AmateurRadio.com

Back from a month in Europe and we had a good time there. Two weeks in Sweden, touring in a motor home and the rest in my native the Netherlands, visiting family and filling our bellies with Dutch goodies like drop and kroketten.

If you have never been to Sweden then I heartily recommend you to visit it. Beautiful scenery with free camping wherever you like and wonderful people who have a very relaxed lifestyle. And they all speak English, too. We rented this motor home….

…and after two days of acclimatizing we parked it in the driveway of Rune and Heide, SM5COP and SM5NZG respectively. Rune was the first Swedish contact in my Taiwanese logbook and I had mailed him some questions before our trip, which he answered more than elaborately. We hadn’t planned to visit his part of Sweden, but the invitation to celebrate the midsommar festivities with them was more than worth the detour. Rune and Heide are such friendly and hospitable people and their guest book shows this abundantly. Rune took us fishing, swimming and rowing on the nearby lake and Heide showed us how her bees keep the honey flowing in (over 300 kg already, this year). Rune also gave us a tour of Strängnäs on the first hot day of the year in Sweden: 27 degrees Celsius. Coming from Taiwan we had less problems with it than Rune did, the poor guy.

We did little ham radio stuff as we were too busy with other fun things (and jet lagged), but I did admire the 40+ meter tower with mono-band antennas in his garden a lot. What a dedication went in to the building of this marvelous outfit, not at least because Rune and Heide moved to their present location especially to be able to do this. Can’t think of a more dedicated ham couple. Their shack features various TenTec rigs and a K3 line with scope and 500W amp. I tuned around a lot, heard some familiar calls from Asia, some from Field Day stations in the US and a lot of Italians. Ah, as if I never left Europe. The one and only QSO I made was with ON5DN and what a nice chat with Diane in Dutch it was.


Apart from the Taiwanese treats I also wanted to bring something special and personal, so I delved into my small key collection and parted with my Chinese DX20-1 straight key. A lot of SKCC contacts were made with this key, but in the hands of two experienced hams like Rune and Heide it would be of much better use.

After getting a lot of honey from Heide and some good advice from Rune we parted to experience more of amazing Sweden.

We’re off for our first real holiday in five years. Two weeks in Sweden in a rented motor home. Can’t wait to enjoy the fresh air and laid-back lifestyle. The results of the end-fed half wave (EFHW) experiments were good enough that I packed it in my suitcase. For transmitter I decided not to take my KX3 but get a simple crystal controlled CW kit from eBay. Only cost a few bucks and it is fun just to see if I can make some QSOs with it at all. If not, then nothing lost. I modified the LPF so I can also stick some 20 meter crystals in it. The straight key is a J37 (SKCC QSOs wanted) and a 5/12 Volt battery pack completes the setup.

See you on the bands!

I’ve made some progress on the EFHW antenna since my last post here on AmateurRadio.com. I wound a new transformer, but now on a thinner plastic tube. Initially it had a 10:1 ratio, but after some initial tests at home I removed some turns and now it is 8:1.

Today, out on the parking lot, I managed to get a good match on 20 meters with 10 meter wire and a 1 meter counterpoise. A short video to prove this.

It was quiet on 20 meters in mid-afternoon. Only HS0ZJF came in with a reasonably strong signal and it was easy to work him. He gave me a 549 for my 5 Watt QRP signal and I was more than happy with that. And as fate would have it HS0ZJF is originally from Belgium, so we exchanged some Dutch greetings as well.

On 40 meters I wasn’t so successful. This time I tried various lengths of wire, ranging from 19 to 23 meters, but the lowest I could get my SWR was 2.4:1. Funny thing was that the KX3 wouldn’t put out the 3 Watts used when tuning at an SWR of 2.4:1, but it had no problem putting out more at a higher SWR of 3:1 or more. Now the SWR is measured behind 3 meters of coax at the KX3, which is not ideal, so the next step is to make a LED-based resistive SWR bridge to be put right behind the antenna and before the coax.
I could make it tonight, but unfortunately I only had two 51 ohm 5W resistors in my junk box. Back to the shops it is.

Not much to report from me lately. The weather was not suitable for portable operations, otherwise too busy or too tired to do anything “radio”. We decided to spend our last money on a trip to Europe this summer (necessary family visits, long overdue) and I am one to prepare way in advance.

“What radio shall I bring along?” was of course the first question I asked myself. But being wise I quickly changed it into: “What antenna shall I use?” Since I never worked with end-fed antennas I thought it would be a good opportunity to learn about them and try them out.

Let’s start with buying stuff: a seven meter fishing rod that fit in my suitcase cost US$20. A length of 30 meter strong light Teflon coated copper wire was about the same. Cut in two lengths of 20 and 10 meter it would cover 20 and 40 meters, hence End Fed Half Wave. For the impedance coupler I turned to M0UKD’s excellent website . End fed antennas are no rocket science: the high impedance of a half wave length of wire has to be turned into a low impedance that matches the radio. A tank circuit is used to optimize the power transfer of the transformer used for this. So I build a tank circuit with a 1:8 air core transformer and a 9-50 pF variable capacitor.

After another hard days work at school I went to the parking lot to do some initial tests before going home. I shot this impromptu video with my phone to show you the result.

So I built myself a Full Wave End Fed! It’s not supposed to be like this! With the 10 meter wire I got the same result: on 20 meters I got a dip, but the SWR wouldn’t get below 2.2:1. I didn’t check the performance on 10 meters, but I guess I will get a near perfect SWR there, too. Of course, on my workbench, using a 3300 ohm resistor as dummy load, I had no problem matching 40 and 20 meters.

I’m a bit baffled and unsure what to do next. I already tried some transformers using ferrite cores from my junk box, but non were giving me a tuned tank circuit (inductance too high). I want coverage from 40-20 meters and my capacitor has a range of 9-50 pF. The inductor should be 11 uH then and with a 1:8 ratio the transformer should make 3300 ohm into 51 ohm. The only thing I can think of right now is that my wire is not suitable, but why? As I said in the video, any suggestions are welcome. In the mean time….I’ll keep studying about EFHW antennas.

The big shack renovation meant I had to put all my stuff back into boxes. No problem spending some time without my rigs and tools, but I didn’t want to spend a couple of months without any form of radio. So I left out the RTL-SDR dongle and a mobile whip to see if I could get some more out of it than digital TV. I have had the dongle for a while now, but I was never impressed by it. Lots of white noise and very few signals to be seen on the waterfall. I even boxed it up nicely to avoid EMI.

The first step was to see if the dongle still worked by scanning the DVB-T bands. After installing the necessary RTL-SDR packages I fired up VLC to see if it would decode signals. There are packages like MythTV and MeTV that can let you watch DVB-T, but I don’t like cluttering up my system especially since VLC is such a versatile piece of software. For it to work you need to open an console though, but the internet is awash with good tutorials to help you get it done.

Step 1: install dvb-apps with sudo apt-get install dvb-apps
Step 2: use the scan application that comes with dvb-apps: scan /usr/share/dvb/dvb-t/tw-All > channels.conf
Step 3: open the channels.conf file with VLC
Step 4: choose your favourite channel and enjoy

Most of the time Linux provides an alternative and in this case it’s w_scan: w_scan -X -c TW

substitute your own country code in place of TW; a list can be retrieved by issuing the command w_scan -c ?

Before I knew it I was watching the WBSC Premier 12 baseball games and found out Taiwan’s public broadcaster is airing Person of Interest. Usually I find that watching tele is just a big waste of time, but I do also find that it is the only time I am not physically active and I do need to rest more. My wife likes PoI too, so now we have a date every Monday through Wednesday at 10.

The FM band was another check to see if the RTL-SDR dongle works as advertised. On Windows the prevalent SDR software is SDR#. On Linux this is GQRX, which is based on GNU Radio, a very powerful but complex piece of software. Before you can start GQRX you need to deactivate the dvb_usb_rtl28xxu driver as this conflicts with the rtl2832 driver. Issue the following command: sudo rmmod dvb_usb_rtl28xxu. If you never watch TV then blacklist the driver in order for it to be never loaded when you insert the dongle.

I could indeed receive FM broadcasts, but as many as I could with my Sangean ATS-909, so no big win there. GQRX also has a build in AFSK demodulator and I tried to decode some APRS signals on our local frequency of 144.640 MHz. I could hear signals and see them on the waterfall, but not decode them. After trying some other antennas and even taking everything outside in the open I grew a bit frustrated and searched for some other signals to decode. Tracking aircraft using ASD-B seemed fun (G4VXE wrote about it before here on AmateurRadio.com ) so I tried to set that up. And in doing so I got a big surprise.

[to be continued]

It’s unseasonally warm this fall. Still wearing a summer outfit, running the AC at night and temperatures up to 30 degrees Celsius during the day. Makes for good portable operation weather and yesterday I had another one. It was the first time that I hooked up a laptop to my KX3 because I wanted to have some digital fun. I really miss my Olivia chat sessions, exspecially with Ken, JA1RZD. My KX3 comes with the stock heat sink, so I turned the power down to 3 Watts and even with long transmissions the KX3 only warmed up a little. Ken had no problem copying me, but that is also due to the power of Olivia and the beautiful view to the north. My school is situated on top of a low mountain range and the elevation of 290 meter ASL really helps in propagating my puny signal.

The wonderful view from our parking lot towards Japan.

The KX3 and Fldigi happily working together.

The idea to do something with satellites again came from my wife. She doesn’t want to participate in the radio hobby, but she does see the value of it and gives me lots of encouragement. Back in Holland I made my own Arrow style antenna and heard some amateur satellites, but I was never able to work one.

Lo and behold, right after she mentioned sats I saw a mention of TAMSAT on our local ham chat site. After the CTARL and the CRA this is the third amateur radio club in Taiwan, (although they are closely associated with the CTARL). As luck would have it they had an activity day late last month with lectures and a DIY activity, namely putting together a Mini-circuit’s PGA-103 low noise pre-amp. I went there and made some new friends as well as seeing some familiar faces from the CTARL. Here some impressions….

The opening of the day by BV2OL, who is a teacher at the Taipei City Tech College where the activity day was organized. He is also heading TAMSAT.

BX1AD came from I-lan to hold a talk about the XW-2 or Hope2 satellite range which was launched last September. This was indeed a very interesting talk. BX1AD is one of the most active Taiwanese when it comes to satellites.

BX2AI introduced webSDR receivers and since I am using those too I was able to add some information to the talk.

In the afternoon we put the PGA-103 pre-amp together. All components were of the SMD variety, so a magnifying glass and extra light were more than necessary for the – mostly – old eyes that put together the kit. Here BX2AN and BV2BJ in action.

BV2AP took care of the testing with an R&S spectrum analyzer.

22 dB gain on VHF, a little less on UHF and above.

A big thanks to BV2OL (middle), BV2AP (right), flanked by BV2FB.

Unfortunately I haven’t been able to put the PGA-103 into action, yet. The reason: I don’t have a shack at the moment.