I've used one of these cheap switch-mode DC-DC converters (available on eBay for a few bucks) for my WSPR U3S transmitter. Checking the transmitted signal reveals strong spurious emissions. Hints from the QRPLabs group leads me to the cause - the DC-DC converter. Replacing it with a linear LM317 one solves the problem.

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Kategorie: Power supply

I've checked this extremly simple concept for spurious emissions and whether they're compliant with the current regulations ...

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Kategorie: QRP

Yesterday I've build the FROG SOUNDS 40m CW QRP transceiver.

I've ordered it as a kit from eBay Seller for about €10,- inclusive shipping to DL. The kit arrived well packed after about 15 days in my postbox.

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Kategorie: QRP

Currently I've done 6 QSOs with the Frog and my dipole antenna.

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Kategorie: QRP

In 2015 I've build the Frog Sounds QRP transceiver.

This little transceiver still needs improvement:

  1. The output is still only 400mW
  2. The key-click is horrible - even with the additional audio cw-filter.
  3. The suppresion of harmonics is very bad. Check below.

If someone has any ideas how to fix this, please Diese E-Mail-Adresse ist vor Spambots geschützt! Zur Anzeige muss JavaScript eingeschaltet sein!.

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Kategorie: QRP

Since last weekend a new QRP transceiver joined my shack V1 I bought her used from a German HAM via the QRPFORUM community. The transceiver is one of the older projects from the DL-QRP-AG but still a neat little transceiver. It is still offered in kit-form from QRP-Project in Berlin.

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Kategorie: QRP

  Live data from my WSPR feed

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Kategorie: WSPR

Here some analysis of my recorded spots data with my spot data collector. As of today there are 45.000 spots recorded in my database.

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Kategorie: WSPR

I've done some measurements on two RF detectors - one on an older diode detector from ELDITEST Elditest 1 and another one on an AD8307 based one SV1AFN from SV1AFN.

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Kategorie: Measuring Technology

  1. WSPR first data analysis
  2. WSPR data collector
  3. PiAware
  4. vna/J ist umgezogen
  5. vna/J moved to a new location
  6. Reflash Arduino UNO ATMEGA16U2
  7. IoT Powersensor #2
  8. IoT Powersensor #1
  9. Arduino Library for AD7887
  10. RF Duinode
  11. ADS-B Filter
  12. IoT System management
  13. IoT MQTT Infrastructure
  14. IoT MQTT configuration
  15. ELECRAFT K-POD
  16. Rotator control with a NodeMCU runs stable
  17. Detailed measurement on audio CW-filter
  18. Audio CW-Filter finished
  19. Rotator control and the NodeMCU - a proof of concept
  20. Wanderungen/Ausflüge
  21. CW-Sensor-Keyer
  22. IoT Lightsensor
  23. Worked all Germany contest 2015
  24. ELECRAFT K2 - Fixing VFO ALC issue
  25. XPhase - Interference reduction
  26. LF-Converter
  27. SMD Solder Station
  28. Connecting an Arduino to MOSQUITTO
  29. Getting started with MOSQUITTO
  30. Getting started with 2lemetry

2014 CW (Morse Telegraphy) was added to the German Nationwide Inventory of Intangible Cultural Heritage.

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