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.

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.

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.

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.

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.

Half a year of APRS temperature monitoring

My APRS-based temperature monitor has now worked flawlessly for half a year. APRS stands for Automatic Packet Reporting System so it can send much more than temperature data, the chief usage is really for GPS position reports.

But I just needed a temperature monitor and here are the readings for December. As one can see, there were no days with temperature above freezing. At 800 m elevation in the mountains of Telemark in Norway, this is not unexpected for this time of year and makes for good skiing!

I use a Quanzheng TG-25AT handheld with a quarter-wave whip antenna on 144.800 MHz. Its signals reach the LD3GT digipeater at 1845 m above sea level. Although I don't have direct line of sight, the low power (1 Watt) setting is adequate as the distance is only 10 km. The APRS-beacon is an OpenTracker USB set up for transmission every 15 minutes. An external DS18S20 temperature sensor which measures the outside temperature is connected to the 1-Wire® bus of the OpenTracker USB.

Thanks to the infrastructure providers: The Tønsberg group of NRRL (LA1T) who operate the LD3GT digipeater, probably the one with the largest coverage in Southern Norway (Gaustadtoppen). Thanks also to the various operators who receive packets from LD3GT and pass them on to the internet, and thanks to aprs.fi for processing and displaying the data on their excellent web site!

The most interesting contact in the CQ WW Contest

Sometimes looking up remote stations on QRZ.com or other sites gives a glimpse of the person behind the callsign. I did this for the Chinese station BY5CD which I contacted on 40 m during the CQ Worldwide contest this weekend.

It turned out to be a club station called "YinZhou Middle School Amateur Radio Club Station" which is located just south of Shanghai.

It is interesting to consider the age of the operators as one can see from the picture. More pictures and some information can be found on their QRZ.com website. With this many young people entering ham radio in China, maybe we will see more stations there in the future. The number of stations is unreasonably low compared to the enormous population of China.

And the most interesting signal was that of GM5X on 21 MHz at 1207 UTC on 25. November. It had a distinct echo which seems to indicate that the signal travelled both on the direct path of about 800 km and the long path of about 39200 km.

The image shows "GM5X GM5X Test". The long path signal seems to fade in and out as there is much less of it in the last part, the word "test", than in the second "GM5X".

F/LA3ZA on Long Delayed Echoes

Laurent, F6GOX, who is one of the primary forces behind the ARP, Radio-Club de Paris, has written a nice little French-language presentation of me since I am a former member of the club. It also includes my interest in Long Delayed Echos (LDE).

Here he also talks about the presentation I gave for the Paris club of radio amateurs on 18 March 2009 on this subject during my year-long stay in Paris. That was a very nice evening which I remember with pleasure.

I also talked then about the interest that the French general Gustave Ferrié (1868 - 1932) took in this phenomenon (The link is in French, but read about Ferrié here in the English Wikipedia). There were French studies of LDEs in Indochina, Senegal, and Mauretania, French territories at the time, which he played a major role in.


Merci Laurent!