06 June, 2015

CQ WPX made my day

From time to time I have heard of those of who manage to contact 100 DXCC countries during one weekend. This past weekend it was my turn to try.

If you have a contest station with 1 kW and monoband yagi antennas, then this goal shouldn't be too hard. But for my station with only an 80 m horizontal loop (loop skywire) circling its way through my garden from treetop to treetop and 100 W of transmitter power from my K3, the challenge was greater.

About 6 hours before the end of the test and with 87 countries, I had almost given up so I sent the tweet above. The status for the second day of the contest was that I had only worked two more countries.

But then in the final hours I heard and then contacted Tunisia, Malaysia, Australia og Kosovo (Z6) to bring me to 91, and then Laos and Albania. But then it took a long while for some new ones: Spanish Africa (EA9) and Argentine. I also managed two more Caribbean stations (J3 and CO) and Peru and Sardinia.

Finally in the last hour of the contest two more Caribbean stations (PJ2 and VP9) and in the end Mexico 21 minutes before the end of the contest. That brought the total to 102. I think that was needed as Kosovo isn't really an approved country and I also had contact with what was probably a pirate and not a station from Andorra. That signature was C31XR which most likely is the name of an antenna and not a real station.

My total was 47 European countries, 19 from Asia, 12 from North America, 10 from Africa, 9 from South America and 3 from Oceania. I think it helps to be in Europe as I had almost half of the countries quite close by, but it would be interesting to hear comments from North Americans on how realistic they consider this goal to be from their location.

23 May, 2015

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!

17 May, 2015

The ultimate WSPR spot

A spot reported by K1JT must be the ultimate goal for the WSPR mode. K1JT, Joseph Taylor, is the Nobel laureate who first developed this mode and other related two-way modes like JT65 and JT9.

My 0.1 W 21 MHz WSPR transmitter regularly makes it over the Atlantic, but never before to K1JT. The SWR was something like 7:1, but apparently that works fine, both for the transmitter and for radiation.

The antenna is a 13 m doublet oriented with the broadside facing East-West (the EU spots in the figure are from my Ultimate 3 on 21 MHz with another antenna and at another location). I feed the doublet with 450 ohm ladder line to a 4:1 Elecraft balun which is connected to the Ultimate 2 transmitter.


07 May, 2015

Ultimate software is up to date

As I have mentioned several times on this blog, I have thoroughly enjoyed WSPR modes ever since Hans, G0UPL came out with the first Ultimate QRSS/WSPR kit.

That means that I have three different versions of the kit. Since Hans has kept on updating the software and even published the compiled versions, it is also possible to upgrade even the old ones.

I have done that and the displays here show the Ultimate 3, the Ultimate 2, and the Ultimate 1 with the latest software.

It is possible to upgrade the chips in-circuit, but I found that it is simpler to remove the chip temporarily from the socket and move it to a simple veroboard with crystal oscillator components. It is connected to my Ebay version of the USBtinyISP.




29 April, 2015

First 475 kHz WSPR decoding

Tonight I made the first successful decoding of WSPR on the 630 m band. What inspired me was all the talk on the Elecraft reflector on the new synthesizer which in addition to having less phase noise, also allows the K3 to go below 500 kHz. I don't have that synthesizer, but the discussion reminded me of the low frequency converter I built many years ago. It converts 0-1 MHz to 14-15 MHz. Using the KXV3 transverter interface of the K3 it was easy to interface and get up and running.

The first signals I decoded are shown in the water fall above, and their origin in Germany and the Netherlands is shown in the next figure.

According to WSPRnet, PA0A's 2 Watt transmitter is 784 km away from me, and DK7FC's 1 Watt is 1164 km away.

The converter is quite simple and is based on a 74HC4053 switch used as a mixer with a 74HC04 for a 14 MHz oscillator. It is the design of SM6LKM, but with a different oscillator frequency and a simplified output filter compared to his. It is one of many small projects that I have built in Altoids tins.

The antenna used was my trusty old 80 meter horizontal loop which has been the main work horse for making my 8-band DXCC (more than 100 countries on all bands 3.5 - 28 MHz) possible. It is fed with ladderline into a 4:1 Elecraft balun in the shack.

Perhaps the next step is to finish the 475 kHz filter of my Ultimate 3 WSPR transmitter and see if others can receive me? That is going to be more of a challenge antenna-wise.


15 April, 2015

A beauty of a crystal radio

This past weekend during Hammeeting - the largest Ham rally in Norway - I met Per LA9DTA.

He showed me his beautiful crystal radio. It can be seen in the center of the table, with some close-ups below. The design has a printed coil and the whole design is made on a PCB which was shaped as shown in the image. It has a bandswitch and a Soviet low forward voltage Ge diode.

I fell for his design, but with the lack of longwave and medium wave transmitters here I am not sure if I would have much use for it. That is unless I set up one of my transmitter projects to support a radio like this.

I was demonstrating WSPR with my Ultimate 3 transmitter. It can be seen on the right hand side of the table. I wanted some fresh spots as I was giving a presentation later that day entitled "WSPR, JT65, JT9: Digital modes by Nobel laureates K1JT for HF DX with simple equipment". As I was spotted both on 40 m and 80 m I was happy with the performance. Per had also brought his Ultimate 3. Not the modified 11-band version, but just a plain one this time.

08 April, 2015

Car upgrade to LEDs

It was time to upgrade the interior lights in my 2004 Volvo. I got some lamps from Ebay specified as 42 mm LED Festoon, 80-85lm, 12V. As many others have experienced also, they kept on glowing faintly after the door was closed. But when the ignition was turned off the lamps were completely off also, so there was no danger of draining the battery. Still this is not the way one expects lamps to behave.

One can get more expensive LED lamps which avoid this faint glow, "Canbus error free" seems to be the way to specify this. But mine were of the plain type, and the problem seems to be the leakage current in the FET switches that turn the lights on and off. It is tiny, but enough to give a voltage large enough to turn the LEDs on. An additional resistor load will lower the voltage below that threshold.

02 April, 2015

All continents in one night on WSPR

For me South America, Australia, and Africa are quite rare on WSPR. But they all heard my tiny 0.2 W signal the night between 31 March and 1 April in addition to North America, Asia and Europe. That's a new one for me and worthy a brag post on the blog, I think! Hopefully, it may also inspire others to try low power WSPR.

In Australia and South America I was heard on the 10 MHz band, in Africa on 21 MHz, in Pakistan on 14 MHz, while 7 and 10 MHz worked into Siberia. North American stations also heard me on the 7 and 10 MHz bands.

This was on my untuned 80 m horizontal loop fed with open-wire feeder and a 4:1 balun. This shows both that the bare-foot Ultimate 3 kit is very tolerant of loads with SWR much different from 1, and that WSPR gives amazing results.