in the bracket 50-54 years and so on.

The graph actually makes me quite optimistic concerning the future of ham radio. There are many young contest operators out there, at least in Asia. This resonates well with what others are saying also. Never before has there been so large activity on the bands as during contests these days.

10 June, 2013

Cosmetic K2 Upgrade

My Elecraft K2 which is now more than 11 years old (serial #2198) has served me well, even earning me QRP DXCC (100 countries with 5 Watts) some years ago. It is still cosmetically in mint condition, except for that single item which sticks out like a sore thumb: The tuning knob.

This became very clear to me a couple of months ago when LA8OKA's and my K2 were displayed side by side at our stand at Oslo Maker Faire. His is less than two years old, serial #7224, and they were similar except for the scratches in the faceplate of my tuning knob. If I am allowed to generalize from my knob only, it seems as if the faceplate had poor quality paint and has been replaced by a better quality version over the years.

Anyway I ordered a new one and paid the price which at present is $30.37 plus shipping. The difference is really striking and I feel like I have a new K2 now, well worth the price! The K2 now serves as my second rig, and I think it has many years of good service still to come.

Related posts:

02 June, 2013

The advantage of the single-lever paddle

My single-lever PCB keyer KI6SN/NB6M-style
It may seem like a bad idea to downgrade from a dual-lever paddle and iambic keyer to a single-lever paddle. It must be inefficient since each individual dash and dot has to be generated by a right or left movement of the paddle. Despite this, many of the champions in the High Speed Telegraphy competitions use single-lever paddles, often home-made ones. How can that be?

K7QO, Chuck Adams, wrote "Using an Iambic Paddle" and compared the dual-lever paddle with the single-lever with respect to number of movements. If all 26 letters of the English alphabet and the numbers from 0 to 9 are sent, the single-lever paddle requires 73 strokes while a dual-lever and an iambic keyer requires 65. This is 11% less.

But when N1FN, Marshall G. Emm, wrote "Iambic Keying - Debunking the Myth" he analyzed the 7 letters that are faster to send with an iambic keyer - C, F, K, L, Y, Q, and R - and found that only one of them, the L, is among the 12 most frequent ones in English. He illustrated it this way:

Guess what't wrong with this figure? He didn't see the R and forgot that it is also among the most frequent letters!

07 May, 2013

The radio amateur who felt compelled to abandon his own call sign

If you mention that you are a radio amateur to any Norwegian who was old enough to watch TV in the mid 70's then he is bound to respond with LA8PV. This was the callsign of the fictious figure Marve Fleksnes in the comedy the "Radiot". To bad for the poor guy who actually was given that callsign some years later. I had contact with him on CW (= morse) in 2002 just after I got my license and I just couldn't believe that anybody actually was using that particular callsign.

It was in 1976 that Rolv Wesenlund (1936 - 2013) one of Norway's most popular comedians, played Marve Fleksnes. As radio amateur LA8PV he talks with his friend JA1NQ in Japan. He also speaks with TF3XU on Iceland in a mixed Icelandic/Norwegian dialect which is always a hit with a Norwegian audience. He then converses with Norwegian/American WONBF (no zero) in Minnesota. He has to handle his angry neighbor who suffers from interference (RFI) and finally LA8PV gets the opportunity of a lifetime when he hears the emergency call, Mayday, in the 15 meter band.



03 May, 2013

Is the ultimatic Morse keyer really that efficient?

Vintage Ten-Tec Ultramatic Keyer KR50. Nice name but the
similarity to ultimatic seems to be coincidental.
Iambic keying with a dual-lever paddle is by far the most popular form for Morse keying. But in recent years an old alternative has reemerged. This is the Ultimatic mode which goes back to W6SRY in the 1950's.

The experience seems to be that it needs less timing precision than the iambic mode for letters like A, N, R, and K (· —, — ·, · — ·, — · —). When both paddles are squeezed, the last one to be pressed takes control. So when right-left is pressed one gets a dah followed by dits, not the dah-di-dah-dit of the iambic keyer.

It is very simple to add code for an ultimatic keyer to an iambic one. In recent years this has led to an ultimatic option in some stand-alone keyers, such as:

28 April, 2013

JT9 and 100 Hz ghosts

Multiple decodes at 100 Hz spacing of K1JT
on 30 m on 28 April 2013, 0101 UTC
From time to time I receive duplicate 'ghost' decodes at 100 Hz intervals on either side of the main signal. Last night I saw the phenomenon on 30 m. You will notice here that I have decoded the message: "TNX 73 GL" four times (press image for better readability):
  • -24 dB, 1063 Hz
  • -19 dB, 1163 Hz
  • -8 dB, 1263 Hz
  • -18 dB, 1363 Hz
The actual contact took place at the frequency of the strongest one, 1263 Hz. The station is only moderately strong at -8 dB and at +/- 100 Hz the first sidebands are 10-11 dB down and at -200 Hz the second one is 16 dB down.

24 April, 2013

Which non-English Morse characters are the most important ones?

The Morse code for the 26 letters of the English language and the digits, you can find everywhere, e.g. here on Wikipedia. All one-, two-, and three-symbol combinations are in use.

In the international alphabet all but four of the four-symbol combinations are used. They are:

MorseGerman
++
Norwegian/
Danish
SpanishEsperantoPolish
16.3.2014
GreekRussianArabic
·-·-ÄÆ--Ą-Яع
---·ÖØ--Ó-Чز
··--Ü--Ŭ--Ю-
----Ch-ChĤ-ΧШش

The two or three first German letters are used in many other languages also, e.g. Swedish, Finnish, Turkish, Hungarian etc.

Note that the Ö/Ø Morse code is an O (---) followed by an E (·), usually written as OE. OE also happens to be how the letter is written if the proper symbol isn't available. That also shows the relationship with the French Œ, but that's a digression that has little to do with Morse code. Likewise, the Morse symbols for both the Ä/Æ and the Ü start with the non-accented letter and are AA and UT respectively.

22 April, 2013

Amazing Reverse Beacon Network

I haven't called CQ for a long time on CW except in contests. Mostly I have just responded to DX calls with a super short "5nn TU" and that's it. But this Saturday I heard a presentation at the Norwegian Ham Meeting by Roland, SM6EAT about a Swedish initiative to increase CW activity. It is called Scandinavian Open CW Activity (SOCWA) and it has at present 452 members from Scandinavia in a wide sense of the word. It really got me interested in improving my CW skills.

So now I have started to call CQ SAX and have had my first long CW QSOs for years with SM and OH.

It is also amazing to look at the reverse beacon network and watch your own CQ being reported almost in real time from various Software Defined Receivers with CW Skimmers. Below is the result of the two CQs I have sent these two last days.

19 April, 2013

Overmodulated JT65 on HF?

Sometimes it is crowded on JT65 on HF due to too little bandwidth. When only 2 kHz is available and each signal needs 175 Hz that's understandable. But then others seem to complain that some overmodulate their transmitters so that they occupy more than the 175 Hz, making it even harder to fit an extra signal in the band.

As I have been running a lot of JT65 lately on HF, I also have seen this phenomenon and it piqued my interest to try to understand what was going on. The image below shows such a strong station to the very left, at about -1000 Hz where the red marker is located. After some seconds I turned on the attenuator of my K3, so the signal was attenuated by 10 dB (press image for zoom).


What one can see is that what appears initially (at the bottom of the waterfall) as a splattering signal, becomes quite fine when the attenuator is turned on. Then it spills into neighboring frequencies again as the attenuator is turned off again.

It appears then that it is the JT65 decoder software which is too sensitive to strong signals. Now, I cannot really say that I understand all of the decoder code, but I think that it has to do with the way the power spectrum is estimated. The FORTRAN code for ps.f is listed below. It comes from the BerliOS repository for WSJT which has the same code for this routine as JT65-HF-Comfort:

29 March, 2013

QOD7 - Can you communicate with me in Norwegian?

The Oseberg viking ship, 820 AD
Not so many nationalities are included in the exclusive group of countries with their own Q-code. I mean of course the QOD-code. I have never heard it used by radio amateurs, but it must have played a role some time ago in shipping.

The Q-codes date back to 1912 and were meant to be a short-hand for use in telegraphy. According to the list of Q-codes which Ralf D. Kloth (DL4TA) has on his web page, the meaning of QOD with a number added is: "Can you communicate with me in ... 0 Dutch, 1 English, 2 French, 3 German, 4 Greek, 5 Italian, 6 Japanese, 7 Norwegian, 8 Russian, 9 Spanish?" As a response to the question the meaning was "I can communicate with you in ..."

The reason for a separate code for Norwegian must be the historically large shipping fleet in Norway. This is still the case as graphically depicted in this overview of the Top 20 Ship Owning Countries, where we seem to rank as number seven - so QOD7 is appropriate!

But today all of them will QOD1.

Image from Wikipedia, user Karamell

16 March, 2013

Why do Norwegian callsigns end in A?

Well actually not all end in A, but almost all of the recent ones do. Amateur callsigns in Norway are not so well documented on the web, so here is a short explanation.

Norwegian callsigns are used in these territories:
Depending on where I go, my callsign may be LA3ZA, JW3ZA, JX3ZA, or 3Y3ZA. We don't have districts so the number does not mean anything, except for 0. Callsigns with 0 are were reserved for non-Norwegian citizens, but this has stopped so LA0 callsigns are no longer issued.

Usually the callsign starts with LA, but why do so many of the LA callsigns end in A?

28 February, 2013

Long Delayed Echo on VOA Chinese Service

Thierry, F4EOB from Paris is still hearing strange echoes on the VOA Chinese service broadcasts. There isn't really any good explanation for this phenomenon.

Now during winter he is hearing it both on 13650 kHz from 9 to 12 UTC and on 21590 kHz from 9 to 11 UTC. The 21590 kHz transmission has been heard by him for a long time and I mentioned it here last year also. As then the echo is about 2 seconds. Thierry also made a youtube video of it with a recording.

The transmitter locations are in Asia. The 19 m band site is on the Mariana Island (Tinian) and the 13 m band transmitter is in Tinang in the Philipines.

In my blog last year I discussed possible explanations such as multiple transmitters or multiple round-the-world travel. But since the delay is so consistent and has had the same delay for such a long time, the probability that it is man-made is rather large.

Thierry tells me that this LDE can easily be heard with the WebSDR at the University of Twente in the Netherlands also. I would be curious to hear from people outside Europe who could compare the Dutch WebSDR with their own local reception and see if the same echoes are heard everywhere.

19 February, 2013

1 Volt/2 Volt Transceivers

Transceivers with a power supply of 1 and 2 Volts, how much can one achieve with that? Well, actually quite a lot according to DL2AVH, Helmut, who together with DL4ALJ, Gero, wrote two articles about that in the German QRP-Report in 2011. I am impressed by the output power, up to 200 mW with one battery cell (1.5 Volts) and 0.5 Watts with two cells.

I wrote about this in April last year where I also mentioned that the 1 Volt design from 2000 later had been corrected. Those corrections can be found in the article in QRP-Report 3/2011: "Niederspannungs-Schaltungstechnik - der 1-V- und der 2-V-transceiver" (Low voltage circuit technology - the 1 Volt and the 2 Volt transceivers). The improvements are concerned with better input filtering at 14 MHz with a quartz crystal in the front-end filter and better efficiency in the mixer and removal of an audio stage in the direct conversion receiver. This design only uses bipolar transistors and no ICs.

13 February, 2013

My grandfather's Blaupunkt radio

As I was clearing out my childhood home I came across an old radio that my father had tucked away in the basement. It was a German Blaupunkt radio, and what a historic dial it had!

It turned out that my father had himself found it as he was clearing out his childhood home many years before and that it had belonged to my grandfather who died in 1959.

It covers longwave, medium wave and three shortwave bands from 5.5 to 21 MHz. I had never before seen a radio with a dial given in meters rather than kHz or MHz, but I have later understood that that was not uncommon for pre world war II radios.

Since the back was missing, I had no information about age or type. The tubes which were all in the 11-series suggested the end of the thirties, but here it turned out that the dial had valuable information.

19 January, 2013

Twine "Internet of Things" Monitor

My children know what kind of gifts that please their father, so they gave me a Supermechanical Twine for Christmas. It is described in this way:
Want to monitor things and environments remotely without a nerd degree? Maybe you want to get a tweet when your laundry's done, an email when the basement floods, or a text message when you left the garage door open.

I am presently using it to monitor the temperature in the outer part of the basement, where there is a chance of freezing when the outside temperature drops below about -15 C (5 F). I can continuously read the status such as the temperature on any web browser on my computer or mobile phone. I can also set threshold values that trigger an email message.

The Twine is easy as a breeze to program, by using simple rules as shown below.

08 January, 2013

GSM phone power control and signalling

When you measure the energy out of a GSM cell phone at the moment of initiating a call, you get the picture to the right. It shows the first 15 seconds.

For the first 3.5 seconds there is the signalling between the phone and the base station. Then the connection is established, but after some time (at 4.2, 5.6, 7.5 and 9.5 seconds) one can see how the phone turns the power down, according to the commands it gets from the base station.