Doppler experiments


inspired by OM DJ0MY (thanks!) I tried to get some nice doppler signals. I tuned to Graves radar on 143.050 MHz and Hamburg ATIS on 123.125 MHz.

With my "new" diy lindenblaad type antenna (new == 1,5 years old ;) ) for 70cm I caught a few nice doppler signals.

Let's go :) .

Doppler by planes on Hamburg ATIS frequency. The transmitter should be about 120km away.

Frequency drift of RTLSDR, maybe.

Distance between QTH and Hamburg ATIS transmitter.

Doppler by ISS on Graves radar frequency 143.050MHz. See pulse/pulse break on ISS. ISS was about 1000km away - or more...

Pulse break from Graves radar on ISS.

Pulse length from Graves radar on ISS.


Latest wx ballon heatmap


last night I did a new heatmap with RTL_POWER. The frequency range is 404MHz to 406MHz. Intervall 30 seconds and binsize is 2000Hz.

I wanted to know which wx balloon signals are available at my place.

This is the result of 13,5 hours recording.

I caught seven balloons on five different frequencies in wx balloon band. Next time I will try to decode them with Sondemonitor by COAA.


Reflections of Graves radar, Dijon, France


Yesterday a well known OM told me about Graves radar located near Dijon in Framce. It's waves are transmitted on 143.050 MHz.

If you tune your rx on this frequency and watch the FFT with HDSDR for e.g. you can see reflections of these waves on objects that are flying in the air above.

There objects could be planes, asteroids, meteroids, ISS and other things in heaven above.

Have a look at this video, please. You can see a few of these reflections. Some a small, some are bigger. The duration of the recording is about 34 minutes.

The distance between my ocation and the Graves radar is about 680km. 



Hi all.

tonight I caught the telemetry beacon of ham radio satellite HO 68.

HO-68 telemetry cw signal. Analysed with SA free. Click to enlarge.

My setup:

TV satellite amplifier 40-2400MHz
Seven element yagi antenna for 70cm band, 30° elevation, about 160° azimut, under roof

I'm waiting for more amateur satellite signals to come...


RTLSDR: rtl_power - another example


yesterday I used rtl_power to create another heatmap. It covers the frequency range from 3 MHz to 5 Mhz.

Have a look at here, please:


ATTENTION: this picture has a size of 17 MB! :)

As you can see there are many stations that come an go again. Ham radio stations, BC stations, Stanag 4285 and many more...


RTLSDR: rtl_power


There's a new utility in the famous RTLSDR package: rtl_power. Coder keenerd says about it:

Rtl_power is a small CLI tool for logging wide swaths of bandwidth. You can specify any chunk of spectrum, with any FFT bin size and any logging rate. (For sane values of any.)

Read more at reddit:


I've done a hf scan with rtl_power lately. It shows a spectrum graphic from 3MHz to about 15MHz.

You can see it here:


Attention: it's a big picture! ;)

You can see many bc stations that come and go. OTHR are visible, too. And many other stations.

My setup was a DVB-Tstick modified as direct sampler. I connected my 12m wire to it.

It's a very cheat solution for non realtime / longterm hf band observations. But you can also use it with a unmodified DVB-T stick, too.

And now have some fun with rtl_power :)


PA0RDT antenna on soundcard

Since yesterday I'm using my good ole PA0RDT antenna again. I connected it directly to the soundcard of my "radio pc". On this pc there is Speclab/DL4YHF running.

The soundcard is a simple 48kHz range type. So a samplerate of 24kHz is possible. That means that Speclab can sample from 0 to 24kHz, too.

Here's the result:

PA0RDT. PC. Soundcard. Speclab.
It's kind of fun to do VLF with a tiny setup like that. Needless to say that a 96kHz of 192kHz soundcard would be more fun ;) .


The latest dump1090 looks nice

I supported the dump1090 project with SVG data for 'real looking' planes. This plane shaped markers are looking way better then the original arrows.

This data is integrated in the bdavenport/terribl fork of the MalcomRobb tree.


They did range rings, visualized reception data and some other cool gmap stuff, too.


So dump1090 looks little like a fusion of VRS and adsbSCOPE :).

Keep up the good work buddies.


Just trying "Remote Transceiver Control" by DK7MW


After DK7MW released his "Remote Tranceiver Control" setup for PPi I'm very impressed of his work.

I couldn't await to try it with my dust covered YAESU FRG-100. An now here it is.

It could last a few seconds to cache the sound data. After caching sound output should start automatically. Thx 2 DK7MW!


EAM overlaps Icelands HFDL transmissions

Today EAM messages overlaps the transmissions of Icelands HFDL station. Have an ear on

No inhibitions found.