My old World Space antenna


Today I'll reassemble my World Space antenna again. I hope that this antenna will work after reassembling.


Wondering where my videos are?


A few days ago Google deleted my Youtube account that I owned lot of years without any warning.

The truth is that I autouploaded some videos instead of upload them manually. It seems that Google don't want this kind of uploading a video or videos with python scripts.

So sorry guys. No videos inmo.


DMR with DSD on Bananapi?


On RTL-SDR addicted blog RTL-SDR.com I read about how to build DSD (Digital Speech Decoder Toolchain) on Linux. Therefore I tried to deocode DMR with this toolchain on Bananapi. The question that has to be answered was: has Bananapi enough power to receive DMR broadcasts and decode data stream with DSD same time? The answer is: almost.

Even if Bananapi has two CPU cores with about 1GHz something seems to be not right. As you can see Bananapi takes "only" 70% CPU on both cores. But the result of the decoded datastream exported as wav file is, uhm, very choppy.

I don't think that problem is power of the signal itself. It's about 20dB above noise.

To be continued...

Very first picture of Meteor M N°2


A few days ago I could get a decent broadcat of Meteor M N°2 satellite. Here's the result.

My very first picture of Meteor M N°2 digital transmission
Great Britain on the left. Baltic sea, golf of Riga, golf of Finland on the right.
My setup was Bananpi and R820T RTLSDR with toolchain by DH1MLJ, DIY QFH, TV SAT PREAMP. Always remember: this was the first test of the setup.

Even if this picture isn't as good as the ones in Satellitenwelt forum it's obvious that the picture qaulity is far better then the quality of the NOAA APT pictures.

NOAA APT analogue transmission


Waiting for Meteor M N°2. Ready to go image.


After I read about a ready to go Bananapi operation system image with Meteor M N°2 recording tools (scripts) on Satellitenwelt forum I'm trying to get a fine record of the satellite signal:

Bananapi is ready to record signals of Meteor M N°2

The image was created by om DH1MLJ. You can read more about it in this threat:


Thank you very much to the fine guys of Satellitenwelt Forum for sharing such an interesting information!

Good luck!


Bananapi and GQRX - works with low samplerate


Yesterday I found this interesting website from OP Michael, DG0OPK. It describes howto use Cubieboard and Bananapi for ham radio stuff:


The section "update: 6.December 2014" refers to Igor's website. Igor created a Bananapi image without any x server or something else. As you can read on Michael's page he writes down howto install x server and ham radio stuff.

Then I decided to install GQRX to test how it works on a 1GHz/1GB dual core embeded system. SDR is the well known RTLSDR R820T.

Here's the result:

GQRX on Bananapi

As you can see GQRX takes about 60% to 70% of CPU. You have to set samplerate to 250kS. All values above 250kS causes the CPU to use 100% of both cores :(.

But it's a beginning.


ISS SSTV pirctures. Me, too.


ISS crew sends some nice SSTV pictures from outer space to earth.

As you can see quality isn't that good. I don't know if it is a problem with my antenna...


I hope next time to get better quality pictures ;).




Yesterday I compared WSRP with two different RX. The first was RTLSDR (E4000 as direktsampler) and YAESU FRG-100. Both on same antenna. 12m wire on 9:1 unun.

The result is not that much different as I expected. Have a look at this animation. It shows stations from within Europe on 30m band.

WPSR on 30m band

Even if the FRG-100 has bigger SNR (-70dB vs -50dB of RTL) WSPR gets not more stations.

Remeber: this is not a high end scientific research! Hower, it's interesting to see that WSPR is able to decode nearly same stations.


12m wire
9:1 unun
YAESU FRG-100 (on soundcard)


Raspberry Pi does NOAA APT


After a long peroid of time using Raspberry Pi as ADS-B decoder I found my good ole Emgo RX137 on the attic again.

I connected the RX to a 3$ chinese USB soundcard. Then I installed the latest beta of WXToImg on Raspian.

After testing the setup it finaly works fine.

Have a closer look at



My setup is Raspberry Pi B, Emgo RX137, USB soundcard, DIY QFH antenna.

Thanks to WXToImg team for transporting this fine software to ARM cpu.


waterfall.py by keenerd


T'day I'm trying waterfall.py by keenderd the first time. You can download the script from here: https://github.com/keenerd/rtlsdr-waterfall.

CLick to enlarge

If you start the script with python waterfall.py 935000000 960000000 for example you'll get a result like the one in the picture above. It's showing the GSM 900 band with hopping and non-hopping signals.