Port sharing for WSJT-X

The program for FT8 and other digital modes, WSJT-X, requires control over the communications port of a rig like the Elecraft K3. But so does the log program. Fortunately there is a solution for sharing ports. I use LP_Bridge and DXLab Commander which are both freeware.

LP_Bridge works OK, although it does abort for mysterious reasons from time to time. The setup is here:

The active ports are COM16 which connects to the radio, COM14 which connects to Commander, and COM13 which is used for the logging program.

Improved GPS reception with a ground plane

My poor-man's 10 MHz reference based on the Ublox Neo-7M GPS module didn't always receive GPS satellites. Since I rely on reception indoors, conditions were sometimes too marginal to lock the oscillator output to 10 MHz. Inspired by the QRPlabs GPS module of Hans Summers (G0UPL) with its large 6 x 6 cm PCB groundplane, I therefore decided to do something similar.

The first picture shows the unit with the 8.5 x 6.5 cm single-sided PCB ground plane attached with double-sided tape. It definitely helped make indoors reception in my shack much more reliable. In addition to the improved conditions for the patch antenna, it probably helps too that the antenna now is shielded from the digital circuitry of the GPS module, the 10 MHz pulse shaper, and the USB interface. I also added a small LED to the right so that I could see from the outside whether the GPS locks properly.

The second picture shows the interior prior to adding the ground plane.

This post is a continuation of these other posts about the 10 MHz reference:

1. Just good enough 10 MHz reference (3 Oct 2015)
2. Better with SMA (15 Oct 2015)
3. Curing amnesia in the 10 MHz GPS reference (19 Nov 2015)

The post Improved GPS reception with a ground plane first appeared on the LA3ZA Radio & Electronics page.

Teeth marks in the K3

DX-expeditions love their K3s. And I love my K3. But look closely at the MENU button and you will find the marks of someone who literally have put the K3 on their menu as well.

Neither has the BAND button escaped this. Judging from the size of the teeth marks it is perhaps not so hard to guess who did this.

This is our club station's K3 and off weekends the only inhabitants there are mice, who seem to have taken their fancy on the soft buttons of the K3. They let every other piece of equipment alone, such as the Yaesu FT-1000MP, so there is definitely something special about the K3. I would guess that this was not part of the original Elecraft design specifications for these buttons.
The remedy is shown here: A custom-designed acrylic cover that is fitted on the K3 whenever it is not in use.


This article originally appeared on the LA3ZA Radio & Electronics blog.

Curing amnesia in the 10 MHz GPS reference

Just good enough 10 MHz GPS reference with
u blox Neo-7M GPS module to the upper right,
10 MHz output buffer lower right,
USB interface to the upper left,
CR2032 lithium battery center left,
GPS antenna in the center,
and SMA output connector lower left.

My "just good enough 10 MHz GPS reference" which drives the external clock input on my Elecraft K3 kept losing its configuration if power was off for a day or so. I have therefore fitted a CR2032 3V lithium battery as seen to the left in this image.

It is connected in series with a 1N4148 diode in order to prevent attempts at charging the lithium cell. The connection goes to pin 22 (V_BCKP) as described by G4ZFQ on his website. The diode is visible to the upper left of the battery.

With this, I consider the 10 MHz reference to be finished.

Other related posts:

• Just good enough 10 MHz GPS reference
• Better with SMA
• Improved GPS reception with a ground plane

Better with SMA

I had some trouble closing the lid on the "Just good enough 10 MHz GPS reference" due to the size of the BNC jack. Therefore I changed it to an SMA (SubMiniature version A) female jack. A thin cable connects it to the K3's SMA input and there is no need for any SMA-BNC adapter on that end.

At the same time I moved the GPS antenna to a more central location in the tin, in the hope that the walls of the tin would interfere less with GPS reception. That's the theory anyway, if it matters much in practice is a different story.

Actually, I think I'm going to use SMA more often with these clear top tins and also Altoids tins. They take up much less space and are easier to install and to work with.

There aren't any high power applications for circuitry in such tins, so I cannot so any reason why the SMA won't work just as well or even better than the BNC.





Other related posts about the 10 MHz reference:

• Just good enough 10 MHz reference (3 Oct 2015)
• Curing amnesia in the 10 MHz GPS reference (19 Nov 2015)
• Improved GPS reception with a ground plane (11 April 2016)

Just good enough 10 MHz GPS reference

Some time ago I noticed that the Ublox Neo-7M GPS has a 10 MHz output which is locked to the GPS system's accuracy. Most people kept saying how useless it was due to excessive jitter unless it was cleaned up with a phase locked loop of some sort.

At about the same time I installed the external reference input for my Elecraft K3. The K3EXREF enables the K3's frequency to be locked to an external 10 MHz reference. What struck me was how its function is described:

• The frequency of the internal oscillator of about 49.38 MHz is continuously measured and averaged, obtaining a value to the nearest 1 Hz.
• The K3EXREF does not phase lock the K3’s reference oscillator and the external 10 MHz source has no impact on the K3’s phase noise performance.

This got me wondering if the Neo-7M would be just good enough as a reference and that all the averaging internally to the K3 would take care of the jitter.

Where can I get APF and DIV stickers for my K3?

The updated Elecraft K3, the K3S, has some nice improvements that would be nice to have, but which I also can live fine without. But even an old K3 can be updated to some of these improvements. They are detailed on the Elecraft K3S FAQ.

I studied the front panel for differences and put red rings around them. The three to the upper left have to do with the new display bezel with silver instead of black screws, the S in K3S, a built-in marker for the VFO A knob, and a soft-touch VFO A knob.

In addition to the marking with OFS (offset) to the left of the RIT/XIT control, there are two markings that also reflect what my present K3 with the latest firmware does:

• APF instead of DUAL PB (Audio Peaking Filter - Dual Passband) - upper right
• New marker for DIV - Diversity reception - to the left of VFO A

It sure would be nice to get stickers with APF and DIV to put on mine!

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.

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.

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:

Morse	German ++	Norwegian/ Danish	Spanish	Esperanto	Polish 16.3.2014	Greek	Russian	Arabic
·-·-	Ä	Æ	-	-	Ą	-	Я	ع
---·	Ö	Ø	-	-	Ó	-	Ч	ز
··--	Ü	-	-	Ŭ	-	-	Ю	-
----	Ch	-	Ch	Ĥ	-	Χ	Ш	ش

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.

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:

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.

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.