Thursday, May 24, 2018

RTL-SDR dongle with new TCXO oscillator

RTL-SDR (RTL2832) is very cheap TV dongle than can be used as PC based scanner. You can use it for various applications as: HF/VHF/UHF SDR receiver, waterfall for your TRX (IF), APRS Igate, ADS-B Aircraft radar etc.

Dongles use classic 28.8 MHz crystal oscillator. With original one the frequency stability and error is quite poor. Frequency mistake is around 15 kHz on 900 MHz...

That is why I decided to try to exchange original oscillator for the NEW 28.8 MHz TCXO with 0,5ppm. There are some pictures of the modification.

TCXO informations

Frequency offset with original crystal oscillator:

And with NEW TCXO installed!

Remove original crystal

Clean piece of GND on PCB and solder TCXO.
Be careful! Do not connect top of the TCXO with the ground!!!
Cu wire from crystal pad to TCXO one.
Cu wire from Vcc to the TCXO with additional capacitor.
Or another possibility:

Example of application of RTL-SDR with great open sw OpenWEB RX:
- 10 GHz SDR RX with SAT LNBs with TXCO :)

Thursday, May 3, 2018

Spring is here ! And new 6/4m 13el Yagi

Thanks to the public holiday we did have four days weekend :) After some month Mike DM5XX/OK8XX came again to see us and enjoy the Policko QTH. There has been really nice WX last days and weeks so we needed to cut the green too. It took almost 3 days! 

I spent one day with antenna building. I do have nice design for 6 and 4 meters antenna on one boom from Popa YU7EF. Antenna is placed on the temporary place and waiting for JA condx :) 

I have also played with new Raspberry PI on TWR7 in 38m. It works as webcam, 2m APRS I-gate and soon also as 10GHz public webRX. 

Feed point of 4/6m Yagi


Temporary palce for 4/6m 13el Yagi, under 10m one.